United States December 2005
Environmental Protection EPA/600/R-05/144bA
Agency
Air Quality Criteria for Lead
(First External Review Draft)
Volume II of II
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EPA/600/R-05/144bA
December 2005
Air Quality Criteria for Lead
Volume II
National Center for Environmental Assessment-RTF Office
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC
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DISCLAIMER
This document is a first external review draft being released for review purposes only and
does not constitute U.S. Environmental Protection Agency policy. Mention of trade names or
commercial products does not constitute endorsement or recommendation for use.
PREFACE
National Ambient Air Quality Standards (NAAQS) are promulgated by the United States
Environmental Protection Agency (EPA) to meet requirements set forth in Sections 108 and 109
of the U.S. Clean Air Act. Sections 108 and 109 of the Clean Air Act require the EPA
Administrator (1) to list widespread air pollutants that reasonably may be expected to endanger
public health or welfare; (2) to issue air quality criteria for them that assess the latest available
scientific information on nature and effects of ambient exposure to them; (3) to set "primary"
NAAQS to protect human health with adequate margin of safety and to set "secondary" NAAQS
to protect against welfare effects (e.g., effects on vegetation, ecosystems, visibility, climate,
manmade materials, etc); and (5) to periodically review and revise, as appropriate, the criteria
and NAAQS for a given listed pollutant or class of pollutants.
Lead was first listed in the mid-1970's as a "criteria air pollutant" requiring NAAQS
regulation. The scientific information pertinent to Lead NAAQS development that was available
at the time was assessed in the EPA document Air Quality Criteria for Lead; published in 1977.
Based on the scientific assessments contained in that 1977 lead air quality criteria document
(1977 Lead AQCD), EPA established a 1.5 |ig/m3 (90-day average) Lead NAAQS in 1978.
To meet Clean Air Act requirements noted above for periodic review of criteria and
NAAQS, newly available scientific information published since the 1977 Lead AQCD was
assessed and discussed in a revised Lead AQCD and Addendum published in 1986 and in a
Supplement to the 1986 AQCD/Addendum published by EPA in 1990. A 1990 Lead Staff
Paper, prepared by EPA's Office of Air Quality Planning and Standards (OPQPS), drew upon
key findings and conclusions from the 1986 Lead AQCD/Addendum and 1990 Supplement
(as well as other OAQPS-sponsored lead exposure/risk analyses) in posing options for the EPA
Il-ii
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Administrator to consider with regard to possible revision of the Lead NAAQS. However,
EPA decided not to revise the lead NAAQS at that time.
The purpose of this revised Lead AQCD is to critically evaluate and assess the latest
scientific information that has become available since the literature assessed in the above 1986
Lead AQCD/Addendum and 1990 Supplement, with the main focus being on pertinent new
information useful in evaluating health and environmental effects of ambient air lead exposures.
This includes discussion in this document of information regarding: the nature, sources,
distribution, measurement, and concentrations of lead in the environment; multimedia lead
exposure (via air, food, water, etc.) and biokinetic modeling of contributions of such exposures
to concentrations of lead in brain, kidney, and other tissues (e.g., blood and bone concentrations,
as key indices of lead exposure).; characterization of lead health effects and associated exposure-
response relationships; and delineation of environmental (ecological) effects of lead. This First
External Review Draft of the revised Lead AQCD mainly assesses pertinent literature published
or accepted for publication through June, 2004.
The present First External Review Draft (dated December 2005) of the revised Lead
AQCD is being released for public comment and review by the Clean Air Scientific Advisory
Committee (CAS AC) to obtain comments on the organization and structure of the document, the
issues addressed, the approaches employed in assessing and interpreting the newly available
information on lead exposures and effects, and the key findings and conclusions arrived at as a
consequence of this assessment. Public comments and CAS AC recommendations will be taken
into account in making appropriate further revisions to this document for incorporation into a
Second External Review Draft of the document to be released in early 2006 for further public
comment and CASAC review. Public comments and CASAC advice received on the Second
External Review Draft materials will then be taken into account in incorporating further
revisions into the final version of this Lead AQCD, which is to be completed and issued by
October 1, 2006. Evaluations contained in the present document will be drawn on to provide
inputs to associated Lead Staff Paper prepared by EPA's Office of Air Quality Planning and
Standards (OAQPS), which will pose options for consideration by the EPA Administrator with
regard to proposal and, ultimately, promulgation of decisions on potential retention or revision,
as appropriate, of the current Lead NAAQS.
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Preparation of this document was coordinated by staff of EPA's National Center for
Environmental Assessment in Research Triangle Park (NCEA-RTP). NCEA-RTP scientific
staff, together with experts from and academia, contributed to writing of document chapters.
Earlier drafts of document materials were reviewed by scientists from other EPA/units
and by non-EPA experts in several public peer consultation workshops held by EPA in
July/August 2005.
NCEA acknowledges the valuable contributions provided by authors, contributors, and
reviewers and the diligence of its staff and contractors in the preparation of this draft document.
Il-iv
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Air Quality Criteria for Lead
(First External Review Draft)
VOLUME I
EXECUTIVE SUMMARY E-l
(To be prepared and included in future Second External Review Draft)
1. INTRODUCTION 1-1
2. CHEMISTRY, SOURCES, AND TRANSPORT OF LEAD 2-1
3. ROUTES OF HUMAN EXPOSURE TO LEAD AND OBSERVED
ENVIRONMENTAL CONCENTRATIONS 3-1
4. MODELS OF HUMAN EXPOSURE THAT PREDICT TISSUE
DISTRIBUTION OF LEAD 4-1
5. TOXICOLOGICAL EFFECTS OF LEAD IN LABORATORY ANIMALS,
HUMANS, AND IN VITRO TEST SYSTEMS 5-1
6. EPIDEMIOLOGIC STUDIES OF HUMAN HEALTH EFFECTS
ASSOCIATED WITH LEAD EXPOSURE 6-1
7. INTEGRATIVE SYNTHESIS
(To be prepared and included in future Second External Review Draft) 7-1
8. ENVIRONMENTAL EFFECTS OF LEAD 8-1
VOLUME II
CHAPTER 5 ANNEX (TOXICOLOGICAL EFFECTS OF LEAD IN LABORATORY
ANIMALS, HUMANS, AND IN VITRO TEST SYSTEMS) AX5-1
CHAPTER 6 ANNEX (EPIDEMIOLOGIC STUDIES OF HUMAN HEALTH
EFFECTS ASSOCIATED WITH LEAD EXPOSURE) AX6-1
II-v
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Table of Contents
List of Tables II-vii
Authors, Contributors, and Reviewers II-xv
U.S. Environmental Protection Agency Project Team for Development
of Air Quality Criteria for Lead II-xix
U.S. Environmental Protection Agency Science Advisory Board (SAB)
Staff Office Clean Air Scientific Advisory Committee (CASAC) II-xxii
Abbreviations and Acronyms II-xxiii
CHAPTER 5 ANNEX (TOXICOLOGICAL EFFECTS OF LEAD IN
LABORATORY ANIMALS, HUMANS, AND IN VITRO TEST SYSTEMS) AX5-1
TABLES AX5-2 AX5-1
TABLES AX5-3 AX5-13
TABLES AX5-4 AX5-25
TABLES AX5-5 AX5-49
TABLES AX5-6 AX5-64
TABLES AX5-7 AX5-100
TABLES AX5-8 AX5-110
TABLES AX5-9 AX5-136
TABLES AX5-10 AX5-146
TABLES AX5-11 AX5-176
CHAPTER 6 ANNEX (EPIDEMIOLOGIC STUDIES OF HUMAN HEALTH
EFFECTS ASSOCIATED WITH LEAD EXPOSURE) AX6-1
TABLES AX6-2 AX6-1
TABLES AX6-3 AX6-44
TABLES AX6-4 AX6-107
TABLES AX6-5 AX6-156
TABLES AX6-7 AX6-188
TABLES AX6-8 AX6-208
TABLES AX6-9 AX6-222
TABLES AX6-10 AX6-263
Il-vi
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List of Tables
Number
AX5-2.1 Effect of Lead on Erythrocyte Morphology, Mobility, and Other
Miscellaneous Parameters AX5-2
AX5-2.2 Lead, Erythrocyte Heme Enzymes, and Other Parameters AX5-5
AX5-2.3 Lead Binding and Transport in Human Erythrocytes AX5-8
AX5-2.4 Lead Effects on Hematological Parameters AX5-9
AX5-2.5 Lead Interactions with Calcium Potassium in Erythrocytes AX5-10
AX5-2.6 Lead, Heme and Cytochrome P-450 AX5-11
AX5-2.7 Lead, Erythrocyte Lipid Peroxidation, and Antioxidant Defense AX5-12
AX5-3.1 Summary of Key Studies on Neurochemical Alterations AX5-14
AX5-3.2 Summary of Key Studies on Neurophysiological Assessments AX5-18
AX5-3.3 Summary of Key Studies on Changes in Sensory Function AX5-19
AX5-3.4 Summary of Key Studies on Neurobehavioral Toxicity AX5-20
AX5-3.5 Summary of Key Studies on Cell Morphology and Metal
Disposition AX5-23
AX5-4.1 Effect of Lead on Reproduction and Development in Mammals
* Effects on Offspring AX5-26
AX5-4.2 Effect of Lead on Reproduction and Development in Mammals
* Effects on Males AX5-33
AX5-4.3 Effect of Lead on Reproduction and Development in Mammals
* Effects on Females AX5-43
AX5-5.1 In Vivo and In Vitro Studies of the Effects of Lead Exposure on
Production and Metabolism of Reactive Oxygen Species (ROS),
Nitric Oxide (NO), and Soluble Guanylate Cyclease (sCG) AX5-50
AX5-5.2 Studies of the Effects of Lead Exposure on PKC Activity,
NFkB Activation, and Apoptosis AX5-55
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List of Tables
(cont'd)
Number Page
AX5-5.3 Studies of the Effects of Lead Exposure on Blood Pressure and
Adrenergic System AX5-56
AX5-5.4 Studies of the Effects of Lead Exposure on Renin-angiotensin
System, Kallikrein-Kinin System, Prostaglandins, Endothelin,
and Atrial Natriuretic Peptide (ANP) AX5-58
AX5-5.5 Studies of Effect of Lead on Vascular Contractility AX5-59
AX5-5.6 Effects of Lead on Cultured Endothelial Cell Proliferation,
Angiogenesis, and Production of Heparan Sulfate Proteoglycans
andtPA AX5-60
AX5-5.7 Studies of the Effect of Lead on Cultured Vascular Smooth
Muscle Cells AX5-63
AX5-6.1 Genotoxic/Carcinogenic Effects of Lead - Laboratory Animal
Studies AX5-65
AX5-6.2 Genotoxic/Carcinogenic Effects of Lead - Human Cell Cultures AX5-67
AX5-6.3 Genotoxic/Carcinogenic Effects of Lead - Carcinogenesis
Animal Cell Cultures AX5-68
AX5-6.4 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity
Laboratory Animal Studies AX5-70
AX5-6.5 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Human
Cell Cultures Mutagenesis AX5-74
AX5-6.6 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Human
Cell Cultures Clastogenicity AX5-75
AX5-6.7 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Human
Cell Cultures DNA Damage AX5-77
AX5-6.8 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal
Cell Cultures Mutagenicity AX5-79
AX5-6.9 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal
Cell Cultures Clastogenicity AX5-81
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List of Tables
(cont'd)
Number Page
AX5-6.10 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal
Cell Cultures DNA Damage AX5-84
AX5-6.11 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity
Non-Mammalian Cultures AX5-86
AX5-6.12 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity as it
Pertains to Potential Developmental Effects AX5-87
AX5-6.13 Genotoxic/Carcinogenic Effects of Lead - Genotoxicity as it
Pertains to Potential Developmental Effects - Children AX5-88
AX5-6.14 Genotoxic/Carcinogenic Effects of Lead - Epigenetic Effects and
Mixture Interactions - Animal AX5-89
AX5-6.15 Genotoxic/Carcinogenic Effects of Lead - Epigenetic Effects and
Mixture Interactions -Human AX5-90
AX5-6.16 Genotoxic/Carcinogenic Effects of Lead - Epigenetic Effects and
Mixture Interactions -DNARepair -Human AX5-91
AX5-6.17 Genotoxic/Carcinogenic Effects of Lead - Epigenetic Effects and
Mixture Interactions - DNA Repair-Animal AX5-92
AX5-6.18 Genotoxic/Carcinogenic Effects of Lead - Mitogenesis -Animal AX5-93
AX5-6.19 Genotoxic/Carcinogenic Effects of Lead - Mitogenesis Human
and Animal Cell Culture Studies AX5-96
AX5-6.20 Genotoxic/Carcinogenic Effects of Lead-Mitogenesis Other AX5-99
AX5-7.1 Light Microscopic, Ultrastructural, and Functional Changes AX5-101
AX5-7.2 Lead and Free Radicals AX5-103
AX5-7.3 Chelation with DMSA AX5-106
AX5-7.4 Effect of Chelator Combinations AX5-107
AX5-7.5 Effect of Other Metals on Lead AX5-108
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List of Tables
(cont'd)
Number Page
AX5-8.1 Bone Growth in Lead-exposed Animals AX5-111
AX5-8.2 Regulation of Bone Cell Function in Animals - Systemic
Effects of Lead AX5-115
AX5-8.3 Bone Cell Cultures Utilized to Test Effects of Lead AX5-118
AX5-8.4 Bone Lead as a Potential Source of Toxicity in Altered
Metabolic Conditions AX5-126
AX5-8.5 Uptake of Lead by Teeth AX5-132
AX5-8.6 Effects of Lead on Enamel and Dentin Formation AX5-133
AX5-8.7 Effects of Lead on Dental Pulp Cells AX5-134
AX5-8.8 Effects of Lead on Teeth-Dental Caries AX5-135
AX5-9.1 Studies on Lead Exposure and Immune Effects in Humans AX5-137
AX5-9.2 Effect of Lead on Antibody Forming Cells (AFC)
(In Vitro Stimulation) AX5-140
AX5-9.3 Studies Reporting Lead-Induced Suppression of Delayed
Type Hypersensitivity and Related Responses AX5-141
AX5-9.4 Effect of Lead on Allogeneic and Syngeneic Mixed Lymphocyte
Responses (MLR) AX5-142
AX5-9.5 Effect of Lead on Mitogen-Induced Lymphoid Proliferation AX5-143
AX5.9.6 Pattern of Lead-Induced Macrophage Immunotoxicity AX5-145
AX5-10.1 Hepatic Drug Metabolism AX5-147
AX5-10.2 Biochemical and Molecular Perturbations in Lead-Induced
Liver Tissue AX5-152
AX5-10.3 Effect of Lead Exposure on Hepatic Cholesterol Metabolism AX5-155
AX5-10.4 Lead, Oxidative Stress, and Chelation Therapy AX5-156
II-x
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List of Tables
(cont'd)
Number Page
AX5-10.5 Lead-induced Liver Hyperplasia: Mediators and Molecular
Mechanisms AX5-161
AX5-10.6 Effect of Lead Exposure on Liver Heme Synthesis AX5-167
AX5-10.7 Lead and In Vitro Cytotoxicity in Intestinal Cells AX5-170
AX5-10.8 Lead and Intestinal Uptake- Effect on Ultrastructure, Motility,
Transport, and Miscellaneous AX5-171
AX5-10.9 Lead, Calcium, and Vitamin D Interactions, and Intestinal
Enzymes AX5-174
AX5-11.1 Lead-binding Proteins AX5-177
AX6-2.1 Analytical Methods for Determining Lead in Blood, Urine,
and Hair AX6-2
AX6-2.2 Summary of Selected Measurements of Blood Lead Levels
in Humans AX6-4
AX6-2.3 Bone Lead Measurements in Cadavers AX6-7
AX6-2.4 Bone Lead Measurements in Environmentally-Exposed Subjects AX6-9
AX6-2.5 Bone Lead Measurements in Occupationally-Exposed Subjects AX6-12
AX6-2.6 Bone Lead Contribution to Blood Lead AX6-19
AX6-2.7 Bone Lead Studies in Pregnant and Lactating Subjects AX6-22
AX6-2.8 Bone Lead Studies of Menopausal and Middle-aged to
Elderly Subjects AX6-30
AX6-2.9 Lead in Deciduous Teeth from Urban and Remote Environments AX6-36
AX6-2.10 Lead In Deciduous Teeth from Polluted Environments AX6-38
AX6-2.11 Summary of Selected Measurements of Urine Lead Levels
in Humans AX6-39
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List of Tables
(cont'd)
Number Page
AX6-2.12 Summary of Selected Measurements of Hair Lead Levels
in Humans AX6-42
AX6-3.1 Prospective Longitudinal Cohort Studies of Neurocognitive
Ability in Children AX6-45
AX6-3.2 Meta- and Pooled-Analyses of Neurocognitive Ability in Children AX6-50
AX6-3.3 Cross-sectional Studies of Neurocognitive Ability in Children AX6-52
AX6-3.4 Effects of Lead on Academic Achievement in Children AX6-54
AX6-3.5 Effects of Lead on Specific Cognitive Abilities in Children —
Attention/Executive Functions, Learning, and Visual Spatial Skills AX6-58
AX6-3.6 Effects of Lead on Disturbances in Behavior, Mood, and Social
Conduct in Children AX6-60
AX6-3.7 Effects of Lead on Sensory Acuities in Children AX6-63
AX6-3.8 Effects of Lead on Neuromotor Function in Children AX6-64
AX6-3.9 Effects of Lead on Direct Measures of Brain Anatomical
Development and Activity in Children AX6-65
AX6-3.10 Effects of Lead on Reversibility of Lead-Related Deficits in
Children AX6-67
AX6-3.11 Neurobehavioral Effects Associated with Environmental Lead
Exposure in Adults AX6-69
AX6-3.12 Symptoms Associated with Occupational Lead Exposure in Adults AX6-72
AX6-3.13 Neurobehavioral Effects Associated with Occupational Lead
Exposure in Adults AX6-75
AX6-3.14 Meta-analy ses of Neurobehavioral Effects with Occupational
Lead Exposure in Adults AX6-87
AX6-3.15 Neurophysiological Function and Occupational Lead Exposure
in Adults AX6-89
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List of Tables
(cont'd)
Number Page
AX6-3.16 Evoked Potentials and Occupational Lead Exposure in Adults AX6-94
AX6-3.17 Postural Stability, Autonomic Testing, Electroencephalogram,
Hearing Thresholds, and Occupational Lead Exposure in Adults AX6-97
AX6-3.18 Other Neurological Outcomes Associated with Lead Exposure
in Adults AX6-100
AX6-3.19 Occupational Exposure to Organolead and Inorganic Lead in
Adults AX6-103
AX6-4.1 Renal Effects of Lead-General Population AX6-108
AX6-4.2 Renal Effects of Lead - Occupational Population AX6-118
AX6-4.3 Renal Effects of Lead-Patient Population AX6-136
AX6-4.4 Renal Effects of Lead-Mortality AX6-149
AX6-4.5 Renal Effects of Lead - Children AX6-151
AX6-5.1 Cardiovascular Effects of Lead AX6-157
AX6-7.1 Recent Studies of Lead Exposure and Genotoxicity AX6-189
AX6-7.2 Key Occupational Studies of Lead Exposure and Cancer AX6-191
AX6-7.3 Key Studies of Lead Exposure and Cancer in the General
Population AX6-197
AX6-7.4 Other Studies of Lead Exposure and Cancer AX6-198
AX6-8.1 Effects of Lead on Immune Function in Children AX6-209
AX6-8.2 Effects of Lead on Immune Function in Adults AX6-213
AX6-9.1 Effects of Lead on Biochemical Effects in Children AX6-223
AX6-9.2 Effects of Lead on Biochemical Effects in Adults AX6-225
AX6-9.3 Effects of Lead on Hematopoietic System in Children AX6-233
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List of Tables
(cont'd)
Number Page
AX6-9.4 Effects of Lead on Hematopoietic System in Adults AX6-236
AX6-9.5 Effects of Lead on the Endocrine System in Children AX6-243
AX6-9.6 Effects of Lead on the Endocrine System in Adults AX6-245
AX6-9.7 Effects of Lead on the Hepatic System in Children and Adults AX6-253
AX6-9.8 Effects of Lead on the Gastrointestinal System AX6-255
AX6-9.9 Effects of Lead on the Respiratory Tract in Adults AX6-257
AX6-9.10 Effects of Lead on Bone and Teeth in Children and Adults AX6-258
AX6-9.11 Effects of Lead on Ocular Health in Children and Adults AX6-261
AX6-10.1 Average Estimated Slopes for Linear and Log-linear Models in
the Presence of Heteroscedasticity AX6-264
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Authors, Contributors, and Reviewers
CHAPTER 5 ANNEX (TOXICOLOGICAL EFFECTS OF LEAD IN HUMANS
AND LABORATORY ANIMALS)
Coordinating Authors
Dr. Anu Mudipalli—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Srikanth Nadadur—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Lori White—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Principal Authors
Dr. Harvey Gonick—University of California, Los Angeles, CA
Dr. Rodney Dietert—Cornell University, Ithaca, NY
Dr. John Rosen—Montefiore Medical Center, Bronx, NY
Dr. Stephen Lasley—University of Illinois, Peoria, IL
Dr. Gene Watson—University of Rochester, Rochester, NY
Dr. John Pierce Wise—University of Southern Maine
Dr. N.D. Vasiri—University of California - Irvine, Irvine, CA
Dr. Gary Diamond—Syracuse Research Corporation, Syracuse, NY
Contributors and Reviewers
Dr. Lester D. Grant—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Paul Reinhart—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
II-xv
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Authors, Contributors, and Reviewers
(cont'd)
Contributors and Reviewers
(cont'd)
Dr. David A. Lawrence—Dept of Environmental and Clinical Immunology, Albany, NY
Dr Michael J. McCabe, Jr.—University of Rochester, Rochester, NY
Dr. Theodore I. Lidsky—N.Y.S. Inst. for Basic Research in Developmental Disabilities,
Staten Island, NY
Dr. Beth Hassett-Sipple—Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, Research Triangle Park, NC 27711
Dr. Zachary Pekar—Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, Research Triangle Park, NC 27711
CHAPTER 6 ANNEX (EPIDEMIOLOGICAL STUDIES OF AMBIENT LEAD
EXPOSURE EFFECTS)
Coordinating Authors
Dr. Jee-Young Kim—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Dennis Kotchmar—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Principal Authors
Dr. David Bellinger—Children's Hospital, Boston, MA
Dr. Margit Bleeker—Center for Occupational and Environmental Neurology, Baltimore, MD
Dr. Gary Diamond—Syracuse Research Corporation, Syracuse, NY
Dr. Kim Dietrich—University of Cincinnati, Cincinnati, OH
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Authors, Contributors, and Reviewers
(cont'd)
Principal Authors
(cont'd)
Dr. Pam Factor-Litvak—Columbia University, NY
Dr. Brian Gulson—Macquarie University, Sydney, Australia
Dr. Vic Hasselblad—Duke University, Durham, NC
Dr. Steve Rothenberg—Centre de Investigation y de Estudios Avanzados, Merida, Mexico
Dr. Neal Simonsen—Louisiana State University Health Sciences Center, New Orleans, LA
Dr. Kyle Steenland—Emory University, Atlanta, GA
Dr. David Svendsgaard—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Virginia Weaver—Johns Hopkins University, Baltimore, MD
Contributors and Reviewers
Dr. J. Michael Davis—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Lester D. Grant—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Beth Hassett-Sipple—Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, Research Triangle Park, NC 27711
Dr. Kaz Ito—New York University, Tuxedo, NY
Dr. Kathryn Mahaffey—Office of Prevention, Pesticides and Toxic Substances,
U.S. Environmental Protection Agency, Washington, DC 20460
Dr. Karen Martin—Office of Air Quality Planning and Standards, U.S. Environmental Protection
Agency, Research Triangle Park, NC 27711
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Authors, Contributors, and Reviewers
(cont'd)
Contributors and Reviewers
(cont'd)
Dr. Zachary Pekar—Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, Research Triangle Park, NC 27711
Dr. Mary Ross—Office of Air Quality Planning and Standards, U.S. Environmental Protection
Agency, Research Triangle Park, NC 27711
[Note: Any inadvertently omitted names of authors/reviewers will be inserted in the Second
External Review Draft and final version of this LeadAQCD, as will more complete addresses
for all authors/reviewers.]
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U.S. Environmental Protection Agency Project Team
for Development of Air Quality Criteria for Lead
Executive Direction
Dr. Lester D. Grant (Director)—National Center for Environmental Assessment-RTF Division,
(B243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Scientific Staff
Dr. Robert Elias (Lead Team Leader)—National Center for Environmental Assessment
(B243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. James S. Brown—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Brooke Hemming—National Center for Environmental Assessment (B243-01), U.S.
Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Dennis Kotchmar—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Jee-Young Kim—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Timothy Lewis—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Paul Reinhart—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Anu Muldipalli—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Srikanth Nadadur—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. David Svendsgaard—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Dr. Lori White—National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
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U.S. Environmental Protection Agency Project Team
for Development of Air Quality Criteria for Lead
(cont'd)
Technical Support Staff
Mr. Douglas B. Fennell—Technical Information Specialist, National Center for Environmental
Assessment (B243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC
27711
Ms. Emily R. Lee—Management Analyst, National Center for Environmental Assessment
(B243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Ms. Diane H. Ray—Program Specialist, National Center for Environmental Assessment
(B243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
Ms. Donna Wicker—Administrative Officer, National Center for Environmental Assessment
(B243-01), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (retired)
Mr. Richard Wilson—Clerk, National Center for Environmental Assessment (B243-01),
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
II-xx
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U.S. Environmental Protection Agency Project Team
for Development of Air Quality Criteria for Lead
(cont'd)
Document Production Staff
Ms. Carolyn T. Perry—Task Order Manager, Computer Sciences Corporation, 2803 Slater Road,
Suite 220, Morrisville, NC 27560
Mr. John A. Bennett—Technical Information Specialist, Library Associates of Maryland,
11820 Parklawn Drive, Suite 400, Rockville, MD 20852
Mr. William Ellis—Records Management Technician, InfoPro, Inc., 8200 Greensboro Drive,
Suite 1450, McLean, VA 22102
Ms. Sandra L. Hughey—Technical Information Specialist, Library Associates of Maryland,
11820 Parklawn Drive, Suite 400, Rockville, MD 20852
Dr. Barbara Liljequist—Technical Editor, Computer Sciences Corporation, 2803 Slater Road,
Suite 220, Morrisville, NC 27560
Ms. Rosemary Procko—Senior Word Processor, TekSystems, 1201 Edwards Mill Road,
Suite 201, Raleigh, NC 27607
Ms. Faye Silliman—Word Processor, InfoPro, Inc., 8200 Greensboro Drive, Suite 1450,
McLean, VA 22102
Mr. Carlton Witherspoon—Graphic Artist, Computer Sciences Corporation, 2803 Slater Road,
Suite 220, Morrisville, NC 27560
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U.S. Environmental Protection Agency
Science Advisory Board (SAB) Staff Office
Clean Air Scientific Advisory Committee (CASAC)
CHAIR
Dr. Rogene Henderson, Scientist Emeritus, Lovelace Respiratory Research Institute,
Albuquerque, NM
MEMBERS
Dr. Ellis Cowling, University Distinguished Professor-at-Large, North Carolina State
University, Colleges of Natural Resources and Agriculture and Life Sciences, North Carolina
State University, Raleigh, NC
Dr. James D. Crapo, Professor, Department of Medicine, National Jewish Medical and
Research Center, Denver, CO
Dr. Frederick J. Miller, Consultant, Gary, NC
Mr. Richard L. Poirot, Environmental Analyst, Air Pollution Control Division, Department of
Environmental Conservation, Vermont Agency of Natural Resources, Waterbury, VT
Dr. Frank Speizer, Edward Kass Professor of Medicine, Channing Laboratory, Harvard
Medical School, Boston, MA
Dr. Barbara Zielinska, Research Professor, Division of Atmospheric Science, Desert Research
Institute, Reno, NV
SCIENCE ADVISORY BOARD STAFF
Mr. Fred Butterfield, CASAC Designated Federal Officer, 1200 Pennsylvania Avenue, N.W.,
Washington, DC, 20460, Phone: 202-343-9994, Fax: 202-233-0643 (butterfield.fred@,epa.gov)
CASAC External Roster FY 2006.wpd
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Abbreviations and Acronyms
aFGF
AA
AAS
ACBP
ACE
ACh
AChE
ADP
AE
AFC
AI
ALA
ALAD
ALAS
ALAU
ALD
ALS
ALT
AMEM
AMP
ANCOVA
ANF
Angll
ANOVA
ANP
AP
AP-1
APDC
ApoE
AQCD
AS52
AST
ASV
SAT
a-fibroblast growth factor
arachidonic acid
atomic absorption spectroscopy
Achenbach Child Behavior Profile
angiotensin converting enzyme
acetylcholine
acetylcholine esterase
adenosine dinucleotide phosphate
anion exchange
antibody forming cells
angiotensin I
5-aminolevulinic acid
5-aminolevulinic acid dehydratase
aminolevulinic acid synthetase
urinary 5-aminolevulinic acid
aldosterone
amyotrophic lateral sclerosis
alanine aminotransferase
Alpha Minimal Essential Medium
adenosine monophosphate
analysis of covariance
atrial natriuretic factor
angiotensin II
analysis of variance
atrial natriuretic peptide
alkaline phosphatase
activated protein-1
ammonium pyrrolidine dithiocarbamate
apolipoprotein E
Air Quality Criteria Document
cells derived from the CHO cell line
aspartate aminotransferase
anode stripping voltammetry
3-amino triazole: 3-amino triazide
-------
ATP
ATPase
ATSDR
AVCD
P
PFGF
I?P-HS
3P-HSD
17P-HSDH
6p-OH-cortisol
Ba(N03)2
BAEP
BAER
Bcell
BCS
BEI
BFU-E
BLL
BM
BMI
BOTMP
BP
BSA
BSI
BTQ
BUN
bw
C3H10T/12
CAS
Ca-ATPase
CaEDTA
CAL
cAMP
CANTAB
CAT
adenosine triphosphate
adenosine triphosphatase
Agency for Toxic Substances and Disease Research
atrioventricular conduction deficit
beta-coefficient; slope of an equation
P-fibroblast growth factor
17p-hydroxysteriod
3p-hydroxysteriod dehydrogenase
17p-hydroxysteriod dehydrogenase
6-p-hydroxycortisol
barium nitrate
brainstem auditory-evoked potentials
brainstem auditory-evoked responses
B lymphocyte
bovine calf serum
biological exposure index
blood erythroid progenitor
blood lead level
basement membrane
body mass index
Bruinicks-Oseretsky Test of Motor Proficiency
blood pressure
bovine serum albumin
Brief Symptom Inventory
Boston Teacher Questionnaire
blood urea nitrogen
body weight
mouse embryo cell line
cornu ammonis 3 region of hippocampus
calcium-dependent adenosine triphosphatase
calcium disodium ethylenediaminetetraacetic acid
calcitonin
cyclic adenosinemonophosphate
Cambridge Neuropsychological Testing Automated Battery
catalase; Cognitive Abilities Test
II-xxiv
-------
CBCL
CBCL-T
CCB
CCS
109Cd
CDC
CESD, CES-D
CFR-GM
CFU-E
CFU-GEMM
cGMP
ChAT
CHD
CHO
CI
CLS
CMI
CNS
57^
Co
ConA
COR
CoRx
COX-2
CP
CPT
cr
ere
CREB
CRT
CSF
CSF-1
CuZn-SOD
CV
CVD
Achenbach Child Behavior Checklist
Total Behavior Problem Score
cytochalasin B
cosmic calf serum
coefficient of component variance of respiratory sinus arrhythmia
cadmium-109 radionuclide
Centers for Disease Control and Prevention
Center for Epidemiologic Studies Depression (scale)
colony forming unit-granulocyte/macrophage progenitor
colony forming unit blood-erythroid progenitor
colony forming unit blood-pluripotent progenitor
cyclic guanosine-3',5'-monophosphate
choline acetyltransferase
coronary heart disease
Chinese hamster ovary cell line
confidence interval
Cincinnati Lead Study
cell-mediated immunity
central nervous system
cob alt-5 7 radionuclide
concanavalin A
cortisol
(co-reaction?)
cyclooxygenase-2
coproporphryn
current perception threshold
creatinine
creatinine
cyclic AMP-response element binding protein
chronic renal insufficiency
cerebrospinal fluid
colony-stimulating factor-1
copper and zinc-dependent superoxide dismutase
conduction velocity
cardiovascular disease
II-XXV
-------
CVLT
CVR.R
CYP1A1
CYpSall
CYP450
D
dbcAMP
DCV
DDT
DPS
dfs
DG
DMEM
DMEM/F12
DMFS
DMSA
DMTU
DNA
DO
DOPAc
dp/dt
DTK
DTT
E
E2
EBE
EBV
ECG
EDTA
EEG
EKG
electro
EMEM
eNOS
EP
California Verbal Learning Test
coefficient of variation of the R-R interval
cytochrome P-450 1A1
cytochrome P-450 Sal 1
cytocrome P-450
D-statistic
dibutyryl cyclic adenosine-3',5'-monophosphate
distribution of conduction velocities
dithiothreitol
decayed or filled surfaces, permanent teeth
covariate-adjusted number of caries
dentate gyrus
Dulbecco's Minimal Essential Medium
Dulbecco's Minimal Essential Medium/Ham's F12
decayed, missing, or filled surfaces, permanent teeth
2,3-dimercaptosuccinic acid
dimethylthiourea
deoxyribonucleic acid
distraction osteogenesis
3,4-dihydroxyphenylacetic acid
rate of left ventricular isovolumetric pressure
delayed type hypersensitivity
dithiothreitol
embryonic day
estradiol
early biological effect
Epstein-Barr virus
electrocardiogram
ethylenediaminetetraacetic acid
el ectroencephal ogram
electrocardiogram
electrophysiological stimulation
Eagle's Minimal Essential Medium
endothelial nitric oxide synthase
erythrocyte protoporphyrin
II-xxvi
-------
EPO
EPSC
ERG
EROD
ERT
ESP
ESRD
EST
ET
ET-ASS
F
FBS
PCS
FEF
FEP
FEV
FI
FMLP
fMRI
FSH
FT3
FT4
FTES
FTII
FVC
Y-GT
G12 CHV79
G6PD, G6PDH
GABA
GAG
GCI
GD
GDP
GEE
serum erythropoietin
excitatory postsynaptic currents
electroretinogram; electroretinographic
ethoxyresorufin-O-deethylase
estrogen replacement therapy
electrostatic precipitator
end-stage renal disease
estradiol
endothelein; essential tremor
electro-thermal atomic absorption spectrometry
F-statistic
fetal bovine serum
fetal calf serum
forced expiratory flow
free erythrocyte protoporphyrin
forced expiratory volume
fixed interval
N-formyl-L-methionyl-L-leucyl-L-phenylalanine
functional magnetic resonance imaging
follicle stimulating hormone
free triiodothyronine
free thyroxine
free testosterone
Fagan Test of Infant Intelligence
forced vital capacity
y-glutamyl transferase
cells derived from the V79 cell line
glucose-6-phosphate dehydrogenase
gamma aminobutyric acid
glycosaminoglycan
General Cognitive Index
gestational day
guanosine diphosphate
generalized estimating equations
II-xxvii
-------
GFAAS
GFR
GI
GLU
GM
GMP
GnRH
GnRH
GPEI
GPx
GRP78
GSD
GSH
GSSG
GST
GTP
H202
H2SO4
Hb
HBSS
HCG; hCG
HC1O4
Hct
HDL
HET
HFE
HFF
Hgb
H-H
HHANES
H-L
HNO3
HOME
HPRT
HR
graphite furnace atomic absorption spectroscopy
glomerular filtration rate
Gastrointestinal
glutamate
geometric mean
guanosine monophosphate
gonadotropin releasing hormone
gonadotropin releasing hormone
glutathione S-transferase P enhancer element
glutathione peroxidase
glucose-regulated protein 78
geometric standard deviation
reduced glutathione
glutathione disulfide
glutathione-S-transferase
guanosine triphosphate
hydrogen peroxide
sulfuric acid
hemoglobin
Hank's Balanced Salt Solution
human chorionic gonadotropin
perchloric acid
hematocrit
high-density lipoprotein (cholesterol)
Binghamton heterogeneous stock
hemochromatosis (gene)
human foreskin fibroblasts
hemoglobin
high-high
Hispanic Health and Nutrition Examination Survey
high-low
nitric acid
Home Observation for Measurement of Environment
hypoxanthine phosphoribosyltransferase (gene)
heart rate
-------
HSPG
HSPGx
hTERT
HTN
i.p., IP
i.v., IV
IBL
IBL x WRAT-R
ICP-AES
ICP-MS
IDMS
IFN
Ig
IGFi
IL
immuno
IMP
iNOS
IPSC
IQ
ISI
IVCD
KABC
KTEA
KXRF, K-XRF
LCso
LDH
LDL
L-dopa
LET
LH
LHRH
L-NAME
heparan sulfate proteoglycan
(heparan sulfate proteoglycan peroxide?)
catalytic subunit of human telomerase
hypertension
intraperitoneal
intravenous
integrated blood lead index
integrated blood lead index x Wide Range Achievement Test-
Revised (interaction)
inductively coupled plasma atomic emission spectroscopy
inductively coupled plasma mass spectrometry
isotope dilution mass spectrometry
interferon (e.g., IFN-y)
immunoglobulin (e.g., IgA, IgE, IgG, IgM)
insulin-like growth factor 1
interleukin (e.g., IL-1, IL-lp, IL-4, IL-6, IL-12)
immunohistochemical staining
inosine monophosphate
inducible nitric oxide synthase
inhibitory postsynaptic currents
intelligence quotient
interstimulus interval
intraventricular conduction deficit
(Kaufman Assessment Battery for Children?)
Kaufman Test of Educational Achievement
K-shell X-ray fluorescence
lethal concentration (at which 50% of exposed animals die)
lethal concentration (at which 74% of exposed animals die)
lactate dehydrogenase
low-density lipoprotein (cholesterol)
3,4-dihydroxyphenylalanine (precursor of dopamine)
linear energy transfer (radiation)
luteinizing hormone
luteinizing hormone releasing hormone
L-NG-nitroarginine methyl ester
II-xxix
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LOWES S
LPO
LPP
LPS
LTP
LVH
LXRF
MA-10
MANCOVA
MAO
MCH
MDA
MDCK
MDI
MDRD
MEM
Mg-ATPase
MIBK
MLR
MMSE
MMTV
MN
MND
MNNG
MRI
mRNA
MROD
MRS
MS
MSCA
MVV
MW
N, n
N/A
NAc
locally weighted scatter plot smoother
lipoperoxide
lipid peroxidation potential
lipopolysaccharide
long term potentiation
left ventricular hypertrophy
L-shell X-ray fluorescence
mouse Ley dig tumor cell line
multivariate analysis of covariance
monoamine oxidase
mean corpuscular hemoglobin
malondialdehyde
kidney epithelial cell line
Mental Development Index (score)
Modification of Diet in Renal Disease (study)
Minimal Essential Medium
magnesium-dependent adenosine triphosphatase
methyl isobutyl ketone
mixed lymphocyte response
Mini-Mental State Examination
murine mammary tumor virus
micronuclei formation
motor neuron disease
N-methyl-N'-nitro-N-nitrosoguanidine
magnetic resonance imaging
messenger ribonucleic acid
methoxyresorufin-O-demethylase
magnetic resonance spectroscopy
mass spectrometry
McCarthy Scales of Children's Abiltities
maximum voluntary ventilation
molecular weight (e.g., high-MW, low-MW)
number of observations
not available
nucleus accumbens
II-XXX
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NAD
NADH
NADP
NAD(P)H
NADS
NAG
Na-K-ATPase
NET
NCD
NCS
NCTB
NDI
NE
NES
NF-KB
NHANES
NIOSH
NK
NMDA
NMDAR
NO
NO2
NO3
NOR
NOS
NOX
NR
NS
NSAID
NTA
NTx
02
OH
7-OH-coumarin
1,25-OH-D
nicotinamide adenine dinucleotide
reduced nicotinamide adenine dinucleotide
nicotinamide adenine dinucleotide phosphate
reduced nicotinamide adenine dinucleotide phosphate
nicotinamide adenine dinucleotide synthase
N-acetyl-p-D-glucosaminidase
sodium-potassium-dependent adenosine triphosphatase
nitro blue tetrazolium
nuclear chromatin decondensation (rate)
newborn calf serum
Neurobehavioral Core Test Battery
nuclear divison index
norepinephrine
Neurobehavioral Evaluation System
nuclear transcription factor kappa B; nuclear transcription factor-KB
National Health and Nutrition Examination Survey
National Institute for Occupational Safety and Health
natural killer
N-methyl-D-aspartate
N-methyl-D-aspartate receptor
nitric oxide
nitrogen dixide
nitrate
nuclear organizing regions
nitric oxide synthase
nitrogen oxides
not reported
nonsignificant
non-steroidal anti-inflammatory agent
nitrilotriacetic acid
N-telopeptides
oxygen
hydroxyl
7-hydroxy-coumarin
1,25-dihydroxyvitamin D
II-xxxi
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25-OH-D
8-OHdG
OR
P
p.o.,PO
P450 1A2
P450CYp3all
PAD
PAI-1
PAR
Pb
203Pb
206pb
PbCl2
Pb(Ac)2
Pb(ClO4)2
Pb(N03)2
PbB
PBG-S
PBMC
PbO
PBP
Pet
PCV
PDE
PDGF
PDI
PEF
PG
PHA
Pi
PKC
PM
PM10
25-hydroxyvitamin D
8-hydroxy-2'-deoxyguanosine
odds ratio
probability value
per os (oral administration)
cytochrome P-450 1A2
cytochrome P-450 Sal 1
peripheral arterial disease
plasminogen activator inhibitor-1
population attributable risk
lead
lead-203 radionuclide
stable isotope of lead-206
lead chloride
lead acetate
lead chlorate
lead nitrate
blood lead concentration
porphobilinogen synthase
peripheral blood mononuclear cells
lead oxides (or litharge)
progressive bulbar paresis
percentile
packed cell volume
phosphodiesterase
platelet-derived growth factor
Psychomotor Development Index
expiratory peak flow
prostaglandin (e.g., PGE2, PGF2)
phytohemagglutinin A
inorganic phosphate
protein kinase C
particulate matter
combination of coarse and fine particulate matter
II-xxxii
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PMA
PMN
PMR
PN
P5N
PND
POMS
ppm
PPVT-R
PRA
PRL
PRR
PTH
PVC
PWM
r
R2
r2
R/ALAD
RAVLT
RBC
RBF
RBP
RCPM
REL
RNA
ROS
RPMI 1640
RR
RT
Rx
SA7
SBIS-4
s.c., SC
SCAN
progressive muscular atrophy
polymorphonuclear leucocyte
proportionate mortality ratio
postnatal (day)
pyrimidine 5'-nucleotidase
postnatal day
Profile of Mood States
parts per million
Peabody Picture Vocabulary Test-Revised
plasma renin activity
prolactin
prevalence rate ratio
parathyroid hormone
polyvinyl chloride
pokeweed mitogen
Pearson correlation coefficient
multiple correlation coefficient
correlation coefficient
ratio of ALAD activity, before and after reactivation
Rey Auditory Verbal Learning Test
red blood cell; erythrocyte
renal blood flow
retinol binding protein
Ravens Colored Progressive Matrices
rat epithelial (cells)
ribonucleic acid
reactive oxygen species
Roswell Park Memorial Institute basic cell culture medium
relative risk; rate ratio
reaction time
(reaction?)
simian adenovirus
Stanford-Binet Intelligence Scale-4th edition
subcutaneous
Test for Auditory Processing Disorders
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SCE
SD
SDH
SDS
SE
SEM
SES
SGC
SHBG
SHE
SIR
SMR
SNP
SOD
SOD
SOPR
SRIF
SRT
SSADMF
SSB
SSEP
StAR
SVC
SVRT
T
TBPS
TCDD
Tcell
TEL
TES
TG
TH
Thl
TIMS
TLC
sister chromatid exchange
Spraque-Dawley (rat); standard deviation
succinic acid dehydrogenase
Symbol Digit Substitution
standard error; standard estimation
standard error of the mean
socioeconomic status
soluble guanylate cyclase
sex hormone binding globulin
Syrian hamster embryo cell line
standardized incidence ratio
standardized mortality ratio
sodium nitroprusside
superoxide dismutase
superoxide dismutase
sperm-oocyte penetration rate
somatostatin
simple reaction time
Social Security Administration Death Master File
single-strand breaks
somatosensory-evoked potential
steroidogenic acute regulatory protein
sensory conduction velocity
simple visual reaction time
testosterone
Total Behavior Problem Score
methionine-choline-deficient diet
T lymphocyte
tetraethyl lead
testosterone
6-thioguanine
tyrosine hydroxylase
T-derived lymphocyte helper 1
thermal ionization mass spectrometry
treatment of lead-exposed children
II-xxxiv
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TNF
tPA
TRH
TSH
TT3
TT4
TIES
TTR
TWA
TX
U
UCP
UDP
Ur
UV
V79
vc
VDR
VE
VEP
vitC
vitE
VMA
VMI
VSMC
WAIS
WHO
wise
WISC-R
WRAT-R
WTHBF-6
XRF
yr
ZPP
tumor necrosis factor (e.g., TNF-a)
plasminogen activator
thyroid releasing hormone
thyroid stimulating hormone
total triiodothyronine
serum total thyroxine
total testosterone
transthyretin
time-weighted average
tromboxane (e.g., TXB2)
uriniary
urinary coproporphyrin
uridine diphosphate
urinary
ultraviolet
Chinese Hamster lung cell line
vital capacity; vitamin C
vitamin D receptor
vitamin E
visual-evoked potential
vitamin C
vitamin E
vanilmandelic acid
Visual-Motor Integration
vascular smooth muscle cells
Wechsler Adult Intelligence Scale
World Health Organization
Wechsler Intelligence Scale for Children
Wechsler Intelligence Scale for Children-Revised
Wide Range Achievement Test-Revised
human liver cell line
X-ray fluorescence
year
zinc protoporphyrin
II-xxxv
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CHAPTER 5 ANNEX
ANNEX TABLES AX5-2
December 2005 AX5-1 DRAFT-DO NOT QUOTE OR CITE
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Table AX5-2.1. Effect of Lead on Erythrocyte Morphology, Mobility, and Other Miscellaneous Parameters
Dose & Route of
Exposure Duration Species
100 |ig/dL lead, 1 h Human erythrocytes
10 mg/dL, lead,
In vitro
24 h
2 jiM lead acetate 0- 1 h MDCK Kidney epithelial cell
2 jiM lead line, In vitro
0-2 h Human erythrocytes, in vitro
10 or 20 mM lead 5 weeks Albino rats
acetate, i.p. once a
week
(100 or 200 jimoles)/
kg b.wt.
20 mM lead acetate, 5 weeks Male Wistar Albino rats
i.p. once a week (200
jimoles/kg b.wt)
200 uM of lead Once a week for Rat
acetate, i.p. 5 weeks
Lead, i.p. 20 mg/ kg 14 consecutive Male Albino rat
b.wt. days
Blood lead Effect
— Plasma lead uptake was at the rate of 0. 17 ji moles/h.
Uptake comparable in erythrocyte ghosts and in intact cells. No
association of lead with membranes at 24 h.
— Anion exchange (AE) plays a critical role in regulating intracellular
pH in erythrocytes and epithelial cells and facilitates Pb uptake.
Control - Exposure to lead significantly decreased the erythrocyte mobility.
1-12 jig/100 mL The decreases in mobility were either simultaneous or prior to the
Exposed - decreases in hemoglobin (Hb) or hematocrit (Ht). In exposed rats, a
100-800 |ig/dL significant negative correlation was found between mobility and
blood lead levels. Decreases in ALAD (6-aminolevulinic acid), was
also apparent in exposed animals.
Control - Exposure to lead significantly decreased RBC membrane sialic acid
1-12 jig/100 mL content, erythrocyte survival, hemoglobin, and hematocrit. This was
Exposed - evident to a minor extent below blood lead levels 100 fig/100 mL
100-800 ng/dL and was generally present from 100 fig/100 mL and higher.
0-600 fig/dL Lead exposure significantly decreases RBC count, Hb values,
hematocrit, mean corpuscular volume, and mean corpuscular
hemoglobin, decreases erythrocyte mobility, membrane sialic acid
content and deformability.
Acetyl choline esterase (AchE), NADH dehydrogenase, and Na+-K+
ATPase activities in rat erythrocyte membranes were inhibited by
lead exposure. Erythrocyte membrane sialic acid, hexose,
hexosamine were inhibited by lead exposure. Membrane
phospholipids and cholesterol were increased.
Authors
Sugawara et al.
(1990)
Bannon et al. (2000)
Terayama et al.
(1986)
Terayma and
Muratsuga( 1988)
Terayama et al.
(1993)
Jehang and Motlag
(1995)
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Table AX5-2.1 (cont'd). Effect of Lead on Erythrocyte Morphology, Mobility, and Other Miscellaneous Parameters
Dose & Route of
Exposure Duration
1 |iM lead nitrate 1 h
1 uM lead nitrate, 1 h
In vitro
6 and 12 mo
0.1-200|J,M, lead l-6h
nitrate in the reaction
buffer
0.1-10 uM lead ions 24 h
from 10 mM
Pb(NO3)2 solution,
In vitro
20 uM lead ion, 2 min- 2 h
In vitro
20 uM lead ions, 1 h
In vitro
0.1 mM lead final Ih
concentration,
In vitro
Species Blood lead
Erythrocytes from lead exposed Controls -
healthy humans 8.3 ug/dL
Exposed
70.5 ug/dL
Erythrocytes from healthy —
human volunteers
Erythrocytes from lead exposed
rats
In vitro, human erythrocytes —
Erythrocytes from healthy —
human volunteers
Erythrocytes from human —
umbilical cord
Human umbilical cord —
erythrocytes
Erythrocytes from healthy —
humans
Effect
Lead exposure in healthy human RBC membranes resulted in
increased levels of arachidonic acid (AA). The increase in AA
correlated in a dose dependent manner with elevation in lead and
with serum iron. On the other hand, a negative correlation was
found between Aa and serum calcium. It is inferred that substitution
of lead to calcium, which is essential for the release of phospholipase
A2 for AA release may be the reason for increased RBC membrane
AA.
Lead inhibits Gordos effect in human erythrocytes; electron spin
labeling studies indicated cell shrinkage and decreased volume.
Cation-osmotic hemolysis (COH) in 12 month lead-exposed rats was
lower in the areas of lower ionic strength on erythrocyte membranes.
Lead crosses the erythrocyte membrane by the anion exchanger and
can also leave erythrocytes by a vanadate - sensitive pathway,
identified with the calcium pump. The high ratio of erythrocyte to
plasma Pb seen in vivo appeared to be due to the presence of a labile
Pb2+- binding component present in erythrocyte cytoplasm.
Pb activates erythrocyte K+ channels, Ca + sensitive erythrocyte
Scramblase, triggers Phosphatidyl serine receptors and result in cell
shrinkage and decreased life span.
Pb attenuates prolytic effect on neonatal erythrocytes in iso-or
hypotonic low ionic strength media.
Hemolytic activity of Organo leads increases with their
hydrophobicity: triethyllead chloride < tri-n-propyllead chloride <
tributyl tin chloride.
Lead ions increase the resistance to lysis in media of diminishing
tonicity. These changes might be mediated by changes in membrane
structure.
Lead particles adhere to the external and internal surfaces of the
human erythrocyte membrane and disturb the lamellar organization
of lipid bilayers
Authors
Osterode and Ulberth
(2000)
Eriksson and Beving
(1993)
Mojzis and Nistiar
(2001)
Simons (1993)
Kempe et al. (2005)
Serrani et al. (1997)
Kleszcynska et al.
(1997)
Corchs et al. (2000)
Suwalsky et al.
(2003)
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Table AX5-2.1 (cont'd). Effect of Lead on Erythrocyte Morphology, Mobility, and Other Miscellaneous Parameters
Dose & Route of
Exposure Duration
1-10 uM lead acetate, 3h
In vitro
0-1 200 nM lead, Ih
In vitro
Species
Erythrocytes from healthy
humans
Erythrocytes from healthy
humans
Blood lead Effect
— Low concentrations of lead alter the physico chemical properties of
proteins and lipids in erythrocyte membranes.
— Significant increase in the phosphorylation of membrane cytoskeletal
proteins in lead treated human erythrocytes at concentrations above
100 nM mediated by enhanced PKC activity.
Authors
Slobozhanina et al.
(2005)
Belloni- Olivi et al.
(1996)
RBC—Red blood cells; Hb—Hemoglobin; NADH—Nicotinamide adenine dinucleotide dehydrogenase;
PKC—Protein kinase C; Ache—Acetyl choline esterase
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Table AX5-2.2. Lead, Erythrocyte Heme Enzymes, and Other Parameters
Dose & Route of
Exposure Duration
Dietary, 35 days
O-lOOug/gdrywt. of
the diet
Lead acetate, oral 3 or 1 1 weeks
gavage, 1.5mg/kg
b.wt, lead acetate
20 |ig/mL as lead 5 weeks
acetate in drinking
water
17|iM Me/kg lead 5 days
acetate, Per OS
1.5 mg lead/ kg body 8 yrs.
wt, oral dose
Occupational 11 -22 yrs
exposure
0-20 mg Pb liter - 1 29 days
Species
Adult male Zebra finches
Red-tailed Hawks
Female Wistar Albino rats
Female
Rabbits
Cynomolgus Monkey,
in vitro
Dogs from urban and rural
areas of Greece.
Human erythrocytes from
exposed populations.
Juvenile Rainbow trout
erythrocytes
Blood lead Effect
0-1.5 ug/mL Significant negative correlation was observed between blood-Pb
concentration and log ALAD activity. RBC ALAD activity ratio is a
sensitive indicator of dietary lead concentration regardless of the mode
of exposure.
0.195-0.752 Erythrocyte phorphobilinogen synthetase was depressed significantly
ug/dL with in the 1st wk of treatment. Rapid but brief increase in free
protoporphyrin. Hematocrit, erythrocyte count, Hb were all decreased
and blood viscosity increased in exposed group.
37.8 ug/dL Lead exposure decreases hematocrit, hemoglobin, and the number of
erythrocytes and enhances blood viscosity
— Lead causes a significant decrease in blood ALAD activity, increases
free erythrocyte protoporphyrins, increases aminolevulinic acid and
coporphyrin excretion in urine.
— Kinetic analyses of erythrocyte 6- aminolevulinic acid revealed
differences in PH optimum and Michaelis constants with lead exposure.
The ALAD enzyme kinetics of lead exposed monkeys and humans are
similar.
326, 97-68 Significant negative correlation existed between blood-lead levels and
ug/L ALAD activity. 807-992 umol/PBG/LRBC/h is established as the
normal erythrocyte ALAD range for dogs
1.39-1.42 u Liquid chromatography with inductively coupled plasma spectrometry
mol/1 had revealed ALAD to be the principle lead binding protein. The
percentage of lead bound to ALAD was influenced by a common
polymorphism in the ALAD gene.
— Significant decreases in the erythrocyte ALAD activity after a 29-day
exposure to 121 and 201 mg Pb liter - 1
Authors
Scheuhammer et al.
(1987)
Redig et al. (1991)
Toplan (2004)
Zareba and
Chmelnicka(1992)
Dorward and
Yagminas (1994)
Polizopoulou et al.
(1994)
Bergdahl et al. (1997)
Burden et al. (1998)
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Dose & Route of
Exposure
Lead acetate 160
mg/L in water
1.46 umol/liter
In vitro
Lead 0.34 uM/L-1. 17
uM/L, subcutaneous
injection
0-60 pM lead ion, in
vitro
200-500 ppm lead in
drinking water
0. 1- 100 uM lead ion,
In vitro
20-5 ug/kg body wt
1 mg/ kg body wt.
Table AX5-2.2 (cont'd). Lead,
Duration Species
8 weeks Wistar rats
— Fish from regions close to the
smelters and down stream
48 h Human whole blood
erythrocyte hemolysates,
normal and lead intoxicated
individuals
1 h Male albino New Zealand
rabbits
20 min Human erythrocyte lysates
14 or 30 days Male ddY mice
5 min Human erythrocyte ghosts
Pregnancy Erythrocytes from Sprague-
through lactation Dawley rats
Erythrocyte Heme Enzymes, and Other Parameters
Blood lead Effect
>20->40 Lead increases blood and liver lead, erythrocyte porphyrin content,
ug/dL hypoactivity of both hepatocytic and erythrocytic ALAD
— Smelter site fish had elevated lead concentrations, decreased ALAD
activity and species differences in this inhibitory activity were apparent
that could be attributed to Zn levels.
— The effects of various divalent cations on erythrocyte porphobilinogen
are concentration and PH dependent. Zn restores the lead inhibited
activity.
— Lead causes the most inhibition and Zn activation of rabbit Erythrocyte
porphobilinogen activity. Cu2+, Cd2+, and Hg2+ are intermediary. Each
divalent ion has a characteristic effect on the PH- activity relationship of
PBG-S.
— Human erythrocyte lysate porphobilinogen activity is increased by Zn2+
with a Km of 1.6 pM and inhibited by lead with a Ki of 0.07 pM, lead
reduced the affinity for the substrate 5- aminolevulinate, non-
competitively.
24-51 Lead inhibits erythrocyte and bone marrow P5'N activity. Erythrocyte
jig/100 mL ALAD activity was inhibited by 90%. Elevation of Urinary excretion of
ALA with no change in erythrocyte protoporphyrin and urinary co
porphyrin as against in the lead exposed humans indicates that
protoporphyrin metabolism might be more resistant to lead in mice than
humans.
— Under normal incubation conditions lead inhibits, Ca2+ -Mg2+ ATPase
with an IC50 of 6.0uM. Lead inhibits Ca2+- Mg2+ ATPase related to
sulphahydryl groups above 1.0 uM lead and by direct action of lead
upon Calmodulin below 1.0 uM.
— Na2+- K+- ATPase and Ca2+- Mg+- ATPase of erythrocyte membranes
from lead-depleted animals did not change in PO generation as compared
to 1 mg/kg b.wt lead animals, where as in Fl generation lead depleted
rats showed reduced activity.
Authors
Santos et al. (1999)
Schmitt et al. (2002)
Farant and Wigfield
(1987)
Farant and Wigfield
(1990)
Simons et al. (1995)
Tomokuni et al.
(1989)
Mas- Oliva (1989)
Ederet al. (1990)
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December 2005
Table AX5-2.2 (cont'd). Lead, Erythrocyte Heme Enzymes, and Other Parameters
Dose & Route of
Exposure Duration
20 mg Pb acetate/ Kg 14 days
b.wt, i.p, In vivo
Species Blood lead Effect
Male Albino rats erythrocytes — Lead significantly decreases erythrocyte membrane acetyl choline
esterase, NADH dehydrogenase, membrane sialic acid, hexose, and
hexosamine.
Lead ions inhibit aerobic glycolysis and diminish ATP level in human
erythrocytes in vitro. Magnesium partly abolishes these effects by
Authors
Jehang and Motlag
(1995)
Grabowska and
Guminska(1996)
stimulating Magnesium dependent enzymes. Effect is seen both by
direct addition of lead acetate to erythrocyte ghosts as well as in the
ghosts obtained after preincubation of erythrocytes with lead acetate.
Ca2+, Mg2+ ATPase is less sensitive and Mg ATPase is practically
insensitive to lead under these conditions.
X
10-200 ug/dL lead
ions (lead acetate)
In vitro
Lead acetate through
water or i.p. 1 or 2
mg/Kg b.wt.
20 h
Human umbilical cord
erythrocytes
Every 4th day for Wistar rats
1 month
Lead significantly decreased the concentration of ATP, ADP, AMP, Bosiacka and
adenosine, GTP, GDP, GMP, Guanosine, IMP, inosine, hypoxanthine, Hlynczak (2003)
NAD and NADP concentrations.
1.51-35.31 The concentrations of adenosine tri phosphate (ATP), Guanosine
ug/dL triphosphate ( GTP),Nicotinamide adenine dinucleotide NAD+,
nicotinamide adenine dinucleotide phosphate NADP+ adenylate and
Guanylate( AEC and GEC) were significantly reduced in erythrocytes of
exposed animals. Results indicate lead ions disrupt erythrocyte energy
pathway.
Bosiacka and
Hlynczak (2004)
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ALAD — Aminolevulinic acid; Cu2+—Copper; Cd2+—Cadmium; Hg2+—Mercury; PBG-S Porphobilinogen synthetase; Zn—Zinc; ATP—Adenosine triphosphate—ADP—Adenosine diphosphate;
AMP-Adenosine monophosphate;
GTP—Guanosine tri phosphate; GDP—Guanosine diphosphate; GMP—Guanosine monophosphate; IMP—Inosine monophosphate;
NAD—Nicotinamide adenine dinucleotide; NADP—Nicotinamide adenine dinucleotide phosphate
-------
o Table AX5-2.3. Lead Binding and Transport in Human Erythrocytes
o
3 Dose & Route of
n> Exposure Duration Species Blood lead Effect Authors
to
Q 0-60 pM lead ion, In 20 minutes Human erythrocyte lysates — Human erythrocyte lysate porphobilinogen activity is increased by Zn2+ Simons et al. (1995)
<-/i vitro with a Km of 1.6 pM and inhibited by lead with a Ki of 0.07 pM, lead
reduced the affinity for the substrate 5- aminolevulinate, non-
competitively.
Zn—Zinc
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Dose & Route of
Exposure Duration
4-6 mg/Kg b.wt, i.p., 15 and 30 days
daily
0.82mglead/kg 3 or 11 weeks
b.wt./day, oral gavage
17 uM Me/Kg b.wt 5 days
lead acetate or 3.5 mg
of Pb/kg body wt, i.p
17 uM Me/Kg b.wt 5 days i.p.
lead acetate or 3.5 mg
of Pb/ kg body wt, i.p.
or per OS 17.5 mg/kg
b.wt single injection
Cu deficient 1 mg 4 weeks
Cu/Kg
Marginal deficient 2
mg/kg
Control 5 mg Cu/Kg
High Zn 60 mg/kg.
0.02 - 40 ppm Pb, 90 days
dietary
20 ug/mL, lead 5 weeks
acetate in drinking
water
Table AX5-2.4. Lead Effects on Hematological Parameters
Species Blood lead Effect
Intact and splenctamized rats — Lead increases urinary 6-amino levulinic acid (ALA) excretion,
depletion in RBC hemoglobin content, and more number of reticulocytes
in peripheral blood, and results in accumulation of immature
erythrocytes both in intact and splenctomized rats.
Red-tailed hawks erythrocytes 0. 195-0.375 Activity of porphobilinogen synthase/ ALAD was depressed
mg/mL significantly in lead exposed rats and did not return to normal values
until 5 weeks after the termination of the treatment. A rapid and
relatively brief increase in erythrocyte free proto porphyrin and a slower,
prolonged increase in Zn complex.
Female Rabbits 17.5 ug/dL Lead causes a significant inhibition of ALAD in the blood , increases
free erythrocyte protoporphyrin, and urinary excretion of
Aminolevulinic acid and coporphyrin
Female Rabbits — Lead induced ALAS activity in liver and kidney, both after i.p and p.o.
administration, i.p. administration of lead also induced kidney heme
oxygen levels.
Rat — Moderately high Zn in the diet reduces plasma copper but not plasma
ceruloplasmin,
Does not affect the recovery of plasma Cu or activity after oral copper
sulphate in Cu deficient diets.
Does not influence RBC Super oxide dismutase activity.
Male and female Swiss mice 0.7-13.0 Increased RBC number and increased hemoglobin and decreased
ug/dL hematocrit up on lead exposure.
Female Wistar Albino rats 37.8 ug/dL Erythrocyte count, hematocrit and hemoglobin were all decreased and
blood viscosity increased in lead exposed workers
Authors
Gautam and Roy
Chowdhury (1987)
Rediget al. (1991)
Zareba and
Chmielnicka(1992)
Chmielnicka et al.
(1994)
Panemangalore and
Bebe (1996)
lavicoli et al. (2002)
Toplan et al. (2004)
ALA — Aminolevulinic acid; ALAS — Aminolevulinic acid synthetase; ALAD — Aminolevulinic acid dehydratase, RBC — Red blood cells
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December 2005
Dose & Route of
exposure
0-325 uM, lead
nitrate,
In vitro
Table AX5-2.5. Lead Interactions with Calcium Potassium in Erythrocytes
Duration Species Blood lead Effect
0-60 min In vitro — Pb modifies the threshold sensitivity of individual K+channels to Ca +
with a biphasic time course. The increase of Pb concentration increased
the extent of the initial inhibition and decreased the duration. The
inhibitory effect was not observed when addition of Calcium preceded
the addition of Pb. Pb decreased the rate of uptake of 86Rb
Authors
Alveraz et al. (1986)
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0 uM- 5 mM lead,
In vitro
0-100 min
Human erythrocyte
hemolysates
Lead and Ca transport was carried out by a passive transport system with
two kinetic components (Michaelis- Menten and Hill) Pb and Ca were
capable of inhibiting the transport of the other metals in a non-
competitive way.
Salinas et al. (1999)
X
1-4 uM lead acetate,
In vitro
1-50 uM lead ion,
In vitro
0-30 min Rabbit reticulocytes
20 min Marine fish erythrocytes
Pb at low concentrations inhibits the uptake of Fe (II) into all three Qian and Morgan et
(heme, cytosolic and stromal) fractions. The saturable components were al. (1990)
inhibited at lower concentrations of Pb than the non- saturable
components.
Lead activates Ca2+ activated potassium channels. Treatment of
erythrocytes with 1-2 uM lead led to a minor intra cellular K loss and at
Pb concentrations of 20-50 uM 70% of potassium was lost.
Silkin(2001)
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Table AX5-2.6. Lead, Heme and Cytochrome P-450
Dose & Route of
exposure
Duration
Species
Blood lead
Effect
Authors
0-75mgofPb2+/Kgb. 0-30 h
wt. i.p., Single
injection
C57 BL/6 male mice
Lead causes an increase in 6- amino levulinic acid levels in plasma and a
decrease in the heme saturation of hepatic tryptophan -2,3 dioxygenase.
P-450- dependent activities, EROD and O-dealkylation of
alkoxyresorufins decreased progressively. Lead exposure decreased
mRNA levels of the P450 CYp3al 1. The decrease in P450 transcription
was a mechanism dependent on heme by inhibition of heme synthesis
and also by a mechanism independent of heme in which lead decreases
P-450 transcription.
Joveret al. (1996)
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EROD—Ethoxy resorufin - O- dealkylase.
CYp3al 1—Cytochrome P-450 Sail.
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Dose & Route of
exposure
7.5 mg of lead acetate
or 4.09 mg of lead Kg"
'b.wt, oral
5.46 mg lead as lead
acetate, oral
10 mg/kg b.wt lead
acetate, intra
muscular, daily
Pre treatment with
melatonin
A. ALA 40 mg/kg
b.wt every other day
and /or
B. Melatonin 10
mg/kg
Lead acetate 0.2%, in
drinking water,
followed by
individual or
combined treatment of
lipoic acid (25 mg/Kg
b.wt and DMSA 20
mg/kg b.wt, i.p.)
6-Aminolevulinic
acid, 1-5 mM, In vitro
Table
Duration
28 days,
multiple
analyses at day
7,14,21 and 28
14 days,
multiple
analyses at day
0, 7 and 14
7 days
Every other day
3 times daily for
2 weeks
5 weeks
10 days
AX5-2.7. Lead, Erythrocyte Lipid Peroxidation, and Antioxidant Defense
Species Blood lead Effect
Erythrocytes from male Calves 0.1-1.6 ppm Lead exposure significantly reduced erythrocyte super oxide dismutase
activity until day 21 followed by a marginal increase by day 28. Total,
protein-bound and non protein- bound -SH content of erythrocytes
declined.
Erythrocytes from female goats 0.09-1. 12 ppm Lead exposure caused a significant increase of erythrocytic GPx, SOD
and CAT activities, total thiol groups and total antioxidant status.
Rat — Lead significantly decreased heme synthesis, decreased Hb, decreased
liver 6- ALAS and erythrocyte ALAD. Markedly elevates hepatic lipid
peroxidation, reduced anti oxidant enzymes such as total sulphahydryl
groups and Glutathione. Pre Treatment with melatonin reduced the
inhibitory effect of lead on both enzymatic and non enzymatic
antioxidants and reduced the iron deficiency caused by lead.
Male Sprague- Dwaley rats — Melatonin effectively protects nuclear DNA and lipids in rat lung and
spleen against the oxidative damage caused by the carcinogen ALA,
Male Albino rats 97.5 ug/dL Lead exposure results in decreased blood hemoglobin, hematocrit,
enhanced erythrocyte membrane lipid peroxidation, decline in the
activities of erythrocyte membrane Na+-K+ ATPase, Ca2+ ATPase, and
Mg2+ ATPase. Treatment with lipoic acid and/or DMSA reduced the
lead induced adverse changes in the biochemical parameters
CHO cells — 6- Aminolevulinic acid treatment induces oxidative stress in Chinese
hamster ovary cells by inducing Glutathione, Glutathione disulphide,
Malandialdehyde equivalents, and Catalase. N-acetyl cysteine
administration reverses the decrease in cell survival and colony
formation induced by 6- ALA.
Authors
Patra and Swarup
et al. (2000)
Mousa et al.
(2002)
El- Missiry (2000)
Karbownik et al.
(2000)
Siva Prasad et al.
(2003)
Neal et al. (1997)
SOD — Super oxide dismutase; CAT — Catalase; ALAS — Aminolevulinic acid synthatase, ALAD — Aminolevulinic acid dehydratase; ALA — Aminolevulinic acid; GPX — Glutathione peroxidase
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CHAPTER 5 ANNEX
ANNEX TABLES AX5-3
December 2005 AX5-13 DRAFT-DO NOT QUOTE OR CITE
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December 2005
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Table AX5-3.1. Summary of Key Studies on Neurochemical Alterations
Subject Exposure Protocol
rat Hippocampal cultures
PND 16-18
rat 1500 ppm Pb(Ac)2
PND 50 chow 10 d before breeding &
maintained to sacrifice
rat 1500 ppm Pb(Ac)2
PND 7, 14, 21 , chow 10 d before breeding &
28 & 50 maintained to sacrifice
rat 750 ppm Pb(Ac)2
PND 2 1 chow from gestational day 0 to
PND 21
Cultured PC 12 cells
adultrat water- 0.1-1. 0%Pb(Ac)2
from gestational day 1 5 to adult
adultrat water- 0.1-1. 0%Pb(Ac)2
from gestational day 1 5 to adult
Cultured PC 12 cells
embryonic rat hippocampal neurons
rat 750 or 1 500 ppm Pb(Ac)2
chow from 10 d pre-mating to
PND 14, 21, & 28
Cultured PC 12 cells
Peak Blood Pb or
[Pb] used
O.l&l.OuM
PbCl2
3 1.9 ug/dL
—
46.5 ug/dL
0.03-10 uM
Pb(NO3)2
61.8ug/100mL
117.6ug/100mL
0.53 uMPb(Ac)2
lOOfM-lOOnM
61.1 ug/dL
5-20 uM Pb(Ac)2
Observed Effects
Pb blockage of IPSCs were partially reversible while EPSCs were not
Decreases the NR1 subunit splice variant mRNA in hippocampus
Alters NMDAR subtypes & reduces CREB phosphorylation
Increased expression of nicotinic receptors
Pb acts as a high affinity substitute for calcium in catecholamine
release
Hippocampal GLU & GABA release exhibits biphasic effects from
chronic Pb
NMDA receptor function is upregulated
PKC is involved in TH upregulation but not downregulation of ChAT
Decreases [Ca2+]i & increases Ca2+ efflux by a calmodulin-dependent
mechanism
Dose-response effect between level of Pb and expression of NR1 gene
Induces expression of immediate early genes but requires PKC
Reference
Braga et al. (2004)
Guilarte and
McGlothan (2003)
Toscano et al. (2002)
Jett et al. (2002)
Westerink and
Vijverberg (2002)
Lasley and Gilbert
(2002)
Lasley et al. (2001)
Tian et al. (2000)
Ferguson et al.
(2000)
Guilarte et al. (2000)
Kim et al. (2000)
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December 2005
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Table AX5-3.1 (cont'd). Summary of Key Studies on Neurochemical Alterations
Subject
rat
PND 50
adult rat
adult rat
PND 2
rat
rat
PND 17
rat
PND 7, 14,21,
28
rat
PND 7, 14,21,
28
rat
PND 22-adult
rat
PND 28 56,
112
Exposure Protocol
750orl500ppmPb(Ac)2
chow from 10 d pre-mating to
PND 50
calcineurin in mixture
cerebrocortical membranes
0.2% Pb(Ac)2
in water and chow
Cultured hippocampal neurons
Cultured hippocampal neurons
750 ppm Pb(Ac)2
chow from 14 d pre-mating to
experimental use
750 ppm Pb(Ac)2
chow from 14 d pre-mating to
experimental use
water - 0.2% Pb(Ac)2
from gestational day 16 to PND 21
water - 1000 ppm Pb(Ac)2
from gestational day 4-use
Peak Blood Pb or
[Pb] used
3 1.9 ug/dL
10- 2000 pM
Pb(NO3)2
0.01-4 uM
free Pb(Ac)2
52.9 ug/100 mL
0.01-10 uMPbC!2
0.1-10uMPbCl2
59.87 ug/dL
59.87 ug/dL
—
39.6 ug/dL
Observed Effects
Reductions in NMDAR receptors result in deficits in LTP and spatial
learning
Has a stimulatory (low) and inhibitory (high) effect on calcineurin
Pb binds to the NMDA receptor channel in a site different from zinc
GLU & GABA release are inhibited independent of Pb exposure period
Inhibits glutamatergic and GABAergic transmission via calcium
channel
Increases tetrodo toxin- insensitive spontaneous release of GLU &
GABA
NMDAR-2A subunit protein expression is reduced in the hippocampus
Alters the levels of NMDA receptor subunits mRNA in hippocampus
Induces loss of septohippocampal cholinergic projection neurons in
neonates lasting into young adulthood
Significant increase in [ HJMK-801 binding after chronic exposure
Reference
Nihei et al. (2000)
Kem and Audesirk
(2000)
Lasley and Gilbert
(1999)
Lasley et al. (1999)
Bragaet al. (1999a)
Bragaet al. (1999b)
Nihei and Guilarte
(1999)
Guilarte and
McGlothan(1998)
Bourjeily and
Suszkiw(1997)
Maet al. (1997)
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Table AX5-3.1 (cont'd). Summary of Key Studies on Neurochemical Alterations
Subject Exposure Protocol
rat 50 or 1 50 ppm Pb(Ac)2
PND 2 1 -adult water for 2 weeks - 8 mo
adult rat water - 0.2% Pb(Ac)2
from PND 0 - adult
rat - 4 mo water - 0.2% Pb(Ac)2
from gestational day 16 to PND 28
rat water at 50 ppm Pb(Ac)2
PND 111 for 90 d; start at PND 21
Cultured bovine chromaffin cells
rat Homogenized cortex
Cultured bovine chromaffin cells
rats neuronal membranes
PND 14 or 56
rat cortical synaptosomes
Peak Blood Pb or
[Pb] used
28.0 ug/dL
37.2 ug/100 mL
22.0 ug/dL
18 ug/dL
variable kind &
concentration
ranging Pb(Ac)2
variable kind &
concentration
chow containing
750 ppm Pb(Ac)2
l-50nMfreePb
orl uMPb(NO3)2
Observed Effects
Differential effects in [ HJMK-801 binding with dopamine & D]
agonists
Presynaptic glutamatergic function in dentate gyrus is diminished
Developmental Pb results in long-lasting hippocampal cholinergic
deficit
Decreases in vivo release of dopamine in the nucleus accumbens
Exerts dual stimulatory and inhibitory effects on adrenal PKC
Pb activates PKC in the range of 10'11 to 10'8 M
Pb and calcium activate the exocytotic release of norepinephrine
Review paper discussing Pb-calcium interactions in Pb toxicity
Review paper exploring Pb as a calcium substitute
Inhibitory effect on [3H]MK-801 binding & loss of binding sites in
neonates
Triggers acetylcholine release more effectively than calcium
Reference
Cory-Slechta et al.
(1997)
Lasley and Gilbert
(1996)
Bielarczyk et al.
(1996)
Kala and Jadhav
(1995)
Tomsig and Suszkiw
(1995)
Longet al. (1994)
Tomsig and Suszkiw
(1993)
Simons (1993)
Goldstein (1993)
Guilarte and Miceli
(1992)
Shao and Suszkiw
(1991)
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o Table AX5-3.1 (cont'd). Summary of Key Studies on Neurochemical Alterations
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rat
rat
Exposure Protocol
hippocampal neurons
brain protein kinase C
Peak Blood Pb
or [Pb] used
2.5-50nMPbCl2
10'10MPb salts
Observed Effects
Pb has a blocking effect on the NMDA subtype of glutamate receptors
Stimulates brain protein kinase C and diacylglycerol-activated calcium
Reference
Alkondon et al.
(1990)
Markovac and
Goldstein (1988)
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Table AX5-3.2. Summary of Key Studies on Neurophysiological Assessments
Subject
rat
PND 22
rat
PND 42-64
rat
PND 130-210
adult rat
adult rat
adult rat
rat
PND 90- 130
rat 7- 18 mo
rat
PND 13-140
adult rat
rat
PND 4-30
rat
Peak Blood Pb
Exposure Protocol or [Pb] used
250 ppm Pb(Ac)2 30.8 ug/dL
3-6 weeks (electro) or 7-13
weeks (immuno)
100, 250, or 500 ppm 54.0 ug/dL
Pb(Ac)2 in chow for 3-6 w
0.2%Pb(Ac)2 75 .4 ug/dL
in water
water - 0.1-1.0% Pb(Ac)2 117.6 ug/dL
from gestational day 16 to adult
0.2%Pb(Ac)2 30.1 ug/dL
in water
0.2%Pb(Ac)2 30.1 ug/dL
in water PND 0-21
750 ppm Pb(Ac)2 16.04 ug/100 mL
chow from 50 d pre-mating to
experimental use
water - 0.2% Pb(Ac)2 —
from gestational day 16 to
experimental use
750 ppm Pb(Ac)2 28.5 ug/dL
chow from 50 d pre-mating to
experimental use
water - 0.2% Pb(Ac)2 —
from PND 0 - adult
Hippocampal neurons 1-100 uM Pb C12
750 ppm Pb(Ac)2 16.2 ug/100 mL
chow from 50 d pre-mating to
experimental use
Observed Effects
Reduces midbrain dopamine impulse flow & decreases dopamine D] receptor
sensitivity in nucleus accumbens
Decrease in number of spontaneously active midbrain dopamine neurons
Review paper examining glutamatergic components contributing to
impairments in synaptic plasticity
Deficits in synaptic plasticity in the dentate gyrus from early exposure
Biphasic dose-dependent inhibition of hippocampal LTP
Chronic Pb exposure significantly decreases range of synaptic plasticity
Impairments in LTP and paired-pulse facilitation in the hippocampal DG
NMDA-dependent forms of synaptic plasticity are more vulnerable than
NMDA-independent potentiation or paired pulse-facilitation
Impairs ability to maintain LTP over time in the dentate gyrus
Paired-pulse stimulation of CA3 region shows inhibitory mechanisms
Chronic Pb increases the threshold for LTP in dentate gyrus in vivo
Identified the nicotinic acetylcholine receptor as a target for Pb
LTP and learning are impaired if exposed to Pb in the immature brain
Reference
Tavakoli-Nezhad
and Pitts (2005)
Tavakoli-Nezhad
et al. (2001)
Lasley and Gilbert
(2000)
Gilbert et al.
(1999a)
Gilbert et al.
(1999b)
Zhao et al. (1999)
Ruan et al.
(1998)
Gutowski et al.
(1998)
Gilbert and Mack
(1998)
Gutowski et al.
(1997)
Gilbert et al.
(1996)
Ishiharaet al.
(1995)
Altmannet al.
(1993)
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Table AX5-3.3. Summary of Key
Subject
mice
PND 7-90
rat
PND 21 or 90
monkey
1 3 years
monkey
adult rat
monkey 6 yr
rat
PND 90
Exposure Protocol
0.15%Pb(Ac)2
in dams water from PND 0-21
rat retinas
0.02% & 0.2% Pb(Ac)2
in dams water PND 0-21 & 3
weeks as adult
2 mg/kg/day Pb(Ac)2
in capsule for 1 3 y
350 or 600 mg Pb(Ac)2
for 9.75 years
bovine retinas
rat retinas
0.02% & 0.2% Pb(Ac)2
in dams water PND 0-21
glycerine capsule with 25 or
2000 ng/kg/day Pb(Ac)2
0.2%Pb(Ac)2
in dams water PND 0-21
Peak Blood Pb
or [Pb] used
26 |ig/dL
0.01-10 iiM
PbCl2
59.0 |ig/dL
168.0 |ig/dL
55 |ig/dL
50pM-100nM
Pb(Ac)2
10-9tolO-4M
59.4 |ig/dL
220 ng/dL
0.59 ppm
Studies on Changes in Sensory Function
Observed Effects
Produces a rod photoreceptor- selective apoptosis inhibited by Bcl-xl
overexpression
Pb & calcium produce rod photoreceptor cell apoptosis via mitochondria
Functional alterations and apoptotic cell death in the retina
Mild increase in detection of pure tones outside of threshold
Consistent prolongations of latencies on the brain stem auditory evoked
potential
Direct inhibition of purified rod cGMP PDE, magnesium can reverse effect
Alters several physiological & biochemical properties of rod photoreceptors
Review paper examining effects upon auditory and visual function
Inhibits adult rat retinal, but not kidney, Na+, K+-ATPase
Morphological damage in the visual cortical area VI and V2
Long-term selective deficits in rod photoreceptor function and biochemistry
Reference
He et al. (2003)
He et al. (2000)
Foxet al. (1997)
Rice (1997)
Lilienthal and
Winneke(1996)
Srivastava et al.
(1995)
Foxet al. (1994)
Otto and Fox
(1993)
Foxet al. (1991)
Reuhlet al.
(1989)
Fox and Farber
(1988)
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Table AX5-3.4. Summary of Key Studies on Neurobehavioral Toxicity
Subject
adult rat
rat
PND70
rat
PND120
rat
PND53
rat
PND60
adult rat
rat
PND80
rat
14-22weeks
Peak Blood Pb
Exposure Protocol or [Pb] used
16mgPb(Ac)2 83.2|ig/dL
via gavage 30 d pre- pregnancy
toPND21
1 6 mg Pb(Ac)2 5 3 .24 |ig/dL
via gavage 30 d pre-pregnancy
toPND21
16mgPb(Ac)2 38.0|ig/dL
via gavage 30 d pre-pregnancy
toPND21
300 or 600 ppm Pb(Ac)2 158 |ig/dL
in drinking water
8orl6mgPb(Ac)2 6.8 |ig/dL
75 or 300 ppm Pb(Ac)2 36 |ig/dL
400 mg/1 Pb C12 —
in dam water PND 1-30
75 or 300 ppm Pb(Ac)2 5 1 |ig/dL
in water gestation day 0-
experimental use
Observed Effects
Developmental Pb exposure results in enhanced acquisition of cocaine self-
administration
Increased sensitivity to cocaine in rats perinatally exposed to Pb
Self-administering rats perinatally exposed to Pb demonstrate and increased
sensitivity to the relapse phase of cocaine abuse
Review paper examining impairments in complex cognitive function
1 ) Impairment of sustained attention, response initiation, & reactivity to errors
2) Specific deficits in associative ability showing damage to the amygdala or
Nac
Long-lasting changes in drug responsiveness to cocaine and related drugs
Impaired learning of a visual discrimination task
Postnatal Pb results in neuroplastic deficits related to long-term memory
Impairment of reversal learning as an associative deficit
Reference
Rocha et al.
(2005)
Nation et al.
(2004)
Nation et al.
(2003)
Cory-Slechta
(2003)
Morgan et al.
(2001)
Garavan et al.
(2000)
Miller et al.
(2001)
Morgan et al.
(2000)
Murphy and
Regan (1999)
Hilson and
Strupp(1997)
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Table AX5-3.4
Subject Exposure Protocol
adult rat 100 or 350 ppm Pb(Ac)2
in water PND 21 -use
adult rat 50 or 1 50 ppm Pb(Ac)2
in water PND 21 -use
adult rat 500 ppm Pb(Ac)2
in water for adult rats
rat 22 weeks 75 or 300 ppm Pb(Ac)2
in water PND 25 - use
rat 50 or 150 ppmPb(Ac)2
in water PND 21 -use
rat 50 or 150 ppmPb(Ac)2
in water PND 21 -use
rat 50 or 250 ppm Pb(Ac)2
in water PND 21 -use
adult rat 500 ppm Pb(Ac)2
in water for adult rats
monkeys mo ther's blood Pb from
gestation week 5-birth
(cont'd). Summary of Key Studies on Neurobehavioral Toxicity
Peak Blood Pb
or [Pb] used Observed Effects
35.0 ng/dL Post-washout decrease in sensitivity to MK-801
30.6 ng/dL 1 ) Enhances the stimulus properties of NMDA via a possible dopaminergic
path
2) Low level Pb exposure is associated with D! subsensitivity.
28.91 |ig/dL Decreases sensitization to the locomotor-stimulating effects of cocaine
Review examining the similarities between experimental & epidemiological
data
39 ng/dL Significantly impaired on the alteration task with variable intertrial delays
— Altered cholinergic sensitivity due to Pb and several agonists
35.7 |ig/dL Postweaning lead exposure resulted in a MK-801 subsensitivity
73.5 ng/dL 1 ) Potentiates the effects of NMDA on repeated learning
2) Learning impairments are not caused by changes in dopaminergic function
20.9 |ig/dL Chronic Pb exposure attenuated the reinforcing effect of brain stimulation
21 to 79 ng/dL Reduced sensitivity to changes in reinforcement contingencies during
behavioral transitions and in steady state
Reference
Cory-Slechta
(1997)
Cory Slechta et
al. (1996aand
1996b)
Nation et al.
(1996)
Rice (1996)
Alber and Strupp
(1996)
Cory-Slechta and
Pokora(1995)
Cory Slechta
(1995)
Cohn and Cory-
Slechta
(1994 a,b)
Burkey and
Nation (1994)
Newland et al.
(1994)
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Table AX5-3.4 (cont'd). Summary of Key Studies on Neurobehavioral Toxicity
Subject
rat
adult rat
young rat
monkeys
3 or 7 yr
monkeys
8-9 yr
monkeys 0.5
or 3 yr
rat
monkey 7-8 yr
monkey 6-7 yr
monkey 5-6 yr
Exposure Protocol
50 or 250 ppm Pb(Ac)2
in water PND 21 -use
500 ppm Pb(Ac)2
in chow for 105 days
100or350ppmPb(Ac)2
in dams water PND 0-21
1500 ng/kg/day Pb(Ac)2
in glycerine capsule
1500|ig/kg/dayPb(Ac)2
in glycerine capsule
2000 (ig/kg/day Pb(Ac)2
in glycerine capsule
50 or 250 ppm Pb(Ac)2
in water PND 21 -use
1500 ng/kg/day Pb(Ac)2
in glycerine capsule
1500|ig/kg/dayPb(Ac)2
in glycerine capsule
1500 ng/kg/day Pb(Ac)2
in glycerine capsule
Peak Blood Pb
or [Pb] used
73.5 |ig/dL
28 ng/dL
34 ng/dL
36 ng/dL
36 ng/dL
115ng/dL
73.2 |ig/dL
36 |ig/dL
36 |ig/dL
36 |ig/dL
Observed Effects
1) Impairs selective learning that are not a result of non-specific performance or
motivational efforts
2) Subsensitivity to the accuracy-impairing & rate-altering effects of MK-801
on a multiple schedule of repeated learning and performance
Chronic Pb exposure attenuates cocaine-induced behavioral activation
Induces functional D2-D3 supersensitivity to the stimulus properties of agonists
Pb exposure during different developmental periods produce different effects
on FI performance in juveniles versus adults
Impairment on concurrent discrimination tasks
Decreased interresponse times & a greater ratio of responses per reinforcement
on the differential reinforcement of low rate schedule
Increased sensitivity to the stimulus properties of dopamine D] & D2 agonists
Pb exposure in only infancy impairs spatial discrimination reversal tasks
There is not an early critical period for impairment on spatial delayed
alternation tasks
Post-infancy exposure impairs nonspatial discrimination reversal while
exposure during infancy exacerbates the effect.
Reference
Cohn et al.
(1993);
Cohn and Cory-
Slechta (1993)
Groveret al.
(1993)
Cory-Slechta et
al. (1992)
Rice(1992a)
Rice(1992b)
Rice(1992c)
Cory-Slechta and
Widowski(1991)
Rice (1990)
Rice and Gilbert
(1990a)
Rice and Gilbert
(1990b)
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Table AX5-3.5.
Subject Exposure Protocol
rat water - 0.2% Pb(Ac)2
PND 110 from gestational day 16 to
PND 2 lor use
Rat C6 glioma cells & human
astrocytoma cells
rat 1500ppmPb(Ac)2
PND 60 for 30-35 days
rat embryos Cultured neurospheres
Cultured oligodendrite
progenitor cells- PND 2
Cultured oligodendrite
progenitor cells- PND 2
Cultured cerebellar granule
neurons
rat Cultured C6 glioma cells
rat and human Cultured rat astroglial, human
neuroblastoma
rat and human PKC isozymes
Cultured GH3, C6, and
HEK293 cells
Summary of Key Studies on Cell Morphology and Metal Disposition
Peak Blood Pb
or [Pb] used
5-10uMPb(Ac)2
20.0 ug/dL
0.1-100 uM
Pb(Ac)2
1 uM Pb(Ac)2
0. 1-100 uM
Pb(Ac)2
5-50 uM
Pb(NO3)2 or
Pb(C104)2
1 uM Pb(Ac)2
1 uM Pb(Ac)2
10-12tolO-4M
Pb(Ac)2
1-10 uM
Pb(NO3)2
Observed Effects
Reduction in hippocampal neurogenesis with no spatial learning impairments
Directly targets GRP78 & induces its compartmentalized redistribution
GRP78 plays a protective role in Pb neurotoxicity
Significant deleterious effects on progenitor cell proliferation
Differentially affects proliferation & differentiation of embryonic neural stem
cells originating from different brain regions
Pb inhibition of proliferation & differentiation of oligodendrocyte cells requires
PKC
Interferes with maturation of oligodendrocyte progenitor cells
Specific transport systems carry Pb into neurons
Induces GRP78 protein expression and GRP78 is a strong Pb chelator
Immature astroglia vs. neuronal cells are most likely to bind Pb in the brain
Concentration dependent differential effects of Pb upon PKC isozymes
Cellular uptake of lead is activated by depletion of intracellular calcium
Reference
Gilbert et al.
(2005)
Qian et al.
(2005)
Schneider et al.
(2005)
Huang and
Schneider (2004)
Deng and Poretz
(2002)
Deng et al.
(2001)
Mazzolini et al.
(2001)
Qian et al.
(2000)
Lindahl et al.
(1999)
Sunet al. (1999)
Kerper and
Hinkle(1997)
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Table AX5-3.5 (cont'd). Summary of Key Studies on Cell Morphology and Metal Disposition
Exposure Protocol
Peak Blood Pb
or [Pb] used
Observed Effects
Reference
frog Elvax implantation for 6 weeks 10"10 to 10"6 M Stunted neuronal growth from low Pb levels are reversible with chelator
tadpoles Pb C12
Cline et al.
(1996)
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CHAPTER 5 ANNEX
ANNEX TABLES AX5-4
December 2005 AX5-25 DRAFT-DO NOT QUOTE OR CITE
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Table AX5-4.1. Effect of Lead on Reproduction and Development in Mammals* Effects on Offspring
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Citation
al-Hakkak et
al. (1998)
Appleton
(1991)
Bataineh et
al. (1998)
Berry et al.
(2002)
Bogden et al.
(1995)
Camoratto et
al. (1993)
Corpas
(2002a)
Corpas
(2002b)
Species/
Strain/ Age
Mouse/BALB/c,
weaning
Rat/Long-Evans
hooded, adult
Rat/Sprague-
Dawley, adult
Rat/Sprague-
Dawley, 21 days
old
Rat/Sprague-
Dawley,
12 weeks old
Rat/Sprague-
Dawley, adult
Rat/Wistar, adult
Rat/ Albino
(NOS), adult
Dose/Route/
Form/Duration
0, 25, 50 mg lead monoxide
alloy/kg in chow for 35-70
days
Lead acetate single dose by i.v.
at 30 mg/kg
1000 ppm lead acetate in
drinking water for 12 weeks
Lead nitrate (1000 ppm lead) in
drinking water for 6 weeks
250 mg/L of lead acetate in
drinking water from GD 1 until
after 1 week after weaning
0.02% lead nitrate in drinking
water from gestation day 5 of
dams until PND 4 of offspring
Lead acetate 0 or 300 mg/L in
drinking water during gestation
and lactation
Lead acetate 0 or 300 mg/L in
drinking water during gestation
and lactation
Endpoint
Reduced number of spermatogenia and spermatocytes in the 50 mg group after 70 days;
reduced number of implantations after mating (after 35 days exposure).
Increase in serum calcium and phosphorous; SEM analysis revealed 'lead line' in tooth
that was composed of hypomineralized interglobular dentine.
Fertility was reduced; total number of resorptions was increased in female rats
impregnated by males.
Mean plasma growth hormone levels decreased by 44.6%; reduced mean growth
hormone amplitude by 37.5%, mean nadir concentration by 60%, and growth hormone
peak area by 35%; findings are consistent with decreased hypothalamic growth
hormone-releasing factor secretion or reduced somatotrope responsiveness; exogenous
growth hormone in lead-treated and control rats, this response was blunted by the lead
treatment; plasma IGF 1 concentration was not significantly affected by lead treatment.
Dam and pup hemoglobin concentrations, hematocrit, and body weights and lengths
were reduced.
Female pups exposed to lead beginning in utero were smaller, no corresponding effect
in males; pituitary responsiveness to a hypothalamic stimulus.
Alterations in hepatic system of neonates (PND 12) and pups (PND 21); reductions in
hemoglobin, iron, alkaline and acid phosphatase levels, and hepatic glycogen, and
elevated blood glucose.
Effects energy metabolism; decrease in testis and seminal vesicle weights, and an
increase in DNA and RNA levels on PN day 2 1 ; protein was significantly decreased,
alkaline and acid phosphatase levels of the gonads were reduced; reduction of the
thickness of the epithelium and seminiferous tubule diameter.
Blood Lead Concentration
(PbB)
PbB not reported
PbB not reported
PbB not reported
PbB 37.40±3.60 ug/dL
PbB <15 ug/dL
PbB 17-43 ug/dL
PbB -22 ug/dL
PbB 54-143 ug/dL
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Table AX5-4.1 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Offspring
Citation
Species/
Strain/Age
Dose/Route/
Form/Duration
Endpoint
Blood Lead Concentration
(PbB)
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Table AX5-4.1 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Offspring
jcember
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Citation
Fox et al.
(1997T)
Gandley et al.
(1999)
Govoni et al.
(1984)
Hamilton et
al. (1994)
Hanet al.
(2000)
Hannah et al.
(1997)
Species/
Strain/ Age
Rat/Long-Evans
hooded, adult
Rat/Sprague-
Dawley, adult
Rat/Sprague-
Dawley, adult
Rat/Sprague-
Dawley, 25 days
old
Rat/Sprague-
Dawley, 5
weeks old
Mouse/Swiss
ICR
preimplantation
embryos
Dose/Route/
Form/Duration
0.02 or 0.2% lead acetate in
drinking water from PND
0-PND 21; 8 female pups per
litter control pups; 8 pups per
litter low level exposure; 8
pups per litter moderate level
exposure
(number of litters per dose
unspecified)
Male rats exposed to 25 or 250
ppm acetate lead in drinking
water
for at least 35 days prior to
breeding
2.5 mg/mL lead acetate in
drinking water from GD 16 to
postnatal week 8
Lead acetate in drinking water
at 250, 500 or 1000 ppm; 8
weeks prior to mating through
GD21
250 mg/mL lead acetate in
drinking water for 5 weeks
followed by 4 week no
exposure (mated at end of
4-week no exposure period)
In vitro incubation of two- and
four-cell embryos with
0.05-200 uM lead acetate for
72 hours (time required for
blastocyst formation)
Endpoint
Developmental and adult lead exposure for 6 weeks produced age and dose-dependent
retinal degeneration such that rods and bipolar cells were selectively lost; at the
ultrastructural level, all dying cells exhibit the classical morphological features of
apoptotic cell death; decrease in the number of rods was correlated with the loss of
rhodopsin content per eye confirming that rods were directly affected by lead (p<0.05);
single-flash rod ERGs and cone ERGs obtained from lead-exposed rats demonstrated
that there were age- and dose-dependent decreases in the rod a-wave and b-wave
sensitivity and maximum amplitudes without any effect on cones; in adult rats exposed
to lead for three weeks, qualitatively similar ERG changes occurred in the absence of
cell loss or decrease in rhodopsin content (p<0.05); developmental and adult lead
exposure for three and six weeks produced age- and dose-dependent decreases in retinal
cGMP phosphodiesterase (PDE) activity resulting in increased CGMP levels (p<0.05);
retinas of developing and adult rats exposed to lead exhibit qualitatively similar rod
mediated ERG alterations as well as rod and bipolar apoptotic cell death (p<0.05);
similar biochemical mechanism such as the inhibition of rod and bipolar cell cGMP
PDE, varying only in degree and duration, underlies both the lead-induced ERG rod-
mediated deficits and the rod and bipolar apoptotic cell death (p<0.05).
Fertility was reduced in males with PbB in range 27-60 ug/dL, lead was found to affect
initial genomic expression in embryos fathered by male rats with blood lead levels as
low as 15-23 ug/dL; dose-dependant increases were seen in an unidentified set of
proteins with a relative molecular weight of approximately 70 kDa.
Decreased sulpiride binding in the pituitary is consistent with the elevated serum PRL
concentrations previously described in lead-exposed rats; DOPAc concentrations were
reduced by 21% in lead-treated rats.
Altered growth rates; reduced early postnatal growth; decreased fetal body weight.
Pups born to lead-exposed dams had significantly (p<0.0001) lower mean birth weights
and birth lengths.
Exposure of embryos to lead was only toxic at 200 uM, which reduced cell proliferation
and blastocyst formation.
Blood Lead Concentration
(PbB)
PbB weanlings 19±3 (low
exposure) or 59±8 ug/dL
(moderate exposure), adult
7±2 ug/dL (at PND 90)
PbB 27-60 ug/dL (fathers)
15-23 ug/dL (offspring)
PbB 71±8 ug/dL
PbB 40-100 ug/dL
PbB 10-70 ug/dL
PbB not reported
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Table AX5-4.1 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Offspring
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Citation
lavicoli et al.
(2003)
Species/
Strain/ Age
Mouse/Swiss,
adult
Dose/Route/
Form/Duration
Lead acetate in food (0.02,
0.06,0.11,0.2,2,4,20,40
Endpoint
Low-level exposure (PbB 2-13 ug/dL) reduced red cell synthesis (p<0.05); high-level
exposure (PbB 0.6-2 ug/dL) enhanced red cell synthesis (p<0.05).
Blood Lead Concentration
(PbB)
PbB 0.6 to <2.0 ug/dL or
>2.0-13 ug/dL
lavicoli et al. Mouse/Swiss,
(2004) adult
Logdberg et Monkey/
al. (1987) Squirrel, adult
Logdberg et Monkey/
al. (1998) Squirrel, adult
McGivern et
al. (1991|)
Nayak et al.
(1989)
Rat/Sprague-
Dawley, adult
Mouse/Swiss
Webster, adult
Piasekand Rat/Wistar, 10
Kostial (1991) weeks old
ppm) exposure began 1 day
after mating until litter was 90
days old one litter of mice
exposed to each dietary
concentration
Lead acetate in feed; exposure
began 1 day after mating until
litter was 90 days old
Lead acetate p.o. exposure of
gravid squirrel monkeys from
week 9 of gestation through
PNDO
Lead acetate (varying
concentrations < 0.1% in diet);
maternal dosing from 5-8.5
weeks pregnant to PND 1; 11
control monkeys, 3 low-lead
exposure group (PbB
24 ug/dL), 7 medium lead
group (PbB 40 ug/dL, 5 high-
lead group (PbB 56 Ug/dL)
0.1% lead acetate in drinking
water from GD 14 to
parturition
Lead nitrate dissolved in NaCl
solution, administered
intravenously, via caudal vein
at dose levels of 100, 150, 200
mg/kg; one time exposure on
GD9
7500 ppm lead acetate in
drinking water for 9 weeks
In females: accelerated time to puberty at PbB <3 ug/dL; delayed time to puberty at 3—
13 ug/dL.
Increase in pre- and perinatal mortality among squirrel monkeys receiving lead acetate
p.o. during the last two-thirds of pregnancy (45% vs. 7-8% among controls); mean
maternal PbB was 54 ug/dL (39-82 ug/dL); statistically significant reductions in mean
birth weight were observed in lead exposed monkeys as compared to controls; effects
occurred without clinical manifestation of toxic effects in the mothers.
Dose-dependent reduction in placental weight (p<0.0007); various pathological lesions
were seen in the placentas (n=4), including hemorrhages, hyalinization of the
parenchyma with destruction of the villi and massive vacuolization of chorion
epithelium; effects occurred without clinical manifestation of toxic effects in the
mothers.
Male offspring of dams exhibited reduced sperm counts, altered male reproductive
behavior, and enlarged prostates later in life; females exhibited delayed puberty,
menstrual irregularities, and an absence of observable corpora lutea; males and females
exhibited irregular release patterns of both FSH and LH later in life.
Chemical analysis showed lead was readily transferred across placenta; lead caused
moderate, statistically significant, increase in frequency of SCEs in maternal bone
marrow cells and significant reduction in NRs at the 2 highest dose levels (150 and 200
mg/kg); animals showed several specific chromosomal aberrations, mostly deletions, in
maternal bone, marrow, and fetal cells; aneupoidy was found to be frequently
associated with the lowest dose levels of lead nitrate (100 mg/kg); increased embryonic
resorption and reduced placental weights.
Decrease in litter size, pup survival, and birth weight; food consumption, body weight,
and fertility were not altered in 20 week exposure period.
PbB 0.6 to <2.0 |ig/dL or >2.0-
13 ug/dL
PbB 54 ugdL (39-82 ugdL)
Mean maternal PbB 37 ugdL
(22-82 ugdL)
24 (22-26) ug/dL (low dose)
40 (35^16) ug/dL (mid dose)
56 (43-82) ug/dL (high dose)
PbB 73 ug/dL
PbB levels at birth in the
exposure groups for these
studies were >180 ug/dL
Maternal PbB >300 ug/dL
Offspring PbB >220 ug/dL
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Table AX5-4.1 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Offspring
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Citation
Pinon-
Lataillade et
al. (1995)
Pillai and
Gupta (2005)
Ronis et al.
(1996|)
Ronis et al.
(1998a|)
Ronis et al.
(1998b|)
Species/
Strain/ Age
Mouse/NMRI,
adult
Rat/Charles
Foster,
200-220 g
Rat/Sprague-
Dawley, 22, 55
days or plug-
positive time-
impregnated
Rat/Sprague-
Dawley, various
ages
Rat/Sprague-
Dawley, adult
Dose/Route/
Form/Duration
0-0.5% lead acetate in
drinking water exposed to
lead during gestation until
post-GD 60
Subcutaneoous injection of
0.05 mg/kg-d lead acetate for
5-7 days prior to mating
through PND 21
0.6% lead acetate in drinking
water for various durations:
PND 24-74 (pubertal
exposure), PND 60-74 (post
pubertal exposure); 1 1 males
and females in pubertal
exposure group (10 each in
control pubertal group); 6
males and females post-
pubertal exposure and control
groups
0.6% lead acetate in drinking
water ad libitum for various
durations: GD 5 to PND 1,
GD 5 to weaning, PND 1 to
weaning
3 control litters, 2 gestation
exposure litters, 2 lactation
exposure litters, 2 gestation
and lactation exposure litters,
2 postnatal litters, 2 chronic
litters (4 male and 4 female
pups per litter)
Lead acetate in drinking
water (0.05% to 0.45% w/v);
Endpoint
Lead exposure during gestation reduces litter size; reduced birth weight and growth
rates.
Long term exposure of rats (premating, gestational, and lactational) to moderate levels
of lead acetate (s.c.) resulted in reduced activities of hepatic steroid (E2) metabolizing
enzymes (17-6-hydroxy steroid oxidoreductase and UDP glucuronyl transferase) and
decreased hepatic CYP450 content.
Reduction in serum testosterone levels in male, not female; in female suppression of
circulating E2 (p<0.05) and LH (p<0.05); reduction in male secondary sex organ weight
(p<0.0005); delayed vaginal opening and disrupted diestrous in females (p<0.005);
increased incidence of stillbirth (2% control vs. 19% Pb) (p<0.005).
Dose-dependent delay in sexual maturation (delayed vaginal opening) (p<0.0002)
following prenatal lead exposure that continued until adulthood (85 days old); reduced
birth weight (p<0.05), more pronounced among male pups.
Prenatal lead exposure that continues until adulthood (85 days old) delays sexual
maturation in female pups in a dose-related manner (p<0.05); birth weight reduced
Blood Lead Concentration
(PbB)
PbB <4-132 ugdL
PbB not reported
In utero PbB 250-300 ug/dL
Pre-pubertal PbB 30-60 ug/dL
Post-pubertal PbB 30-60 ug/dL
PbBs in the dams and offspring
in this experiment were
>200 ug/dL.
Group: pup PbB
Naive: —6 ug/dL
Control: <2 ug/dL
Gest: -10 ug/dL
Lact: —3 ug/dL
Gest+Lact: -13 ug/dL
Postnatal: -260 ug/dL
Chronic: -287 ug/dL
PbBs in the pups between the
ages of 2 1 and 85 days were
dams exposed until weaning,
exposure of pups which
continued until PND 21, 35,
55, or 85; 5 control litters
(0%), 10 low-dose litters
(0.05%), 8 mid-dose litters
(0.15%), 9 high-dose litters
(0.45%); 4 male and 4 female
pups per litter
(p<0.05), more pronounced among male pups; decreased growth rates (p<0.05) in both
sexes accompanied by decrease in plasma concentrations of IGF 1 through puberty
(p<0.05) and a significant increase in pituitary and growth hormone during puberty
(p<0.05).
>100 ug/dL and reached up to
388 ug/dL.
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Table AX5-4.1 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Offspring
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Species/
Citation Strain/Age
Ronis et al. Rat/Sprague-
(1998c) Dawley, adult
Dose/Route/
Form/Duration
Lead acetate 0.05, 0.15, or
0.45% in drinking water
beginning GD 5 continuing
until PND 21, 35, 55, or 85; 5
control litters (0%),
10 low-dose litters (0.05%),
8 mid-dose litters (0. 15%),
9 high-dose litters (0.45%);
4 male and 4 female pups per
litter
Endpoint
Dose-responsive decrease in birth weight (p<0.05), and crown-to-rump length (p<0.05);
dose-responsive delay in sexual maturity in male (p<0.05) and female (p<0.05);
neonatal decrease in sex steroids (p<0.05); pubertal decrease in testosterone (male)
(p<0.05) and E2 (female) (p<0.05); decrease estrous cyclicity at high dose (p<0.05).
Blood Lead Concentration
(PbB)
Dams: 0, 48, 88, or 181 ug/dL
Pups PND 1: <1, -40, -70, or
>120 ug/dL
Pups PND 21: <1, >50, >160, or
-237 ug/dL
Pups PND 35: <1, -22, >70, or
>278 ug/dL
Pups PND 55: <1, >68, >137, or
-380 ug/dL
Pups PND 85: <1, >43, >122, or
X
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Ronis et al.
(2001|)
Sant'Ana et
al. (2001)
Singh et al.
(1993)b
Watson et al.
(1997)
Rat/Sprague-
Dawley,
neonate, male
(100 days) and
female pup
Rat/Wistar, 90
days old
Rat/ITRC,
albino (NOS), 6
weeks old
Rat/Sprague-
Dawley, adult
Lead acetate in drinking
water to 825 or 2475 ppm ad
libitum from G'D 4 to GD 55
postpartum; 1 male and
female pup/litter (5 litters per
group) control group, 1 male
and female pup/litter (5 litters
per group) 825 ppm lead
acetate group, 1 male and
female pup/litter (5 litters per
group) 2475 ppm lead acetate
group
0.1 and 1% lead in drinking
water
7 days
250, 500, 1000, and 2000
ppm lead nitrate in drinking
water from GD 6 to GD 14
Lead in drinking water at 34
ppm from weaning of
mothers through gestation
and weaning of offspring
until birth; 6 pups control
group, 6 pups experimental
group
Dose-dependent decrease of the load of failure in male (p<0.05); no difference in
plasma levels of vitamin D metabolites; reduced somatic growth (p<0.05), longitudinal
bone growth (p<0.05), and bone strength during the pubertal period (p<0.05); sex
steroid replacement did not restore skeletal parameters in lead exposed rats; L-Dopa
increased plasma IGFi concentrations, rates of bone growth, and bone strength
measures in controls while having no effect in lead exposed groups; DO gap x-ray
density and proximal new endostreal bone formation were decreased in the distration
gaps of the lead-treated animals (p<0.01); distraction initiated at 0.2 mm 30 to 60 days
of age.
1% Pb exposure reduced offspring body weight during treatment, no changes observed
after 0.1% exposure; no altered offspring sexual maturation, higher Pb improved sexual
behavior, while 0.1% reduced it; 0.1% Pb caused decrease in testis weight, an increase
in seminal vesicle weight, and no changes in plasma testosterone levels, hypothalamic
VMA levels were increased compared to control group; reduced birth weight and
growth rates.
Significantly reduced litter size, reduced fetal weight, and a reduced crown-to-rump
length, increased resorption and a higher blood-lead uptake in those groups receiving
1000 and 2000 ppm Pb; these also had a higher placental uptake; however the level was
the same in both groups; fetal lead uptake remained the same whether or not 2000 ppm
lead was given to an iron-deficient or normal iron groups of mothers.
Reduced body weight (p=0.04); parotid function was decreased by nearly 30%
(p=0.30); higher mean caries scores than the control pups (p=0.005); pre- and perinatal
lead exposure had significantly increased susceptibility to dental caries (p=0.015).
>214 ug/dL
PbB at 825 ppm was
67-192 ug/dL
PbB at 2475 ppm was
120-388 ug/dL
PbB36.12±9.49ug/dLor
13.08±9.42 ug/dL
PbB not reported
PbB 48±13 ug/dL
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Table AX5-4.1 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Offspring
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4.5 ugdL.
Fertility was reduced in males.
Lead in testis and epididymis increased with dose; administration of zinc reduced lead
levels; dose related changes in activities of enzyme alkaline phosphatase and Na+-K+-
on Males
Blood Lead Concentration
(PbB)
Not reported
PbB not applicable— in vitro study
PbB not reported
PbB not applicable-in vitro study
PbB not reported
PbB 2, 4.5, 7,80 ugdL
PbBs >40 ug/dL
PbB not reported
PbB not reported
H
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Batra et al.
(2004)
Bizarro et al.
(2003)
Boscolo et al.
(1998)
Rat/Portan,
8 weeks old
Mouse/CD-I,
adult
Rat/Sprague-
Dawley,
weanling
10, 50, 200 mg/kg lead
acetate orally for 3 months
0.01 M lead acetate twice a
week for 4 weeks
60 mg lead acetate/mL in
drinking water for 18 months
ATPase, which decreased with increased dose of lead; improvement in activities of
enzymes was seen in groups given lead and zinc; disorganization and disruption of
spermatogenesis with accumulation of immature cells in lumen of tubule; highest dose
of lead resulted in arrest of spermatogenesis, and decrease in germ cell layer
population; highest dose levels, damage of basement membrane, disorganization of
epithelium and vacuolization cells; tubules were found almost empty, indicating arrest
of spermatogenesis.
LH and FSH concentrations were decreased at 200 mg/kg; decrease in fertility status at
200 mg/kg; decline in various cell populations at 200 mg/kg; 50 mg/kg group hormone
levels, cell numbers, and fertility status were found close to normal.
Dose-time relationship was found; ROS role.
Increased vacuolization in Sertoli cells; no other ultrastructural modifications; no
impairment of spermatogenesis.
PbB not reported
PbB not reported
PbB 4-17 ugdL
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Table AX5-4.2 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Males
Citation
Species/
Strain/Age
Dose/Route/
Form/Duration
Endpoint
Blood Lead Concentration
(PbB)
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Chowdhury et Mouse/
al. (2001) BALB/c,
3 months old
Chowdhury et Rat/Albino,
al. (1984) (NOS), adult
Chowdhury et Rat/NOS, adult
al. (1986)
Chowdhury et Rat/Charles
al. (1987) Foster, 150±5 g
Coffigny et al. Rat/Sprague-
(1994|) Dawley, adult
Corpas et al. Rat/Wistar,
(1995) adult
Corpas et al. Rat/Wistar,
(2002a) adult
Corpas et al. Rat/Wistar,
(2002b) adult
0.0,0.2,0.5, 1.0, 2.0 ug/mL
lead acetate in culture
medium for 2 hours
(superovulated ova and
sperm)
Dietary concentrations of
0.25, 0.50, or 1.0 g/L lead
acetate for 60 days
0, 1, 2, 4, 6 mg lead
acetate/kg-d i.p. for 30 days
0, 1, 2, 4, 6 mg lead
acetate/kg-d/i.p. for 30 days
Inhalation exposure to 5
mg/m3 lead oxide daily for
13 days during gestation (GD
2, 3, 6-10, 13-17, 20)
300 mg/L lead acetate via
drinking water beginning GD
1 through 5 day postnatal or
throughout gestation and
early lactation
300 mg/L acetate lead in
drinking water beginning at
mating until PND 12 and 21
300 mg/L acetate lead in
drinking water beginning at
mating until PND 12 and 21
Significant dose dependent decrease in the number of sperm attaching to the ova in both
exposed groups; decrease in the incorporation of radio-labeled thymdine, uridine, and
methionine.
Testicular atrophy along with cellular degeneration was conspicuous at 1 g/L; high
cholesterol concentration and significantly low ascorbic acid concentration were found
in the testes at 1 g/L; lowest dose (0.25 g/L) had no significant morphological and
biochemical alterations, whereas as 0.5 g/L resulted in partial inhibition of
spermatogenesis.
Dose-related decrease oftestis weight; at 187 ugdL: degenerative changes intesticular
tissues; at 325 ugdL: degenerative changes and inquiry of spermatogenetic cells;
edematous dissociation in interstitial tissue.
Dose related decrease oftestis weight at 56 |_lg of spermatoids; at 91 ugdL: inhibition of
post-meiotic spermatogenic cell; at 196 ugdL: decreased spermatogenic cell count (6),
detachment of germinal call layers; at 332 ugdL: Decreased spermatogenic cell count,
degenerative changes, Interstitial edema, and atrophy of Leydig cells.
Adult male offspring exhibit no change in sperm parameters or sex hormones T, FSH,
and LH (because of duration or timing).
Testicular weight and gross testicular structure were not altered; seminiferous tubule
diameter and the number of prospermatogonia were reduced; total DNA, RNA, and
protein content of the testes in treated rats was significantly reduced, DNA: RNA ratio
remained unaltered.
Neither abnormalities in the liver structure nor depositions of lead, toxicant produced
biochemical alterations; pups exhibited decrease in hemoglobin, iron and alkaline, and
acid phosphatase levels and an increase in Pb content; protein, DNA, and lipid total
amounts were reduced, and hepatic glycogen content was diminished at 12 and 21 PN,
with a higher dose of glucose in blood; decrease in alkaline phosphatase in liver of pups
at day 21 PN, but acid phosphatase was unaltered.
Neither abnormalities in the liver structure nor depositions of lead, toxicant produced
biochemical alterations; pups exhibited decrease in hemoglobin, iron and alkaline, and
acid phosphatase levels and an increase in Pb content; protein, DNA, and lipid total
amounts were reduced, and hepatic glycogen content was diminished at 12 and 21 PN,
with a higher dose of glucose in blood; decrease in alkaline phosphatase in liver of pups
at day 21 PN, but acid phosphatase was unaltered.
PbB not applicable-in vitro study
PbB 54-143 ugdL
PbB 20, 62, 87, 187, or 325 ugdL
PbB 56-3332 ugdL
PbB 71.1 ug/dL(dam)
PbB 83.2 ug/dL (fetal)
PbB 14 ugdL
PbB 22 ugdL
PbB 22 ugdL
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Table AX5-4.2 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Males
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Citation
Cory-Slechta
et al. (2004|)
Foote (1999)
Foster et al.
(1993)
Foster et al.
(1996a)
Foster et al.
(1998)
Gandley et al.
(1999)
Gorbelet al.
(2002)
Species/
Strain/Age
Rat/Long-Evans,
adult
Rabbit/Dutch-
belted, adult
Monkey/
Cynomolgus,
adult
Monkey/
Cynomolgus,
adult
Monkey/
Cynomolgus,
adult
Rat/Sprague-
Dawley, adult
Rat/(NOS),
90 days old
Dose/Route/
Form/Duration
Lead acetate in drinking
water beginning 2 months
before breeding until the end
of lactation
0, 0.005, 0.01, and 0.025 mM
PbC12 in vitro; one time dose
0-1500 |lg lead acetate/kg-d
in gelatin capsules p.o. for
various durations: 9 control
monkeys, 4 monkeys in
lifetime group (birth to 9
years), 4 in infancy group
(first 400 days of life), 4 in
post-infancy exposure (from
300 days to 9 years)
0-1500 |lg lead acetate/kg-d
in gelatin capsules p.o. from
birth until 9 years of age: 8
control monkeys, 4 monkeys
in low group (6-20 ug/dL), 7
monkeys in high group (22-
148 ug/dL)
0-1500 |lg lead acetate/kg-d
in gelatin capsules p.o. for
various durations: birth to 10
years (lifetime); PND 300 to
10 years (post-infancy); birth
to 300 days (infancy); 3
control monkeys, 4 lifetime, 4
infancy, 5 post-infancy
Male rats received lead
acetate 25 or 250 ppm in
drinking water for 35 days
prior to mating
3mg(Pl)or6mg(P2)lead
acetate in drinking water for
15, 30, 45, 60, or 90 days
Blood Lead Concentration
Endpoint
Observed potential effects of lead and stress in female; Pb alone (in male) and Pb plus
stress (in females) permanently elevated corticosterene levels in offspring.
Six out of 22 males tested showed appreciable spontaneous hyperactivation, lead did
not affect hyperactivation, or associated capacitation.
Suppressed LH response to GnRH stimulation in the lifetime group (p=0.0370); Sertoli
cell function (reduction in the inhibin to FSH ratio) (p=0.0286) in lifetime and post-
infancy groups.
Mean PbB of 56 ug/dL showed no significant alterations in parameters of semen
quality (count, viability, motility, or morphology).
Circulating concentrations of FSH, LH, and testosterone were not altered by treatment;
semen characteristics (count, motility, morphology) were not affected by treatment
possibly because not all Sertoli cells were injured; degeneration of seminiferous
epithelium in infancy and lifetime groups (no difference in severity between these
groups); ultrastructural alterations in seminal vesicles, most prominent in infancy and
post-infancy groups.
High dose reduced fertility; low dose altered genomic expression in offspring.
Male rats, absolute and relative weights of testis, epididymis, prostate and seminal
vesicles were found to significantly decrease at day 15 in P2 group and at day 45 in PI
group, at day 60 these absolute values and relative weights returned to control values; at
day 15 arrest of cell germ maturation, changes in the Sertoli cells, and presence of
apoptotic cells were observed; serum testosterone level was found to be lowered at day
15 in both PI and P2, and peaked at day 60, then returned to normal values.
(PbB)
PbB 30-40 ug/dL
PbB not applicable-in vitro study
Lifetime group 3-26 ugdL at 4-5
years; infancy group 5-36 u;
jdL
at 100-300 days, 3-3 ugdL at 4-5
years; post-infancy group
20-35 ug/dL
PbB 10±3 or 56±49 ug/dL
PbB -35 ug/dL
PbB 15-23 ug/dL or
27-60 ug/dL
PbB not reported
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Table AX5-4.2 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Males
Citation
Graca et al.
(2004)
Hsu et al.
(1997)
Hsu et al.
(1998a)
Hsu et al.
(1998b)
Huang et al.
(2002)
Johansson
(1989)
Johansson and
Pellicciari
(1998)
Johansson and
Wide (1986)
Species/
Strain/Age
Mouse/CD- 1,2
months old
Rat/Sprague-
Dawley,
7 weeks old
Rat/Sprague-
Dawley,
100-120 g
Rat/Sprague-
Dawley,
7 weeks old
Mouse MA- 10
cells
Mouse, 9 weeks
old
Mouse/NMRI, 9
weeks old
Mouse/NMRI, 9
weeks old
Dose/Route/
Form/Duration
Subcutaneous injection of 74
mg/kg-d of lead chloride for
1 to 3 days
10 mg/kg lead acetate
through i.p. injection to males
for 6 or 9 weeks
20 or 50 mg lead acetate via
i.p. route weekly to males for
6 weeks
10 mg/kg lead acetate weekly
via i.p. injection to males for
6 weeks
10"8 to 10"5 M lead incubated
for 3 hours
0-1 g lead chloride/L in
drinking water for 112 days
1 g/L lead chloride in
drinking water for 16 weeks
0-1 g/L lead chloride in
drinking water for 84 days
Endpoint
Reversible changes in sperm (count) and ultrastructural changes in testes (reduced
diameter of seminiferous tubules).
Six- week group had unchanged epididymal sperm counts, percent of motile sperms, and
motile epididymal sperm counts compared with control group; 9-week group showed
statistically lower epididymal sperm counts, and lower motile epididymal sperm counts;
good correlation between blood lead and sperm lead; significantly higher counts of
chemiluminescence, they were positively associated with sperm lead level; epididymal
sperm counts, motility, and motile epididymal sperm counts were negatively associated
with sperm chemiluminescence; SOPR were positively associated with epididymal
sperm counts, motility and motile epididymal sperm counts, sperm chemiluminescence
was negatively associated with SOPR.
Serum testosterone levels were reduced; percentage of capacitation and the
chemiluminescence were significantly increased in fresh cauda epididymal
spermatozoa; serum testosterone levels were negatively associated with the percentage
of acrosome-reacted spermatozoa; sperm chemiluminescence was positively correlated
with the percentage of both capacitated and acrosome-reacted spermatozoa; SOPR was
negatively associated with the percentage of both capacitated and acrosome-reacted
spermatozoa.
Intake of VE and/or VC in lead exposed rats prevented the lead associated sperm ROS
generation, increased the epididymal sperm motility, enhanced the capacity of sperm to
penetrate eggs harvested from unexposed female rats in vitro; protective effect of VE
and VC not associated with reduced blood or sperm lead levels.
Higher decreases in human chorionic gonadotropin (hCG)-stimulated progesterone
production, expressions of StAR protein, and the activity of 36-HSD compared to 2
hours; no affect on P450scc enzyme activity.
No effects on frequency of motile spermatozoa, nor on swimming speed; decreased
fertilizing capacity of the spermatozoa by in vitro fertilization; premature acrosome
reaction .
Decreased uptake of PI was found in spermatozoa from the vas deferens of the lead-
exposed mice; after thermal denaturation of the DNA, the spermatozoa showed a higher
uptake of PI in comparison to those of the controls; after reductive cleavage of S-S
bonds with DTT and staining with a thiol-specific reagent significantly fewer reactive
disulfide bonds were also observed in the spermatozoa; significant delay in the capacity
for NCD was noted.
No effects on sperm count; no effects on serum testosterone; reduced number of
implantations after mating.
Blood Lead Concentration
(PbB)
PbB not reported
PbB after 6 weeks 32 ug/dL,
after 9 weeks 48±4.3 ug/dL
PbBs >40 ug/dL
PbB30.1±3.4to36.1±4.6
PbBs >40 ug/dL
PbB not applicable-in vitro study
PbB 0.5-40 ugdL
PbB 42±1.6 ug/dL
PbB <0.5-32 ug/dL
Mean tissue lead content
difference between lead treated
and controls: testicular 11 ug/g
(epididymal 67 ug/g)
PbB<0.5 ug/lOOmL
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Table AX5-4.2 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Males
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Citation
Johansson et
al. (1987)
Kempinas et
al. (1998)
Kempinas et
al., 1990
Kempinas et
al. (1994)
Klein et al.
(1994)
Liu et al.
(2001)
Liu et al.
(2003)
Species/
Strain/ Age
Mouse/NMRI,
9-10 weeks old
Rat/Wistar,
adult
Rat/NOS,
pubertal
Rat/Wistar,
50 days old
Rat/Sprague-
Dawley,
100 days old
Mouse, MA-10
cells
Mouse, MA-10
cells
Dose/Route/
Form/Duration
1 g/L lead chloride in
drinking water for 16 weeks
0.5 g/L and 1.0 g/L lead
acetate in drinking water for
90 days
(1.0 g/L) lead acetate in
drinking water in addition to
i.v. injections of lead acetate
(0.1 mg/ 100 gbw) every 10
days, 20 days
(1.0 g/L) lead acetate in
drinking water in addition to
i.v. injections of lead acetate
(O.lmg/100 gbw) every
1 5 days, 9 months
0-1 g/lead acetate/L in
drinking water + 0.1 mg/kg
i.v. every 10 days for 20 days
0-1 g lead acetate/L in
drinking water + 0.1 ugkg i.v.
every 1 5 days for 270 days
0.1, 0.3, or 0.6% lead acetate
in distilled water for 21 days
10"8 to 10"5 lead acetate in
vitro for 2 hours
10"8 to 10"5 lead acetate in
vitro for 6 hours incubated
Endpoint
Spermatozoa had significantly lower ability to fertilize mouse eggs; morphologically
abnormal embryos were found.
PbB exhibited a significant increase in both groups; decrease in hematocrit and
hemoglobin, together with a rise in glucose levels; no signs of lesion were detected
upon histological examination of testes, caput, and cauda epididymidis; an increase in
ductal diameter, and a decrease in epithelial height were observed in the cauda
epididymidis; concentration of spermatozoa stored in the caudal region of the
epididymis exhibited a significant increase in lead-treated animals.
Basal levels of testosterone were higher both in the plasma and in the testes of acutely
intoxicated animals; levels of LH were not affected in either group, nor was the LHRH
content of the median eminence; density of LH/hCG binding sites in testicular
homogenates was reduced by saturnism in both groups, apparent affinity constant of the
hormone-receptor, complex significantly increased.
Increased plasma and testicular testosterone concentrations; no effects on testicular
weight; reduced weight of prostate; increased weight of seminal vesicle and seminal
secretions.
2-3 fold enhancement of mRNA levels of GnRH and the tropic hormone LH; 3-fold
enhancement of intracellular stores of LH; mRNA levels of LH and GnRH and pituitary
levels of stored LH are proportional to blood levels of lead.
Significantly inhibited hCG- and dbcAMP-stimulated progesterone production in MA-
10 cells; steroid production stimulated by hCG or dbcAMP were reduced by lead;
expression of StAR protein and the activities of P450 side-chain cleavage (P450) and
36-HSD enzymes detected; expression of StAR protein stimulated by bdcAMP was
suppressed by lead at about 50%; progesterone productions treated with 22R-
hydroxycholesterol or pregnenolone were reduced 30^10% in lead treated MA-10 cells.
Lead significantly inhibited hCG- and dbcAMP-stimulated progesterone production
from 20 to 35% in MA-10 cells at 6 hours; lead suppressed the expression of
steriodogenesis acute regulatory (StAR) protein from 30 to 55%; activities P450 side-
chain cleavage (P450scc) enzyme and 36-HSD were reduced by lead from 15 to 25%.
Blood Lead Concentration
(PbB)
PbB not reported
PbB 65-103 ug/dL
PbB -40 ug/dL
PbB 10-41 ug/dL
PbB 8.5^10 ug/dL
PbB 42-102 ug/dL
PbB not applicable-in vitro study
PbB not applicable-in vitro study
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Table AX5-4.2 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Males
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Citation
Marchlewicz
et al. (1993)
McGivern et
al. (1991|)
McMurry et
al. (1995)
Mishra and
Acharya(2004)
Species/
Strain/Age
Rat/Wistar,
90 days old
Rat/Sprague-
Dawley, adult
Rat/Cotton,
adult
Mouse/Swiss,
9-10 weeks old
Dose/Route/
Form/Duration
0-1% lead acetate in drinking
water for 270 days
0. 1% lead acetate in drinking
water from GD 14 to
parturition: 8 control litters; 6
lead acetate litters (5 males
per litter)
0, 100, or 1000 ppm lead in
drinking water for 7 or 13
weeks
10 mg/kg lead acetate in
drinking water for 5 to 8
weeks
Endpoint
No histological or weight changes in testicle or epididymis; fever spermatozoa in all
zones of the epididymis.
Decreased sperm count (21% at 70 days and 24% at 165 days; p<0.05); reduced male
behavior (p<0.05); enlarged prostate (25% increase in weight; p<0.07); irregular release
patterns of both FSH and LH (p<0.05).
Immune function was sensitive to lead exposure; spleen mass was reduced in cotton rats
receiving 100 ppm lead; total leukocytes, lymphocytes, neutrophils, eosinophils, total
splenocyte yield, packed cell volume, hemoglobin, and mean corpuscular hemoglobin
were sensitive to lead exposure; reduced mass of liver, seminal vesicles, and epididymis
in males after 7 week exposure.
Stimulates lipid peroxidation in the testicular tissue, associated with increased
generation of noxious ROS; reduced sperm count, increased sperm abnormality
Blood Lead Concentration
(PbB)
PbB not reported
Control PbB <5 ug/dL at birth
Maternal PbB 73 ug/dL at birth
Pup PbB 64 ug/dL at birth
PbB not reported
PbB not reported
Moorman et Rabbit/NOS,
al. (1998) adult
Murthy et al.
(1991)
Murthy et al.
(1995)
Rat/ITRC,
(NOS),
weanling
Rat/Druckrey,
adult
Nathan et al.
(1992)
Pace et al.
(2005)
Rat/Sprague-
Dawley, adult
Mouse/BALB/c,
adult
Piasecka et al. Rat/Wistar,
(1995) adult
3.85 mg/kg lead acetate
subcutaneous injection for 15
weeks
0-250 ppm lead acetate in
drinking water for 70 days
Pb 5 mg/kg i.p. lead acetate
in drinking water for 16 days
0,0.05, 0.1, 0.5, or 1% lead
acetate in drinking water for
70 days
0.1 ppm lead acetate in
drinking water (lactational
exposure as neonates and
drinking water from PND 21
to PND 42)
1% aqueous solution of lead
acetate for 9 months
Increased blood levels associated with adverse changes in the sperm count, ejaculate
volume, percent motile sperm, swimming velocities, and morphology; hormonal
responses were minimal; dose-dependent inhibition of sperm formation; semen quality,
threshold estimates ranged from 16 to 24 ug/dL.
At 20 ug/dL no impairment of spermatogenesis; vacuolization of Sertoli cell cytoplasm
and increase in number and size of lysosomes.
Swelling of nuclei and acrosomes round spermatids; in Sertoli cells, nuclei appeared
fragmented, whereas the cytoplasm exhibited a vacuolated appearance and a few
structures delimitated by a double membrane that contains microtubules arranged in
parallel and cross-striated fin fibrils, cell tight junction remain intact; no significant
change in epididymal sperm motility and counts, testicular blood levels were found to
be elevated after lead exposure.
No effects on spermatogenesis in all groups; at 124 ugdL: decreased seminal vesicle
weight; decreased serum testosterone in the 0.5% group at 10 weeks; no effects in the
other exposure categories; no effects on serum FSH, LH, nor pituitary LH content.
Reduction in fertility when mated with unexposed females; no change in sperm count;
increase in number of apoptotic cells intestes.
Lead-loaded (electron dense) inclusions were found in the cytoplasm of the epididymal
principal cells, especially in the caput of epididymis, also present, but smaller, in
smooth muscle cells; inclusions were located in the vacuoles, rarely without any
surrounding membrane; similar lead-containing structures were found in the epididymal
lumen.
PbB 0, 20, 40, 50, 70, 80, 90, and
110ug/dL
PbB20.34±1.79ug/dL
PbB 7.39 ugdL
PbB 2.3, 40, 44, 80, or 124 ugdL
Neonatal PbB 59.5 ug/dL
Post PND 21 PbB 20.3 ug/dL
PbB not reported
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Table AX5-4.2 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Males
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Citation
Piasek and
Kostial(1987)
Pinon-
Lataillade et
al. (1993)
Pinon-
Lataillade et
al. (1995)
Rodamilans et
al. (1998)
Ronis et al.
(1996T)
Ronis et al.
(1998a)
Species/
Strain/Age
Rat/ Albino,
(NOS), adult
Rat/Sprague-
Dawley, 90 days
old
Mouse/NMRI,
adult
Mouse/BALB/c,
63 days old
Rat/Sprague-
Dawley, adult
Rat/Sprague-
Dawley, adult
Dose/Route/
Form/Duration
1500, 3500, and 5500 ppm of
lead acetate in drinking water
for 18 weeks
0-0.3% lead acetate in
drinking water for 70 days
5 mg/m2 lead oxide in
aerosol for 6 hours/day, 5
days/week, 90 days
0-0.5% lead acetate in
drinking water, day 1 of
gestation until 60 days of age
0-366 mg lead acetate/L in
drinking water for 30, 60, 90,
120, 150, 180 days
0.6% lead acetate in drinking
water for various durations:
PND 24-74 (pubertal
exposure); PND 60-74 (post
pubertal exposure); 1 1 males
and females in pubertal
exposure group (10 each in
control pubertal group); 6
males and females post-
pubertal exposure and control
groups
0.6% lead acetate in drinking
water ad libitum for various
durations as follows: GD 5 to
PND 1; GD 5 to weaning;
PND 1 to weaning; 3 control
litters, 2 gestation exposure
litters, 2 lactation exposure
litters, 2 gestation and
lactation exposure litters, 2
postnatal exposure litters, 2
chronic exposure litters; 4
male and 4 female pups per
litter
Endpoint
No overt signs of general toxicity in adult female rats, only at the end of the exposure
period the mean body weight of males exposed to two higher levels was slightly lower;
no affect of lead exposure on male fertility either after first or after second mating;
values in the pups did not differ from control group.
Decreased weight of seminal vesicles in inhalation study; no effects on spermatogenesis
(epididymal sperm count, spermatozoal motility or morphology) or plasma testosterone,
LH, and FSH; no effects on fertility; decrease in epididymal sperm count of progeny of
sires of the inhalation group, however without effect on their fertility.
No effects on testicular histology, nor on number and morphology of epididymal
spermatozoa; no effects on plasma FSH, LH, and testosterone, nor on testicular
testosterone; decreased weight of testes, epididymis, seminal vesicles, and ventral
prostate; no effects on fertility.
Reduction of intra-testicular testosterone concentrations after 30 days; reduction of
andrenostenedione concentrations after 150 days; no changes in intratesticular
progesterone and hydro xy-progesterone.
PbB>250 ug/dL reduced circulating testosterone levels in male rats 40-50% (p<0.05);
reduction in male secondary sex organ weight (p<0.005); delayed vaginal opening
(p<0.0001); disrupted estrous cycle in females (50% of rats); increased incidence of
stillbirth (2% control vs. 19% Pb) (p<0.005).
Suppression of adult mean serum testosterone levels was only observed in male pups
exposed to lead continuously from GD 5 throughout life (p<0.05).
Blood Lead Concentration
(PbB)
PbB not reported
PbB 58±1.7 ugdL (oral)
PbB 51.1±1.8 ugdL (inhalation)
PbB <4-132 ugdL
PbB 48-67 ugdL
Pubertal PbB 30-60 ug/dL
Post pubertal PbB 30-60 ug/dL
Mean PbBs in male rats 30-
60 ug/dL, respectively
Group: male PbB
Naive: 5.5±2.0 ug/dL
Control: 1.9±0.2 ug/dL
Gest: 9.1±0.7ug/dL
Lact: 3.3±0.4 ug/dL
Gest+Lact: 16.1±2.3 ug/dL
Postnatal: 226.0±29 ug/dL
Chronic: 316.0±53 ug/dL
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Table AX5-4.2 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Males
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Citation
Ronis et al.
(1998b)
Ronis et al.
(1998c|)
Sant'Ana et
al. (2001)
Saxena et al.
(1984)
Saxena et al.
(1986)
Saxena et al.
(1987)
Species/
Strain/ Age
Rat/Sprague-
Dawley, adult
Rat/Sprague-
Dawley, adult
Rat/Wistar,
90 days old
Rat/ITRC,
albino (NOS),
12 weeks old
Rat/ITRC,
albino (NOS),
40-50 g
Rat/Wistar,
40-50 g
Dose/Route/
Form/Duration
Lead acetate in drinking
water (0.05% to 0.45% w/v);
dams exposed until weaning,
exposure of pups which
continued until PND 21, 35,
55, or 85; 5 control litters
(0%), 10 low-dose litters
(0.05%), 8 mid-dose litters
(0.15%), 9 high-dose litters
(0.45%); 4 male and 4 female
pups per litter
Lead acetate 0.05, 0.15, or
0.45% in drinking water
beginning GD 5 continuing
until PND 21, 35, 55, or 85; 5
control litters (0%), 10 low-
dose litters (0.05%), 8 mid-
dose litters (0. 15%), 9 high-
dose litters (0.45%); 4 male
and 4 female pups per litter
0.1 and 1% lead acetate in
drinking water for 7 days
8 mg/kg lead acetate i.p. for
15 days
5, 8, or 12 mg Pb+2/kg lead
acetate i.p. for 15 days
8 mg Pb2/kg-d lead acetate
i.p. for 100 days (from PND
21 to PND 120)
Endpoint
Dose-response reduction in birth weight (p<0.05), more pronounced in male pups;
decreased growth rates in both sexes (p<0.05) were accompanied by a statistically
significant decrease in plasma concentrations of IGF1 through puberty PND 35 and 55
(p<0.05); increase in pituitary growth hormone during puberty (p<0.05).
Dose-responsive decrease in birth weight (p<0.05); dose-responsive decrease in crown-
to-rump length (p<0.05); dose-dependent delay in sexual maturity (p<0.05); decrease in
prostate weight (p<0.05); decrease in plasma concentration of testosterone during
puberty (p<0.05); decrease in plasma LH (p<0.05); elevated pituitary LH content
(p<0.05); decrease in plasma testosterone/LH ratio at high dose (p<0.05).
0.1% Pb caused decrease in testis weight, an increase in seminal vesicle weight and no
changes in plasma testosterone levels, hypothalamic VMA levels were increased
compared to control group.
Histoenzymic and histological alterations in the testes; degeneration of seminiferous
tubules; patchy areas showing marked loss in the activity of succinic dehydrogenase
and adenosine triphosphatase, whereas alkaline phosphatase activity showed only slight
inhibition.
Increasing dose of lead resulted in significant loss of body weight, as well as testicular
weight in groups 3 and 4; cholesterol in the testis of rats markedly decreased at all
given doses of lead and was statistically significant in groups 3 and 4; in phospholipid
contents, the significant decrease was observed only at two highest doses, while at the
lowest dose the decrease was not significant; activity of ATPase remained unaffected at
all three doses of lead; no significant increase in lead content in the testis was noticed at
lower dose levels as compared to control; however, significant increase was found in
groups 3 and 4 which was dose dependent.
Disturbed spermatogenesis; Leydig cell degeneration; altered enzyme activity
(G6PDH).
Blood Lead Concentration
(PbB)
Mean PbB in offspring at 0.05%
(w/v) 49±6 ug/dL
Mean PbB in offspring at 0.15%
(w/v) 126±16 ug/dL
Mean PbB in offspring at 0.45%
(w/v) 263±28 ug/dL
Dams: 0, 48, 88, or 181 ug/dL
Pups PND 1:<1,40, 83, or
120 ug/dL
Pups PND 21: <1, 46, 196, or
236 ug/dL
Pups PND 35: <1, 20, 70, or
278 ug/dL
Pups PND 55: <1, 68, 137, or
379 ug/dL
Pups PND 85: <1, 59, 129, or
214 ug/dL
PbB 36.12±9.49 ug/dL and
13.08±9.42 ug/dL
PbB not reported
PbB not reported
PbB not reported
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Table AX5-4.2 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Males
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Citation
Saxena et al.,
1990
Singh et al.
(1993a)
Sokol(1987)
Sokol (1989)
Sokol, 1990
Sokol and
Berman(1991)
Sokol et al.,
1985|
Sokol et al.
(1994)
Species/
Strain/ Age
ITRC albino,
(NOS), adult
Monkey/
Cynomolgus,
birth
Birth:
300 days:
Rat/Wistar,
52 days old
Rat/Wistar,
27 days old
52 days old
Rat/Wistar,
52 days old
Rat/Wistar,
NOS
Rat/Wistar,
52 days old
Rat/Sprague-
Dawley, 100
days old
Dose/Route/
Form/Duration
8 mg/kg-day lead acetate for
45 days
0-1500 |lg lead acetate/kg-d
in gelatin capsules for various
durations: 3 control monkeys,
4 monkeys in infancy group
(exposure first 400 days), 5 in
post-infancy group (exposure
300 days to 9 years of age), 4
in lifetime group (exposure
from birth until 9 years)
0-0.3% lead acetate in
drinking water for 30 days
0-0.6% lead acetate in
drinking water for 30 days +
30 days recovery
0-0.6% lead acetate in
drinking water for 30 days +
30 days recovery
0-0.6% lead acetate in
drinking water for 7, 14, 30,
60 days
0, 0.1, or 0.3% lead acetate in
drinking water for 30 days
beginning at 42, 52, or 70
days old; 8-11 control rats
for each age, 8-1 1 rats for
each age in 0.1% group, 8-11
rats for each age in 0.3%
group
0. 1 or 0.3% lead acetate in
drinking water for 30 days
0.3% lead acetate in drinking
water for 14, 30, or 60 days
Endpoint
Alterations in SDH, G6PDH activity, cholesterol, and ascorbic acid contents and
reduced sperm counts associated with marked pathological changes in the testis, after
combined treatment with lead and immobilization stress in comparison to either alone.
Degeneration of seminiferous epithelium in all exposed groups (frequency not
specified); ultrastructural alterations in seminal vesicles, most prominent in infancy and
post-infancy groups (frequency not specified).
Hyper-responsiveness to stimulation with both GnRH and LH (10); blunted response to
naloxone stimulation (10).
Suppressed intratesticular sperm counts, sperm production rate, and serum testosterone
in both lead treated groups (10-10); sperm parameters and serum testosterone
normalized at the end of the recovery period in the pre-pubertal animals (27 days at
start) (10) but not in the pubertal animals (52 days at start) (5).
Decreased sperm concentration, sperm production rate and suppressed serum
testosterone concentrations after 14 days of exposure; not dose related (NS).
Dose-related suppression of spermatogenesis (decreased sperm count and sperm
production rate) in the exposed rats of the two highest age groups (p<0.05); dose-
related suppression of serum testosterone in 52-day old rats (p=0.04) and in 70-day old
rats (p<0.003).
Negative correlations between PbB levels and serum and intratesticular testosterone
values; dose-dependent reduction in intratesticular sperm count; FSH values were
suppressed; no change in LH; decrease in ventral prostatic weight; no difference in
testicular or seminal vesicle weights.
Lead exposed fertilized fewer eggs; increased duration of exposure did not result in
more significant percentage of eggs not fertilized; no ultrastructural changes were noted
in the spermatozoa of animals; no difference in histogram patterns of testicular cells.
Blood Lead Concentration
(PbB)
PbB >200 ug/dL
Chronic PbB <40-50 ug/dL
PbB 30±5 ug/dL
<3-43 ugdL (<4-18 ugdL after
recovery period)
Bl <3^t3 ugdL(<4-18 ugdL
after recovery period)
Controls: <8 ugdL at any time
exposed: 42, 60, 58, 75 ugdL
after?, 14, 30, and 60 days,
respectively
0% All <7 ug/dL
42 d 25 ug/dL
0.1% 52 d 35 ug/dL
70 d 37 ug/dL
42 d 36 ug/dL
0.3% 52 d 60 ug/dL
70 d 42 ug/dL
PbB 34±3 ug/dL or PbB
60±4 ug/dL
PbB -40 ug/dL
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Table AX5-4.2 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Males
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Citation
Sokol et al.
(2002)
Thoreux-
Manlay et al.
(1995a)
Thoreux-
Manlay et al.
(1995b)
Wadi and
Ahmad (1999)
Wenda-
Rozewicka et
al. (1996)
Yu et al.
(1996)
Species/
Strain/Age
Rat/Sprague-
Dawley, adult
Rat/Sprague-
Dawley, 97 days
old
Rat/Sprague-
Dawley, adult
Mouse/CF-1,
adult
Rat/Wistar,
adult
Rat/Sprague-
Dawley,
neonates
Dose/Route/
Form/Duration
lead acetate in water for 1
week
0-8 mg lead acetate/kg i.p.
for 5 days/week, 35 days
8 mg/kg-d lead for 5
days/week, 35 days
0.25 and 0.5% lead acetate in
drinking water for 6 weeks
1% aqueous solution of lead
acetate for 9 months
Neonatal and lactational
exposure to 0.3% lead acetate
in drinking water beginning
PND 1 to PND 21
Endpoint
Dose-related increase in gonadotropin-releasing hormone (GnRH) mRNA; no effect on
the serum concentrations of hypothalamic gonadotropin-releasing hormone (GnRH) or
LH.
No effects on spermatogenesis; decreased plasma and testicular testosterone by 80%;
decreased plasma LH by 32%, indications for impaired Leydig cell function, no effects
on fertility.
Germ cells and Sertoli cells were not major target of lead, accessory sex glands were
target; epididymal function was unchanged; plasma and testicular testosterone dropped
about 80%, plasma LH only dropped 32%.
Low dose significantly reduced number of sperm within epididymis; high dose reduced
both the sperm count and percentage of motile sperm and increased the percentage of
abnormal sperm within the epididymis; no significant effect on testis weight, high dose
significantly decreased the epididymis and seminal vesicles weights as well as overall
body weight gain; LH, FSH, and testosterone were not affected.
Electron microscopic studies did not reveal any ultrastructural changes in the
semiferous epithelium or in Sertoli cells; macrophages of testicular interstitial tissue
contained (electron dense) lead-loaded inclusions, usually located inside
phagolisosome-like vacuoles; x-ray micro-analysis revealed that the inclusions
contained lead.
Neonatal exposure to lead decreased cold-water swimming endurance (a standard test
for stress endurance) and delayed onset of puberty in males and female offspring, which
was exacerbated by swimming stress.
Blood Lead Concentration
(PbB)
PbB 12-28 ug/dL
PbB not reported
PbB 1700 ugdL
PbB not reported
PbB not reported
PbB 70 ug/dL
*Not including effects on the nervous or immune systems.
| Candidate key study.
36-HSD, 36-hydroxysteriod dehydrogenase; dbcAMP, dibutyryl cyclic adenosine-3',5'-monophosphate; DTT, dithiothreitol; FSH, follicle stimulating hormone; G6PDH, glucose-6-phosphate
dehydrogenase; GD, gestational day; GnRH, gonadotropin releasing hormone; hCG, human chorionic gonadotropin; IGFi, insulin-like growth factor 1; i.p., intraperitoneal; LDH, lactate
dehydrogenase; LH, luteinizing hormone; LHRH, luteinizing hormone releasing hormone; LPP, lipid peroxidation potential; NCD, nuclear chromatin decondensation rate; NOS, not otherwise
specified; PbB, blood lead concentration; PND, post-natal day; p.o., per os (oral administration); ROS, reactive oxygen species; SDH, succinic acid dehydrogenase; SOPR, sperm-oocyte penetration
rate; StAR, steroidogenic acute regulatory protein; VC, vitamin C; VE, vitamin E; VMA, vanilmandelic acid
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Table AX5-4.3. Effect of Lead on Reproduction and Development in Mammals* Effects on Females
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Citation
Burright et al.
(1989)
Coffigny et al.
(1994|)
Corpas et al.
(2002a)
Cory-Slechta
et al. (2004|)
Dearth et al.
(2002|)
Dearth et al.
(2004)
Species/
Strain/Age
Mouse/HET,
neonates
Rat/Sprague-
Dawley, adult
Rat/Wistar,
adult
Rat/Long-Evans,
adult
Rat/Fisher 344,
150-175 g
Rat/Sprague-
Dawley and
Fisher-344,
adult
Dose/Route/
Form/Duration
0.5% lead acetate solution via
milk, or drinking water
chronic beginning PND 1
Inhalation exposure to 5
mg/m3 lead oxide daily for
13 days during gestation (GD
2, 3, 6-10, 13-17, 20)
300 mg/L acetate lead in
drinking water from mating
until PND 12 or PND 21
Lead acetate in drinking
water beginning 2 months
before breeding through
weaning
12 mg/mL lead acetate
gavage from 30 days prior
breeding until pups were
weaned 21 day after birth;
10-32 litters per group,
control group, gestation and
lactation exposure, gestation
only exposure, lactation only
exposure
12 mg/mL lead acetate by
gavage 30 days prior to
breeding through PND 21
(gestation and lactation
exposure)
Endpoint
Plasma prolactin levels implied that lead exposure alone decreased circulating prolactin
in primiparous; low prolactin levels in non-behaviorally tested females suggests that
dietary lead alone may alter plasma-hormone in these lactating HEX dams; pattern of
plasma prolactin appear to be inconsistent with the observation that lead exposure
decreases dopamine; prolactin levels of lead exposed dams were very low.
No effects on the incidence of pregnancy, prenatal death, or malformations when male
and female rats from mothers who had been exposed.
Neither abnormalities in the liver structure nor depositions of lead, toxicant produced
biochemical alterations; pups exhibited decrease in hemoglobin, iron and alkaline, and
acid phosphatase levels and an increase in Pb content; protein, DNA, and lipid total
amounts were reduced, and hepatic glycogen content was diminished at 12 and 21 PN,
with a higher dose of glucose in blood; decrease in alkaline phosphatase in liver of pups
at day 2 1 PN, but acid phosphatase was unaltered.
Observed potential effects of lead and stress in female; Pb alone (in male) and Pb plus
stress (in females) permanently elevated corticosterene levels in offspring.
Delay in onset of puberty (p<0.05); reduced serum levels of IGF1 (p<0.001), LH
(p<0.001), and E2 (p<0.001).
Lead delayed the timing of puberty in PbB 37.3 ug/dL lead group and suppressed
serum levels of LH and E2, these effects did not occur in PbB 29.9 ug/dL lead group,
when doubling dose to 29.9 ug/dL group the PbB levels rose to 62.6 ug/dL, yet no
effect was noted; results indicate that offspring are more sensitive to maternal lead
exposure with regard to puberty related insults than are 29.9 ug/dL rats.
Blood Lead Concentration
(PbB)
PbB -100 ug/dL
PbB 7 1.1 ug/dL (dam)
PbB 83.2 ug/dL (fetal)
PbB 22 ugdL
PbB 30-40 ug/dL
Maternal PbB -40 ug/dL
Pups PbB as follows:
Gest+lact: -38 ug/dL PND 10
Gest+lact: -15 ug/dL PND 21
Gest+lact: -3 ug/dL PND 30
Gest: -14 ug/dL PND 10
Gest: -3 ug/dL PND 21
Gest: -1 ug/dL PND 30
Lact: -28 ug/dL PND 10
Lact:~15 ug/dLPND21
Lact: -3 ug/dL PND 30
PbB 29.9 ug/dL (Sprague-
Dawley)
PbB 37.3 ug/dL (Fisher)
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Table AX5-4.3 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Females
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Species/
Citation Strain/Age
Foster (1992) Monkey/
Cynomolgus,
0-10 years old
Foster et al. Monkey/
(1992) Cynomolgus, 10
years old
Foster et al. Monkey/
(1996b) Cynomolgus,
15-20 years old
Franks et al. Monkey/Rhesus,
(1989) adult
Fuentes et al. Mouse/Swiss,
(1996) adult
Gorbelet al. Rat/NOS,
(2002) 3 months old
Dose/Route/
Form/Duration
Daily dosing for up to 10
years with gelatin capsules
containing lead acetate (1.5
mg/kg); 8 control group
monkeys, 8 lifetime exposure
(birth-10 years), 8 childhood
exposure (birth-400 days),
and 8 adolescent exposure
(postnatal day 300-10 years
of age)
Daily dosing for up to 10
years with gelatin capsules
containing lead acetate (1.5
mg/kg); 8 control group
monkeys, 8 childhood (birth-
400 days), 7 adolescent
(postnatal day 300-10 years),
7 lifetime (birth-10 years)
Chronic exposure to lead
acetate 50 to 2000 ug/kg-d
p.o. beginning at birth for 15-
20 years; 20 control
monkeys, 4 monkeys in 50
ug/kg-d group, 3 monkeys in
100 ug/kg-d, 2 monkeys in
500 ug/kg-d group, and 3
monkeys in 2000 ug/kg-d
group
Lead acetate in drinking
water (2-8 mg/kg-d) for 33
months; 7 control and 10 lead
monkeys
14, 28, 56, and 112 mg/kg
lead acetate via i.p; one time
exposure on GD 9
3 mg (PI) or 6 mg (P2) lead
acetate in drinking water for
15, 30, 45, 60, or 90 days
Endpoint
Statistically significant reductions in circulating levels of LH (p<0.042), FSH
(p<0.041), and E2 (p<0.0001) during menstrual cycle; progesterone concentrations
were unchanged and menstrual cycle was not significantly affected.
No effect on endometrial response to gonadal steroids as determined by ultrasound.
Reduced corpora luteal production of progesterone (p=0.04), without alterations in E2,
20alpha-hydroxyprogesterone, or menstrual cyclicity.
Reduced circulating concentration of progesterone (p<0.05); treatment with lead did not
prevent ovulation, but produced longer and more variable menstrual cycles and shorter
menstrual flow.
Absolute placental weight at 1 12 mg/kg and relative placental weight at 14, 56, and 112
mg/kg were diminished significantly; most sections of placenta showed vascular
congestion, and increase of intracellular spaces, and deposits of hyaline material of
perivascular predominance; trophoblast hyperplasia was also observed, whereas there
was a reinforcement of the fibrovascular network in the labyrinth
Female rats absolute and relative weights of ovary and uterus were unchanged, vaginal
smears practiced in females revealed the estrus phase; fertility was found to be reduced;
lead level in blood was poorly correlated with the level of poisoning.
Blood Lead Concentration
(PbB)
PbB <40 ug/dL
PbB <40 ug/dL
PbB 10-15 ug/dL in low group
(50 or 100 ug/kg-d)
PbB 25-30 ug/dL in moderate
group (500 or 2000 ug/kg-d)
PbB 68.9±6.54 ug/dL
PbB not reported
PbB not reported
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Table AX5-4.3 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Females
Citation
lavicoli et al.
(2004)
Junaid et al.
(1997)
Laughlin et al.
(1987)
Logdberg et
al. (1987)
Logdberg et
al. (1998)
McGivern et
al. (1991|)
Nilsson et al.
(1991)
Piasek and
Kostial(1991)
Pinon-
Lataillade et
al. (1995)
Species/
Strain/Age
Mouse/Swiss,
33-37 days old
Mouse/Swiss,
adult
Monkey/Rhesus,
adult
Monkey/
Squirrel, adult
Monkey/
Squirrel, adult
Rat/Sprague-
Dawley, adult
Mouse/NMRI,
adult
Rat/Wistar,
10 weeks old
Mouse/NMRI,
adult
Dose/Route/
Form/Duration
0.02,0.06,0.11,0.20,2.00,
4.00, 20.00, 40.00 ppm in
food lead acetate
concentration beginning GD
1 to 3 months after birth
0, 2, 4, or 8 mg/kg-d lead
acetate, subchronic exposure,
5 days/week, 60 days
Lead acetate in drinking
water at 3. 6, 5.9, or 8.1
mg/kg-d for 1-2 years; 7
control and 10 experimental
monkeys per group
Lead acetate in drinking
water from 9th week of
gestation to PND 1; per oral
exposure similar to Laughlin
et al. (1987)
Lead acetate maternal dosing
from 5-8.5 weeks pregnant to
PND1
1 1 control monkeys, 3 low-
lead exposure group (PbB
24 ug/dL), 7 medium lead
group (PbB 40 ug/dL, 5 high-
lead group (PbB 56 ug/dL)
0. 1% lead acetate in drinking
water from GD 14 to
parturition
75 ug/g bw lead chloride via
i.v.; one time injection on
gestation day 4
7500 ppm lead acetate in
drinking water for 9 weeks
0-0.5% lead acetate in
drinking water exposed to
lead during gestation until
post-GD 60
Endpoint
Increase in food consumption; however, did low-dose group increase food consumption
because of sweet nature of lead? body weight may contribute to delay in onset of
puberty and confound results.
Altered follicular development.
Reductions in cycle frequency (p<0.01); fewer days of flow (p<0.01); longer and more
variable cycle intervals (p<0.025).
Increase in pre- and perinatal mortality during the last two-thirds of pregnancy;
statistically significant reduction in mean birth weight was observed in lead exposed
monkeys as compared to controls.
Dose-dependent reduction in placental weight (p<0.0007); various pathological lesions
were seen in the placentas, including hemorrhages, hyalinization of the parenchyma
with destruction of the villi, and massive vacuolization of chorion epithelium.
Female rats showed delay in vaginal opening; 50% exhibited prolonged and irregular
periods of diestrous and lack observable corpora lutea; both sexes showed irregular
release patterns of both FSH and LH.
Electron microscopy showed that the uterine lumen, which was closed in control mice,
was opened in lead-injected mice; suggested that lead caused increase in uterine
secretion; study suggested lead could have a direct effect on the function of the uterine
epithelium and that lead was secreted into the uterine lumen and affect the blastocysts.
Decrease in litter size, pup survival, and birth weight; food consumption, body weight,
and fertility were not altered in 20 week exposure period.
Exhibited reduced fertility as evidenced by smaller litters and fewer implantation sites.
Blood Lead Concentration
(PbB)
PbB 0.69, 1.32, 1.58, 1.94,3.46,
3.80, 8.35, 13.20 ug/dL
PbB 22.3-56.5 ug/dL
PbB 44-89 ug/dL
51.2 ug/dL (low dose)
80.7 ug/dL (mid dose)
88.4 ug/dL (high dose)
Mean maternal PbB 54 ug/dL
(39-82 ug/dL)
PbB 37 ugdL (22-82 ugdL)
24 (22-26) ug/dL (low dose)
40 (35^16) ug/dL (mid dose)
56 (43-82) ug/dL (high dose)
PbB 73 ug/dL
PbB not reported
Maternal PbB >300 ug/dL
Offspring PbB >220 ug/dL
PbB 70 ug/dL
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Decembe
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Table AX5-4.3
Citation
Priya et al.
(2004)
Ronis et al.
(1996)
Ronis et al.
(1998a|)
Ronis et al.
(1998b)
Ronis et al.
(1998c)
Sierra and
Tiffany-
Castiglioni
(1992)
Srivastava et
al. (2004)
Species/
Strain/Age
Rat/Charles
Foster,
6-9 months old
Rat/Sprague-
Dawley, various
ages
Rat/Sprague-
Dawley, adult
Rat/Sprague-
Dawley, adult
Rat/Sprague-
Dawley, adult
Guinea
pig/NOS, adult
Rat/Fisher 344,
adult
(cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Females
Dose/Route/
Form/Duration
0.03 uM lead in vitro for 1
hour
lead acetate in the drinking
water or male and female rats
for the following durations:
PND 24-74 (pubertal
exposure); PND 60-74
(post pubertal exposure)
0.6% lead acetate in drinking
water; ad libitum for various
durations as follows: GD 5 to
PND 1, GD 5 to weaning,
PND 1 to weaning
Ad libitum intake of lead
acetate (0.05 to 0.45% w/v);
lead exposure of dams until
weaning, exposure of pups
until day 21, 35, 55, 85
0.05, 0.15, or 0.45% lead
acetate in drinking water
beginning GD 5 for 21, 35,
55, 85 days
0, 5.5, or 1 1 mg/kg lead
acetate, oral dose from GD 22
until GD 52 or 62
12 mg/mL lead acetate by
gavage for 30 days prior to
breeding until weaning
Endpoint
LH binding was dropped to 84% in Pb treated cells; lead exposed cells showed 31%
reduction in the enzymes 176-HSDH and 176-HS; lead can cause a reduction in LH and
FSH binding, which significantly alters steroid production in vitro and exerts a direct
influence on granulose cell function.
Data suggest that both the temporary and the long-lasting effects of lead on
reproductive endpoints in male and female experimental animals are mediated by the
effects of lead on multiple points along the hypothalamic-pituitary-gonad axis;
exposure of male and female Sprague-Dawley rats pre-pubertally (age 24—74 days) to
lead acetate in the drinking water resulted in significant reduction in testis weight and in
the weight of secondary sex organs in males; these effects were not observed in rats
exposed post-pubertally (day 60-74); there is convincing evidence that pre-pubertal
female rats exposed in utero and during lactation have reduced levels of circulating E2
andLH.
Female pups exposed to lead from birth through adulthood or from GD 5 through
adulthood were observed to have significantly delayed vaginal opening and disrupted
estrus cycling; these effects on female reproductive physiology were not observed in
animals where lead exposure was confined only to pregnancy or lactation.
Prenatal lead exposure that continues until adulthood (85 days old) delays sexual
maturation in female pups in a dose-related manner; dose-dependent delay in sexual
maturation (delayed vaginal opening) among female rats following prenatal lead
exposure that continued until adulthood (85 days old); a growth hormone-mediated
effect on growth that differs depends upon the developmental state of the animal, birth
weight was significantly reduced and more pronounced among male pups; decreased
growth rates in both sexes were accompanied by a statistically significant decrease in
plasma concentrations of IGF 1 through puberty and a significant increase in pituitary
growth hormone during puberty; growth suppression of male and female rats involves
disruption of growth hormone secretion during puberty.
Dose-responsive decrease in birth weight and crown-to-rump length was observed in
litters; dose-dependent delay in sexual maturity (delay in vaginal opening); decrease in
neonatal sex steroid levels and suppression of E2 during puberty; elevation in pituitary
LH content was observed during early puberty; E2 cycle was significantly disrupted at
the highest lead dose; data suggests that the reproductive axis is particularly sensitive to
lead during specific developmental periods, resulting in delayed sexual maturation
produced by sex steroid biosynthesis.
Hypothalamic levels of SRIF; lower serum concentrations of progesterone at higher
dose only; hypothalamic levels of GnRH and SRIF were reduced in a dose-dependent
manner by lead treatment in both dams and fetuses; reduction of SRIF levels in 52-day
old fetus was particularly severe (92%) in the 1 1 mg group.
Lead decreased StAR protein expression and lowered E2 levels; suggested that the
primary action of Pb to suppress E2 is through its known action to suppress the serum
levels of LH and not due to decreased responsiveness of StAR synthesizing machinery.
Blood Lead Concentration
(PbB)
PbB not applicable-in vitro study
Materal PbB 30-60 ug/dL
Offspring PbB >200 ug/dL.
Pups continuously exposed to
lead 225 to 325 ug/dL
Mean PbB in offspring at 0.05%
(w/v) 49±6 ug/dL
Mean PbB in offspring at 0. 15%
(w/v) 126±16 ug/dL
Mean PbB in offspring at 0.45%
(w/v) 263±28 ug/dL
PbB in dams 181±14 ug/dL
PbB in pups ranged from 197±82
to 263±38 ug/dL, increasing with
age of pups
PbB not reported
PbB of dams 39±3.5 SEM ug/dL
and offspring PbB 2.9±0.28 SEM
Ug/dL
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Table AX5-4.3 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Females
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Citation
Taupeau et al.
(2001)
Tchernitchin
et al. (1998a)
Tchernitchin
et al. (1998b)
Wide, 1985
Wide and
D'Argy (1986)
Wiebe and
Barr(1998)
Wiebe et al.
(1998)
Species/
Strain/Age
Mouse/C57blxC
BA, 8 weeks old
Rat/Sprague-
Dawley, 14 days
old
Rat/Sprague-
Dawley, 20 or
21 days old
Mouse/NMRI,
10 weeks old
Mouse/NMRI,
adult
Rat/Sprague-
Dawley, adult
Rat/Sprague-
Dawley, adult
Dose/Route/
Form/Duration
10 mg/kg-d lead nitrate via
i.v
for 15 days
172 ug/g bw lead from day
14 every 2nd day until day 20
(75 mg/g bw) lead via i.v.
one time exposure at 1 or 24
before hormone stimulation
20 ug/dL/g bw lead chloride
via i.v. single exposure on
days 8, 12, or 16 after mating
20 ug/g bw by i.v. single
injection on GD 8
20 or 200 ppm lead chloride
in drinking water; 3 exposure
durations; prior to mating
through weaning, GD 7 to
weaning, PND 21 to PND 35
20 or 200 ppm lead chloride
in drinking water; 4 exposure
durations; prior to mating
through weaning, GD 7 to
weaning, PND 21 to PND 35,
prior to mating only
Endpoint
Low lead concentration in the ovary caused dysfunction of folliculogenesis, with fewer
primordial follicles and an increase in atretic antral follicles.
Lead inhibits estrogen- induced uterine eosinophilia at 6 and 24 hours after treatment;
lead also inhibits estrogen-induced edema in deep and superficial endometrial stoma at
24 hours but not 6 hours after treatment; myometrial hypertrophy is inhibited under the
effect of exposure at 24 hours of treatment.
Enhanced some parameters of estrogen stimulation and inhibited other estrogenic
responses; interaction with responses to estrogen was different depending on whether
lead pretreatment was 1 or 24 hours before hormone stimulation; estrogenic responses
mostly affected were uterine eosinophilia, endometrial edema, uterine liminal epithelial,
hypertrophy, and mitosis in various, but not all, uterine cell types, in some cell types,
estrogen-induced mitotic response developed earlier under the effect of lead exposure.
Litter size and fetal survival varied significantly; small litters and increased numbers of
fetal deaths were observed in mice exposed to lead on day 8 of intrauterine life; live
fetuses were normal with respect to weight and morphological appearance; ovarian
follicle counts revealed a significantly smaller number of primordial follicles in the
latter group, it suggested that the exposure to lead at a time of early organogenesis
caused the observed fertility decrease by interfering with the development of the female
germ cells.
Primordial germ cells showed a normal body distribution but were significantly fewer
at all four stages compared with those of control embryos of corresponding age; lead
had interfered with the production or activity of alkaline phosphatase.
Treatment with lead prior to mating resulted in significant increase in E2-receptor
affinity in 21-day old offspring without a change in E2 receptor number; treatment from
day 7 of pregnancy until weaning of the pups resulted in approximately 35% decrease
in E2 receptors per mg uterine protein when these offspring reached 150 days of age;
lead treatment from 21-35 days old or until 150 days resulted in a significant decrease
in uterine E2 receptor number at 35 and 150 day, respectively.
Exposure to lead did not affect tissue weights but did cause a significant decrease in
gonadotropin-receptor binding in the pre-pubertal, pubertal, and adult females;
conversion of progesterone to androstenedione and dihydrotestosterone was
significantly decreased in 21-day old rats and in 150-day old females; significantly
increased conversion to the 5-alpha-reduced steroids, normally high during puberty.
Blood Lead Concentration
(PbB)
PbB not reported
PbB 47 ug/dL
PbB not reported
PbB not reported
PbB not reported
PbB likely 4.0±1.4 to 6.6±2.3
ug/dL (similar design as Wiebe
et al. (1988))
PbB range 4. Oil. 4 to
6.6±2.3 ug/dL
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Table AX5-4.3 (cont'd). Effect of Lead on Reproduction and Development in Mammals* Effects on Females
Citation
Yu et al.
(1996)
Species/
Strain/Age
Rat/Sprague-
Dawley, adult
Dose/Route/
Form/Duration
Neonatal and lactational
exposure to 0.3% lead acetate
in drinking water (PND 30)
Endpoint
Neonatal exposure to lead decreased cold-water swimming endurance (a standard test
for stress endurance); delayed onset of puberty in males and female offspring, which
was exacerbated by swimming stress.
Blood Lead Concentration
(PbB)
PbB 70 ug/dL
*Not including effects on the nervous or immune systems.
•(•Candidate key study.
E2, estradiol; FSH, follicle stimulating hormone; GD, gestational day; GnRH, gonadotropin releasing hormone; HEX, Binghamton Heterogeneous Stock; IGFi, insulin-like growth factor 1; i.p.,
intraperitoneal; LH, luteinizing hormone; NOS, not otherwise specified; PbB, blood lead concentration; PND, post-natal day; p.o., per os (oral administration); SRIF, somatostatin; StAR,
steroidogenic acute regulatory protein
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CHAPTER 5 ANNEX
ANNEX TABLES AX5-5
December 2005 AX5-49 DRAFT-DO NOT QUOTE OR CITE
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Table AX5-5.1. In Vivo and In Vitro Studies of the Effects of Lead Exposure on Production and Metabolism of Reactive
Oxygen Species (ROS), Nitric Oxide (NO), and Soluble Guanylate Cyclease (sCG).
>
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Species/ Age/
Reference Tissue Weight n
Khalil- Male SD 200 g N/A
Manesh et al. rats
(1994)
Gonick et al. Male SD 2 months 6
(1997) rats 200 g
Ding et al. Male SD 2 months N/A
(1998) rats
Vaziri (1997) Male SD 190 g 12
rats
Dursun Male SD 24
(2005) rats
Pb Exposure
Dosage Duration
Pb-acetate, 6 months
100 ppm in
water
Pb-acetate, 3 months
100 ppm in
water
Pb-acetate, 3 months
100 ppm in
water
Pb-acetate, 3 months
100 ppm in
water
Pb acetate 2 weeks
8 mg/kg IP
Measured Parameters
Pb Level CVS Other
7 ± 3.6 ug/d BP, tail art. ET-3, cGMP
ring response
toNE
12.4 ± 1.8 ug/dL BP cGMP, NO2 +
NO3, ET-1,
ET-3, MDA,
eNOS, iNOS
3.2 ± 0.2 ug/dL BP urine NO2 +
NO3- plasma
MDA
17±9|ig/dL BP plasma MDA
urine NO2 +
N03
BP, RBF UrNa, Ur
NO2 + NO3,
24 hr UrNa
(Na+ intake
Not given )
Interventions Results
DMSA Rx Pb caused HTN, |ET3,
|U cGMP (NS) (no
effect on NE reactivity).
DMSA Rx lowered BP
and Vase response to NE
& raised cGMP
— HTN, |MDA, feNOS,
fiNOS (protein and
activity in kidney)
DMSA (0. 5% H2O) Pb caused HTN, |urine
x 2 wks, IV NO2+NO3, tplasma
infusions of L. MDA. DMSA lowered
Arg., SOD & SNP BP, blood lead & MDA
+ raised urine NO2 +
NO3. L-Arg lowered BP
and MDA, raised
NO2+NO3, SNP lowered
BP
Antioxidant Rx Pb caused HTN, fMDA,
(Lazaroid) jurine NO2+NO3 in
untreated animals.
Antioxidant Rx improved
HTN, urine NO2+NO3
and lowered MDA
without changes in blood
Pb level
|BP, |RBF, |UrN02 +
NO3, unchanged UrNa+
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Table AX5-5.1 (cont'd). In Vivo and In Vitro Studies of the Effects of Lead Exposure on Production and Metabolism of
Reactive Oxygen Species (ROS), Nitric Oxide (NO), and Soluble Guanylate Cyclease (sCG).
>
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Species/
Reference Tissue
Vaziri et al. Male SD rats
(1999)
Vaziri et al. Male SD rats
(2001)
Vaziri and Human
Ding (2001) coronary
endothelial
cells
Pb Exposure Measured Parameters
Age/
Weight n Dosage Duration Pb Level CVS Other
200 g 6 per group Pb-acetate, 3 months 8.2±.8&10.8± BP Aorta & kidney
per time point lOOppmin lug per g. eNOS protein
water Kidney tissue in abundance, Ur
untreated & NO2 + NO
antiox-treated
groups
200 g 6 per group Pb acetate 3 months N/A BP Aorta, heart,
kidney & brain
NOS isoforms,
urine NO2 +
N03
N/A >4 per 0 and 1 ppm 24 hrs w/ Pb 1 ppm medium N/A eNOS
experiment lead acetate or Na acetate expression
followed by
24 hrs w/
tempol or
vehicle
Interventions
Subgroups
treated with high-
dose vitamin E
Subgroups
studied after 2
wks of Rx
w/tempol and
those studied 2
wks after
cessation of
tempol Rx
Co-treatment
w/O2' scavenger,
tempol
Results
Pb exposure resulted in a
time-dependent rise in
BP, aorta & kidney
eNOS&iNOS. This
was associated w/ a
paradoxical fall in NO
availability (Ur NO2 ±
NO3). Antioxidant Rx
attenuated upregulation
ofiNOS&eNOS&
raised NO availability.
Pb exposure resulted in
rises in BP, eNOS, iNOS
& nNOS in the tested
tissues + jurine NOX.
Tempol administration
attenuated HTN, reduced
NOS expressions &
increased urine NOX.
The effects of tempol
disappeared within 2
weeks of its
discontinuation.
Pb exposure for 48 hours
upregulated eNOS
expression. Co-treatment
w/ tempol resulted in
dose-dependent reversal
of Pb-induced
upregulation of eNOS
but had no effect on
control cells.
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Table AX5-5.1 (cont'd). In Vivo and In Vitro Studies of the Effects of Lead Exposure on Production and Metabolism of
Reactive Oxygen Species (ROS), Nitric Oxide (NO), and Soluble Guanylate Cyclease (sCG).
>
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Species/ Age/
Reference Tissue Weight n
Vaziri et al. Male SD rats 200 g 6 per group
(1999)
Vaziri et al. Male SD rats 200 g 6 per group
(2003)
Niet al. Cultured N/A >4per
(2004) human experiment
coronary
endothelial &
VSM cells.
Pb Exposure Measured Parameters
Dosage Duration Pb Level CVS Other Interventions
lOOppmin 3 months 8.3 - 10.8 ug/g BP Urine NO2 + Antioxidant Rx
water kidney tissue NO3, tissue and (Vit E)
plasma
nitrotyrosine
(marker of NO-
ROS
interaction).
100 ppm in 3 months N/A BP Urine NO2 + Tempol (O2'
water NO3, kidney, scavenger
heart, brain infusion)
SOD, catalase,
GPX, NAD(P)H
oxidase
abundance
0,l&10ppm short 0,1, 10 ppm N/A O2' and H2O2 None
Pb acetate exposure productions
(5-30 min) & SOD, catalase,
long exposure GPX &
(60 hours) NAD(P)H
oxidase
(gp91phox)
Results
Pb exposure raised BP,
reduced Ur NO2 + NO3
& increased nitrotyrosine
abundance in plasma,
heart, kidney, brain &
liver. Anti ox Rx
ameliorated HTN,
lowered nitrotyrosine &
raised Ur NO2 + NO3.
Pb caused HTN,
|NAD(P)H oxidase
(gp91phox), fSOD, un-
changed catalase and
GPX, |UrNO2 + NO3.
Tempol resulted in J.BP
+ furine NO2 + NO3 in
lead-exposed but not
control rats.
Short-term incubation
with Pb at 1 & 10 ppm
raised O2'& H2O2
productions by both
endothelial & VSM cells,
long-term incubation
resulted in further rise in
H2O2 generation &
normalization of
detectable O2y'. This was
associated with increases
in NAD(P)H oxidase &
SOD & reduced or
unchanged catalase &
GPX.
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Table AX5-5.1 (cont'd). In Vivo and In Vitro Studies of the Effects of Lead Exposure on Production and Metabolism of
Reactive Oxygen Species (ROS), Nitric Oxide (NO), and Soluble Guanylate Cyclease (sCG).
>
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Species/
Reference Tissue
Ding et al. Male SD rats
(2001)
Ding et al. Cultured rat
(2000) aorta
endothelial
cells
Attri (2003) Male Wistar
Kyoto rats
Malvezzi Male Wistar
(2001) rats
Pb Exposure
Age/
Weight n Dosage Duration Pb Level
2 months N/A 100 ppm 3 months Blood lead 12.4
200 g ±1.8ug/dLvs.
1 mg/dL in
controls
N/A >4 0-1 ppm 1,2,24,84 0- 1 ppm culture
experiment hours media
150-200 g 10 per group Pb acetate, 1-3 months Blood Pb
100 ppm in 1.5 mg/dL all
water ± Vit C mo
20 mg/day/rat
& y 2. 4 mg/dL at 2
mos
4. 1 mg/dL at 3
mos
5-6 wks 4- 10 per group Pb acetate 100 days Blood, bone,
(170 g) 750 ppm in kidney, aorta,
water liver
Measured Parameters
CVS Other Interventions
BP Response to IV infusion of
DMTU DMTU
administration,
tissue
nitrotyrosine,
hydro xyl radical
N/A Hydroxyl radical None
production using
the following
reaction (Na
Salicylate + . OH
— > 2,3dihydroxy
benzoic acid),
MDA
BP Total antioxidant Response to
capacity, ferric- vitamin C.
reducing
antioxidant
power, NO
metabolites,
MDA,
8-hydroxy guano
sine
BP — Response to L.
arg, DMSA, L.
arg .+ DMSA
(given together
w/Pb in last 30
days
Results
Pb caused HTN, fplasma
nitrotyrosine,
tplasma.OH
concentration all reversed
with .OH-scavenger,
DMTU infusion
Pb exposure resulted in
cone-dependent rise in
MDA and . OH
production by cultured
endothelial cells.
Pb caused |BP, |MDA,
|DNA damage/
oxidation, |NOX,
jantioxidant. and ferric-
reducing antioxidant.
Concomitant Rx with Vit-
C ameliorated all
abnormalities.
|BP w/lead, partial |BP
w/L. Arg or DMSA,
greater reduction w/both,
blood and aorta PB
remained | in all but
DMSA + L. Arg group.
Significant Pb
mobilization shown in
other organs.
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Table AX5-5.1 (cont'd). In Vivo and In Vitro Studies of the Effects of Lead Exposure on Production and Metabolism of
Reactive Oxygen Species (ROS), Nitric Oxide (NO), and Soluble Guanylate Cyclease (sCG).
>
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Species/ Age/
Reference Tissue Weight n
Khalil- Male SD 8 wks N/A
Manesh et al. rats
(1993)
Marques et Male 3 months 20
al. (2001) Wistarrats
Farmland et Male SD 200 g 8
al. (2005) rats
Courtois et Rat N/A 6/experiment
al. (2003) thoracic
aorta
Pb Exposure
Dosage Duration
Pb acetate 100 or 1-12 months
5000 ppm in
water
Pb acetate 5 ppm 30 day
± Vit C (3
mmol/L) in
water
Pb acetate 100 3 months
ppm in water
0-1 ppm 24 hr
Measured Parameters
Pb Level CVS Other Interventions
29 ± 4 ug/dL BP, vascular cGMP, ET-3, ANP —
contractility to
NE in vitro
N/A BP, arch-, SNP- sGC protein mRNA CoRx with Vit C
vasorelaxation & activity. cGMP
response in aorta production, eNOS
rings protein
N/A BP Aorta sGC, SOD, —
catalase,
glutathione
peroxidase
0-1 ppm cGMP sGC expression, Vit C, COS-2
production superoxide inhibitor
production, COX-2
Results
Pb caused HTN,
jserum and urine
cGMP, tserum ET-3
without changing ANP
or response to NE
Pb caused HTN,
^relaxation to Ach &
SNP, feNOS, |sGC
protein mRNA and
activity. These
abnormalities were
prevented by
antioxidant Rx.
|sGC, fCuZn SOD
activity, unchanged
catalase & GPX
activities.
Pb caused |sGC,
|cGMP, tO2, fCOX-2.
All abnormalities
improved by Vit C.
COX-2 inhibitor
improved sGC
expression but not O2
production.
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Table AX5-5.2. Studies of the Effects of Lead Exposure on PKC Activity, NFkB Activation, and Apoptosis
>
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Species/ Age/
Reference Tissue Weight n
Watts et al. Isolated rabbit N/A 5-6 sets per
(1995) mesenteric experiment
artery
Rodriquez- Male SD rats 200 g 8 Pb group
Iturbe et al. 9 controls
(2005)
Pb Exposure Measured Parameters
Dosage Duration Pb Level CVS Other Interventions Results
Pb acetate 10" immediate 5"10 -10"3M vascular Preincubation Pb acetate induced
10-10"3M (contraction) medium contraction w/PKC contraction which was
activators, PKC potentiated by PKC
inhibitor or activators &
verapamil for 30- attenuated by PKC
60 minutes + inhibitor (role of
endothelium PKC). CCB
denudation attenuated Pb-induced
contraction
(contribution of Ca2+
entry). Removal of
endothelium did not
affect lead-induced
vasoconstriction.
Pb acetate 3 months N/A NFkB activation, Pb-exposed animals
100 ppm in apoptosis, Ang II showed
drinking positive cells, tubuloniterstitial
water macrophage/T cell accumulation of
infiltration & activated T-cells,
nitrotyrosine staining macrophages & Ang II
in renal tissue positive cells, NFkB
activation increased
apoptosis and
nitrotyrosine staining
in the kidney.
-------
o
O
to
O
O
Table AX5-5.3. Studies of the Effects of Lead Exposure on Blood Pressure and Adrenergic System
>
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Pb Exposure Measured Parameters
Species/ Age/
Reference Tissue Weight n
Chang et al. Wistarrats 190-200 g 20
(1997)
Tsaoetal. Wistarrats 190-200 g 70
(2000)
Carmignani Male SD rats 3 mo 24
et al. (2000)
Dosage
Pb acetate
0.5% in
drinking
water
Pb acetate
0-2% in
drinking
water
60 ppm
Duration Pb Level CVS
2 months blood 29. 1± BP
1.9 ug/dL
aorta; 1.9±
0.2 Mg/g
2 months blood, heart, BP, p agonist-
aorta, kidney stimulated
cAMP
production (10
uM
isoproterenol
in vitro)
10 months Blood 22. 8 ± BP, HR,
1.2 ug/dL cardiac
contractility
(dP/dt), blood
flow
Other
Plasma
catecholamines +
aorta; p receptor
binding assay &
cAMP generation
pi NEpi, cAMP p
receptro densities
Plasma NE, Epi,
dopamine, monoamine
oxidase (MAO)
activity, histology
Reference Species/Tissue
— Pb exposure caused
HTN, elevated plasma
NE (unchanged
plasma Epi).
I isoproterenol-
stimulated plasma
cAMP, I p receptor
density in aorta.
— Pb exposure raised BP
and pi NE + lowered
aorta and heart p
receptor density, basal
and stimulated cAMP
productions +
increased kidney p
receptor density and
basal and stimulated
cAMP productions.
— Pb exposure raised BP
and dp/dt, lowered
carotid blood flow, (no
change in HR) raised
plasma NE and Epi
and MAO (all tissues)
lowered plasma NOx
+ 4 aorta media
thickness,
| lymphocyte
infiltration in
periaortic fat,
nonspecific change in
kidney (congestion,
edema, rare prox.
tubular cell necrosis).
-------
o
O
to
O
O
Table AX5-5.3 (cont'd). Studies of the Effects of Lead Exposure on Blood Pressure and Adrenergic System
>
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Species/ Age/
Reference Tissue Weight n
Lai et al. Male SD rats 300 g Acute
(2002) response
Chang et al. Male Wistar 10 wks 70
(2005) rats
Pb Exposure
Dosage Duration Pb Level
In vivo: — —
Intrathecal
injection of
PbC12, 10-100
uM.
In vitro:
Thoracic cord
slices exposed
to 5-50 uM
PbC12
2% Pb acetate 2 mo, blood:
(drinking observed for 7 85 ug/dL
water) mo after
cessation aorta:
8 n/g/g
heart:
1 ug/g
kidney:
60 ug/g
Measured Parameters
Intervention
CVS Other s Results
BP, HR, (In vivo) Electophysiologic — In vivo: IT injection
w/without measures (In vitro) of PbC12 raised BP
ganglionic blockade before/after saline and HR. This was
(Hexomethonium) washout reversed by ganglionic
blockade. In vitro: Pb
raised excitatory &
lowered inhibitory
postsynaptic potentials
which were reversed
by removal of lead
(saline washout)
BP Plasma NE, p Cessation of Pb exposure raised
recaptor density Pb exposure BP, plasma NE, &
(aorta, heart, renal tissue p receptor
kidney) & lowered aorta/heart
p receptor density.
Plasma and tissue lead
fell to near-control
values within 7 mo.
after Pb cessation.
This was associated
with significant
reductions (not
normalization) of BP,
plasma NE and partial
correction of tissue p
receptor densities
(Bone lead was not
measured).
-------
o
O
to
O
O
Table AX5-5.4. Studies of the Effects of Lead Exposure on Renin-angiotensin System, Kallikrein-Kinin System,
Prostaglandins, Endothelin, and Atrial Natriuretic Peptide (ANP)
>
X
oo
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
z
Species/ Age/
Reference Tissue Weight n
Carmignani Male SD rates Weaning 16
et al. (1999)
Sharifi et al. Male SD rates 200 g 32
(2004)
Gonickatal. Male SD rates 2 mo 21
(1998)
Dorman and VSMC (rat — —
Freeman aorta)
(2002)
Giridharand Male SD rats 150- 175 g 20
Isom (1990)
Pb Exposure
Dosage Duration
Pb acetate 10 months
60 ppm
drinking water
Pb acetate 2-8 wks
100 ppm
drinking water
Pb acetate 12 wks
100 ppm
drinking water
0.0, 0.02, 0.2, up to 48 hrs
2.0 mg/dL
Pb acetate 0.01, 30 days
0.01,0.5, 1.0
mg/Kg, BiW, IP
Measured Parameters
Pb Level CVS Other
Blood 24. 2 ± BP, HR, carotid Plasma ACE,
1.8 ug/dL blood flow Kininase Kallikrein
activities dp/dt
— BP ACE activity in
plasma, aorta, heart,
kidney
— BP Urinary Tx B2, 6-
ketoPGFl
0.0 to 2 — Arachidonic acid
mg/dL (AA), DNA
synthesis, cell
proliferation + cell
viability
— — ANF
Interventions Results
— Lead exposure raised BP
& dp/dt, lowered carotid
blood flow without
changing HR. This was
associated with marked
increase in plasma ACE,
Kininase II and Kininase I
activities.
— Lead exposure raised BP,
ACE activity in plasma &
tested tissues markedly
increased peaking within
2-4 wks followed by a
decline to subnormal
values.
— Lead exposure raised BP
but did not affect urinary
PG metabolite excretion
rates.
Ang II, FCS Pb augmented Ang II
stimulated AA release in
a concentration-
dependent fashion. At
low concentrations, Pb
augmented Ang II-
stimulated DNA synthesis
& lowered cell count in
unstimulated cells.
— Pb exposure resulted in
fluid retention (jurine
flow + unchanged fluid
intake + weight gain).
This was associated with
decreased plasma &
hypothalamic ANF levels.
-------
o
O
to
O
O
Table AX5-5.5. Studies of Effect of Lead on Vascular Contractility
>
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Species/ Age/
Reference Tissue Weight n
Shelkovnikov Rat aorta rings
and Gonick
(2001)
Purdy et al. Male SD rats 8 weeks
(1997)
Oishi (1996) Male Wistar
rats
Valencia et Wistar rat 7 weeks 6 sets/
al. (2001) thoracic aorta experiment
rings
Pb Exposure Measured Parameters
Dosage Duration Pb Level CVS Other
Pb acetate short — Vasoconstriction/
10"8to W4 incubations vasodilation
Pb acetate 100 3 months — BP Aorta ring
ppm in water response to NE,
phenylephrine,
acetylcholine, and
nitroprusside
Pb acetate 1-3 months Mesenteric art &
aorta response to
acetylcholine in
presence or
absence of NOS
inhibitor (L-
NAME)
Pb acetate rapid response — In vitro
0.1-3.1mM in vitro contractile
response
Interventions Results
Lead acetated did not
cause Vasoconstriction &
did not modify the
response to NE,
isoproterenol, phorbol
ester or acetylcholine but
raised contractile
response to submaximal
Ca2+ concentration
Pb exposure raised BP.
Aorta ring
vasoconstrictive response
to NE & phenylephrine
& vasodilatory response
to acetylcholine &
nitroprusside were
unchanged.
Vasorelaxation response
to acetylcholine in
presence of L-NAME
was significantly reduced
in mesenteric art, but not
aorta of lead-exposed
animals (Inhibition of
hyperpolarizing factor)
Lead induced a
concentration-dependent
Vasoconstriction in intact
& endothelial-denuded
rings in presence or
absence of a- 1 blacker,
PKC inhibitor, L. type
Ca + channel blocker or
intra- & extracellular
Ca2+ depletion.
However, the response
was abrogated by
lanthanum (a general Ca
channel blocker)
-------
o
O
to
O
O
Table AX5-5.6. Effects of Lead on Cultured Endothelial Cell Proliferation, Angiogenesis, and
Production of Heparan Sulfate Proteoglycans and tPA
X
spindle) & reduced
pFGF- and aFGF-
mediated proliferation.
stimulation Pb inhibited appearance
w/Zn of endothelial cells in the
denuded section of
monolayer & attenuated
the healing response to
Zinc
— Lead inhibited tube
formation concentration-
dependently & tube
lengthening time
dependently.
PKC activator Lead inhibited tube
and inhibitor formation concentration-
dependently & tube
lengthening time
dependently. These
effects were independent
of PKC.
-------
o
O
to
O
O
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Table AX5-5.6 (cont'd). Effects of Lead on Cultured Endothelial Cell Proliferation, Angiogenesis, and
Production of Heparan Sulfate Proteoglycans and tPA
Reference
Fujiwara &
Kaji (1995)
Pb Exposure
Species/ Age/
Tissue Weight n Dosage Duration Pb Level
Bovine aorta — 4 sets per Pb nitrate 0. 5, 12-48 hrs
endothelial experiment 1, 2 uM
cells
Measured Parameters
CVS Other
-pFGF production/
distribution
-Heparan sulfate
production (sulfate
incorporation)
-DNA synthesis (cell
proliferation)
(3FGF binding assay
Interventions Results
Heparin, Anti- Pb & anti-pFGF alone or
pFGF antibody together equally reduced
DNA synthesis. PB did
not change endogenous
pFGF production but
reduced its HSPG-bound
component. This was
due to diminished
Kaji et al.
(1991)
Bovine aorta
endothelial
cells
4-5 sets per
experiment
Pb nitrate 0,
1-20 uM
24-48 hrs
Kaji et al.
(1997)
Bovine aorta
endothelial
cells
(confluent)
N/A
Pb chloride 10
uM
24 hrs
N/A
Glycosaminoglycan
(GAG) synthesis
(sulfate incorporation)
Synthesis of heparan
sulfate proteoglycans
(HSPGs) & their core
proteins
heparan sulfate synthesis
as opposed to
interference with pFGF
binding property.
At 10 /^M, Pb
significantly reduced
production of total
GAGs. Heparan sulfate
was reduced more
severely than other
GAGs. Cell surface
GAG was reduced more
severely than found in
the medium.
In confluent cells, lead
suppressed incorporation
of precursors into HSPG
in the cell layer to a
geater extent than
chondroitin/dermatan
sulfate proteoglycans.
Lead suppressed low-
molecular weight HSPGs
more than the high-
molecular weight
subclass. The core
proteins were slightly
increased by Pb
exposure.
-------
o
O
to
O
O
X
-------
o
O
to
O
O
Table AX5-5.7. Studies of the Effect of Lead on Cultured Vascular Smooth Muscle Cells
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Reference
Fugiwara et
al. (1995)
Corsia RV
(1995)
Yamamoto C
(1997)
Pb Exposure
Species/ Age/
Tissue Weight n Dosage Duration
Bovine aorta 4 sets per lead nitrate 24 hrs
vascular experiment 0.5-10 uM
smooth
muscle cell
rat aorta > 3 sets per lead citrate time to
VSMC cells experiment 100 & 500 confluence
(80-90% ug/L (-90% for
confluent) control
experiments)
Human aorta 5 sets per lead chloride 24 hrs
VSMC& experiment 0.5-10 uM
fetal lung
fibroblasts
(confluent)
Measured Parameters
Pb Level CVS Other
— DNA synthesis
cell density (cell
#/Cm2), cell
morphology,
membrance lipid
analysis, receptor
densities (Ang-II,
a, P, ANP
t-PA&PAI-l
release
Reference Species/Tissue
Coincubation Pb caused a
w/pFGF, concentration-dependent
aFGF. pDGF increase in DNA
synthesis. Co-incubation
w/pFGF & Pb resulted in
an additive stimulation of
VSMC DNA synth.
However, Pb inhibited
PDGF & aFGF-induced
DNA synthesis.
At low concentration, Pb
caused VSMC
hyperplasia, phenotypic
transformation from
spindle-to-cobblestone
(neointima-like) shape,
reduced Ang II receptor
density without changing
a, P, ANP receptors,
increased arachidonic
acid content of cell
membrane.
At 2 uM or higher
concentrations, lead
resulted in a
concentration-dependent
decline in t-PA release in
both cell types. Lead
increased P AI- 1 release
in fibroblasts but lowered
PAI-linVSMC.
-------
CHAPTER 5 ANNEX
ANNEX TABLES AX5-6
December 2005 AX5-64 DRAFT-DO NOT QUOTE OR CITE
-------
o
O
Compound
Table AX5-6.1. Genotoxic/Carcinogenic Effects of Lead - Laboratory Animal Studies
Dose and Duration
Cell Type
Co-exposure
Effects
Reference
Lead Acetate
to
O
O
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Lead as lead
acetate
Lead Acetate
0.5, 5, or 25 ppm given in drinking
water - duration not given.
Number of animals per group was
not given.
0-4000 ppm given in drinking
water for 104 weeks.
50, 250, or 1000 ppm given in
drinking water for 15 weeks.
Number of mice per group in initial
exposures not given.
Number of mice at analysis ranged
from 19-25.
Female C3HSI mice
infected with MMTV
(Murine mammary
tumor virus) - age not
given
Female albino Swiss
Mice - 3 weeks old
Selenium, 0.15-1 ppm
(duration not given) in
diet ( Se prevents
spontaneous tumors in
these mice)
Wild type (WT) and None
metallothionine null (MT
null) mice
Urethane 1.5 mg
given i.p.
Lead acetate exposed mice exhibited greater mortality unrelated Schrauzer (1987)
to the tumor formation.
25 ppm suppressed tumor formation, but increased the
aggressiveness of the tumors.
5 ppm increased tumor formation, but had no effect on growth
rates.
0.5 ppm with low selenium exhibited 80% tumor formation and
reduced weight gains that recovered.
0.5 ppm with high selenium exhibited normal weight gain, but
tumor incidence still reached 80%.
Control data described as "significantly lower" but not given.
Methods poorly described and data not shown.
Renal proliferative lesions were much more common and severe Waakes et. al.
in MT null mice than WT mice. MT null mice could not form (2004)
renal inclusion bodies even with prolonged lead exposure and
this could have contributed to increase in the carcinogenic
potential of lead.
No signs of lead poisoning. No lead effects on growth or weight Blakley
gain. (1987)
Urethane added to induce lung tumors.
Lead did not affect urethane metabolism.
Lead did not affect number of tumors or affect tumor size.
Lead alone was not evaluated.
Lead levels did increase in tissues.
-------
o
O
to
O
O
Compound
Table AX5-6.1 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Laboratory Animal Studies
Dose and Duration
Cell Type
Co-exposure
Effects
Reference
Lead Acetate 50 or 1000 ppm 50 or 1000 ppm
given in drinking water for 280
days.
Number of mice pre group in initial
exposures not given.
Number of mice at end were 50 per
dose.
Female albino Swiss
Mice - 8 weeks old
None
Mice have high rate of spontaneous leukemia from endemic viral Blakley
infection. (1987)
No signs of lead poisoning. No lead effects on growth or weight
gain.
Lead did increase leukemia-related mortality possibly due to
immunosuppression.
Lead levels did increase in tissues.
Data indicate that lead may be immunosuppressive, though the
exact mechanism is not understood.
X
-------
o
O
cr
to
o
o
(^
Table AX5-6.2. Genotoxic/Carcinogenic Effects of Lead - Human Cell Cultures
X
ON
Compound
Lead
Chromate
Lead
Chromate
Lead
Chromate
Lead Acetate
Dose and Duration
Anchorage Independence
(0.1-1 uMfor48h)
Anchorage Independence
(0.1-1 uMfor48h)
Morphological Transformation
(2 ug/mL for 24 h, performed 3
times immediately after passage)
Anchorage Independence (0.2-2
ug/mL or cells isolated during
morphological transformation)
Neoplastic Transformation (cells
isolated during morphological
transformation)
Anchorage Independence
(500-2000 uM for 24 h)
Cell Type Co-exposure
Human Foreskin None
Fibroblasts
InH-MEM+15%FCS
Human Foreskin None
Fibroblasts
InH-MEM+15%FCS
HOS TE 85 in DMEM None
+ 10% FBS
Human Foreskin 3-aminotriazole (3-AT)
Fibroblasts (Chinese) (80 mM to inhibit
In DMEM +10% FCS catalase)
Effects
Lead chromate-induced concentration-dependent increase in
anchorage independence.
Lead chromate-induced concentration-dependent increase in
anchorage independence.
Lead chromate induced foci of morphological
transformation after repeated exposure and passaging.
Lead chromate did not induce anchorage independence, but
cells from the foci obtained during morphological
transformation.
Lead chromate did not induce neoplastic transformation in
the cells from the foci obtained during morphological
transformation.
Studied as a chromate compound. Role of lead not
mentioned or considered.
Lead acetate-induced concentration-dependent increase in
anchorage independence. Anchorage independence not
affected by 3-AT.
Reference
Biedermann and
Landolph (1987)
Biedermann and
Landolph (1990)
Sidhuet al.
(1991)
Hwua and Yang
(1998)
H
6
o
o
H
O
o
H
W
O
O
HH
H
W
-------
Table AX5-6.3. Genotoxic/Carcinogenic Effects of Lead - Carcinogenesis Animal Cell Cultures
o
ft>
cr
2t
to
o
o
^
X
ON
OO
O
^
c
I
o
o
2!
-^H
o
^^
H
O
o
H
W
o
O
H
W
Compound
Lead Acetate
Lead Chloride
Lead
Chromate
Lead
Chromate
Lead
Chromate (and
pigments
containing
lead chromate)
Lead
Chromate
Dose and Duration
Morphological Transformation
(10-50 uM for 48 h)
Morphological Transformation
(doses not given)
Enhancement of Simian
Adenovirus (SA7) induced
morphological transformation.
(80- 1,240 uM for 20 h)
Morphological Transformation
(10-50 uM for 24 h)
Anchorage Independence for cells
isolated during morphological
transformation
Neoplastic Transformation for cells
isolated during morphological
transformation.
Morphological Transformation
(0.04 - 8 ug/mL as Cr for 7 days)
Anchorage Independence for cells
isolated during morphological
transformation
Neoplastic Transformation for cells
isolated during morphological
transformation
Morphological Transformation
(0.02 - 0.88 ug/mL as Cr for 7
days)
Cell Type Co-exposure
Primary SHE cells in None
AMEM + 10% FBS
C3H10T1/2 cells in None
EMEM +10% FBS
Primary SHE cells in None
DMEM + 10% FBS
C3H10T1/2 cells in None
EMEM + 10% FBS
Primary SHE cells in None
DMEM + 10% FCS
Primary SHE cells in None
DMEM + 10% FCS
Effects
Lead acetate was weakly positive inducing a 0. 19-1.6%
increase in transformation. There was a weak dose
response. There were no statistical analyses of these data.
Lead chloride did not induce morphological transformation.
Lead chromate enhanced SA7-induced morphological
transformation.
Studied as a chromate compound. Role of lead not
mentioned or considered.
Lead chromate induced morphological and neoplastic
transformation.
Cells exhibiting morphological transformation grew in soft
agar and grew in nude mice.
Studied as a chromate compound.
Lead chromate induced morphological and neoplastic
transformation.
Cells exhibiting morphological transformation grew in soft
agar and grew in nude mice.
Studied as a chromate compound.
Lead chromate induced morphological transformation more
potently (9-fold) than other chromate compounds.
Reference
Zelikoffet al. (1988)
Patierno et al. (1988),
and Patierno and
Landolph (1989)
(both papers present
the same data)
Schechtman et al.
(1986)
Patierno et al. (1988)
and Patierno and
Landolph (1989)
(both papers present
the same data)
Elias et al. (1989)
Eliaset al. (1991)
-------
o
O
to
O
O
Table AX5-6.3 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Carcinogenesis Animal Cell Cultures
Compound
Lead Nitrate
Dose and Duration
Morphological Transformation
(0.04 - 8 ng/mL as Cr for 7 days)
Cell Type
Primary SHE cells in
DMEM + 10% PCS
Co-exposure
Calcium chromate
Effects
Lead nitrate alone did not induce significant levels of
transformation.
Reference
Eliaset al. (1991)
Lead nitrate plus calcium chromate increased the potency
of calcium chromate to that of lead chromate. Data suggest
lead ions are synergistic with chromate ions in inducing
neoplastic transformation.
X
-------
December 2005
Table AX5-6.4. Genotoxic/Carcinogenic Effects of Lead
Compound Dose and Duration Species
Lead Acetate 2.5 mg/100 g given i.p. as Female Norway Rat
daily injection for 5-15
days
Co-exposure
Selenium (0.0 12-0.047
mg/lOOg or 0.094-0.188
mg/100 g given i.p.
with lead)
- Genotoxicity Laboratory Animal Studies.
Effects
Lead induced chromosome damage after chronic treatment.
It was not dose dependent as only 1 dose was studied. The
effects of selenium on lead effects are unclear as selenium
alone induced substantial chromosome damage.
Reference
Chakraborty
et al. (1987)
10-20 mg/100 g given i.p. a
single injection and animals
studied after 15 days
5 animals per group.
Chromosome damage in
bone marrow
The single dose exposure also induced chromosome damage,
but untreated controls were not done in this regimen. There
is some mention that this dose regimen is toxic to the animals
as selenium modulated the lethal effects, but no explanation
of how many animals died.
Lead Acetate
X
-------
o
O
to
O
O
Table AX5-6.4 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Laboratory Animal Studies.
Compound
Dose and Duration
Species
Co-exposure
Effects
Reference
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Lead Nitrate
Lead Nitrate
Lead Nitrate
100-200 mg/kg given iv on ICR Swiss Webster Mice
9th day of gestation onwards - 6-8 week old
for 9 days.
Mothers and fetuses
analyzed on G18.
Group size not given.
Resorptions, fetal viability
and chromosome damage,
SCE and NOR in the
mother and fetus were
examined. Mother-bone
marrow; fetus liver or lung
3 mothers and fetuses per
dose were analyzed.
10, 20, or 40 mg/kg given Swiss Albino Mice -
ip 24 h weeks old
6 animals per group.
Chromosome damage and
Mitotic Index in bone
marrow
5, 10, or 20 mg/kg given ip Swiss Albino Mice -
24 h weeks old
6 animals per group.
Chromosome damage in
bone marrow.
50 metaphases per animal
for a total of 300 (X6).
None
Phyllanthus fruit extract
(685 mg/kg) or ascorbic
acid (16.66 mg/kg)
given by gavage for 7
days
Ferric chloride (18
mg/kg) given ip for 24 h
administered 1 h
before-, 1 h after- or
together with- lead
nitrate
Lead levels were found in both mother and fetus indicating
no problems crossing the placenta.
All doses indicated increased resorption and decreased
placental weights. No effects on fetal weight.
Significant increase in SCE in mothers at 150 and 200 mg/kg.
No increase in SCE in fetuses.
Significant decrease in NOR in both mother and fetuses.
No gaps or breaks in mothers or fetuses.
Some weak aneuploidy at lowest dose.
Some karyotypic chromosome damage was seen. No
explanation of how many cells analyzed per animal (3
animals per dose were analyzed) as only 20- 40 cells were
analyzed.
There was no dose response and no statistical analyses for
chromosome damage. No details on how many animals
analyzed for metaphase damage or how many cells per
animal.
Data interpretation is also complicated as too few metaphases
were analyzed 10-25 for SCE. Not given for CA.
No detail on potential maternal toxicity.
Lead nitrate increased the amount of chromosome damage at
each dose. But there was no dose response and a similar
level of damage was seen for each dose.
Phyllanthus fruit extract reduced the amount of damage at
each dose. Acrorbic acid reduced the damage at the lowest
dose but increased it at the higher doses.
Higher concentrations of lead nitrate reduced the mitotic
index. This effect was reversed by ascorbate and Phyllanthus
only at the moderate dose.
Lead nitrate increased the amount of chromosome damage in
a dose-dependent manner.
Iron exhibited some modifications of lead induced damage:
If administered 1 h before lead plus simultaneously it reduced
the damage. If administered with lead only at same time it
reduced damage in the lower doses. If lead was started 1 h
before iron there was no effect.
Thus iron may antagonize lead perhaps by blocking uptake.
Nayaket al. (1989b)
Dhiret al. (1990)
Dhiret al. (1992)a
-------
o
O
to
O
O
Table AX5-6.4 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Laboratory Animal Studies.
Compound
Dose and Duration
Species
Co-exposure
Effects
Reference
X
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O Table AX5-6.4 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Laboratory Animal Studies.
o
ft>
X
H
6
o
o
H
O
o
H
W
O
O
HH
H
W
Compound Dose and Duration Species Co-exposure Effects Reference
o>
"i Lead Acetate 10 mg/kg given by gavage Male Wistar rats - 30 days Cypermethrin No effects on weight gain. Nehez et al. (2000)
g 5 times a week for 4 weeks. old Lead Acetate induced an increase in aneuploidy, and the
^ 10 animals per group percent of cells with damage, but did not increase structural
Chromosome Aberrations damage or alterations in organ weight.
with 20 metaphases scored Cypermethrin and lead together increased structural
per animal aberrations that were predominately acentric fragments.
However, this was compared to untreated controls and not the
individual treatments. Considering the individual treatments,
the two together are less than additive.
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Decembi
CD
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to
o
O
^
Table AX5-6.5. Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Human Cell Cultures Mutagenesis
Compound Dose and Duration
Lead Acetate, Cytotoxicity - tritium
In vitro incorporation (0.1-100
uM/mL for 2-24 h)
Mutagenesis - HPRT
modified to labeling of 6-
thioguanine resistant cells
(0.1-100 uM/mL for 2-24
h)
Lead Acetate Cytotoxicity (500-2,000
uM for 24 h)
Mutagenicity - HPRT assay
Cell Type
Human Keratinocytes-
pooled in MEM and low
calcium MEM+2% FBS
Human Foreskin
Fibroblasts (Chinese) in
DMEM +10% FCS
Co-exposure Effects
None Decrease in tritium incorporation at 10-100 uM/mL. 6 uM/L
was selected as the concentration to study as tritium-
incorporation was highest and greater than control.
Tritium incorporation in the presence of 6-thioguanine (TG)
was optimal after 4 h lead acetate exposure and 5 days of
expression time. It was concluded that the significant
increase relative to control indicated mutations. The
argument made was that because these cells are TG resistant
they must be mutated. However, this argument was not
proven by sequencing or colony formation in TG.
3-aminotriazole (3-AT) LC50 = 500 uM. Cytotoxicity not affected by 3-AT.
(80 mM to inhibit Lead acetate was not mutagenic.
catalase)
Mutagenicity not affected by 3-AT.
Reference
Ye (1993)
Hwua and Yang
(1998)
X
H
6
o
o
H
O
o
H
W
O
O
HH
H
W
Lead Chromate
Mutagenicity as 6-
thioguanine resistance
(0.25-1 nMfor24h)
Human Foreskin None
Fibroblasts
InEMEM+15%FCS
Lead chromate was not mutagenic.
Biedermann and
Landolph (1990)
Abbreviations:
Medium and Components
MEM = Minimal Essential Medium;
DMEM = Dulbecco's Minimal Essential Medium;
EMEM = Eagle's Minimal Essential Medium;
FBS = Fetal Bovine Serum
FCS = Fetal Calf Serum
Differences between the serum types are unclear as insufficient details are provided by authors to distinguish.
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O
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Table AX5-6.6. Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Human Cell Cultures Clastogenicity
Compound
Assay (Concentration
and Exposure Time)
Cell Type and Culture
Medium
Co-exposure
Effects
Reference
X
H
6
o
O
H
O
o
H
W
O
Lead Chromate Chromosome Aberrations Human Foreskin Fibroblasts
(0.08-2 jig/cm2 for 24 h) (Caucasian) in EMEM + 15%FBS
Lead Chromate Chromosome Aberrations
(0.1-5 ug/cm2 for 24 h)
Lead Chromate Chromosome Aberrations
(0.1-5 ug/cm2 for 24 h)
Lead Chromate Chromosome Aberrations
(0.1-5 ug/cm2 for 24 h)
Lead Chromate Chromosome Aberrations
(0.05-5 ug/cm2 for 24 h)
Lead Chromate Chromosome Aberrations
(0.05-5 ug/cm2 for 24 h)
Primary Human Lung Cells in
DMEM/F12 + 15%FBS
Primary Human Lung Cells and
WTHBF-6 -human lung cells with
hTERT in DMEM/F12 + 15%FBS
WTHBF-6 -human lung cells with
hTERT in DMEM/F12 + 15%CCS
WTHBF-6 -human lung cells with
hTERT in DMEM/F12 + 15%CCS
WTHBF-6 -human lung cells with
hTERT in DMEM/F12 + 15%CCS
None
None
None
Vitamin C (2 mM
co-exposure for
24 h)
Vitamin C (2 mM
co-exposure for
24 h)
None
Lead Chromate induced chromosome damage in a Wise et al.
concentration dependent manner. (1992)
This study was focused on chromate.
Lead Chromate induced chromosome damage in a Wise et al.
concentration dependent manner. (2002)
This study was focused on chromate.
Lead Chromate induced chromosome damage in a Wise et al.,
concentration dependent manner. Effects were similar in (2004a)
both cell types establishing the WTHBF-6 cells as a useful
model.
This study was focused on chromate.
Lead Chromate induced chromosome damage in a Xie et al. (2004)
concentration dependent manner.
Vitamin C blocked Cr ion uptake and the chromosome
damage after lead chromate exposure.
This study was focused on chromate.
Lead Chromate induced chromosome damage in a Wise et al.
concentration dependent manner. (2004b)
This study was focused on showing chromate and not lead
ions were the clastogenic species.
Lead Chromate induced chromosome damage in a Wise et al.
concentration dependent manner. (2004c)
This study was focused on comparing particulate chromate
compounds.
O
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Table AX5-6.6 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Human Cell Cultures Clastogenicity
Compound
Assay (Concentration
and Exposure Time)
Cell Type and Culture
Medium
Co-exposure
Effects
Reference
H
6
o
Lead Glutamate
Lead Glutamate
Lead ion uptake - ICPMS
(250-2,000 uM for 24 h)
Chromosome Aberrations
(250-2,000 uM for 24 h)
Lead ion uptake - ICPMS
(250-2,000 uM for 24 h)
Mitotic Index (250-2,000 uM
for 24 h)
Growth Curve (250-2,000
uM for 24 h)
Cell cycle Analysis (250-
2,000 uM for 24 h)
WTHBF-6 -human lung cells with None
hTERT in DMEM/F12 + 15%CCS
WTHBF-6 -human lung cells with None
hTERT in DMEM/F12 + 15%CCS
Lead glutamate induced a concentration-dependent increase
in intracellular lead ions.
Lead glutamate did not induce chromosome damage.
Lead glutamate induced a concentration-dependent increase
in intracellular lead ions.
Lead glutamate increased the mitotic index, but inhibited
growth and did not induce chromosome damage.
Wise et al.
(2005)
X
1
ON
Radioactive
Lead Ions
no further
specification
LET= 13,600keV/uM
Fluence of 2 X106 particles/
cm2
Chromosome Aberrations
Human Foreskin Fibroblasts in DF- None
12 + 10% FCS
Lead induced chromosome damage that recurred with time
and cell passaging. Analysis limited to approximately 25
metaphases.
Focused on radioactive effects of lead
Martins et al.
(1993)
Abbreviations:
hTERT = hTERT is the catalytic subunit of human telomerase
Medium and Components
EMEM = Eagle's Minimal Essential Medium;
DMEM/F12 = Dulbecco's Minimal Essential Medium/Ham's F12;
CCS = Cosmic Calf Serum
FBS = Fetal Bovine Serum
FCS = Fetal Calf Serum
O
H
O
c
O
H
W
O
V
O
HH
H
W
Differences between the serum types are unclear as insufficient details are provided by authors to distinguish.
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o
O
to
O
O
Table AX5-6.7. Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Human Cell Cultures DNA Damage
X
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o
O
H
O
o
H
W
O
O
HH
H
W
Compound
Lead Acetate
Lead Acetate
Lead Chromate
Lead Chromate
Lead Acetate
Assay (Concentration and
Exposure Time)
DNA strand breaks as nucleiod
sedimentation (500 uM for 20-
25 h)
DNA strand breaks as nucleoid
sedimentation assay (100 uM
for 30 min - 4 h)
DNA adducts (0.4-0.8 jig/cm2
for 24 h)
DNA double strand breaks
(0.1-5 ug/cm2 for 24 h) by
Comet assay and H2A.X foci
formation
DNA strand breaks and DNA
protein crosslinks and oxidative
lesions by comet assay (1-100
uM for 1 h)
Cell Type and
Culture Medium
HeLa Cells in AMEM
+ 5%FBS
HeLa Cells in
HEPES/
glucose buffer
Primary Human Small
Airway Cells in
Clonetics growth
medium
WTHBF-6 -human
lung cells with
hTERT in
DMEM/F12 +
15%CCS
Primary lymphocytes
in RPMI 1640 without
serum
Co-exposure
None
See also Table
AX5-6-16
Buthionine
sulfoximine (BSO) to
deplete cells of thiols
None
None
Vitamins A (10 uM),
C (10 uM), E
(25 uM), calcium
chloride (100 uM)
magnesium chloride
(lOOnM)orzinc
chloride (100 uM)
Effects
Lead acetate alone did not induce single strand breaks.
Lead acetate did not induce DNA strand breaks.
Lead chromate induced lead inclusion bodies and Cr-DNA adducts and
Pb-DNA adducts in a concentration-dependent manner.
Lead Chromate induced DNA double strand breaks in a concentration
dependent manner.
This study showed the damage was due to chromate and not lead.
Lead acetate induced an increase in DNA single strand breaks at 1 uM
that went down with increasing dose. The highest concentration was
significantly less than the damage in untreated controls. For double
strand breaks, all concentrations had more damage than the controls,
but there was less damage in the highest concentrations than the two
lower ones. Lead only induced a slight increase in the amount of
DNA-protein crosslinks at the highest concentration.
Co exposure to magnesium had no effect. Co-exposure to Vitamins A,
C, and E or zinc exacerbated the DNA single strand break effects at the
highest concentration. Co-exposure to calcium exacerbated the single
strand break effect at all concentrations.
Reference
Hartwig et al
(1990)
Snyder and
Lachmann
(1989)
Singh et al.
(1999)
Xie et al.
(2005)
Wozniak and
Blasiak (2003)
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to
O
O
Table AX5-6.7 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Human Cell Cultures DNA Damage
Compound
Lead Nitrate
Assay (Concentration and
Exposure Time)
DNA-protein crosslinks by
SDS precipitation (1-10 mM
for 6 h)
Cell Type and
Culture Medium Co-exposure
Human Burkitt's None
lymphoma cells -
EBV transformed in
RPMI 1640 +
10%FCS
Effects
Lead nitrate did not induced DNA protein crosslinks. Independent
samples were analyzed by 5 different laboratories.
Reference
Costa et al.
(1996)
X
Abbreviations:
hTERT = hTERT is the catalytic subunit of human telomerase.
Medium and Components
AMEM = Alpha Minimal Essential Medium;
EMEM = Eagle's Minimal Essential Medium;
DMEM/F12 = Dulbecco's Minimal Essential Medium/Ham's F12;
FBS = Fetal Bovine Serum
FCS = Fetal Calf Serum
Differences between the serum types are unclear as insufficient details are provided by authors to distinguish
oo
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6
o
O
H
O
o
H
W
O
O
HH
H
W
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o
O
to
O
O
Table AX5-6.8. Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal Cell Cultures Mutagenicity
Compound
Lead Acetate
Lead Acetate
-insoluble
precipitate at high
dose.
Assay and Duration
Cytotoxicity (1-25 uM for 24 h)
Mutagenesis- HPRT (0.5-5 uM for 44 h)
Cytotoxicity (0.5-2000 uM for 5 days)
Mutagenesis - gpt (0.5-1700 uM for 5 days)
Cell Type
V79 in AMEM +
10%FBS
G12-CHV79 cells
with 1 copy gpt gene
in Ham's F 12 +
5%FBS
Co-exposure
None
See also Table AX5-
6-16
See also Table AX5-
6-17
Effects
LC50 = 3 uM
Lead acetate alone was not mutagenic.
LC50 = 1700 uM
Lead acetate was mutagenic, but only at toxic
concentration (1700 uM) where precipitate formed
not at lower concentrations (500 or 1000 uM).
Reference
Hartwig et al (1990)
Roy and Rossman
(1992)
There were no statistical analyses of these data.
X
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Table AX5-6.8 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal Cell Cultures Mutagenicity
cember 2005
Compound
Lead Nitrate
Precipitate at 1000
uM and higher.
Lead nitrate
-no insoluble
precipitate
Lead Sulfide
Assay and Duration
Cytotoxicity (50-5,000 uM for 5 days)
Mutagenesis at HPRT locus (50-2,000 uM
for 5 days)
Cytotoxicity (0.5-2000 uM for 5 days)
Mutagenesis - gpt (0.5-1700 uM for 5 days)
Cytotoxicity (100-1,000 uM for 24 h)
Mutagenicity at HPRT locus (100-1,000 uM
for 24 h)
Cell Type Co-exposure
V79CHL-HPRT None
low clone in Ham's
F12+10%FBS
G12-CHV79 cells See also Table AX5-
with 1 copy gpt gene 6-17
in Ham's F 12 +
5%FBS
V79CHL-HPRT None
low clone in Ham's
F12+10%FBS
Effects
LC50 = 2950 uM
Lead nitrate was mutagenic at 500 uM, but there
was no dose response as higher doses less
mutagenic though still 2-4 fold higher. There were
no statistical analyses of these data.
LC 50 = 1500 uM
Lead nitrate was not mutagenic. There were no
statistical analyses of these data.
LC50 = 580 uM; did not increase with longer
exposures.
Mutagenic at 376 and 563 uM. Not mutagenic
Reference
Zelikoffet
(1988)
al.
Roy and Rossman
(1992)
Zelikoffet
(1988)
al.
X
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Table AX5-6.9. Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal Cell Cultures Clastogenicity
jcember 2005
X
i
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o
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6
o
0
H
O
o
H
W
O
O
HH
H
W
Assay (Concentration and
Compound Exposure Time)
Lead Chromate Chromosome Aberrations (0.4-8
ug/cm for 24 h)
Lead Chromate Chromosome Aberrations (0.8-8
ug/cm for 24 h)
Lead Chromate Chromosome Aberrations (0.8 or 8
ug/cm for 24 h)
Lead Chromate Chromosome Aberrations (0.8-8
ug/cm2 for 24 h)
Lead Glutamate Chromosome Aberrations (500-2,000
uM for 24 h)
Lead Nitrate Chromosome Aberrations (500-2,000
uM for 24 h)
Insoluble precipitate at all
concentrations
Lead Nitrate Chromosome Aberrations
(3-30 uM for 2h +16 h recovery)
Lead Nitrate Chromosome aberrations (0.05- 1 uM
for 3-12 h)
Cell Type and Culture
Medium
Chinese Hamster Ovary AA8
cells in AMEM + 10%FBS
Chinese Hamster Ovary AA8
cells in AMEM + 10%FBS
Chinese Hamster Ovary AA8
cells in AMEM + 10%FBS
Chinese Hamster Ovary AA8
cells in AMEM + 10%FBS
Chinese Hamster Ovary AA8
cells in AMEM + 10%FBS
Chinese Hamster Ovary AA8
cells in AMEM + 10%FBS
Chinese Hamster Ovary cells
in EMEM + 10%FBS
Chinese Hamster Ovary AA8
cells in DMEM +10% NCS
Co-exposure
None
Vitamin C (1 mM for
24 h as co-exposure to
block Cr uptake)
Vitamin E (25 uM as
pretreatment for 24 h)
Vitamin C (1 mM as
pretreatment for 24 h)
Vitamin E (25 uM as
pretreatment for 24 h)
Vitamin E (25 uM as
pretreatment for 24 h)
Vitamin E (25 uM as
pretreatment for 24 h)
None
Crown ethers to
modify effect through
chelation and uptake
Effects
Lead chromate induced chromosome damage in a
concentration dependent manner.
This study was focused on chromate.
Lead chromate induced chromosome damage in a
concentration dependent manner. This effect and uptake
of Cr ions were blocked by vitamin C.
This study was focused on chromate.
Lead chromate induced chromosome damage in a
concentration dependent manner. Vitamin E blocked
clastogenic activity of lead chromate, but had no effect on
other lead compounds.
This study found that the chromosome damage was
mediated by chromate ions and not lead ions
Lead chromate induced chromosome damage in a
concentration dependent manner. Vitamins C and E
blocked clastogenic activity of lead chromate.
This study was focused on chromate.
Lead glutamate induced chromosome damage at 1 mM
but not at higher or lower concentrations.
Vitamin E did not modify this effect.
Lead nitrate did not induce chromosome damage.
Lead nitrate did not induce chromosome damage.
Lead nitrate did not induce chromosome damage.
Reference
Wise et al.
(1992)
Wise et al.
(1993)
Wise et al.
(1994)
Blankenship
et al. (1997)
Wise et al.
(1994)
Wise et al.
(1994)
Lin et al.
(1994)
Cai and
Arenaz
(1998)
-------
Table AX5-6.9 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal Cell Cultures Clastogenicity
O
ft>
3
cr
^
to
O
O
l^ft
>
X
i
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to
O
H
I
0
O
0
H
O
O
H
W
O
O
H
W
Assay (Concentration and Cell Type and Culture
Compound Exposure Time) Medium Co-exposure
Lead Acetate SCE (1-10 uM for 26 h+) V79 in AMEM + 10%FBS None
See also Table
AX5-6-17
Lead Acetate Micronucleus assay (0.01-10 uM for Chinese Hamster V79 cells in None
18h) DMEM + 10%FCS
Lead Nitrate SCE Formation (500-3,000 uM for 24 h) V79 CHL - HPRT low clone in None
Precipitate at 1000 uM and higher. Ham's F12 +10% FBS
Lead Nitrate Micronucleus Formation (3-30 uM for CHO cells in EMEM + None
2h +16 h recovery) 10%FBS
SCE (3-30 uM for 2h +16 h recovery)
Lead Nitrate SCE (0.05- 1 uM for 3-12 h) CHO AA8 in DMEM +10% Crown ethers to
NCS modify effect
through chelation
and uptake
Effects
Lead acetate alone did not induce SCE. Only 25 cells per
treatment analyzed.
Lead acetate induced an increase in micronuclei that
increased with concentration and reached a plateau. Two
experiments were done and presented separately as a
Figure and a Table. The magnitude of the effects was
small to modest and statistics were not done.
No SCE. Only 30 cells analyzed per treatment.
Lead nitrate did not induce micronuclei formation
Lead nitrate induces a concentration-dependent increase
in SCE (3, 10, 30 uM).
Lead nitrate caused a weak concentration-dependent
increase in SCE. These data were not statistically
analyzed. The effect was reduced by a crown ether
probably because a similar reduction was seen in
spontaneous SCE.
Reference
Hartwig et al
(1990)
Bonacker et
al. (2005)
Zelikoffet
al. (1988)
Lin et al.
(1994)
Cai and
Arenaz
(1998)
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to
o
o
Table AX5-6.9 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal Cell Cultures Clastogenicity
Assay (Concentration and
Compound Exposure Time)
Cell Type and Culture
Medium
Co-exposure
Effects
Reference
LeadSulfide SCE Formation (100-1,000 uM for
24 h)
V79 CHL - HPRT low clone
in Ham's F12 +10% FBS
None
No SCE. Only 30 cells analyzed per treatment.
Zelikoffet al.
(1988)
^
Abbreviations:
V79 are a Chinese Hamster Lung Cell Line;
CHO are a Chinese Hamster Ovary Cell Line ;
Medium and Components
AMEM = Alpha Minimal Essential Medium;
DMEM = Dulbecco's Minimal Essential Medium;
EMEM = Eagle's Minimal Essential Medium;
HBSS = Hank's Balanced Salt Solution
FBS = Fetal Bovine Serum
FCS = Fetal Calf Serum
NCS = Newborn Calf Serum
Differences between the serum types are unclear as insufficient details are provided by authors to distinguish.
H
6
o
o
H
O
c
o
H
W
O
V
O
HH
H
W
-------
December 2005
Table AX5-6.10. Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal Cell Cultures DNA Damage
Compound Assay (Concentration
and Exposure Time)
Lead Acetate DNA damage as alkaline
elution (exposure time and
dose not given*)
Cell Type and Culture Medium Co-exposure
V79 CHL - HPRT low clone in Ham's None
F12+10%FBS
Effects
No DNA damage (Single strand breaks, DNA-
protein crosslinks or DNA-DNA crosslinks).
However, the data was not shown
Reference
Zelikoffet al. (1988)
X
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Table AX5-6.10 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Animal Cell Cultures DNA Damage
Compound Assay (Concentration and
Exposure Time)
Cell Type and Culture
Medium
Co-exposure
Effects
Reference
Lead Nitrate DNA strand breaks as nick
translation (1700 uM for 5 days)
G12 - CHV79 cells with 1 copy See also Table
gpt gene in Ham's F12 + 5% AX5-6-17
FBS
Lead nitrate (1700 uM) did increase nick translation when an Roy and Rossman
exogenous polymerase was added. There were no statistical (1992)
analyses of these data.
X
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O Table AX5-6.11. Genotoxic/Carcinogenic Effects of Lead - Genotoxicity Non-Mammalian Cultures
o
ft>
X
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O Table AX5-6.12. Genotoxic/Carcinogenic Effects of Lead - Genotoxicity as it Pertains to Potential Developmental Effects
o
to
o
o
X
er arouc daily for 3 days given 2 were not done. Calcium appeared to block this effect.
weeks after lead
Sperm Morphology exposure)
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to
O
O
Compound
Table AX5-6.13. Genotoxic/Carcinogenic Effects of Lead - Genotoxicity as it Pertains to
Potential Developmental Effects - Children
Exposure Regimen
Species
Co-exposure
Effects
Reference
X
oo
oo
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Lead chloride
Lead Nitrate
Lead Nitrate
Administered in drinking water
1.33 g/L for 6 weeks
12.5-75 mg/kg given iv on 9th day of
gestation for 9 days.
Mothers and fetuses analyzed on
G18.
5 animals per group
Resorptions, fetal viability, and
chromosome damage in the mother
and fetus were examined.
100-200 mg/kg given iv on 9th day
of gestation for 9 days.
Mothers and fetuses analyzed on
G18.
Group size not given.
Resorptions, fetal viability and
chromosome damage, SCE and
NOR in the mother and fetus were
examined. Mother - bone marrow;
fetus liver or lung
3 mothers and fetuses per dose were
analyzed.
Male NMRI
Mice - 9 weeks old
ICR Swiss Webster
Mice - 6-8 week old
Cyclophosphamide - Pb did not increase resorptions indicating no dominant lethal
120 mg/kg b.w. given mutagenic effect. Pb appeared to have a small, but statistically
i.p 7 days prior to start insignificant reduction in the number of resorptions.
of breeding Cyclophosphamide reduced live implants in female mice.
None
ICR Swiss Webster
Mice - 6-8 week old
None
12.5-50 mg/kg had no effect on resorption or fetal viability.
75 mg/kg demonstrated some increased resorption though
statistics were not done.
No chromosome damage was seen in untreated controls. A low
level 1-3 and 2-5 aberrations were seen in mothers and fetuses
respectively.
There was no dose response and no statistical analyses. Data
interpretation is also complicated as too few metaphases were
analyzed 20-40 total.
No descriptions of potential effects on maternal health parameters
or fetal weights.
No indication of how many animals included in the chromosomal
analysis.
Lead levels were found in both mother and fetus indicating no
problems crossing the placenta.
All doses indicated increased resorption and decreased placental
weights. No effects on fetal weight.
Significant increase in SCE in mothers at 150 and 200 mg/kg.
No increase in SCE in fetuses.
Significant decrease in NOR in both mother and fetuses.
No gaps or breaks in mothers or fetuses.
Some weak aneuploidy at lowest dose.
Some karyotypic chromosome damage was seen. No explanation
of how many cells analyzed per animal (3 animals per dose were
analyzed) as only 20- 40 cells were analyzed.
There was no dose response and no statistical analyses for
chromosome damage. No details on how many animals analyzed
for metaphase damage or how many cells per animal.
Data interpretation is also complicated as too few metaphases
were analyzed 10-25 for SCE. Not given for CA.
No detail on potential maternal toxicity.
Kristensen et al.
(1993).
Nayak et al.
(1989)a
Nayak et al.
(1989)b
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Table AX5-6.14. Genotoxic/Carcinogenic Effects of Lead - Epigenetic Effects and Mixture Interactions - Animal
Compound
Exposure Regimen
Species
Co-exposure
Effects
Reference
X
oo
VO
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Lead Acetate Administered as an i.p. injection of
100 nl/kg.
Animals were studied either 24 h
after a daily dose for 3 days or for
various times (5 min-48 h) after a
single dose.
Lead Nitrate
Administered as an i.p. injection of
100 umol/kg.
Animals were studied either 24 h
after a daily dose for 3 days or for
various times (5 min-48 h) after a
single dose.
Lead Nitrate Administered as an i.p. injection of
100 umol/kg. Some rats were
partially hepatectomized.
Animals were studied 48 h after
injection.
Lead Nitrate Administered as an i.v. injection of
20, 50, or 100 umol/kg.
Animals were studied 24 h after
injection.
Male Wistar Rats -
10 weeks old
Male Wistar Rats -
10 weeks old
Male Sprague
Dawley rats
Actinomycin D
(0.8 mg/kg)
administered i.p. for 4
h before a single dose
of lead acetate.
Actinomycin D
(0.8 mg/kg)
administered i.p. for 4
h before a single dose
of lead acetate.
Partial Hepatectomy
Male Fisher 344 rats 2-methoxy-
- 7 weeks old 4-aminobenzene to
induce P4501A2
or
3-methylcholanthrene
to induce 4501A1
Lead acetate induced GST-P, which required the cis element, GPEI Suzuki et al.
(GST-P enhancer I). (1996)
Actinomycin D blocked the effects indicating that regulation was
at the mRNA level.
Lead acetate induced c-jun, which exhibited three peaks of
exposure over 48 h.
Lead acetate was more potent than lead nitrate.
Lead nitrate induced GST-P, which required the cis element, GPEI Suzuki et al.
(GST-P enhancer I). (1996)
Actinomycin D blocked the effects indicating that regulation was
the mRNA level.
Lead nitrate induced c-jun, which exhibited three peaks of
exposure over 48 h.
Lead nitrate was less potent than lead acetate.
Lead nitrate induced GSH and GST 7-7 activity. Dock (1989)
Partial hepatectomy did not induce GSH or GST 7-7.
Lead nitrate selectively inhibited P4501A2 and its induction by 2- Degawa et al
methoxy-4-aminobenzene at the mRNA and protein level in a (1993)
dose-dependent manner.
Lead nitrate had minimal effect on P4501A1 and its induction by
3- methyl cholanthrene.
Lead nitrate did not affect microsomal activity.
Lead nitrate induced GST-P in a dose-dependent manner.
O
H
O
c
O
H
W
O
V
O
HH
H
W
-------
o
O
to
O
O
Table AX5-6.15. Genotoxic/Carcinogenic Effects of Lead - Epigenetic Effects and Mixture Interactions - Human
X
-------
o
O
to
O
O
Table AX5-6.16. Genotoxic/Carcinogenic Effects of Lead - Epigenetic Effects and Mixture Interactions -
DNA Repair - Human
Compound
Assay (Concentration and
Exposure Time)
Cell Type
and Culture
Medium
Co-exposure
Effects Reference
Lead Acetate DNA strand breaks as nucleoid
sedimentation (500 uM for
20-25 h)
HeLa Cells in UV (5 J/m")
AMEM +
5%FBS
Lead acetate alone did not induce single strand breaks. UV did induce
strand breaks. Co-exposure of lead and UV cause DNA strand breaks
to persist longer suggesting an inhibition of repair.
Hartwigetal(1990)
X
Abbreviations:
Medium and Components
AMEM = Alpha Minimal Essential Medium;
FBS = Fetal Bovine Serum
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
-------
o
o
3
CT*
to
O
o
Table AX5-6.17. Genotoxic/Carcinogenic Effects of Lead - Epigenetic Effects and Mixture Interactions -
DNA Repair - Animal
Assay (Concentration and
Compound Exposure Time)
Cell Type
and Culture
Medium
Co-exposure
Effects
Reference
X
to
Lead Acetate Cytotoxicity (0.5-5 uM for 24 h)
Mutagenesis- HPRT (0.5-5 uM
for 44h)
SCE(l-10nMfor26h+)
Lead Acetate Mutagenesis - gpt (0.5-1700 mM
for 24 h)
DNA strand breaks as
supercoiled relaxation (1000 mM
for 24 h)
V79in
AMEM +
10%FBS
UV (5 J/m2)
G12-CHV79
cells with 1
copy gpt gene
in Ham's F12
+ 5%FBS
UV (2 J/m2), or MNNG
(0.5 ug/L)
Lead acetate ( 3 and 5 uM) increased UV-induced increased
cytotoxicity with no dose response (plateau). There were no statistical
analyses of these data.
Lead acetate (0.5-5) increased UV mutagenicity though with no dose
response (plateau). There were no statistical analyses of these data
Lead acetate (1-10 uM) increased UV-induced SCE. Significant at
p<0.01. Only 25 cells per treatment analyzed.
Lead acetate was co-mutagenic with UV and MNNG increasing
frequency 2-fold.
Lead acetate does not increase strand breaks induced by UV.
Hartwigetal(1990)
Roy and Rossman
(1992)
Abbreviations:
G12 - CHV79 are derived from V79;
V79 are a Chinese Hamster Lung Cell Line;
H
6
o
Medium and Components
AMEM = Alpha Minimal Essential Medium;
FBS = Fetal Bovine Serum
o
H
O
c
o
H
W
O
V
O
HH
H
W
-------
o
O
to
O
O
Table AX5-6.18. Genotoxic/Carcinogenic Effects of Lead - Mitogenesis - Animal
Compound
Exposure Regimen
Species
Co-exposure
Effects
Reference
X
Lead Acetate Administered lead acetate (12.5 mg/kg) i.p. Male B6 Mice
Animals studied 24 h after injection.
Lead Nitrate Liver initiation induced by the resistant hepatocyte Male Wistar Rats-
model 4 per group
Initiation followed by iv injection of lead nitrate (100
jiM/kg ) or partial hepatectomy
Studied DNA synthesis (30 h after injection) and
preneoplastic nodule formation
(5 weeks after injection)
Lead Nitrate Liver initiation induced by the resistant hepatocyte Male Wistar Rats-
model (diethylnitrosamine followed by 2- 4 per group
acetylaminofluorene plus carbon tetrachloride)
Initiation followed by iv injection of 4 doses of lead
nitrate (100 uM/kg ) given once every 20 days or
partial hepatectomy, ethylene dibromide, or
nafenopine
Animal were evaluated for preneoplastic foci at 75 or
155 days after inititiation.
None Lead acetate induced TNF-alpha in glial and Cheng et al. (2002)
neuronal cells in the cerebral cortex and
subcortical white matter and on Purkinje cells in
the cerebellum, but did not induced apoptosis in
these areas
Partial Hepatectomy Lead nitrate stimulated DNA synthesis and liver Columbano et al.
cell proliferation (1987)
Lead nitrate did not induce preneoplastic nodule.
Partial hepatectomy did.
Diethylnitrosamine Lead nitrate, partial hepatectomy, ethylene Columbano et al.
dibromide, or nafenopine all stimulated DNA (1990)
synthesis and liver cell proliferation
Lead nitrate, ethylene dibromide, or nafenopine
did not induce preneoplastic nodule. Partial
hepatectomy did.
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Lead Nitrate Liver initiation induced by the orotic acid model
(diethylnitrosamine plus orotic acid)
Initiation followed by iv injection of lead nitrate (100
uM/kg) or partial hepatectomy, or by gavage:
ethylene dibromide, or cyproterone
DNA synthesis was examined at various time
intervals (24 h -5 days) after injection.
Male Wistar Rats- Diethylnitrosamine Lead nitrate, partial hepatectomy, ethylene
4 per group dibromide, or cyproterone all stimulated DNA
synthesis within 30 minutes.
Lead nitrate induced DNA synthesis for 5 days.
Coniet al. (1991)
-------
o
O
to
O
O
Table AX5-6.18 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Mitogenesis -Animal
Compound
Exposure Regimen
Species
Co-exposure
Effects
Reference
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Lead Nitrate Liver initiation induced by the resistant hepatocyte Male Wistar Rats- Partial
model (diethylnitrosamine followed by 2- 4 per group Hepatectomy,
acetylaminofluorene plus carbon tetrachloride) or the carbon tetrachloride
phenobarbital model (diethylnitrosamine plus orotic
acid), or the orotic acid model (diethylnitrosamine
plus orotic acid)
Initiation followed by iv injection of lead nitrate
(100 uM/kg ) or partial hepatectomy, or carbon
tetrachloride by gavage
Animals were studied 6 weeks after initiation.
Lead Nitrate Liver initiation induced by the resistant hepatocyte Male Wistar Rats- Diethylnitrosamine,
model (diethylnitrosamine followed by 4 per group 2-AAF
2-acetylaminofluorene plus carbon tetrachloride)
Initiation followed by iv injection of lead nitrate
(100 uM/kg ) or partial hepatectomy, or by gavage:
ethylene dibromide, or cyproterone, or nafenopine
Also tried either 1 or 2 additional iv injections of lead
over 3 day intervals.
Animals were studied at various intervals (1-6 days)
after injection
Lead Nitrate Administered as i.v. injection of lead nitrate (100 Male Wistar Rats- Partial
uM/kg ) or partial hepatectomy, or by gavage: carbon 4 per group Hepatectomy,
tetrachloride, or ethylene dibromide, or cyproterone, carbon tetrachloride
or nafenopine
Animals were studied at various time intervals (0.25-
24 h) after injection.
Lead Nitrate Administered as i.v. injection of lead nitrate (100 Male Wistar Rats- None
uM/kg ) or partial hepatectomy, or nafenopine by 4 per group -
gavage. 8 weeks old
Animals were studied at various time intervals (24-96
h) after injection.
Lead Nitrate Administered as i.v. injection of lead nitrate (10 Male Wistar rats - None
uM/100 g) 4 rats per group
Studies for apoptosis at 12, 24, 36, 48, 72, 96, 120,
168, 336 h after injection
Lead nitrate, partial hepatectomy, carbon
tetrachloride all stimulated DNA synthesis and
liver cell proliferation
Lead nitrate, did not induce preneoplastic nodules.
Partial hepatectomy and carbon tetrachloride did.
Ledda-Columbano
et al. (1992)
Coni et al. (1993)
Coni et al. (1993)
This study aimed to determine if mitogens induce
nodules at different time points.
Lead nitrate, ethylene dibromide, cyproterone, or
nafenopine did not induce preneoplastic nodules
at all. Partial hepatectomy did within 3 days.
Multiple injections of lead nitrate did not induce
preneoplastic lesions.
Lead nitrate, ethylene dibromide, cyproterone, or
nafenopine induced c-jun and c-myc but did not
induce c-fos.
Partial hepatectomy and carbon tetrachloride
induced c-jun, c-fos, and c-myc.
Lead nitrate induced a high incidence of
polyploidy and binucleated cells. These changes
were irreversible after 2 weeks. Many of these
cells were the newly synthesized cells.
Partial hepatectomy and carbon tetrachloride
induced tetraploid and octaploid mononucleated
cells.
Liver weight increased until day 5 then returned to Nakajima et al.
control levels. (1995)
DNA synthesis peaked at 36 h
Apoptosis peaked at day 4 and then decreased
gradually.
Melchiorri et al.
(1993)
-------
Table AX5-6.18 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Mitogenesis -Animal
o
cr
to
o
Compound
Lead Nitrate
Lead Nitrate
Exposure Regimen
Administered as i.v. injection of lead nitrate (100
uM/kg) or TNF-alpha.
Animals were studied at various time intervals (12-48
h) after injection.
Administered after diethylnitrosamine (200 mg/kg
given i.p) as i.v. injection of lead nitrate (100 uM/kg )
Species
Male Wistar Rats-
4 per group - 5-6
weeks old
Male Wistar rats -
4 per group
Co-exposure
None
Carbon
tetrachloride
Effects
Lead nitrate and TNF-alpha induced similar
proliferative responses.
Lead nitrate induced apoptosis affects both newly
synthesized cells and non-replicative cells.
Reference
Shinozuka,
1996
Columbano et al.
(1996)
X
or instead carbon tetrachloride by gavage
Animals were studied at various time intervals (3-21
days) after injection.
Lead Nitrate Administered as i.v. injection of lead nitrate (100
uM/kg ) or partial hepatectomy, or by gavage: carbon
tetrachloride, or cyproterone, or nafenopine
Animals were studied at various time intervals (0.5-
24h) after injection.
Male Wistar Rats
- 8 weeks old
Partial
Hepatectomy,
ethylene
dibromide,
nafenopine, or
cyproterone
Lead nitrate decreased the number and had no effect
on the size of placental glutathione-S-transferase
lesions. Carbon tetrachloride substantially
increased these lesions both in number and in size.
Lead nitrate induced NF-kB, TNF-alpha and iNOS, Menegazzi et al.
butnotAP-1. (1997)
Carbon tetrachloride induced and activated NF-kB,
TNF-alpha iNOS, and AP-1.
Nafenopine and cyproteone did not induce or
activate NF-kB,TNF-alpha iNOS, or AP-1.
H
6
o
o
H
O
o
H
W
O
O
HH
H
W
-------
o
O
to
O
O
Table AX5-6.19. Genotoxic/Carcinogenic Effects of Lead - Mitogenesis Human and Animal Cell Culture Studies
Assay (Concentration and Cell Type and
Compound Exposure Time) Culture Medium Co-exposure
Effects
Reference
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Lead Acetate
Lead Acetate
Lead Acetate
Lead Acetate
Lead Acetate
Lead Acetate
H4-II-C3 - human
hepatoma cells in DMEM
+ 2.5% PCS
Cell Proliferation (0.1-100 uM for
2-6 days)
DNA synthesis (1-100 uM for 72
h)
Tyrosine aminotransferase
expression and activity (0.3-10 uM
for 24- 48 h)
Cell proliferation (10 uM- ImM for REL cells- Rat Epithelial
24 h-7 days) cells in Ham's F10
medium + 10%FBS
Cell growth (0.01-10 uM for 12-72 U-373MG - human
h) glioma cell line in DMEM
Expression of genes in cytokine + 10 or 20% FBS
pathways (0.01-10 uM for 24 h)
Cell proliferation (0.078-320 uM
for 48 h)
Apoptosis (1.25-80 uM)
Cell cycle analysis
DNA synthesis (1-50 uM for 24 h)
Expression of genes in mitogen
activated pathways (1-50 uM for 5
min-4h)
Cell proliferation (1 uM for 24 h)
Cell differentiation (1 uM for
48 h)
PKC activation (1 uM for 24 h)
Rat-1 fibroblasts in
EMEM +10% FBS
1321N1- human
astrocytoma cells in
DMEM + 0.1%BSA
Primary oligodendrocyte
progenitor cells - in
DMEM + 1% FBS
Dexamethasone (0.1
uM for 16 h)
None
None
None
None
None
Lead acetate inhibited cell growth in a time- and dose-
dependent manner.
Lead acetate inhibited DNA synthesis in a dose-dependent
manner.
Lead acetate alone did not inhibit tyrosine aminotransferase.
Lead acetate inhibited glucocorticoid -induction of tyrosine
aminotransferase in a time- and dose-dependent manner.
Lead acetate inhibited cell growth at all concentrations for
24 h - 7 days.
Lead acetate did not affect gap junction capacity, which is
often inhibited by tumor promoters.
Lead acetate did not inhibit or enhance cell growth.
Lead acetate enhanced the expression of TNF-alpha, but
decreased interleukin- 1 beta, interleukin-6, gamma-
aminobutyric acid transaminase, and glutamine synthetase
under 10% FBS.
Lead acetate further enhanced the expression of TNF-alpha
under 20% serum, but had no effect at all on expression of
the other genes.
Lead acetate inhibited cell growth at 0.635-320 uM.
Lead acetate induced apoptosis from 2.5-10 uM.
Lead acetate caused GS/M and S-phase arrest.
Lead acetate induced DNA synthesis.
Lead acetate induced activation of MAPK, ERK1. ERK2,
MEK1 , MEK2, PKC, andpgO^.
Lead acetate did not activate PI3K or p70s*
Lead acetate inhibited basal and growth factor stimulated
growth.
Lead acetate inhibited cell differentiation in a PHC
dependent-manner.
Lead acetate redistributes PKC from the cytosol to the
membrane, but did not increase PKC activity.
Heiman and
Tonner(1995)
Apostoli et al.
(2000)
Liu et al. (2000)
lavicoli et al.,
2001
Lu et al. (2002)
Deng and Portez
(2002)
-------
Table AX5-6.19 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Mitogenesis Human and Animal Cell Culture Studies
O
ft>
cr
^
to
O
O
;>
X
1
^3
O
>
H
6
O
2|
O
H
O
Cj
O
H
W
O
O
HH
H
W
Compound
Lead Acetate
Lead Chloride
Lead Oxide
Lead Sulfate
Lead Chromate
Lead Chromate
Lead Chromate
Lead
Glutamate
Lead
Glutamate
Assay (Concentration and
Exposure Time)
Expression of TNF-alpha (0. 1-
10uMfor24h)
Cell proliferation (10 uM-lmM
for 24 -48 h)
Cell proliferation (10 uM-lmM
for 24 h -7 days)
Cell proliferation (10 uM-lmM
for 24 -48 h)
Apoptosis (350 uM for 24 h)
Apoptosis (0.4-2 ug/cm2 for 24 h)
Growth Curve (0.5-5 ug/cm2 24 h)
Growth Curve (250-1,000 uM for
24 h)
Mitotic Index (250-2,000 uM for
24 h)
Growth Curve (250-2,000 uM for
24 h)
Cell cycle Analysis (250-2,000
uM for 24 h)
Cell Type and
Culture Medium Co-exposure
U-373MG - human None
glioma cell line in
DMEM + 20% FBS
REL cells- Rat Epithelial None
cells in Ham's F10
medium + 10% FBS
REL cells- Rat Epithelial None
cells in Ham's F10
medium + 10% FBS
REL cells- Rat Epithelial None
cells in Ham's F10
medium + 10% FBS
Chinese Hamster Ovary None
AA8 cells in AMEM +
10%FBS
Primary Human Small None
Airway Cells in Clonetics
growth medium
WTHBF-6 -human lung None
cells with hTERT in
DMEM/F12 + 10%CCS
WTHBF-6 -human lung None
cells with hTERT in
DMEM/F12 + 10%CCS
WTHBF-6 -human lung None
cells with hTERT in
DMEM/F12 + 10%CCS
Effects
Lead acetate did not induce apoptosis.
Lead acetate increased the expression of TNF-alpha in a
dose-dependent manner.
TNF-alpha was not involved in lead-induced apoptosis.
Lead chloride inhibited cell growth at all concentrations for
24-48 h.
Lead chloride did not affect gap junction capacity, which is
often inhibited by tumor promoters.
Lead oxide inhibited cell growth at all concentrations for 24
h - 7 days.
Lead oxide did not affect gap junction capacity, which is
often inhibited by tumor promoters.
Lead sulfate inhibited cell growth at all concentrations for
24-48 h.
Lead sulfate did not affect gap junction capacity, which is
often inhibited by tumor promoters.
Lead chromate induced apoptosis.
This study was focused on chromate.
Lead chromate induced apoptosis in a concentration-
dependent manner.
Lead chromate inhibited cell growth.
Lead glutamate had no effect on growth.
Lead glutamate induced a concentration-dependent increase
in intracellular lead ions.
Lead glutamate increased the mitotic index, but either had
no effect or inhibited growth and induced mitotic arrest.
Reference
Cheng et al.
(2002)
Apostoli et al.
(2000)
Apostoli et al.
(2000)
Apostoli et al.
(2000)
Blankenship et
al. (1997)
Singh et al.
(1999)
Holmes et al.
(2005)
Wise et al.
(2005)
Wise et al.
(2005)
-------
o
O
cr
to
o
o
(^
Table AX5-6.19 (cont'd). Genotoxic/Carcinogenic Effects of Lead - Mitogenesis Human and Animal Cell Culture Studies
X
oo
H
6
o
o
H
O
o
H
W
O
O
HH
H
W
Compound
Lead Nitrate
Lead Nitrate
Lead Nitrate
Assay (Concentration and
Exposure Time)
Mitotic Index (3-30 uM for 2h +16
h recovery)
Mitotic Index (0.05- 1 uM for 3-
12 h)
Apoptosis (15-240 uM for 3 h)
Cell Type and
Culture Medium
CHO cells in EMEM +
10%FBS
CHO AA8 in DMEM
+10%NCS
Rat Alveolar
Macrophages in DMEM
+ 10% FBS
Co-exposure
None
Crown ethers to modify
effect through chelation
and uptake
None
Effects
Lower concentrations (1 and 3 uM) of lead nitrate
significantly increased the mitotic index. Higher
concentrations (10 and 30 uM) had no effect.
Lead nitrate dramatically reduced the mitotic index at 1 uM
though this was not statistically analyzed. There was no
effect on mitotic index at lower concentrations. Crown
ethers had no modifying effect.
Lead nitrate induced apoptosis in a dose-dependent manner.
Reference
Linet al. (1994)
Cai and Arenaz
(1998)
Shabani and
Rabbani (2000)
Abbreviations:
G12 - CHV79 are derived from V79;
V79 are a Chinese Hamster Lung Cell Line;
hTERT = hTERT is the catalytic subunit of human telomerase
Medium and Components
AMEM = Alpha Minimal Essential Medium;
DMEM = Dulbecco's Minimal Essential Medium;
DMEM/F12 = Dulbecco's Minimal Essential Medium/Ham's F12;
EMEM = Eagle's Minimal Essential Medium;
BSA = Bovine Serum Albumin
CCS = Cosmic Calf Serum
FBS = Fetal Bovine Serum
FCS = Fetal Calf Serum
NCS = Newborn Calf Serum
Differences between the serum types are unclear as insufficient details are provided by authors to distinguish.
-------
Table AX5-6.20. Genotoxic/Carcinogenic Effects of Lead - Mitogenesis Other
o
ft>
cr
^
to
o
o
*Tl
H
1
0
O
2|
0
H
O
o
H
W
O
O
H
W
Assay (Concentration and
Compound Exposure Time)
Lead Acetate Production of reactive oxygen
species (1 mM for 180 min)
Glutathione levels (1 mM for 0-180
min)
Lead Acetate Catalase Activity (500-2,000 uM
for 24 h)
Lead Acetate Thiol Levels (100 uM for 30 min -
4h)
Lead Chloride Oxidative Metabolism (0. 1-100
uM for 20 h)
Phagocytosis (0.1-100 uM for 20h)
Lead Chloride Oxidative Enzyme Levels (0.1-1
uM for 1 h)
Abbreviations:
AS 52 are derived from CHO;
CHO are a Chinese Hamster Ovary Cell Line;
Medium and Components
DMEM = Dulbecco's Minimal Essential Medium;
EMEM = Eagle's Minimal Essential Medium;
HBSS = Hank's Balanced Salt Solution
FBS = Fetal Bovine Serum
FCS = Fetal Calf Serum
Cell Type and
Culture Medium
SH-SY5Y- Human
neuroblastoma cells in
DMEM + 7% FCS
Human Foreskin
Fibroblasts (Chinese) in
DMEM +10% FCS
HeLa in HEPES/glucose
buffer
Macrophages from NMRI
mice in EMEM (serum
not given)
AS52-CHO-gpt, lackhprt
in HBSS followed by
Ham's F 12 + 5% FBS
Co-exposure
Glutamate (1 mM)
or PKC inhibitor
(IjiM)
3-aminotriazole
(3-AT) (80 mM to
inhibit catalase)
Buthionine
sulfoximine
(BSO) to deplete
cells of thiols
Zymosan and
latex particles as
substrates for
phagocytosis
Allopurinol (50
uM) to inhibit
xanthine oxidase
Effects
Lead acetate alone did not produce reactive oxygen species.
Glutamate alone did.
Lead acetate plus glutamate increase glutamate induced increases in
reactive oxygen species.
Lead acetate alone did not deplete glutathione. Glutamate alone did.
Lead acetate plus glutamate decreased glumate-induced decrease in
glutathione.
Lead acetate had no effect on catalase activity.
Lead acetate only lowered thiols marginally
Lead inhibited oxidative metabolism.
Lead inhibited phagocytosis, but only significantly at the highest
dose.
Lead chloride at low concentrations produced H2O2 at 1 h and not at
24 h. Lead chloride at high concentrations produced no change at 1
h and increased H2O2 at 24 h. Allopurinol inhibited H2O2 formation
at high lead concentrations.
Lead chloride had no effect on catalase, glutathione peroxidase,
glutathione reductase. Lead chloride inhibited glutathione-S-
transferase, CuZn-superoxide dismutase, and xanthine oxidase.
Reference
Naarala et al.
(1995)
Hwua and
Yang (1998)
Snyder and
Lachmann
(1989)
Hilbertz et al.
(1986)
Ariza et al.
(1998)
Differences between the serum types are unclear as insufficient details are provided by authors to distinguish.
-------
CHAPTER 5 ANNEX
ANNEX TABLES AX5-7
December 2005 AX5-100 DRAFT-DO NOT QUOTE OR CITE
-------
o
O
Table AX5-7.1. Light Microscopic, Ultrastructural, and Functional Changes
Author
Animal Species
Lead Dosage
Blood Lead
Findings
to
O
O
>
X
Khalil-Manesh et Sprague-Dawley
al. (1992a) rat
Khalil-Manesh et Sprague-Dawley
al. (1992b) rat
0.5% Pb acetate in drinking water
for 12 mo.
0.5% Pb discontinued after 6 mo
0.01% Pb discontinued after 6 mo
DMSA 0.5% used in 1/2
Khalil-Manesh et Sprague-Dawley 0.01% Pb acetate for 12 mo.
al. (1993a) rat
Max 125.4 ug/dL
Mean 55 ug/dL
Hi Pb @12 mo
Disc 30.4 ug/dL
Disc + DMSA 19.1 ug/dL
Ctrl 3.1 ug/dL
Lo Pb@12mo
Disc 6.9 ug/dL
DMSA5.5 ug/dL
Max 29.4 ug/dL
Range 9-34 ug/dL
Hyperfiltration at 3 mo. Decreased filtration at 12 mo.
NAG and GST elevated.
Nuclear inclusion bodies at all times.
Tubulointerstitial scarring from 6 mo.
No arterial or arteriolar pathology.
High Pb:
Nuclear inclusion bodies prominent.
Tubulointerstitial disease severe but less than 12 mo
continuous DMSA caused reduction in nuclear inclusion
bodies and tubuloint decrease, and an increase in GFR.
LowPb:
Neg pathology and increase in GFR with DMSA
GFR increased at 1 and 3 mo.
NAG increased but GST normal.
Pathology neg except at 12 mo-mild tubular atrophy and
interstitial fibrosis seen.
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Sanchez- Wistar rat
Fructuoso et al.
(2002a)
Sanchez-
Fructuoso et al.
(2002b)
Papaioannou et
al. (1998)
Wistar rat
Dogs
500 ppm (0.05%) Pb acetate for 2
mo, then EDTA
500 ppm (0.05%) Pb acetate for 2
mo, then EDTA
12 mg Pb acetate i.p. x 10
Max 52.9 ug/dL
Day 90: 33.2
Day 137:22.8
Ctrl: 5.90 ug/dL
Max 52.9 ug/dL
Day 90: 33.2
Day 137:22.8
Ctrl: 5.90 ug/dL
Rats given Pb to day 90, then treated with EDTA or untreated
today 137.
Marked decrease in kidney, liver, and brain Pb with EDTA but
no change in femur Pb
Hypertrophy and vacuolization of medium and small arteries,
mucoid edema and muscular hypertrophy of arterioles, include
bodies and fibrosis.
EDTA slowed progression.
Lead includes bodies intracytoplasmically in mesothelial and
giant cells of peritoneum and in interstitial connective tissue
cells of kidney. None in prox tubules of kidney.
-------
December 2005
X
o
to
DRAFT-DO I
^
0
H
O
O
H
W
O
O
H
W
Author
Vyskocil et al.
(1989)
Vyskocil et al.
(1995)
Vyskocil and
Cizkova(1996)
Sanchez et al.
(2001)
Herak-
Krambergeret al.
(2001)
Fujiwara et al.
(1995) and Kaji
et al. (1995)
Table AX5-7.1 (cont'd). Light Microscopic, Ultrastructural, and Functional Changes
Animal Species Lead Dosage Blood Lead Findings
Wistar rat 0.5%,1%, and 2% Pb acetate for 2-3 0.5%-105 ug/dL 0.5%-no morphologic or functional changes
mo. 1%- 196 ug/dL 1%-Incr in P-2 microglobulin excretion.
2%-320 ug/dL 2%-Incr in P2micr, glucose, protein, lysozyme, and LDH.
Hyperplasia and include bodies of prox tubules seen in both
I%and2%
Wistar rat 1% or 0. 1% Pb acetate for 2-4 mo. 1%- 173 ug/dL 1% caused increase in P-2 microglobulin excretion and injury
0.1%-37.6 ug/dL to proximal tubule.
0.1% caused no changes.
Wistar rats Unleaded petrol vapor (4mg/m3) B-2 microglobulin excretion increased at 60 days
8 hrs/day for 60 days
Sprague-Dawley 0.06% Pb acetate for 4 mo. 13.9 ug/dL vs. <0.5 ug/dL Decrease in expression of laminin-1 and increase in expression
rat in ctrl of fibronectin in kidneys.
Rat brush border 500 uM Pb 58% loss of sealed brush border membrane vesicles. Lower
membranes loss of sealed basolateral membrane vesicles.
Bovine cultured 0.5 - 10 uMPb nitrate Stimulated proliferation in smooth muscle cells. Reduced
vascular smooth proliferation in endothelial cells No leakage of LDH.
muscle and
endothelial cells
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December
to
8
!>
X
^
o
V
!>
-n
H
1
u
o
!2
O
H
/C)
r*^S
O
H
W
O
H
W
Author
Pereiraet al.
(1992)
Somashekaraiah
et al. (1992)
Bondy and Guo
(1996)
Blazka et al.
(1994)
Quinn and Harris
(1995)
Ercal et al.
(1996)
Vaziri and co-
workers (1997-
2004)
Farmandet al.
(2005)
Gurer et al.
(1999)
Animal Species
Rats
Chick embryos
Sprague-Dawley
rat cerebral
synapto somes
Mouse brain
micro vascular
endothelial cell
culture
Rat cerebellum
homogenates
C57BL/6 mice
Sprague-Dawley
rats
Sprague-Dawley
rats
Fischer 344 rats
Table AX5-7.2.
Lead Dosage
ALA-treated (40 mg/kg every
2 days for 15 days)
1.25 and 2.5 umol/kg of Pb acetate
0. 5 mMPb acetate
10, 100, and 1,000 nM Pb acetate
17-80 nMPb nitrate
1300 ppm Pb acetate for 5 weeks.
Nac, 5.5 mmol/kg, or DMSA, 1
mmol/kg, given in 6th week.
See Section 5.5 for details
100 ppm Pb acetate for 3 months
1 100 ppm Pb acetate for 5 wks.
Captoprilfor6thwk
Lead and Free Radicals
Blood Lead Findings
Fatigued earlier than controls.
Increase of CuZn SOD in brain, muscle and liver
Lipoperoxides maximal at 9 hrs and returned to normal at 72
hrs.
GSH depleted. GST, SOD and catalase increased in liver,
brain and heart at 72 hrs
Generation of ROS not increased by Pb alone but increased
when 50 uM iron sulfate added.
Constitutive production of nitrite, but not inducible, decreased
by Pb. Extracellular calcium abolishes this effect.
—
Constitutive NOS activity inhibited 50% by 17 nM Pb and
— 100% by 80 nM Pb. Reversed by increasing Ca concentration.
36.5 ug/dL in Pb-treated; Liver and brain GSH depleted by Pb and MDA increased.
13.7 ug/dL in Pb+ Both were restored by either DMSA or NAC. However,
DMSA-treated. DMSA reduced blood, liver, and brain Pb levels while NAC
did not.
Variable. See section 5.5 for details.
CuZnSOD activity increased in kidney. CuZnSOD activity
increased in aorta whereas protein abundance unchanged.
Guanylate cyclase protein abundance in aorta decreased.
24.6ug/dL in Pb-treated. MDA in liver, brain, and kidney increased by Pb. GSH
23.8 ug/dL in Pb + decreased. Captopril reversed these findings.
Captopril-treated
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Table AX5-7.2 (cont'd). Lead and Free Radicals
Author
Animal Species
Lead Dosage
Blood Lead
Findings
Acharya and
Acharya(1997)
Swiss mice
200 mg/kg Pb acetate i.p. x 1
MDA-TBA increased x 4 in liver, brain, kidney, and testis by
end of 1st wk and persisted for 4 wks.
Upasani et al.
(2001)
Rats
100 ppm Pb acetate for 30 days.
Groups given vit C, vit E, or algae
MDA, conj dienes, and H2C>2 increased in liver, lung, and
kidney by Pb. Treatment with vit C, vit E, or Blue Green algae
reversed these findings.
Pande et al. Wistar rats Lead nitrate 50 mg/kg i.p. x 5
(2001) Lead + DMSA,MiADMSA,NAC,
DMSA + NAC,DMSA +
MiADMSA
DMSA most effective in blocking inhib of ALAD, elev of
ZPP, and inhib of GSH. Combined DMSA+NAC most
effective when given during or post-exposure.
>
X
Pande and Flora Wistar rats 2000 ppm Pb acetate x 4 wks.
(2002) DMSA,MiADMSA, DMSA +
LA,MiADMSA + LA x 5 days
Lead caused decrease in ALAD, GSH, and increase ZPP.
Lipoic acid (LA) did not chelate Pb in contrast to DMSA, but
both agents increased ALAD and GSH
Flora et al. Wistar rats 1000 ppm Pb acetate x 3 mo.
(2002) DMSA or MiADMSA + vit C or
vit E x 5 days
13.3 ng/dL
lead Rx
3 ng/dL DMSA Rx
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Table AX5-7.2 (cont'd). Lead and Free Radicals
Author
Animal Species
Lead Dosage
Blood Lead
Findings
Sivaprasad et al. Wistar rats 2000 ppm Pb acetate x 5 wks.
(2002) LA and DMSA during 6th week.
Senapati et al.
(2000)
Rats
1% sol of 5mg/kg Pb acetate x43 d.
Thiamine 25 mg/kg
Patra et al. IVRI 2CQ rats 1 mg/kg Pb acetate for 4 wks.
(2001) Vit E, vit C or methionine in 5th wk.
VitE + EDTA.
6.8 ng/dL Pb-Rx
6.3 ng/dL
lead, vit E +EDTA
Lead caused red in kidney GOT & NAG, decline in GSH,
catalase, SOD, GPx and Glut reductase, and increased MDA.
Lipoic acid
+DMSA restored these changes
Thiamine reduced Pb content and MDA levels of both liver
and kidney and improved pathology.
Lead in liver, kidney and brain reduced by vit E + EDTA
treatment. MDA increased by Pb in all 3 organs but decreased
by vit E + EDTA.
>
X
McGowan and Chicks
Donaldson (1987)
2000 ppm Pb acetate x 3 wks.
GSH, non-protein SH, lysine and methionine increased in liver
and non-prot SH, glycine, cysteine and cystathionine in
kidney. Cysteine reduced in plasma.
H
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HH
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December 200!
Author
Cory-Slechta
(1988)
Animal Species
Rats
Table AX5-7.3.
Lead Dosage
50 ppm Pb acetate for 3-4 mo.
Chelation with DMSA
Blood Lead Findings
20 ng/dL-lead DMSA 25-50 mg/kg i.p. for 1-5 d mobilized Pb from blood,
, , , , „ brain, kidney and liver, but not femur.
ue/dL- ead+25 me/ke
Pappas et al.
(1995)
Sprague-Dawley
rats
550-1100 ppm Pb acetate for 35
days
DMSA
52 ng/dL @ 550 ppm Pb DMSA @16-240 mg/kg/day p.o. for 21 days given with and
without concurrent Pb exposure. Rats showed dose-related
65 lig/dL @ 1 lOOppmlead reductlon m pb content of bloodj bralri5 femurj kldney> wd
liver with or without concur Pb.
Smith and Flegal Wistar rats
(1992)
206Pb 210 ng/mL for l.Sdays.DMSA 5.1 ng/g-ctrl
20 mg/kg i.p. 3.0 ng/g-DMSA
Rats on low Pb diet given DMSA decreased soft tissue but not
skeletal Pb. Lead redistributed to skeleton.
X
O
Os
Varnai et al.
(2001)
Wistar rats
(suckling)
2 mg/kg/d for 8 d
DMSA 0.5 mmol/kg 6x/d on dl-3 &
6-8
DMSA reduced Pb concentration
_ brain by ~ 50%.
in carcass, liver, kidneys, and
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Table AX5-7.4. Effect of Chelator Combinations
Author
Animal Species
Lead Dosage
Blood Lead
Findings
Flora et al.
(2004)
Wistar rats
1000 ppm Pb acetate for 4 mo
46 ng/dL-lead
12.8 ng/dL-combined Rx
5 days Rx with DMSA. CaNa2EDTA, or DMSA +
CaNa2EDTA. Comb Rx resulted in increased ALAD &
decreased Pb in blood, liver, brain, and femur.
Jones et al.
(1994)
Mice
10 i.p. injections of Pb acetate, 5.0
mg/kg
Mice Rx'ed with DMSA, CaNa2EDTA, ZnNa2EDTA, or
ZnNa3DTPA 1 .0 mmol/kg/d 4-8 d. CaNa2EDTA most
effective in removing brain Pb; DMSA in removing kidney
and bone Pb.
X
H
6
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o
H
O
O
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W
O
O
HH
H
W
Kostial et al.
(1999)
Flora et al.
(2004)
Sivaprasadet al.
(2004)
Malvezzi et al.
(2001)
Tandonet al.
1997)
Wistar rats
(suckling)
5 mg Pb/kg i.p. x 1
Chel agents d 2 & 3
Wistar rats 1000 ppm Pb acetate x 2 mo
Wistar rats 2000 ppm Pb acetate x 5 wks
Wistar rats 750 ppm Pb acetate x 70 days
DMSA, arginine, DMSA + arg or
H20 x 30 d
Rats 1000 ppm Pb acetate for 7 wks.
Dithiocarbamate x 4 days
67.8ng/dLtoll.2ng/dL
in H2O Rx'ed to 6.1
Hg/dL in DMSA + arg
105.3|ig/dLinPb.
86ng/dL in
dithiocarbamate.
EDTA, DMSA, racemic DMSA, EDTA + DMSA, EDTA +
rac DMSA given. EDTA reduced Zn in carcass & liver; rac
DMSA reduced Zn in kidneys. DMSA reduced Pb w/o
affecting Zn
DMSA, taurine or DMSA + taurine given for 5 d. Both taurine
& DMSA restored GSH. Comb of DMSA + taurine increased
RBC SOD & decreased TEARS, while most effectively
depleting blood, liver, & brain Pb.
DMSA, lipoic acid or combination given during 6th week.
Renal enzymes, kidney Pb and renal ALAD restored by
combined Rx
Lead increased BP and Pb levels in blood, liver, femur, kidney,
and aorta. DMSA + L-arginine most effective in lowering BP
and mobilizing Pb from tissues.
Two dithiocarbamates were compared: N-benzyl-D-glucamine
and N-(4-methoxybenzyl)-D-glucamine. They were only
partially effective in restoring ALAD, reducing liver & kidney,
but not brain Pb. They depleted Zn, Cu, and Ca.
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Table AX5-7.5. Effect of Other Metals on Lead
Author
Animal Species
Lead Dosage
Blood Lead
Findings
>
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H
6
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O
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W
O
O
HH
H
W
Maldonado-Vega Wistar rats
et al. (1996) (pregnant & non-
pregnant)
Olivi et al. (2002) MDCK canine
kidney cells
Bogden et al.
(1991)
Wistar rats
Skoczynska et al. Buffalo rats
(1994)
Othman & Albino rats
Missiry (1998)
Tandonet al.
(1992)
Flora et al.
(1989)
Flora et al.
(1994)
Albino rats
Albino rats
Wistar albino rats
100 ppm Pb acetate for 144-158
days
0,1,100 ppm Pb for 31 wks
0.2% or 4.0% Ca diet
Pb 70 mg/kg 2x/wk for 7 wks Cd
20 mg/kg Ix/wk for 7 wks.
All intragastric.
Pb acetate 100 (omol/kg I.M. x 1
Se 10 (imol/kg I.M. 2 hrs before Pb
Pb acetate 10 mg/kg/d p.o. x 6 wks.
EDTA or DTPA given for 5 d w or
w/o Se
Pb acetate 10 mg/kg/d p.o. x 6 wks
Thiamine, Zn or thiamine + Zn x 6
wks
Pb acetate 10 mg/kg/d x 56 d p.o.
EDTA or EDTA + Zn x 5 days p.o.
5.2 (ctrl) to 27.3 ng/dL in
Pb-exposed
8 (non-preg)to 17 ng/dL
in rats exposed only
during lactation
1.9 to 39.1 |ig/dLonlow
Ca diet and 2.0 to 53.3
Hg/dL on high Ca diet
5.1 to 29.6 ng/dL in Pb-
exposed. 37.4 ng/dL in
Pb + Cd
17tol38|ig/dLafterPb
58 ng/dL after EDTA.
50 ng/dL after EDTA + Se
6.2 to 120.9 ng/dL after
Pb
44.1 ng/dL after thiamine
+ Zn
4.6to43.0|ig/dLinPb.
22.5ng/dLinEDTA
16.5|ig/dLinEDTA +
Zn.
Lead administered to period before lactation (144 d) or to mid-
lactation (158 d).Lead in blood, kidney, liver, and bone
increased.
ALAD decreased and FEP incr. Lactation increased
Blood Pb from 24.7 to 31.2 ng/dL and decreased bone Pb from
83.4 to 65.2 nmol/g.
In response to agonists ADP or bradykinin levels of
intracellular Ca increased
3-fold and 2-fold. Lead inhibited the response.
At 100 ppm Pb high Ca diet produced higher BP and more
renal cancers than low Ca diet and higher levels of Pb in brain,
liver, bone, heart, and testis but lower levels in kidney. Serum
Ca on high Ca diet was 13.2 mg/dL.
Simultaneous Pb and Cd administration increased blood Pb but
decreased Pb in liver and kidneys as compared to Pb
administration alone.
Sodium selenite (Se is a well-known anti-oxidant) prevented
lipid peroxidation (TEARS) and reduction in GSH caused by
Pb. SOD & glut reductase also normalized.
Selenium had no additional benefit over chelators except for
higher ALAD and lower ZPP in blood, lower Pb in liver and
kidney.
Thiamine given as 25 mg/kg/d and Zn sulfate as 25 mg/kg/d.
ALAD restored by combined Rx. Liver and kidney Pb affected
to a minor degree but brain Pb not affected.
CaNa2EDTA given as 0.3 mmol/kg/d i.p. and Zn sulfate as 10
or 50mg/kg/d. ALAD partially restored after EDTA + Zn but
not after EDTA. EDTA reduced Pb in bone, kidney, and liver
but not in brain. Zn cone increased in blood, kidney, & brain
by 50 mg Zn dosage.
-------
December 2005
>
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CHAPTER 5 ANNEX
ANNEX TABLES AX5-8
December 2005 AX5-5-110 DO-NOT QUOTE OR CITE
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Table AX5-8.1. Bone Growth in Lead-exposed Animals
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
Lead Acetate
41.7mgPb/l
83.3 mg Pb/1
166.6 mgPb/1
12 to 16 weeks
Drinking water
Lead aerosol
77,249,orl546ug/m3
for 50 to70 days
Inhalation
Rat Lead level in bone of control animals
Wk 0 = 1.3 ± 0.83 ug Pb/g; Wk4 = 1.2 ± 0.99 ng Pb/g;
Wk 8 = 1.3 ± 1.08 ug Pb/g; Wk 12 = 0.8 ± 0.13 ug Pb/g;
Wkl6 = 1.3±0.95ngPb/g
Lead level in bone of animals receiving 41.7 mg Pb/1
Wk 0 = 1.0 ± 0.50 ng Pb/g; Wk4 = 5.9* ± 1.76 ng Pb/g;
Wk 8 = 2.9* ±1.15 ug Pb/g; Wk 12 = 6.2* ±1.01 ^g Pb/g;
Wk 16 = 6.0* ± 0.75 ug Pb/g
Lead level in bone of animals receiving 83.3 mg Pb/1
Wk 0 = 2.0 ± 0.97 ug Pb/g; Wk4 = 11.7* ± 3.56 ug Pb/g;
Wk 8 = 8.8* ± 3.37 ug Pb/g; Wk 12 = 14.3* ± 4.29 ng Pb/g
Lead level in bone of animals receiving 166.6 mg Pb/1
Wk 0 = 0.9 ± 0.23 ng Pb/g; Wk 4 = 17.0* ± 3.89 ug Pb/g;
Wk 8 = 35.7* ± 3.64 ug Pb/g; Wk 12 = 21.7* ± 5.11 ug Pb/g;
* significantly higher than control animals at corresponding time point
Rat 16.9 ± 6.6 ug Pb/g bone taken up in animals exposed to 77 ug/m3 for
70 days versus 0.2 ± 0.2 ug Pb/g in control animals;
15.9 ± 4.3 ug Pb/g bone in rats exposed to 249 ug/m3 for 50 days;
158 ± 21 ug Pb/g bone in rats exposed to 1546 ug/m3 for 50 days
Not given
Hac and Kruchniak
(1996)
Control: 2.6 ug/dL
77 ug/m3: 11.5 ug/dL
249 ug/m3: 24.1 ug/dL
1546 ug/m3: 61.2 ug/dL
Grobleret al. (1991)
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Lead acetate
250 ppm or 1000 ppm
7 weeks to females
prior to mating,
continuing through
gestation and lactation
Drinking water
Rat Offspring body weight was depressed relative to controls during
suckling (Day 11) and after weaning (Day 24) in high dose and
continuously lead-exposed groups.
Continuous lead exposure caused a greater decrease in offspring body
weight than lead exposure only prior to or after parturition.
Decreased tail length growth suggested possible effects of lead on tail
vertebral bone growth.
Dams prior to mating:
Control = 2.7 ± 0.6 ug/dL
250 ppm =39.9 ±3.5 ug/dL
1000 ppm = 73.5 ±9.3 ug/dL
Hamilton and
O'Flaherty(1994)
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Table AX5-8.1 (cont'd). Bone Growth in Lead-exposed Animals
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
H
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Lead acetate
Hi Pb animals 5000
ppm for 6 months,
reduced to 1000 ppm;
Lo Pb animals 100 ppm
Drinking Water
Rat
Lead acetate
17 mg per kg of feed
50 days
In diet
Lead acetate
17 mg per kg of feed
50 days
In diet
Rat
Rat
In male rats exposed to 100 ppm lead in drinking water and a low
calcium diet for up to one year, bone density was significantly
decreased after 12 months, while rats exposed to 5000 ppm lead had
significantly decreased bone density after 3 months. Lead content of
femurs was significantly elevated over the content of control rats at all
time points (1, 3, 6, 9, 12 months). Trabecular bone from the low dose
animals was significantly decreased from 3 months forward.
No differences in the length of the femurs, but the mean length of the
5th lumbar vertebra was significantly decreased. The mean length of
the femur growth plate cartilage was also significantly decreased in
lead-exposed animals.
No differences in the length of the femurs, but the mean length of the
5th lumbar vertebra was significantly decreased. The mean length of
the femur growth plate cartilage was also significantly decreased in
lead-exposed animals.
LowPb(|ig%):
1 month
Control = 2 ± 1; Exp = 19 ± 10*
3 months
Control = 2 ± 1; Exp = 29 ± 4*
6 months
Control = 3 ± 1; Exp = 18 ± 2*
9 months
Control = 1 ± 1; Exp = 17 ± 3*
12 months
Control = 3 ± 1; Exp = 21 ± 3*
Hi Pb (ng%):
1 month
Control = 3 ± 1; Exp = 45 ± 13*
3 months
Control = 3 ± 1; Exp = 90 ± 15*
6 months
Control = 4 ± 1; Exp = 126 ± 10*
9 months
Control = 4 ± 1; Exp = 80 ± 39*
12 months
Control = 3 ± 1; Exp = 59 ± 18*
*p< 0.001
Not given
Not given
Gruberet al. (1997)
Gonzalez-Riola et al.
(1997)
Escribanoet al. (1997)
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Table AX5-8.1 (cont'd). Bone Growth in Lead-exposed Animals
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
Lead acetate
0.6%
GD 5 to Adulthood
(various)
In drinking water
Rat Early bone growth was significantly depressed in a dose-dependent
fashion in pups of lead-exposed pups, with growth suppression in male
offspring considerably greater than females. Significant decreases in
plasma insulin-like growth factor and plasma sex steroids and
increased pituitary growth hormone were also observed.
Groups:
DDW = Dams and pups received distilled deionized water entire study
Ac/Ac = Dams and pups received acetic acid solution entire study
Preg = Dams received 0.6% lead water from GD 5 to parturition
Lact = Dams received 0.6% lead water during lactation only
P + L = Dams received 0.6% lead water from GD 5 through lactation
Postnatal = Dams and pups received 0.6% lead water from parturition
through adulthood
Pb/Pb = Dams and pups received 0.6% lead water from GD 5 through
adulthood
Whole blood lead (ug/dL) in
male/female offspring at age Day
85:
DDW =5.5 ±2.0/6.8 ±1.5;
Ac/Ac = 1.9 ±0.2/1.4 ±0.3;
Preg = 9.1±0.7*/11.6±4.6*;
Lact =3.3 ±0.4/3.4 ±0.8;
P + L= 16.1 ± 2.3*710.4 ± 1.8*;
Postnatal = 226.0 ± 29.0*/292.0 ±
53.0*;
Pb/Pb = 316.0 ±53.0*/264.0 ±
21.0*
*p< 0.05 compared to Ac/Ac
group.
Ronis et al. (1998a)
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Lead acetate Rat
0.05% to 0.45%
GD 5 through sacrifice
of pups at 21, 35, 55,
and 85 days
In drinking water
Lead nitrate Rat
0.02% (125 ppm)
GD5 to 1 day before
sacrifice
In drinking water
Early bone growth was significantly depressed in a dose-dependent
fashion in pups of all lead-exposed groups, with growth suppression in
male offspring considerably greater than females. Significant
decreases in plasma insulin-like growth factor and plasma sex steroids
and increased pituitary growth hormone were also observed.
Between age 57 and 85 days growth rates were similar in control and
lead-exposed pups, suggesting exposure at critical growth periods such
as puberty and gender may account for differences in growth reported
by various investigators.
Exposure to 0.2% lead nitrate (125 ppm lead) did not significantly
affect growth, though males weighed significantly less than females.
Offspring:
0.05% Pb = 49 ± 6 ug/dL; 0.15%
Pb = 126 ± 16 ug/dL; 0.45% Pb =
263 ± 28 ug/dL
Ronis et al. (1998b)
Rat Pups
5 days old: 43.3 ±2.7 ug/dL
49 days old: 18.9 ± 0.7 ug/dL
(females: 19.94 ±0.8 ug/dL;
males: 17.00 ±1.1 ug/dL)
Camorattoet al. (1993)
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Table AX5-8.1 (cont'd). Bone Growth in Lead-exposed Animals
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
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H
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H
O
o
H
W
O
O
HH
H
W
Lead acetate
0.15% or 0.45%
GD 4 until Day 55
In drinking water
Lead acetate
lOOOppm
22-26 days
In drinking water
Rat A dose-dependent decrease in load to failure in tibia from lead-exposed
(0.15% and 0.45% lead acetate in drinking water) male pups only.
Hormone treatments (L-dopa, testosterone or dihydrotestosterone in
males, or estradiol in females) failed to attenuate lead deficits during
the pubertal period. Distraction osteogenesis experiments performed
after stabilization of endocrine parameters (at 100 days of age) found
decreased new endosteal bone formation and gap x-ray density in the
distraction gaps of lead-exposed animals.
Rat Lead disrupted mineralization during growth in demineralized bone
matrix implanted subcutaneously into male rats. In the matrix that
contained 200 micrograms lead/g of plaque tissue, alkaline phosphatase
activity and cartilage mineralization were absent, though calcium
deposition was enhanced. Separate experiments found enhanced
calcification and decreased alkaline phosphatase activity in rats
implanted with a control (no lead) matrix and given 1000 ppm lead in
drinking water for 26 days.
Offspring:
0.15%Pb = 67-192 ng/dL; 0.45%
Pb = 120-388 ng/dL
Roniset al. (2001)
Blood Pb(ngML)
Control:
Implantation Day 0 = 1.3 ± 0.6;
Day 8 = 2.2 ± 0.9; Day 12 = 2.1 ±
0.7.
Lead added to matrix:
Implantation Day 0 = 1.5 ± 0.8;
Day 8 = 5.7 ± 0.8a'b; Day 12 = 9.5
±0.5a>b
Lead in drinking water:
Implantation Day 0 = 129.8 ± 6.7
a; Day 8= 100.6 ± 6.8 a'b; Day 12
= 96.4±5.3a'b.
a Significant (p<0.05) difference
from control.
b Significance (p<0.05) difference
from corresponding value at
implantation (Day 0).
Hamilton and
O'Flaherty(1995)
Abbreviations
Mg-
ppm-
GD-
Pb-
g-
ng%-
milligram
microgram
parts per million
gestational day
lead
gram
microgram percent
Exp
wk-
dL-
liter
cubic meter
experimental group
week
deciliter
percent
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Table AX5-8.2. Regulation of Bone Cell Function in Animals - Systemic Effects of Lead
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
H
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HH
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Lead acetate
30 mg/kg
Single IV injection
Lead acetate
0.82%
1 week
In diet
Rat
Rat
Lead acetate
0.15% or 0.45%
GD 4 until Day 55
In drinking water
Rat
Groups of male rats were killed 0.5, 5,15, and 30 min and 1, 2, 6, and 12 h after the single
lead injection. Serum calcium and phosphorus levels both initially increased after lead
injection with serum phosphorus reaching a maximum value (13.5 mg%) after 30 min and
calcium (17 mg%) after 1 h. Calcium and phosphorus levels decreased after 1 h and
returned to baseline levels after 12 h.
Ingestion of 0.82% lead in male rats fed either a low phosphorus or low calcium diet
reduced plasma levels of 1,25-(OH)2CC, while lead had no effect in rats fed either a high
calcium diet or a normal phosphorus diet.
Effect of lead on serum 1 ,25-(OLTbCC levels in rats fed low P or normal P diet
Dietary Phosphorus
0.1%
0.1%
0.1%
0.3%
0.3%
0.3%
Supplement
Control
Cholecalciferol
0.82% Pb+Cholecalciferol
Control
Cholecalciferol
0.82% Pb+Cholecalciferol
Serum 1,25-(OH)2CC
<10 pg/mL
248 ± 7 pg/mL
94 ± 13pg/mL
<10 pg/mL
285 ± 44 pg/mL
245 ± 46 pg/mL
Effect of lead on serum 1,25-(OLTbCC levels in rats fed low Ca or high Ca diet
Dietary Calcium
0.02%
0.02%
0.02%
1.2%
1.2%
1.2%
Supplement
Control
Cholecalciferol (50ng/day)
0.82% Pb+Cholecalciferol
Control
Cholecalciferol (50ng/day)
0.82% Pb+Cholecalciferol
Serum 1,25-(OH)2CC
<10 pg/mL
754±18pg/mL
443 ± 79 pg/mL
<10 pg/mL
285 ± 44 pg/mL
245 ± 46 pg/mL
No effects of lead on plasma concentrations of vitamin D metabolites, 25-OH D3 or 1,25-
(OH2)D3, in pubertal male rats exposed to either 0.15% or 0.45% lead acetate in drinking
water and maintained on an adequate diet.
Not given
Kato et al.
(1977)
Smith et al.
(1981)
ug/lOOmL
3±1
9±8
352 ± 40
<3
<3
284 ± 36
ug/lOOmL
<3
<3
284 ± 36
Offspring:
0.15%Pb = 67-192
ug/dL; 0.45% Pb =
120-388 ug/dL
Roniset al. (2001)
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to
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Table AX5-8.2 (cont'd). Regulation of Bone Cell Function in Animals - Systemic Effects of Lead
>
X
Compound
Dose/Concentration
Duration Exposure
Route
PbCl2
0,0.2, or 0.8%
1 or 2 weeks
In diet
PbCl2
0,0.2, or 0.8%
1 or 2 weeks
In diet
Lead acetate
l%for 10 weeks or
0.00 1-1% for 24 weeks
In drinking water
Species Effects
Chicks Compared with control animals, lead exposure significantly increased intestinal calbindin
protein and mRNA levels in addition to plasma 1,25-dihydroxyvitamin D concentration.
The effect was present after 1 week of exposure and continued through the second week.
In calcium-deficient animals increased plasma 1,25-dihydroxyvitamin D and calbindin
protein and mRNA were significantly (p < 0.05) inhibited by lead exposure in a dose
dependent fashion over the 2 week experimental period.
Chicks Dose dependent increases in serum 1,25-(OH2)D3 levels (and Calbindin-D protein and
mRNA) with increasing dietary lead exposure (0. 1% to 0.8%) in experiments performed on
Leghorn cockerel chicks fed an adequate calcium diet.
Rat Short term administration of 1% lead resulted in significant increases in bone lead. Total
serum calcium and ionized serum calcium were significantly decreased, as compared to
controls. Circulating levels of 1 ,25-(OH2)D3 were also decreased, though the rats were
maintained on a normal calcium diet (0.95%). In the long term study, a dose-dependent
increase in parathyroid weight occurred with increasing exposure to lead in drinking water.
Blood Level
None given
None given
Short term (10
week) study:
Control: < 0.02
Hg/1
Lead-exposed:
> 5ng/l
Reference
Fullmer (1995)
Fullmer (1996)
Szabo et al.
(1991)
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Short term (10 weeks) exposure
Serum Calcium (mM) Ionized Calcium
(mM)l,25(OH)2D3(pM)
Parathyroid Weight (jig/gland)
*p<0.01
Long term (24 weeks) exposure
Pb in water
Controls
2.42 ±0.03
1.25 ±0.03
232 ±18.9
96 ±34
Normalized Parathyroid
Weight (|ig/g body wt)
Lead-exposed
2.32 ±0.02*
1.15±0.03*
177 ±10.8*
178 ±25*
l,25(OH)2D3(pM)
0%
0.001%
0.01%
0.1%
1.0%
p<0.01
0.50 ±0.06
0.72 ± 0.25
0.81 ±0.28
0.94 ±0.27
0.81 ±0.29*
241 ± 32
188 ±27
163 ±17
206 ± 24
144 ± 33*
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to
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Table AX5-8.2 (cont'd). Regulation of Bone Cell Function in Animals - Systemic Effects of Lead
>
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Compound
Dose/Concentration
Duration Exposure
Route Species
Lead nitrate Rat
0.02% (125 ppm)
GD5 to 1 day before
sacrifice
In drinking water
Lead acetate Rat
0.05% to 0.45%
GD 5 through sacrifice
of pups at 21, 35, 55,
and 85 days
In drinking water
Abbreviations
mg - milligram
h - hour
Effects
Basal release of growth hormone from control and lead-exposed pups at age 49 days was
not significantly different. Growth hormone releasing factor-stimulated release of growth
hormone from pituitaries of lead-exposed pups was smaller than the stimulated release of
growth hormone from pituitaries of control animals (75% increase over baseline vs. 171%
increase, respectively), but the difference did not achieve significance (P = 0.08). Growth
hormone content of the pituitary glands was also not influenced by lead exposure.
Pituitary GH content (ug/mg) at postnatal day 55:
Control Male Pups = 56.6 ± 8.0; Female Pups = 85.6 ± 9.3
0.05% Pb Male Pups = 107.2 ± 10.5*; Female Pups = 116.2 ±9.1
0.15% Pb Male Pups = 96.8 ± 5.0*; Female Pups = 105.1 ± 7.3
0.45% Pb Male Pups = 106.0 ± 9.8*; Female Pups = 157.0 ± 9.9*
*significantly different from control, p < 0.05
GD - gestational day
mM millimolar
Blood Level Reference
Rat Pups Camoratto et al.
5 days old: 43.3 ± (1993)
2.7 ug/dL
49 days old: 18.9 ±
0.7 ug/dL
(females: 19.94 ±
0.8 ug/dL; males:
17.00 ±1.1 ug/dL)
Offspring: Ronis et al.
0.05%Pb = 49±6 (1998b)
ug/dL; 0.1 5% Pb =
126 ±16 ug/dL;
0.45% Pb = 263 ±
28 ug/dL
1,25- (OH)2CC-l,25-dihydroxycholecalcigerol Pb - lead
ug - microgram
pM - picomolar
25 - OH D3- 25-hydroxycholecalciferol IV - intravenous
PbCl2 lead chloride
1 ,25 - (OH)2 D3 - vitamin D3
kg - kilogram
mg% - milligram percent
pg - picogram
% - percent
mL - milliliter
dL deciliter
mRNA - messenger ribonucleic acid
ppm - parts per million
GH - growth hormone
min - minute
-------
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O
Table AX5-8.3. Bone Cell Cultures Utilized to Test Effects of Lead
>
X
oo
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Compound
Dose/Concentration
Duration Exposure
Route
210Pb nitrate
5 uM
20 hours
In medium
Lead acetate
0 to 50 uM
20 h
In medium
Species
Effects
Blood Level
Reference
Stable "Pb"
5 mg/mL in drinking
water given during
gestation.
On GDI 8, SOuCi
210PbgivenIVto
pregnant dams
210Pb nitrate
6.5 to 65 uM
5 min to 2 h
In medium
Rat
(Fetal Bone
Organ
Culture)
Mice
(bone cell
isolation from
calvaria)
PTH (3885 lU/mg bone) enhanced cell-mediated release of 210Pb from bone. Release Not given/Not
of 210Pb was accompanied by proportional loss of stable lead and calcium from treated applicable
bones.
Time Release of 210Pb (EM/CM ratio)
Omin 1.00
10 min 0.82 ±0.05
2hr 1.12 ±0.04
6hr 1.59 ±0.08*
24 hr 3.69 ±0.15*
48 hr 3.75 ±0.09*
48 hr 0.78 ± 0. 14* (in presence of 30 mU/mL salmon calcitonin)
*Different from 1 .00, p < 0.01 .
Uptake of 210Pb by OC cells rapid. Not applicable
OC cells have greater avidity for lead compared to OB cells.
OC cell uptake of lead almost linear vs. little increase in lead uptake by OB cells with
increasing Pb concentrations in media.
Rosen and Wexler
(1977)
Rosen (1983)
Mice
(osteoclastic
bone cell
isolation from
calvaria)
Mice
(osteoclastic
bone cell
isolation from
calvaria)
15-30% release of 210Pb label occurred in OC cells over 2 h time period.
Physiological concentrations of PTH resulted in marked increase in 210Pb and 45Ca
uptake by OC cells. 210Pb uptake linear over PTH concentrations of 50 to 250 ng/mL).
Media concentrations of lead > 26 uM enhanced calcium uptake by cells.
Three readily exchangeable kinetic pools of intracellular lead identified, with the
majority (approximately 78%) associated with the mitochondrial complex.
Cultures were labeled with Ca (25 uCi/mL) for 2 or 24 h and kinetic parameters
were examined by analysis of 45Ca washout curves.
In kinetic analysis using dual-label (1-2 uCi/mL 210Pb and 25 uCi/mL 45Ca) wash out
curves, the Ca:Pb ratios of the rate constants were approximately 1:1, suggesting
similar cellular metabolism.
Not applicable
Not applicable
Pounds and Rosen
(1986)
Rosen and Pounds
(1988)
-------
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3
CT*
to
O
o
Table AX5-8.3 (cont'd). Bone Cell Cultures Utilized to Test Effects of Lead
X
^o
H
6
o
o
H
O
o
H
W
O
O
HH
H
W
Compound
Dose/Concentration
Duration Exposure
Route
Lead acetate and 210Pb
label
0-100 uM
20 hours
In medium
Lead acetate
5 or 25 uM
Up to 5 hours
In medium
Lead nitrate
5 uM
20 minutes
In medium
Pb2+
5 or 12.5 uM
Up to 100 minutes
In medium
Species
Mice
(osteoclastic
bone cell
isolation from
calvaria)
and
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Rat
Osteosarcoma
Cells
(ROS 17/2.8)
Rat
(osteoblastic
bone cell
isolation from
calvaria)
Rat
(osteoblastic
bone cell
isolation from
calvaria)
Effects Blood Level
Concentrations as high as 100 uM did not cause toxicity in either cell culture. There Not applicable
was a slight decrease in growth of ROS cells at 5 uM lead concentration and a 50%
decrease in growth at 25 uM lead at day 9.
210Pb washout experiments with both cell cultures indicated similar steady-state lead
kinetics and intracellular lead metabolism. Both cell cultures exhibited one large,
slowly exchanging pool of lead, indicative of the mitochondrial pool.
Used 19F NMR in combination with l,2-bis(2-amino-5-fluorophenoxy)ethane- Not applicable
N,N,N',N'-tetraacetic acid (5F-BAPTA) to distinguish and measure concentrations of
Pb2+ and Ca2+ in aqueous solution.
Basal concentration of [Ca2+]; was 128 ± 24 nM. Treatment of cells with 5 and 25 uM
Pb2+ produced sustained 50% and 120% increases in [Ca2+];, respectively, over a 5
hour exposure period.
At a medium concentration of 25 uM Pb2+ a measurable entry of Pb2+into the cells
([Pb2+], of 29 ± 8 pM) was noted.
Lead (5 uM) linearly raised the emission ratio of FURA-2 loaded cells 2-fold within Not applicable
20 minutes of application, most likely due to increase in [Pb2+]; rather than increase in
[Ca2+]r
Intracellular calcium increased even in the absence of extracellular calcium.
5 or 12.5 uM Pb2+ applied simultaneously with re-added calcium reduced immediate Not applicable
CRAC to 70% or 37% of control value, respectively.
During CRAC a large influx of Pb2+ occurred, leading to a 2.7-fold faster increase in
the FURA-2 excitation ratio. These effects were exclusive of any inhibitory action of
Pb2+on calcium ATPase activity.
Reference
Long et al.
(1990a)
Schanne et al.
(1989)
Schirrmacher et
al. (1998)
Wiemannet al.
(1999)
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O
Table AX5-8.3 (cont'd). Bone Cell Cultures Utilized to Test Effects of Lead
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
Lead nitrate
0-150 uM
Up to 72 hours
In medium
Mice (bone
cell isolation
from parietal
bones)
Pb2+ concentrations of 50 |iM and above stimulated release of hydroxyproline and
previously incorporated 45Ca from organ culture. This did not occur in bone
inactivated by freezing and thawing. Eel calcitonin, bafilomycin AI, and scopadulcic
acid B significantly inhibited Pb mediated 45Ca release. There was a high correlation
between 45Ca and PGE2
release (p < 0.001), inferring Pb-induced bone resorption mediated by PGE2. This
was further supported by the significant depression of Pb-stimulated 45Ca release that
occurred with concurrent exposure to 10 uM of either indomethacin or flurbiprofen,
both inhibitors of cyclooxygenase.
Not applicable
Miyaharaet al.
(1995)
>
X
to
O
Lead acetate
0-25 uM
48 hours
In medium
Rat Osteocalcin production in cells treated with 100 pg 1,25-dihydroxyvitamin D3/mL of
Osteosarcoma medium and 0 uMPb2+for 16, 24, or 36 h was 20.1 ±2.1,23.5 ± 3.4, 26.1 ±2.5 in cell
Cells digests, and 87.2 ± 3.3, 91.6 ± 6.7, 95.1 ± 5.2 in the medium, respectively. The
(ROS 17/2.8) presence of 25 uM Pb2+in the medium, reduced osteocalcin levels to as low as 30% of
control levels.
Cells treated with 0, 5, 10, or 25 uM lead acetate for 24 h, followed by an additional
24 h exposure to 0 or 100 pg of 1,25-dihydroxy vitamin D3 and continued Pb2+
exposure, resulted in a concentration-dependent reduction of 1,25-dihydroxy vitamin
D3-stimulated osteocalcin secretion. 10 uM Pb resulted in medium osteocalcin levels
similar to control levels, however, 25 uM Pb resulted in about a 30% decrease.
Cellular osteocalcin levels were unaffected.
Not applicable
Long et al.
(1990b)
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Lead glutamate
4.5X10-5to4.5XlQ-
M
2, 4, or 6 days
In medium
Rat In the presence of serum in the cultures, concentrations of Pb2+ less than 4.5 X 10"5 M Not applicable
Osteosarcoma had no effect on cell proliferation. In the absence of serum, 4.5 X 10"7 M Pb2+
Cells increased proliferation at Day 4 and 4.5 X 10"6 M Pb2+ inhibited proliferation at Day 6.
(ROS 17/2.8) Lead exposure for 48 h (4.5 X 10'6 M) significantly (p < 0.01) increased total protein
production in cells and media of cultures labeled with [ H] proline, but did not
increase collagen production. Protein synthesis and osteonectin were enhanced in
cells following Pb + exposure.
Sauket al. (1992)
-------
o
O
to
O
O
Table AX5-8.3 (cont'd). Bone Cell Cultures Utilized to Test Effects of Lead
>
X
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Compound
Dose/Concentration
Duration Exposure
Route
Lead glutamate
4.5xlO'5M-10'7M
1,3, or 5 days
incubation
In medium
Lead glutamate
5-20 \iM
48 hours
In medium
Lead
0.5 to 5 uM
40min
In medium
Lead nitrate
5X10'4to5X10-15M
24 h
In medium
Species
Human
Dental Pulp
Cells
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Effects Blood Level Reference
All concentrations significantly increased cell proliferation on Day 1, 3 and 5 of Not applicable Thaweboon et al.
exposure in serum free conditions. Lead exposure resulted in dose-dependent (2002)
decrease in intracellular protein and procollagen I production over 5 days. In presence
of serum only, 4.5 x 10" M Pb + significantly increased protein production, however, at
that same concentration lead significantly decreased osteocalcin production (i.e.
reduced the level of osteocalcin by 55% at 12 hours).
Cells treated with 0, 5, 10, or 20 uM lead acetate for 24 h, followed by an additional Not applicable Guity et al. (2002)
24 h exposure to 0 or 100 pg of 1,25-dihydroxy vitamin D3 and continuted Pb +
exposure, resulted in a significant (p < 0.05 or less) reduction of osteocalcin secretion,
both in the presence and absence of 1,25-dihydroxy vitamin D3 at all Pb2+
concentrations. This effect is not mediated by PKC.
1 and 5 |iM Pb2+ significantly increased [Ca2+]; in the absence of 1,25- Not applicable Schanne et al.
dihydroxyvitamin D3 and significantly reduced the peak elevation in [Ca2+]j induced (1 992)
by 1,25-dihydroxy vitamin D3.
Simultaneous treatment of previously unexposed cells to Pb2+and 1,25-
dihydroxy vitamin D3 produced little reduction in the 1,25-dihydroxy vitamin D3-
induced 45Ca uptake, while 40 min of treatment with Pb2+ before addition of 1,25-
dihydroxy vitamin D3 significantly reduced the 1,25-dihydroxy vitamin D3-induced
increase in 45Ca influx.
Osteocalcin secretion significantly reduced below control values by culture with 1 uM Not applicable Angle et al.
Pb2+ in the presence or absence of added 1 ,25-dihydroxyvitamin D3 or 1 ,25- (1 990)
dihydroxyvitamin D3 and IGF-I. Inhibition of osteocalcin secretion was almost
complete in either hormone- stimulated or basal cultures with the addition of 100 uM
Pb +. Cellular alkaline phosphatase activity paralleled those of osteocalcin, though
there was no response to IGF-I alone or in combination with 1,25-dihydroxy vitamin
D3. Pb2+at 10"15, 10"12, and 10"9 to 10"7M did not influence DNA contents of cell
cultures, but 1 uM significantly (p < 0.05) inhibited basal cultures and those with IGF-
I + D3. Cell cultures exposed to 1 ,25-dihydroxyvitamin D3 and Pb2+ were inhibited at
10uMPb2+.
-------
o
O
to
O
O
Table AX5-8.3 (cont'd). Bone Cell Cultures Utilized to Test Effects of Lead
>
X
to
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Compound
Dose/Concentration
Duration Exposure
Route
Lead acetate
2 to 200 uM
72 h
In medium
Unidentified Pb2+
Various incubation
times
Not applicable
Unidentified Pb2+
Various incubation
times
Not applicable
Lead acetate
10 uM
2h
In medium
Lead acetate
5 or 25 uM
Up to 24 h
In medium
Species
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Bovine
(Bovine-
derived
osteocalcin)
Bovine
(Bovine-
derived
osteocalcin)
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Effects Blood Level
Lead (2 to 200 uM) had no effect on cell number or DNA and protein synthesis. Not applicable
Alkaline phosphatase activity was significantly reduced (p < 0.001) by lead in a dose-
and time-dependent manner.
Pb Concentration Alkaline Phosphatase Inhibition
2uM 10.0 ±1.1%
20 uM 22.0 ± 6.4%
200 uM 57.8 ±8.8%
Reductions in alkaline phosphatase mRNA levels mirrored Pb2+ -induced inhibition of
enzyme activity.
Binding studies of Ca + to osteocalcin suggested a single binding site with a Not applicable
dissociation constant (Kd) of 7 ± 2 uM for Ca-osteocalcin. Competitive displacement
experiments by addition of Pb + indicated the Kd for Pb-osteocalcin is 1 .6 ± 0.42 nM,
approximately 3 orders of magnitude higher.
Circular dichroism indicated Pb2+ binding induced a structural change in osteocalcin Not applicable
similar to that found in Ca2+ binding, but at 2 orders of magnitude lower concentration.
Pb + has 4 orders of magnitude tighter binding to osteocalcin (Kd = 0.085 uM) than
Ca2+ (Kd = 1 .25 mM). Hydroxyapatite binding assays showed similar increased
adsorption of Pb + and Ca +to hydroxyapatite, but Pb + adsorption occurred at a
concentration 2-3 orders lower than Ca2+.
Pb2+ treatment reduced the unidirectional rate of ATP synthesis (P; to ATP) by a factor Not applicable
of 6 or more (AM/H,: Control = 0.18 ± 0.04, Pb2+< 0.03). Intracellular free Mg2+
concentration decreased 21% after 2 h of 10 uM Pb + treatment (0.29 ± 0.02 mM prior
to Pb2+ treatment and 0.23 ± 0.02 mM after 2 h of Pb2+ treatment, p < 0.05).
5 uM Pb2+ significantly altered effect of EOF on intracellular calcium metabolism. In Not applicable
cells treated with 5 uM Pb + and 50 ng/mL EGF, there was a 50% increase in total cell
calcium over cells treated with 50 ng/mL EGF alone.
Reference
Klein and Wiren
(1993)
Dowd et al.
(1994)
Dowdet al.
(2001)
Dowdet al.
(1990)
Long and Rosen
(1992)
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to
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O
Table AX5-8.3 (cont'd). Bone Cell Cultures Utilized to Test Effects of Lead
>
X
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Compound
Dose/Concentration
Duration Exposure
Route
Lead acetate
5 or 25 uM
20 h
In medium
Lead acetate
10-utolO-7M
3 min
In medium
Lead acetate
0.5 to 60 uM
24 to 48 h
In medium
Species
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Human
Osteo sarcoma
Cells (HOS
TE85)
and
Rat
Osteo sarcoma
Cells
(ROS 17/2.8)
Effects Blood Level
Treatment with 400 ng/mL culture medium for 1 h or with 25 uM Pb2+ for 20 h Not applicable
increased total cell calcium:
Treatment Cell Calcium
Control 7.56 ± 1.05 nmol/mg protein
PTH (400 ng/mL) 23.28 ± 1 .40* nmol/mg protein
Pb (25 uM) 1 1 .37 ± 0.57* nmol/mg protein
PTH + Pb 37.88 ± 4.21 * nmol/mg protein
* p < 0.05 from control
Treatment of ROS cells with Pb at 1 or 5 uM concentrations produced a rise in [Ca2+]j Not applicable
to 170 nM and 230 nM, respectively, over the basal level of 125 nM. An elevation in
[Ca2+]i to 210 nM occurred during treatment with an activator of PKC, phorbol 12-
myristate 13-acetate (10 uM). Pretreatment with a selective inhibitor of PKC,
calphostin C, did not change basal [Ca2+]j, but prevented the Pb-induced rise in [Ca2+];.
Free Pb2+activated PKC in a range from 10"11 to 10"7 M, with a Kcat (activation
constant) of 1 . 1 X 10"10M and a maximum velocity (Vmax) of 1.08 nmol/mg/min
compared with Ca activation of PKC over a range of 10"8 to 10"3 M, with a Kcat of 3.6
X 10"7M, and a Vmax of 1 . 12 nmol/mg/min.
HOS TE 85 Cells Not applicable
Inhibition of proliferation (IC50) = 4 uM lead
Cytotoxicity = 20 uM lead
ROS 17/2.8 Cells
Inhibition of proliferation (IC50) = 6 uM lead
Cytotoxicity = 20 uM lead
Highest lead concentration in both cell types found in mitochondrial fraction.
Reference
Long et al. (1992)
Schanne et al.
(1997)
Angle et al.
(1993)
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Table AX5-8.3 (cont'd). Bone Cell Cultures Utilized to Test Effects of Lead
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
to
Lead acetate or lead
chloride
O.lto200 uM
24 h to 6 d
In medium
Lead acetate
0.1 to 30 uM
24 h
In medium
Chick growth Growth plate chondrocytes were exposed to 3 or 30 uM for up to 6 days. Maximal Not applicable
plate inhibition of cell proliferation as measured by thymidine incorporation occurred after a
chondrocytes 3-day exposure to lead. A similar 40% inhibition was found at both concentrations.
Higher concentrations (up to 100 uM) did not produce further inhibition.
In cultures treated for 24 h, lead produced a dose-dependent inhibition of alkaline
phosphatase, with 10 uM producing maximal inhibition (40-50% inhibition). Effects
of lead on proteoglycan synthesis were not found until after 48 h of exposure, with
maximal effect after 72 h of exposure (twofold, 30 uM). Lead exposure (10 to 200
uM) for 24 h produced a dose-dependent inhibition of both type II and type X
collagen synthesis.
Chicken A dose-dependent inhibition of thymidine incorporation into growth plate Not applicable
growth plate chondrocytes was found with exposure to 1-30 uM lead for 24 h. A maximal 60%
and sternal reduction occurred at 30 uM. Lead blunted the stimulatory effects on thymidine
chondrocytes incorporation produced by TGF-pl (24% reduction) and PTHrP (19% reduction),
however, this effect was less than with lead alone. Lead (1 and 10 uM) increased type
X collagen in growth plate chondrocytes approximately 5.0-fold and 6.0-fold in TGF-
pl treated cultures and 4.2-fold and 5.1-fold in PTHrP treated cultures when compared
with controls, respectively. Lead exposure alone reduced type X collagen expression
by 70-80%.
Hicks et al. (1996)
Zusciket al.
(2002)
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
-------
o
O
to
O
O
Table AX5-8.3 (cont'd). Bone Cell Cultures Utilized to Test Effects of Lead
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
Abbreviations
>
X
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Pb - lead
uCi - microCurie
IU - international units
hr - hour
OB - osteoblast
5F-BAPTA - l,2-bis(2-amino-5-£luorophenoxy)ethane-N,N,N',N'-tetraacetic acid
[Pb2+]i-free intracellular lead
FLTRA-2 - l-[6-Amino-2-(5-carboxy-2-oxazolyl)-5-benzofuranyloxy]-2-(2-amino-5-methylphenoxy)
ethane-N,N,N',N'-tetraacetic acid
M - molar
DNA - deoxyribonucleic acid
AM - decrease in magnetization of intracellular P; upon prolonged saturation of gamma-phosphate of ATP
mM - millimolar
Kcat - activation constant
IC50 - inhibitory concentration 50%
mg - milligram
210Pb - lead-210 radionuclide
EM - experimental medium
mU - milliunits
45Ca - calcium-45 radionuclide
CRAC - calcium release activated calcium reflux
pg - picogram
mRNA - messenger ribonucleic acid
ng - nanogram
Vmax - maximum velocity
TGF-p1! - transforming growth factor-beta 1
mL - milliliter
IV - intravenous
CM - control medium
uM - micromolar
ng - nanogram
[Ca2+]i -free intracellular calcium
PGE2 - prostaglandin E2
PKC - protein kinase C
Kd - dissociation constant
nmol - nanomole
HOS TE 85 cells - human osteosarcoma cells
PTHrP - parathyroid hormone-related protein
GD - gestational day
PTH - parathyroid hormone
min - minute
OC - osteoclast
ROS 17/2.8 -rat osteosarcoma cells
nM - nanomolar
h - hour
IGF-I- insulin growth factor -1
ATP - adenosine triphosphate
EGF - epidermal growth factor
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Table AX5-8.4. Bone Lead as a Potential Source of Toxicity in Altered Metabolic Conditions
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Lead acetate
200 ug/mL
105 days prior to mating
or 105 days prior to
mating and during
gestation and lactation
(160 days)
In drinking water
Lead acetate
12 mM
8 weeks prior to mating
and during gestation
In drinking water
Lead acetate
100 ppm
(A) Exposure for 158 ±
2 days from 21 days of
age to midlactation; (B)
Exposure 144 ± 2 days
from day 21 up to
delivery; (C) Exposure
only during lactation;
(D, E, and F) groups of
non-pregnant rats
exposed for periods
equivalent to groups A,
B and C, respectively.
In drinking water
Mice Results suggested very little lead was transferred from mother to fetus during
gestation, however, lead transferred in milk and retained by the pups
accounted for 3% of the maternal body burden of those mice exposed to lead
prior to mating only. The amount of lead retained in these pups exceeded that
retained in the mothers, suggesting lactation effectively transfers lead burden
from mother to suckling offspring. Transfer of lead from mothers was
significantly higher when lead was supplied continuously in drinking water,
rather than terminated prior to mating.
Rat
Rat
Considerably higher lactational transfer of lead from rat dams compared to
placental transfer was reported. Continuous exposure of rat dams to lead until
day 15 of lactation resulted in milk lead levels 2.5 times higher than in whole
blood, while termination of maternal lead exposure at parturition yielded
equivalent blood and milk levels of lead, principally from lead mobilized from
maternal bone.
In rats exposed to lead 144 days prior to lactation (B), the process of lactation
itself elevated blood lead and decreased bone lead, indicating mobilization of
lead from bone as there was no external source of lead during the lactation
process. Rats exposed to lead for 158 days (A)(144 days prior to lactation and
14 days during lactation) also experienced elevated blood lead levels and loss
of lead from bone. Lead exposure only during the 14 days of lactation was
found to significantly increase intestinal absorption and deposition (17 fold
increase) of lead into bone compared to non-pregnant rats, suggesting
enhanced absorption of lead takes place during lactation. The highest
concentration of lead in bone was found in non-pregnant, non-lactating control
animals, with significantly decreased bone lead in lactating rats secondary to
bone mobilization and transfer via milk to suckling offspring.
Not given
Concentration (ug/1) in
whole blood at day 15 of
lactation:
Controls = 14 ± 4; Lead-
exposed until parturition =
320 ± 55; Lead-exposed
until day 15 of lactation =
1260 ±171*
*p < 0.001 compared with
dams at parturition.
Concentration (ug/dL) in
whole blood at day 14 of
lactation or equivalent:
Group A =31.2 ±1.1;
Group B = 28.0 ± 1.7;
Group D = 27.3 ±2.2;
Group E = 24.7 ±1.2
Keller and Doherty
(1980a)
Palminger Hallen
et al. (1995)
Maldonado-Vega
et al. (1996)
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Table AX5-8.4 (cont'd). Bone Lead as a Potential Source of Toxicity in Altered Metabolic Conditions
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
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to
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6
o
O
H
O
o
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W
O
O
HH
H
W
Lead acetate Rat
100 ppm
(A) Exposure for 158 ±
2 days from 21 days
through 14 days of
lactation; (B)
Nonpregnant control
Group A; (C) Exposure
144 ±2 days from day
21 up to delivery; (D)
Nonpregnant control
Group C; (E) Lactating
rats not exposed to Pb;
(F) Nonpregnant rats
not exposed to Pb.
In drinking water
Lead acetate Rat
250 mg/mL
Beginning at 5 weeks of
age, rats exposed to lead
for 5 weeks, followed
by no additional
exposure.
In drinking water
When dietary calcium was reduced from the normal 1% to 0.05%, bone
calcium concentration decreased by 15% and bone lead concentration
decreased by 30% during the first 14 days of lactation. In non-lactating rats on
the 0.05% calcium diet, there were also decreases in bone calcium, but no
incremental bone resorption nor lead efflux from bone, suggesting the efflux
from bone during lactation was related to bone resorption. Enhancement of
calcium (2.5%) in the diet of lactating rats increased calcium concentration in
bone by 21%, but did not decrease bone resorption, resulting in a 28%
decrease in bone lead concentration and concomitant rise in systemic toxicity.
Demonstrated adverse effects in rat offspring bom to females whose exposure
to lead ended well before pregnancy. Five week-old-female rats given lead
acetate in drinking water (250 mg/mL) for five weeks, followed by a one
month period without lead exposure before mating. To test the influence of
dietary calcium on lead absorption and accumulation, some pregnant rats were
fed diets deficient in calcium (0.1%) while others were maintained on a normal
calcium (0.5%) diet. All lead-exposed dams and pups had elevated blood lead
levels, however pups bom to dams fed the diet deficient in calcium during
pregnancy had higher blood and organ lead concentrations compared to pups
from dams fed the normal diet. Pups born to lead-exposed dams had lower
mean birth weights and birth lengths than pups born to non-lead-exposed
control dams (p < 0.0001), even after confounders such as litter size, pup sex,
and dam weight gain were taken into account.
Concentration (ng/dL) in
whole blood at day 14 of
lactation or equivalent:
Group B = 26.1 ±2.1,
Group A =32.2 ±2.7*;
Group D = 23.8 ±2.1,
Group C = 28.2 ± 2.2*;
Groups E and F = 5.1 ±
0.4.
* p < 0.01, compared to
appropriate control
Blood lead concentration
of pups (nM): Low
calcium/no Pb = 0.137 ±
0.030°; Low calcium/Pb =
1.160 ±0.053A; Normal
calcium/No Pb = 0.032 ±
0.003°; Normal
calcium/Pb = 0.771 ±
0.056B.
Values that are not
marked by the same letter
are significantly different
(p<0.05).
Maldonado-Vega
et al. (2002)
Han et al. (2000)
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Table AX5-8.4 (cont'd). Bone Lead as a Potential Source of Toxicity in Altered Metabolic Conditions
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
to
oo
Lead acetate
1500 ug/Common
Pb/kg/day
approximately 10 years,
replaced by a 204Pb-
enriched dose (50 days),
then 206Pb-enriched dose
(50 days), and finally a
207Pb-enriched dose (50
days, with reduced
concentration)
Orally, in gelatin
capsule
Nonhuman
Primate
Sequential doses of lead mixes enriched in stable isotopes (204Pb, 206Pb, and
207Pb) were administered to a female cynomolgus monkey (Macaco
fascicularis) that had been chronically administered a common lead isotope
mix. The stable isotope mixes served as a marker of recent, exogenous lead
exposure, while the chronically administered common lead served as a marker
of endogenous (principally bone) lead. From thermal ionization mass
spectrometry analysis of the lead isotopic ratios of blood and bone biopsies
collected at each isotope change, and using end-member unmixing equations,
it was determined that administration of the first isotope label allowed
measurement of the contribution of historic bone stores to blood lead.
Exposure to subsequent isotopic labels allowed measurements of the
contribution from historic bone lead stores and the recently administered
enriched isotopes that incorporated into bone. In general the contribution from
the historic bone lead (common lead) to blood lead level was constant
(approximately 20%), accentuated with spikes in total blood lead due to the
current administration of the stable isotopes. After cessation of each
sequential administration, the concentration of the signature dose rapidly
decreased.
Total blood lead range:
31.2 to 62.3 ug/lOOg.
Inskip et al.
(1996)
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Lead acetate
1300 to 1500
ug/Common Pb/kg/day
approximately 10 years,
replaced by a 204Pb-
enriched dose (47 or
281 days), then 206Pb-
enriched dose (50 or
105 days), and finally a
207Pb-enriched dose
(50 days, with 650 ug
concentration in only
one primate)
Orally, in gelatin
capsule
Nonhuman Initial attempts to apply a single bone physiologically based model of lead
Primate kinetics were unsuccessful until adequate explanation of these rapid drops in
stable isotopes in the blood were incorporated. Revisions were added to
account for rapid turnover of the trabecular bone compartment and slower
turnover rates of cortical bone compartment, an acceptable model evolved.
From this model it was reported that historic bone lead from 11 years of
continuous exposure contributes approximately 17% of the blood lead
concentration at lead concentration over 50 ug/dL, reinforcing the concept that
the length of lead exposure and the rates of past and current lead exposures
help determine the fractional contribution of bone lead to total blood lead
levels. The turnover rate for cortical (approximately 88% of total bone by
volume) bone in the adult cynomolgus monkey was estimated by the model to
be approximately 4.5% per year, while the turnover rate for trabecular bone
was estimated to be 33% per year.
Various
O'Flaherty et al.
(1998)
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Table AX5-8.4 (cont'd). Bone Lead as a Potential Source of Toxicity in Altered Metabolic Conditions
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
to
VO
Lead acetate
1100 to 1300
ug/Common Pb/kg/day
approximately 14 years,
replaced by a 204Pb-
enriched dose, 206Pb-
enriched dose, and/or
finally a 207Pb-enriched
dose of varied durations
and concentrations.
Orally, in gelatin
capsule
Nonhuman Using the method of sequential stable isotope administration examined flux of
Primate lead from maternal bone during pregnancy of 5 female cynomolgus monkeys.
Blood lead levels in maternal blood attributable to lead from mobilized bone
were reported to drop 29 to 56% below prepregnancy baseline levels during
the first trimester of pregnancy. This was ascribed to the known increase in
maternal fluid volume, specific organ enlargement (e.g. mammary glands,
uterus, placenta), and increased metabolic activity that occurs during
pregnancy. During the second and third trimesters, when there is a rapid
growth in the fetal skeleton and compensatory demand for calcium from the
maternal blood, the lead levels increased up to 44% over pre-pregnancy levels.
With the exception of one monkey, blood lead concentrations in the fetus
corresponded to those found in the mothers, both in total lead concentration
and proportion of lead attributable to each isotopic signature dose (common =
22.1% vs. 23.7%, 204Pb = 6.9% vs. 7.4%, and 206Pb = 71.0% vs. 68.9%,
respectively). Between 7 and 25% of lead found in fetal bone originated from
maternal bone, with the balance derived from oral dosing of the mothers with
isotope during pregnancy. In offspring from a low lead exposure control
monkey (blood lead <5 ug/100 g) approximately 39% of lead found in fetal
bone was of maternal origin, suggesting enhanced transfer and retention of
lead under low lead conditions
Various, with total blood
lead as high as
approximately 65 ug/lOOg
Franklin et al.
(1997)
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Lead acetate
250 mg/1
Exposure began either
at 5, 10, or 15 weeks of
age and continued for a
total of 5 weeks.
Drinking water
Rat
Exposed rats for five weeks to 250 mg/1 lead as acetate in drinking water
beginning at 5 weeks of age (young child), 10 weeks of age (mid-adolescence),
or 15 weeks of age (young adult), followed by a 4 week period of without lead
exposure. An additional group of rats were exposed to lead beginning at 5
weeks, but examined following an 8 or 20 week period after cessation of lead.
Significantly lower blood and bone lead concentrations were associated with
greater age at the start of lead exposure and increased interval since the end of
exposure. Young rats beginning exposure to lead at 5 weeks and examined 20
weeks after cessation of exposure still, however, had bone lead concentrations
higher than those found in older rats only 4 weeks after cessation of exposure.
Lead concentration (uM)
4 weeks after cessation of
lead exposure:
Exposure started at 5
weeks of age = 1.39 ±
0.09; Exposure started at
10 weeks of age =1.18 ±
0.12;
Exposure started at 15
weeks of age = 0.82 ±
0.05.
Hanet al. (1997)
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Table AX5-8.4 (cont'd). Bone Lead as a Potential Source of Toxicity in Altered Metabolic Conditions
>
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HH
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Compound
Dose/Concentration
Duration Exposure
Route
Lead acetate
50 ppm
1 1 months
Drinking water
Lead acetate
0, 2, or 10 mg/kg/day
9.5 months
Drinking water
Lead acetate
7 years total
Drinking water
Species Effects
Rat Studied differences in tissue distribution of lead in adult and old rats. Adult (8
months old) and old (16 months old) rats were exposed to 50 ppm lead acetate
in drinking water for 1 1 months at which time the experiment was completed.
Bone (femur) lead levels in older rats were found to be less than those in
younger rats, however, blood lead levels were higher in the older rats. Brain
lead concentration in the older rats exposed to lead were significantly higher,
and brain weight significantly less than the brain lead concentration and
weights of unexposed older control rats or adult rats exposed to lead,
suggesting a potential detrimental effect. Authors suggested that a possibility
for the observed differences in tissue concentrations of lead was due to
changes in the capacity of bone to store lead with advanced age.
Rat Examined kinetic and biochemical responses of young (21 day old), adult (8
months old), and old (16 months old) rats exposed to lead at 0, 2, or 10 mg
lead acetate/kg/day over a 9.5 month experimental period. Results suggested
older rats may have increased vulnerability to lead due to increased exposure
of tissues to lead and greater sensitivity of the tissues to the effects of lead.
Nonhuman In studies of bone lead metabolism in a geriatric, female nonhuman primates
primate exposed to lead approximately 10 years previously, there were no significant
changes in bone lead level over a 10 month observation period as measured by
Blood Level Reference
Approximate median Cory-Slechta et al.
values after 6 months of (1 989)
exposure: Adult rats : 23
ug/dL
Old rats: 31 ug/dL
After 1 1 months of
exposure:
Adult rats: 16 ug/dL
Old rats: 31 ug/dL
Various from Cory-Slechta
approximately 1 ug/dL up (1990)
to 45 ug/dL
Historic concentrations McNeill et al.
during exposure: 44 to 89 (1997)
ug/lOOmL.
Lead (type unidentified)
occurring naturally in
diet (0.258 ng/mg dry
wt) and water (5.45
ppb).
Exposure from age 1
month up to 958 days.
Drinking water and diet
Mice
109CD K X-ray fluorescence. The mean half-life of lead in bone of these
animals was found to be 3.0 ± 1.0 years, consistent with data found in humans,
while the endogenous exposure level due to mobilized lead was 0.09 ± 0.02
ug/dL blood.
The lead content of femurs increased by 83% (values ranged from 0.192 to
1.78 ng Pb/mg dry wt), no significant relationship was found between lead and
bone density, bone collagen, or loss of calcium from bone. The results suggest
against low levels of bone lead contributing to the osteopenia observed
normally in C57BL/6J mice.
None given
Massie and Aiello
(1992)
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Table AX5-8.4. (cont'd). Bone Lead as a Potential Source of Toxicity in Altered Metabolic Conditions
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
Lead acetate
250 mg/1
Exposure for 5 weeks
Drinking water
Rat
Rats were exposed to lead for 5 weeks, followed by a 4 week washout period
without lead to allow primarily accumulation in the skeleton. Rats were then
randomly assigned to a weight maintenance group (WM), a moderate weight
loss (MWL) group (70% of maintenance diet), or a substantial weight loss
(SWL) group (40% of maintenance diet) for a four week period. At the end of
this experimental period the blood and bone levels of lead did not differ
between groups, however, the amount and concentration of lead in the liver
increased significantly.
Treatment Group Lead (nmol/g)
Femur WM 826 ± 70
MWL 735 ±53
SWL 935 ± 84
Spinal Column Bone
WM
MWL
SWL
702 ± 67
643 ± 59
796 ± 59
WM=1.25±0.10uM;
MWL = 1.16±0.10uM;
WM=1.32±0.10uM;
Hanet al. (1996)
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o
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W
O
O
HH
H
W
Lead acetate
250 ng/1
14 days
Drinking water
Rat
Study was undertaken to determine the effect of weight loss and exercise on
the distribution of lead. Weight loss secondary to dietary restriction was a
critical factor elevating organ lead levels and, contrary to prior study (Han et
al. (1996)), elevated blood levels of lead. No significant difference in organ or
blood lead concentrations were reported between the exercise vs. no exercise
groups.
Graphs indicate
concentrations ranging
from 0.20 to 2.00 uM.
Hanet al. (1999)
Abbreviation
ug - microgram
mL - milliliter
% - percent
mM - millimolar
1 - liter
ppm - parts per million
dL - deciliter
mg - milligram
uM - micromolar
Pb - lead
kg - kilogram
g - gram
204r>K 206
'Pb, 206Pb, 207Pb - Stable isotopes of lead 204, 206, 207, respectively
wt - weight
ppb - parts per billion
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Table AX5-8.5. Uptake of Lead by Teeth
>
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to
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Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
Lead acetate Rat
1 Hg/kg body weight
Single IP injection
Uptake of lead label into incisors of suckling rats:
0.7% of injected dose in 4 incisors of suckling rat after 24 h,
1 .43% after 1 92h. 0.6% of injected dose in 4 incisors of adult after 24 h,
0.88% after 192h.
Mean percent of dose after
time:
Suckling:
3.04%after24h
Momcilovic and
Kostial(1974)
1.71% after 72h
1.52% after 144h
1.18%afterl92h
Adult:
6.40%after24h
3.41% after 24h
1.92% after 24h
1.04% after 72h
0.72% after 144h
0.48% after 192h
Lead aerosol Rat
77,249,orl546|ig/m3
for 50 to70 days
Inhalation
Lead acetate Rat
0, 3, orlOppm
During pregnancy and
21 days of lactation
Drinking water
Abbreviations
Hg - microgram
kg - kilogram
IP - intraperitoneal
% - percent
h - hour
1 1 micrograms Pb/g incisor taken up in animals exposed to 77 ng/m3 for 70 Control: 2.6 ng/dL
days versus 0.8|ig Pb/g in control animals 77 |ig/m3: 11.5 ng/dL
13.8 |ig Pb/g incisor in rats exposed to 249 ng/m3 for 50 days 249 |ig/m3: 24.1 ng/dL
153 \ig Pb/g incisor in rats exposed to 1546 |ig/m for 50 days 1546 ng/m : 61.2 |ig/dL
Lead concentration in teeth of offspring: Not given
0 ppm group - Incisors (1 .3 ppm), 1st molars (0.3 ppm)
3 ppm group - Incisors (1 .4 ppm), 1st molars (2.7 ppm)
10 ppm group - Incisors (13.3 ppm), 1st molars (1 1.4 ppm)
m3 - cubic meter
Pb - lead
g - gram
ppm - parts per million
Grobler et al.
(1991)
Grobler et al.
(1985)
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Table AX5-8.6. Effects of Lead on Enamel and Dentin Formation
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
>
X
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O
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O
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HH
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Pb "salt" Rat
0.075 mM/lOOg, 0.15
mM/100gorl.5
mM/lOOg
Single, SC injection
Pb acetate Rat
30 mg/kg
Single, IV injection
Pb acetate Rat
3 mg/kg
Single, IV injection
Pb acetate Rat
Omg/1, 34mg/l, or 170
mg/1
70 days
Drinking water
Pb acetate Rat
40 mg/kg
Single, IP injection
0.075 mM dose, no disruption of dentin and enamel.
0.15 mM dose, mild mineralization disruption of dentin and enamel.
1.5 mM dose, mild to moderate disruption of dentin and enamel.
Rapid rise in serum calcium and phosphorus after injection. Formation of a
"lead line" in growing dentin within 6 hours after injection.
Production of a hypomineralized band in dentin
Increased in relative amount of protein in enamel matrix.
Significant (p<0.05) decrease in microhardness values of groups exposed to
lead in regions of maturation enamel, but not fully mature enamel.
Delay in enamel mineralization in animals exposed to lead.
Significantly (p<0.05) reduced eruption rates at various time points (days 8,
14,16, 22, 24, 28) under hypo functional conditions.
Not given
Not given
Not given
0 mg/1 group: 0 ppm
34 mg/1 group: 18.1 ppm
170 mg/1 group: 113.3
ppm
Days after injection
0 d: 48 ug/dL
10 d: 37 ug/dL
20 d: 28 ug/dL
30 d: 16 ug/dL
(Values estimated from
graph)
Eisenmann and Yaeger
(1969)
Appleton(1991)
Appleton(1992)
Gerlach et al. (2002)
Gerlach et al. (2000b)
Abbreviations
Pb - lead
mM - millimolar
g-gram
SC - subcutaneous
mg - milligram
kg - kilogram
IV - intravenous
1 - liter
ppm - parts per million
IP - intraperitoneal
ug - microgram
dL - deciliter
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Table AX5-8.7. Effects of Lead on Dental Pulp Cells
Compound
Dose/Concentration
Duration Exposure
Route
Species
Effects
Blood Level
Reference
Pb glutamate
4.5xlO'5M-10'7M
1,3, or 5 days
incubation
Human All concentrations significantly increased cell proliferation on Day 1, 3 and
Dental 5 of exposure in serum free conditions. Lead exposure resulted in dose-
Pulp Cells dependent decrease in intracellular protein and procollagen I production
over 5 days. In presence of serum only 4.5 x 10"5M significantly increased
protein production. Lead significantly decreased osteocalcin production.
Not applicable
Thaweboon et al. (2002)
>
X
Abbreviations
Pb - lead
M - molar
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Table AX5-8.8. Effects of Lead on Teeth - Dental Caries
O
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"-»
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X
(^
f , 'i
Compound
Dose/Concentration
Duration Exposure
Route
Lead acetate
0.5 mEq
84 d males
98 d females
Drinking water
Lead acetate
34 ppm
Pre- and perinatal
Drinking water
Lead acetate
10 or 25 ppm lead
3 weeks
Drinking water
Species Effects
Hamster Significant increase in dental caries in male hamsters only (85
mean molar caries score control vs. 118 for lead exposed).
No significant difference in dental caries in female hamsters (68
mean molar caries score control vs. 85 for lead exposed).
Rat Lead exposure resulted in an almost 40% increase in the
prevalence of caries and nearly 30% decrease in stimulated
parotid salivary gland function.
Rat When 1 5 ppm fluoride was concurrently given in diet, lead did
not increase prevalence of caries.
Blood Level
Not given
Control: < 5 ng/dL
34 ppm Pb: 48 ±13
Hg/dL
Not given
Reference
Wisotzky and Hein (1958)
Watson et al. (1997)
Tabchoury et al. (1999)
H
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O
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O
HH
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Abbreviations
mEq - milliequivalents
d - days
ppm - parts per million
% - percent
Hg - microgram
dL - deciliter
-------
CHAPTER 5 ANNEX
ANNEX TABLES AX5-9
December 2005 AX5-5-136 DO-NOT QUOTE OR CITE
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1 — I
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Table AX5-9.1. Studies on Lead Exposure and Immune Effects in Humans
Nature of
Exposure
Environmental
Occupational
Environmental
Environmental
Occupational
Environmental
Occupational
Occupational
Dose or Blood Lead Levels
(BLLs)
10.1-48.2 ug/L (BLL)
22 ug/dL: <30 years old
23.0 ug/dL: 30-39 years old
24. 1 ug/dL: > 40 years old
3.47 -49. 19 ug/dL
2.56-43.69 ug/dL (mean
9.52 ug/dL)
Range of 10.0-400.9 ug/dL
Mean=88.3 ug/dL
Controls all below 10 ug/dL
2.56 - 43.69 ug/dL
(BLL mean of 9.52 ug/dL)
10-20 year exposure (original
BLL mean 60 ug/dL; at time of
study BLL mean = 30 ug/dL)
74.8 ± 17.8 ug/dL vs. 16.7 ±
5.0 ug/dL for controls
Sample Population
2ntl grade children living near
industrial waste incinerator or other
industries causing pollution
Employees of lead storage battery
factories in Korea
554 Men
52 Women
Children 6- 1 1 years of age
30 girls
35 boys
Proximity to smelter
38 preschool children (3-6 years of
age);
35 controls
Male lead-exposed workers
96 females
121 males
(3-6 years old)
30 lead workers from battery
manufacturing plant (43 males and
21 females)
25 male storage battery workers
exposed >6 months; age 33 ± 8.5
years
Reported Effects
Increased blood lead concentration associated w/ increased IgE, especially above
28 ug/dL
Also decreased T-cells, cytotoxic T-cells, and B-cells (non-linear relation)
Serum IgE higher when BLL >30 ug/dL - Correlation of BLL with serum IgE
For employees less than 30 years old, IL-4 was lower when BLL >30 ug/dL
Indirect (PHA) macrophage activation
NO production negatively associated with BLL
With proximity closest to smelter monocytes had increased superoxide anion
production by indirect and direct activation (positive correlation with BLL -
stronger for boys than girls)
Percent of CD4+ and CD4+CD+ cells decreased while CD8+ increased
PHA-mitogen response decreased; and IFN-gamma production increased.
No effect on NK cytotox.
IgG and IgM lower in high BLL group (>9.52 ug/dL)
IgE greater in high BLL group (P < 0. 10)
No difference among males but females exposed to higher lead had significant
decreases in IgG and IgM and increased in IgE
Correlation of BLL and serum IgE r = 0.48; P = 0.002
Increased percentage of monocytes while percentage of B-cells, numbers of
lymphocytes, monocytes, and granulocytes decreased
Decreased blood hemoglobin, TCD4+ cells, IgG, IgM, C3 and C4 compliment
proteins.
Increased zinc protoporphyrin.
Impaired neutrophil chemotaxis and random migration
Reference
Karmaus et
al. (2005)
Heo et al.
(2004)
Pineda-
Zavaleta et al.
(2004)
Zhao et al.
(2004)
Mishra et al.
(2003)
Sun et al.
(2003)
Sune et al
(2003)
Basaran and
Undeger
(2000)
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Nature of
Exposure
Environmental
Epidemiological
study
Occupational
Occupational
Occupational
Occupational
Occupational
Occupational
Occupational
In Vitro
Occupational
Table AX5-9.1
Dose or Blood Lead Levels
(BLLs)
1.7-16.1 ug/dL
(Range in <3 yr old group)
Blood leads from 1-45 ug/dL
BLL=39
Range 15-55 ug/dL
Lead workers with BLL
between 7-50 ug/dL; mean
19 ug/dL
Exposed— Range of 38-100
ug/dL mean = 74.8 ug/dL;
Controls 11-30 ug/dL mean =
16.7 ug/dL (high controls!)
BLL 12-80.0 ug/dL
Males
high BLL > 25 ug/dL
lower BLL <25 ug/dL
control BLL < 10 ug/dL
>60 ug/dL for group showing
best IgE effect
BLL 14.8-91.4 ug/dL
207-1035 ug/L
33.2 ug/dL in lead-exposed
group
2.7 ug/dL in controls
(Cont'd). Studies on Lead Exposure and Immune Effects in Humans
Sample Population
1561 children and adults in high
lead community
480 controls
Urban Children population in
Missouri; 56% male
279 children 9 months-6 yr. of age
145 lead exposed workers
84 controls
71 male chemical plant workers vs.
29 controls
25 Male battery plant workers vs.
25 controls
33 male workers in a storage
battery plant
5 1 Firearms instructors (high and
lower) vs. controls
2 groups of male workers
occupationally exposed
39 male workers of storage battery
plant
(4 year mean exposure)
Human lymphocytes from adults
25-44 years of age
10 Male workers in scrap metal
refinery vs. 10 controls
Reported Effects
6-35 months:
increased IgA, IgG, IgM, number and proportion of B lymphocytes
decreased proportion of T-lymphocytes especially true when BLL > 1 5 ug/dL
>3 years of age - no differences
Correlation of blood lead levels and serum IgE levels in Missouri children
No major effects; only subtle effects
Elev. B cells elevated CD4+/CD45RA+ cells
Deer. Serum IgG
T cell populations,
Naive T cells correlated positively with PBB levels. Memory T cells reduced
with lead.
Absolute and relative numbers of CD4+ T cells reduced in exposed group.
IgG, IgM C3 and C4 serum levels all lower in workers.
No changes in serum Igs of PHA response of PBMC
T cell phenotypes and response — lead reduced relative CD3+ cells and relative
and absolute CD4+ cells also reduced PHA
(high lead)and PWM mitogen responses, reduced MLR also(high lead)
IgE positively correlated with BLL
Impaired neutrophil migration
Impaired nitroblue tetrazolium positive neutrophils
Greater for those exposed up to 1 year than those with longer exposure "safe"
levels of lead can still cause immunosuppression
Lead associated with greater IgG production after stimulation with PWM - not
dose dependent
PMN chemotaxis reduced to 2 different chemoattractants
Reference
Sarasua et al.
(2000)
Lutz, et al.
(1999)
Pinkerton et
al. (1998)
Sataet al.
(1998)
Undeger et al.
(1996)
Queiroz et al.
(1994)
Fischbein et
al. (1993)
Horiguchi et
al. (1992)
Queiroz et al.
(1993)
Borella and
Giardino
(1991)
Valentino et
al. (1991)
-------
Table AX5-9.1 (Cont'd). Studies on Lead Exposure and Immune Effects in Humans
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to
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Nature of Dose or Blood Lead Levels
Exposure (BLLs)
Sample Population
Reported Effects
Reference
X
OJ
VO
Occupational 10 lead exposure workers vs.
controls
worker BLLs of 41-50 ug/dL
no controls >19 ug/dL
Occupational Blood leads 64 ug/dL Range
21-90
Occupational Comparison of workers with
25-53 ug/dL vs. controls with
8-17ug/dL
Environmental Near smelter BLLs varied
seasonally 25-45 ug/dL
Control area BLLs varied
seasonally 10-22 ug/dL
Occupational Workers (18-85.85.2 ug/dL
BLL)
controls (6.6-20.8 ug/dL BLL)
Environmental 12 Afr.- American children
BLLs41-51ug/dL;
7 controls BLLs 14-30 ug/dL
39 male workers in lead exposed
group
Workers exposure to lead
Boys and girls —11.5 years old
living near lead smelting plant
73 workers vs. 53 controls
12 African American preschool
children vs. 7 controls
ConA-generated suppressor cell production—increased,
Some other cellular parameters unchanged
PHA response of lymphocytes from workers decreased
No change in serum Ig levels PHA response of cells or NK activity
Higher BLL associated with: decreased A-amino levulinic acid dehydrogetase
Decreased IgM and secretory IgA
Inversely related to IgG
Negative correlation of BLL and serum IgG and C3.
Positive correlation of BLL and saliva IgA
No difference in anti-tetanus antibody levels or in complement levels
Cohen et al.
(1989)
Alomran and
Shleamoon
(1988)
Kimber et al.
(1986b)
Wagnerova et
al. (1986)
Ewers et al.
(1982)
Reigart and
Graber(1976)
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Table AX5-9.2. Effect of Lead on Antibody Forming Cells (AFC) (In Vitro Stimulation)
1, J
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Species Strain/Gender Age
Mouse Various Adult
Mouse Various Adult
Mouse CBA/J females Adult
Mouse BDFi females Adult
Mouse CBA/J females Adult
Mouse CBA/J Adult
Mouse CBA/J females Adult
Mouse Swiss males Adult
Mouse Swiss Adult
Rat SD Neonate-
Juvenile
Mouse Swiss Adult
Mouse Swiss Adult
In Vivo/ Ex Lead Dose/
Effect Vivo Concentration
TAFC No 10 uM
AFC No change Yes 10 mM in water
| AFC primary response No 100 uM
|AFC - T dependent antigen 50 ug lead acetate in water
AFC - T independent antigen, no
change
|AFC Yes 0.08 mM and
0.4 mM
|AFC No 10"5 M
TAFC No 10'4 M
I AFC Yes 0.5 ppm tetraethyl lead
|AFC Yes 1300 ppm
|AFC (IgM) Yes 25 ppm and 50 ppm
|AFC - IgM Yes 4 mg i.p. or oral
|AFC - IgG
|AFC-IgM Yes 13.75 ppm- 1,375 ppm
|AFC - IgG
Duration
of Exposure
5 days
8 weeks
5 days
3 weeks
4 weeks
5 days
1 hr preincubation
3 weeks
10 weeks
3 weeks prenatal
and 6 weeks
postnatal
Single dose
8 weeks
Reference
McCabe and
Lawrence (1991)
Mudziuski et al.
(1986)
Warner and
Lawrence (1986)
Blakley and
Archer (1981)
Lawrence (1981a)
Lawrence (1981b)
Lawrence (1981c)
Blakley et al.
(1980)
Koller and Roan
(1980)
Luster et al ( 1978)
Koller et al.
(1976)
Koller and
Kovacic (1974)
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Table AX5-9.3. Studies Reporting Lead-Induced Suppression of Delayed Type Hypersensitivity and Related Responses
1, J
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Species
Rat
Chicken
Rat
Rat
Rat
Chicken
Mouse
Rat
Rat
Goat
Rat
Mouse
Rat
Mouse
Age
Embryo
Embryo
Fetal
Embryo - fetal
Embryo - fetal
Embryo
Adult
Embryo- fetal
Embryo- fetal
Adult
Adult
Adult
Neonatal/ Juvenile
Adult
Strain/Gender Route
SD females Oral to Dam
Cornell K females in ovo
CD females Oral to Dam
F344 and CD females Oral to Dam
F344 females Oral to Dam
Cornell K females in ovo
BALB/c females Oral
F344 females Oral to Dam
F344 females Oral to Dam
Females Gastric intubation
Wistar males Oral
Swiss s.c.
CD females Oral
BALB/c i.p.
Lowest Effective Dose
250 ppm (BLL at 4 wk = 6.75 ug/dL)
200 ug
500 ppm
250 ppm
250 ppm (BLL = 34.8ug/dL at birth)
200 ug (BLL =11 ug/dL)
512 ppm (BLL = 87 Ug/dL)
250 ppm lead acetate
250 ppm lead acetate
50 mg/kg lead acetate
6.3 mmol kg "'
0.5 mg/kg/day
25 ppm lead acetate (BLL= 29.3 ug/dL)
0.025 mg lead acetate
Duration
of Exposure
5 weeks
Single injection E12
6 days
3 weeks
3 weeks
Single injection E12
3 weeks
5 weeks (2 before, 3
during gestation)
5 weeks (2 before, 3
during gestation)
6 weeks
8 weeks
Shortest = 3 days
just prior to
challenge
6 weeks
30 days
Reference
Chen et al. (2004)
Lee et al. (2002)
Bunn et al.
(200 Ic)
Bunn et al.
(200 Ib)
Bunn et al.
(200 la)
Lee et al. (2001)
McCabe et al.
(1999)
Chen et al. (1999)
Miller et al.
(1998)
Haneefet al.
(1995)
Kumar et al.
(1994)
Laschi-Loquerie
et al. (1984)
Faith et al. (1979)
Mulleret al.
(1977)
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Species
Table AX5-9.4. Effect of Lead on Allogeneic and Syngeneic Mixed Lymphocyte Responses (MLR)
Strain/Gender
Age
Proliferation
Effects
In Vivo/
Ex Vivo
Lead Dose/Concentration
Duration
of Exposure
References
Mouse
Rat
Mouse
Mouse
Mouse
C57B1/6 and
BALB/c
Lewis males
CBA/J females
CBA/J females
DBA/2J males
Adult fAllo-MLR No
Adult fAllo-MLR No
fSyngeneic-MLR
Adult fAllo-MLR No
Adult fAllo-MLR Yes
Adult Allo-MLR no Yes
significant change
0.1 nM
50 ppm lead acetate
0.08 mM and 0.4 mM
13, 130 and 1300 ppm
4 days McCabe et al. (2001)
4 days Razani-Boroujerdi et al.
(1999)
5 days Lawrence (1981b)
4 weeks Lawrence (1981a)
10 weeks Roller and Roan (1980a)
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Table AX5-9.5. Effect of Lead on Mitogen-Induced Lymphoid Proliferation
Species
Human
Mouse
Mouse
Rat
Mouse
Rat
Mouse
Mouse
Rat
Mouse
Mouse
Mouse
Mouse
Rat
Mouse
Mouse
Strain/ Gender
-
TO males
Several
Lewis and F344
males
CBA/J
AP strain males
CBA/J females
BDF1 females
SD males
CBA/J females
CBA/J females
CBA/J females
C57 Bl/6 males
SD females
BALB/c
Swiss males
Age
Adult
Adult
Adult
Adult
Adult
Adult
Adult
Adult
Adult
Adult
Adult
Adult
Adult
Neonatal -
Juveniles
Adult
Adult
Proliferation Effects
|PHA
|ConA
|LPS
PHA stimulation No
change
|ConA
|LPS
LPS No change
PHA No change
ConA
LPS
No change
|ConA
TPHA
fStaph A enterotoxin
LPS no change
|ConA
TPHA
|LPS
PHA no change
|LPS (high doses only)
ConA, PHA no change
TLPS
ConA, PHA no change
TLPS
|PHA
|ConA
LPS No change
|PHA
|ConA
|LPS
|PHA
|PWM
In Vivo/
Ex Vivo Lead Dose/ Concentration
Yes Not available
Yes 1 mg/kg daily
No 25 uM
No 25 ppm
No 10 uM
Yes 100 ppm and 1,000 ppm
No 10"4 M
Yes 0-1, 000 ppm
Yes 1% lead acetate in diet
Yes 10 mM
No 1Q-6 - 1Q-4 M
No 10'6 - 10'4 M
Yes 1,300 ppm
Yes 25 ppm
No 10'5 - 10'3 M
Yes 2,000 ppm
Duration
of Exposure
Occupational
2 weeks
3 days
3 days
3 days
2-20 weeks
2 days
3 weeks
2 weeks
4 weeks
2.5 days
2-5 days
8 weeks
6 weeks
3 days
30 days
References
Mishra et al. (2003)
Fernandez - Carbezudo et al.
(2003)
McCabeet al., 2001
Razamni -Boroujerdi et al.
(1999)
McCabe and Lawrence (1990)
Kimberet al. (1986)a
Warner and Lawrence (1986)
Blakley and Archer (1982)
Bendich et al. (1981)
Lawrence (1981a)
Lawrence (1981)b
Lawrence (1 98 l)c
Neilan et al. (1980)
Faith et al. (1979)
Gallagher et al. (1979)
Gaworski and Sharma (1978)
-------
O Table AX5-9.5 (cont'd). Effect of Lead on Mitogen-Induced Lymphoid Proliferation
g In Vivo/ Duration
*L Species Strain/Gender Age Proliferation Effects Ex Vivo Lead Dose/Concentration of Exposure References
1-1 Mouse Swiss males Adult |PHA No 0.1 mM -1.0 mM 2-3 days Gaworski and Sharma
o TPWM (I978)
^ Mouse CBA/J Adult |LPS Yes 13 ppm 18 months Roller et al. (1977)
Mouse BALB/c Adult |LPS No 10'5-10'3M 2-3 days Shenker et al. (1977)
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Table AX5.9.6. Pattern of Lead-Induced Macrophage Immunotoxicity
1, J
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Species
Strain/
Gender Age
Nitric Oxide
Human Both genders Juvenile
Rat
Chicken
Mouse
Chicken
Mouse
Mouse
Reactive
Human
Rat
Mouse
Rabbit
CD males Embryo
Cornell K Embryo
strain females
BALB/c Adult
females
HD- 11 cell
line
CBA/J females Adult
CBA/J females Adult
Oxygen Intermediates
Associated in Juvenile
males
Not indicated NK
BALB/c Adult
females
New Zealand Adult
white males
Function
|NO
|NO
|NO
|NO
|NO
|NO
|NO
tROI
tROI
tROI
tROI
In Vivo/ Lowest Effective Duration
Ex Vivo Dose of Exposure References
Yes NK Pineda-Zavaleta et al.
(2004)
Yes 500 ppm 6 days Bunn et al., 2001c
Yes 10 jig One injection (E5) Lee et al., 2001
No 20 |ig/mL 2 hrs Krocova et al. (2000)
one lower dose tNO
No 4.5 ng 18 hrs Chen et al. (1997)
No 1.0 jig 4 days Tian & Lawrence (1996)
No 0.625 |iM 4 days Tian & Lawrence, 1995
Yes NK NK Pineda-Zavaleta et al.
(2004)
No 240 |iM 3 hrs Shabani & Rabbani (2000)
Yes l.Smg/kgdiet 30 days Baykov et al. (1996)
Yes 31 ng/m3 inhaled 3 days Zelikoff et al. (1993)
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CHAPTER 5 ANNEX
ANNEX TABLES AX5-10
December 2005 AX5-146 DO-NOT QUOTE OR CITE
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Concentration
Triethyl Pb
chloride, 0-3.0
mg/kg b. wt.
In vitro, 0.0-3.0
mM triethyl Pb
5 or 10
umol/lOOgb. wt.
Pb nitrate; i.v.
5, 10, 50 mg Pb
acetate kg"1 b. wt.
100 umol/kg; i.v.
Pb acetate
100 umol/kg
Pb nitrate; i.v.
100 umol/kg; i.v.
Pb acetate
100 umoles/kg;
i.v.
Table AX5-10.1. Hepatic Drug Metabolism
Duration Species Effects3
2 days In vitro, rat microsomes Triethyl Pb increased microsomal N-oxygenation in vivo and
._ , T . decreased microsomal C oxygenation by in vitro treatment. Either
Not specified In vivo, rat microsomes ^^ thug gaye nse fo m mcrease m ^ N.oxygenatlon/c.
oxygenation ratio, which may lead to tumor potentiation.
36 h Male Fischer 344 rats Lead decreases phase I components (liver microsomal cyt.P-450), and
increases Phase II components (GST, DT diaphorase etc). Liver
cytosol in treated animals had a polypeptide that cross-reacted with
GSTP.
Multiple durations (15 days, Female albino rats Over all induction of cyt-p - 450 and b5 in liver, long-term increase in
2 and 3 months) liver GST and GSH.
24 h Male Fischer 344 rats Decrease in total CYP amount, selective inhibition of CYP1 A2 and
decrease in the expression at m-RNA and protein level, induction of
placental form of glutathione s-transferase (GST-P).
9 h before or 6 h after Male Fischer 344 rats Male fisher rats treated with different metal ions — Pb nitrate, nickel
2-methoxy-4-aminoazobenzene chloride, cobalt chloride or cadmium chloride exhibited decreased
(2-Meo-AAB) total CYP amount in liver microsomes. However, only Pb reduced
the levels of the mRNA and protein of CYP 1A2 induced with 2-
methoxy-4-aminoazobenzene (2-Meo-AAB) and decreased the
microsomal activity (Per CYP), Pb also induced placental form of
Glutathione, a marker enzyme for preneoplastic lesion.
24 h Male F 344 rats Inhibition of C YP1 A mRNA(s) by Pb nitrate is by aromatic amines,
not by aryl hydrocarbons.
Multiple durations (3, 6, 12, 24, Male Wistar rats Stimulation of TNFa preceding hepatocyte DNA synthesis indicates a
and 36 h) role for it in liver cell proliferation.
Lead nitrate enhances sensitivity to bacterial LPS, in hepatocytes.
Reference
Odenbro and
Arhenius(1984)
Roomi et al.
(1986)
Nehru and
Kaushal(1992)
Degawaet al.
(1994)
Degawaet al.
(1995)
Degawaet al.
(1996)
Shinozukaet al.
(1994)
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Table AX5-10.1 (cont'd). Hepatic Drug Metabolism
Concentration Duration Species
Single 0.33 Multiple durations Male Wistar rats
mg/kg- 1 Pb
nitrate
Lead acetate, Multiple analyses up to 30 h C57BL/6 male mice
75 mg of Pb2+/kg,
intraperitonial
0-10~6MPb 3 days Fish hepatoma cell line
nitrate PLHC-1
DT Diaphorase 24h-120h Male Wistar rats
activity 0-125
mg/kg Pb acetate,
Pb nitrate
Time course
experiments
100 mg/kg Pb
acetate, i.p.
Cell viability 24 h in general and for EROD Primary human
assays 0-30 |iM, assays by PAHs24 -72 h hepatocytes
for all other As,
Pb, Hg, 5(iM, Cd,
l^M
Effects3
Lead confers protection against the CCL4 induced hepatotoxicity as
evident by marked reduction in serum Alanine aminotransferase
(AST) and aspartate aminotransferase (AST) and this protection is
not associated with the mitotic response of Pb.
The decrease in P-450 as a result of Pb poisoning occurs at two
levels. (1 ) A mechanism unrelated to heme, where Pb interferes with
P-450 in 2 ways. (2) A mechanism dependent on heme, in which Pb
inhibits heme synthesis.
Effect of heavy metals Cu(II), Cd(II), Co(II), Ni(II), Pb(II), and
Zn(II), on Cytochrome induction (CYP1A) induction response and
Ethoxy resorufin-o-deethylase (EROD) activity.
All metals had a more pronounced effect on EROD activity than
Cypl A protein. The rank order of the metal inhibition on EROD is
Cd(II) > Ni(II) > Cu(II) > Co(II) = Zn(II), Pb(II), Cd(II) and (Cu).
May affect Cypl A system of the fish liver at low concentrations
through the direct inhibition of CYP 1A enzyme activity.
Lead acetate and nitrate induce DT diaphorase activity which is
inhibited significantly by Dil a calcium antagonist, showing that these
changes are mediated by intracellular calcium changes. Lead acetate
induces DT diaphorase activity with out thymus atrophy and hence
was suggested to be a monofunctional inducer as against the Methyl
cholanthrene induced DT diaphorase activity
The effect of metals on PAH induced CYP1A and 1A2 as probed by
Ethoxy resorufin o- deethylase activity has demonstrated, metals -
Arsenic, Pb, mercury and cadmium decreased CYP1A1/ A2
expression by polycyclic aromatic hydrocarbons depending on the
dose, metal and the PAH. Arsenic was most effective, followed by
Pb, cadmium, and mercury. Cell viability was decreased by 20-28%
by metals.
Reference
Calabrese et al.
(1995)
Jover (1996)
Bruschweiler et
al. (1996)
Arizono et al.
(1996)
Vakharia(2001)
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Table AX5-10.1 (cont'd). Hepatic Drug Metabolism
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Concentration Duration
1 0-100 nM, 24 h
in vitro
5 and 10 —
|imoles/100g of
b.wt, single i.p
100 nmoles/100 g Animals were sacrificed at
b. wt. Pb nitrate, 1 , 2, 3, 4, and 1 5 days
single injection,
i.v.
100 mg/kg i.p., Multiple analyses 0-96 h
single exposure
lOOpmol/kg 70 h
body wt, i.v
1 00 pmol/kg b. Multiple time point analyses
wt., intra cardiac starting 6 days to 5 months.
10 |imol/100g b. Analyses at multiple time
wt. , Pb nitrate, points 0-10 day s
i.v. Single dose
Species
Murine hepatoma cell
line.
Wistar Rat
Wistar rats
Male DDY strain mice
Male Sprague Dawley
rats
Male and female Wistar
rats
Male Fischer 344 young
adult rats.
Effects3
Effect of heavy metals on Aryl hydrocarbon regulated genes -metals
alone did not induce a significant change in the cyplal activity and
protein levels but increased its m-RNA expression. AHR ligand -
mediated induction of cyplal activity and protein was observed by
all the metals. Pre and post translational modulation in this
regulation have been implicated. These results demonstrate that the
heavy metals differentially modulate the constitutive and the
inducible expression of AHR regulated genes.
Lead nitrate induced the expression of Placental form of Glutathione
transferase along with liver cell proliferation. The biochemical
lesions induced by Pb under these conditions were similar to that of
hepatic nodules.
Acute Pb treatment results in induced activity of Gamma- glutamyl
transpeptidase, induced GSTP, a typical marker of pre neoplastic
lesion in most hepatocytes. Lead also inhibited liver adenylate
cyclase activity 24 h post exposure.
Lead decreased Glutathione content and decreased Glutathione s-
transf erase activity that is independent of Glutathione levels.
Acute Pb nitrate treatment caused a significant increase of GST
activity in liver and kidney. While in liver the activity increase is
mainly due to isozyme GST 7-7, in kidney it is through the induction
of all the isozymes.
Intracardiac administration of Pb acetate results in elevation of
glutathione transferase (GST) in Kupffer cells, the early response to
GST. Yp was observed in sinusoidal cells and had a later patchy
response in the expression of GST Yp Yp in hepatocytes
Glutathione transferase Pl-1 is induced significantly by a single
intravenous dose of Pb nitrate through increased transcription and
modulations at post transcription and translational levels.
Reference
Korashy and
El-Kadi (2004)
Roomi et al.
(1987)
Columbano et al.
(1988)
Nakagawa et al.
(1991)
planas- Bhone
and Elizalde
(1992)
Boyce and Mantel
(1993)
Kooet al. (1994)
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to
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O
Table AX5-10.1 (cont'd). Hepatic Drug Metabolism
Concentration Duration
Lead nitrate, 100 48 h
urn/kg i.p, 3 times
every 24 h
Lead acetate 0.5-24 h
100 urn/kg.
Species
Transgenic rats with 5
different constructs
having GST-P and/or
chloromphenical acetyl
transf erase coding
sequence.
Effects3
GSTP (placental GST), is regulated by Pb at transcriptional level.
GST-P enhancer (GPEI), is an essential cis- element required for the
activation of the GST-P gene by Pb and is involved in the activation
regardless of the trans-activators involved. GPEI element consists of
two AP-1 binding sites. Activation of GST-P gene by Pb is mediated
in major part by enhancer GPEI, which may involve AP-1 activation
partially.
Reference
Suzuki et al.
(1996)
lOnMPb nitrate
24 h before transfection with
ECAT deletion mutant, every
24 h there after till 48 h after
transfection
NPJC Kidney fibroblasts Lead induces GST-P in NPJC normal rat kidney fibroblast cell line.
>
X
H
6
o
o
H
O
o
H
W
O
O
HH
H
W
1 Omg Triethyl Pb, Analyses at multiple durations
i.p. single dose (3, 4, 7, 10, or 14 days)
114mg Pb
acetate/kg b. wt.
i.p
Single (0.5-12 h group) or
multiple (72 h and 7 d group)
exposure
A. 1.5-3.0 mg/kg 2 exposures for 48 h
wt
Triethyl Pb (TEL)
i.p.
B. 0.05-0.5, TEL
to liver
microsomal
fractions
30 min incubations
Fischer 344 rats
Sprague Dawley
Female Wistar
Liver microsomes from
female Wistar rats
Decreased liver Glutathione s-transferase (GST) activity and lower Daggett et al.
levels of several hepatic GST (1997)
Increase in quinone reductase activity by day 14 in liver.
Pb exposure resulted in hepatic Glutathione (GSH) depletion and Dagget et al.
increased malondialdehyde (MDA) production. (1998)
Pretreatment of rats did not affect the liver microsomal Oestradiol- Odenbro and
17p metabolism or the content of cytochrome P-450 and cytochrome Rafter (1988)
b5.
TEL at 0.05 mM significantly reduced 17p-hydroxy steroid oxidation
and at concentration of 0.05 mM decreased 16a-hydroxylation
-------
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cr
to
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o
(^
Table AX5-10.1 (cont'd). Hepatic Drug Metabolism
Concentration
Duration
Species
Effects3
Reference
X
50mg/kg,
intragastric
8 weeks
Male Albino Wistar rats
Accentuation of liver membrane lipid peroxidation. significant Sandhir and Gill
inhibition of liver antioxidant enzymes. Reduced ratio of reduced (1995)
glutathione(GSH) to oxidized glutathione (GSSG),
b. wt.
CYP
GSH
GSSG
TEL
CCL
GSTP
MDA
ALA
PAH
LPS
body weight
Cytochrome P-450
Glutathione
Oxidized glutathione
Triethyl lead
Carbon tetrachloride
Placental glutathione transf erase
Malondialdehyde
Alanine aminotransferase
Polycyclic aromatic hydrocarbons
Lipopolysaccharides
Cu
Cd
Al
Zn
Pb
Ni
Copper
Cadmium
Aluminum
Zinc
Lead
Nickel
TNFa Tumor necrosis factor
H
6
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o
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O
o
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O
O
HH
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W
-------
o
O
Table AX5-10.2. Biochemical and Molecular Perturbations in Lead-induced Liver Tissue
Concentration
Duration
Species
Effects3
Reference
to
O
O
>
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to
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6
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O
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O
o
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W
O
O
HH
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W
Lead - diethyl
dithiocarbomate complex,
Pb (DTC) 2, or lead acetate
0.033- 10 pM
100 |xmol/kg b. wt. i.v
single dose
Lead nitrate, Single dose
100 (imol/kg b. wt.
Lead nitrate
0.5 - 20 h Primary Effect of interactions between lead and diethyl dithiocarbomate (DTC) on the Oskarsson and
hepatocytes enzyme 5 amino levulinic acid dehydratase in primary hepatocytes. Lipophilic Lindahl (1989)
Pb (DTC)2 caused a more rapid and stronger inhibition of ALAD activity than
lead acetate. Lead uptake is higher and more rapid with Pb (DTC) 2 than lead
acetate. This increased inhibition of ALAD activity by Pb (DTC) 2 might be due
to facilitated cellular transport in the complexed form resulting in higher cellular
concentrations of lead.
— Primary rat DTC decreases cellular effects of Pb and Cd despite unchanged/even slightly Hellstrom-
hepatocytes increased concentrations of the metals. Hepatic ALAD was significantly Lindahl and
inhibited in cells treated with Pb Ac and Pb (DTC)2. Oskarsson
(1990)
— DBAandC57 DBA mice(with a duplication of the ALAD gene accumulated twice the amount Claudio et al.
mice of lead in their blood and had higher lead levels in liver and kidney than mice (1996)
with the single copy of the gene (C57), exposed to the same oral doses of the
lead during adult hood. Blood Zinc protoporphyrin (ZPP) increased with lead
exposure in C57 mice and were not affected in DBA mice
Single dose, Male Wistar First in vivo report showing association between lead induced liver hyperplasia, Dessi et al.
analyses Albino Rats Glucose - 6 - phosphate levels, and cholesterol synthesis. (1984)
performed 12, 24, Lead treatment increased hepatic de novo synthesis of cholesterol as evident by
48, 72, 96 and increased cholesterol esters and increase of G-6-PD to possibly supply the
168 h reduced equivalents for de novo synthesis of cholesterol. Changes in these
biochemical parameters were accompanied by liver hyperplasia.
0-168h Male Wistar rats Lead nitrate induces hepatic cell proliferation folio wed by reabsorption of excess Pani et al.
tissue with in 10-14 days. The proliferation was correlated with hepatic denovo (1984)
synthesis of cholesterol, stimulation of hexose monophosphate shunt pathway
and alterations in serum lipo proteins.
— Wistar rats Lead nitrate induces multiple molecular forms of Glucose-6- phosphate Batetta et al.
dehydrogenase with an increase of band 3 and a concomitant increase of band 1, (1990)
shifting from the pattern induced by fasting with an increase in band 1.
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O
Table AX5-10.2 (cont'd). Biochemical and Molecular Perturbations in Lead-induced Liver Tissue
>
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Concentration
Lead nitrate, single i.v.
10|iM/ lOOgb.wt.
—
10 or 20 mg/kg as lead
acetate, subcutaneous
100|iM/kgb. wtlead
nitrate, i.v
2000 ppm lead acetate in
diet.
0- 4000 ppm
lead acetate, oral
Duration
Multiple time
points
24-72 h and 20
days
—
Once a wk for 5
wks.
36 h post
exposure
3 wks
21 days
Species
Male Wistar rats
Rats
Occupationally
exposed workers
Rats
Male Wistar
Albino rats
Arbor Acres male
Chicks
Arbor Acre
broiler chicks
Effects3
Lead nitrate exposure results in complete loss of liver glycogen between 24 and
48 h, which was replenished and was found in excess in treated liver hepatocytes
by 20 days. Glycogen synthase and glycogen phosphorylase activities were
diminished by 24 h and return to normal values by day 20. The pentose
phosphate enzymes were upregulated, which coincided highly with the increase
in mitotic rate. Overall lead nitrate induces drastic alterations in hepatic
carbohydrate metabolism along with increased hepatic cell proliferation.
Lead acetate induced mitotic response much more effectively in renal epithelial
cells than liver cells (675 fold less).
Lead induces lipid peroxidation in serum of manual workers, while blood
superoxide dismutase (SOD) activity decreased. Similar phenomenon was
observed with rats that were subcutaneously injected with lead acetate. At higher
than 20 pM concentration, lead in untreated microsomes increased NADPH
dependent lipid peroxidation.
Endogenous source of newly synthesized cholesterol together with increase of
HMP shunt enzyme activities is essential for hepatic cell proliferation by lead
nitrate
Liver non protein sulphahydryl (NPSH) and glutathione (GSH) were increased
upon lead exposure. The concentrations of liver glutamate, glycine, and
methionine were also elevated upon lead exposure.
Lead increases tissue peroxidation via a relative increase of 20:4 fatty acids.
Decrease in the hepatic ratio of 18:2/20:4 might be specific to lead toxicity
Reference
Hacker et al.
(1990)
Calabrese and
Baldwin et al.
(1992)
Itoet al. (1985)
Dessi et al.
(1990)
Me Gowan and
Donaldson et
al. (1987)
Donald and
Leeming,
(1984)
-------
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to
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O
Table AX5-10.2 (cont'd). Biochemical and Molecular Perturbations in Lead-induced Liver Tissue
Concentration
Sodium Vanadate,
30 mg/kg subcutaneous in
mice
30 mg/kg b.wt, i.p. in rats
0.5mM
Duration
Acute studies,
24 h
Species
Male Swiss-
Webster mice
Male Sprague
Dawley Rat
Effects3
Sodium orthovandate increases lipid peroxidation in kidneys of mice and rats.
Malondialdehyde (MDA) formation increased 100%, with in 1 h. after injection.
In both rat and mice, no significant increase in lipid peroxidation was observed in
brain, heart, lung, and spleen.
Chronic exposure to vanadium, through maternal milk and drinking water for 10
weeks increased MDA formation and lipid peroxidation in kidneys.
Reference
Donaldson et
al. (1985)
Vanadium sulphate in
drinking water for chronic
treatment
Chronic studies
10 wks
>
X
H
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O
H
O
o
H
W
O
O
HH
H
W
250 -2000 ppm lead acetate
in diet
1. 25-20.00 mg/L lead
nitrate, oral
250 mg/L of lead as lead
acetate, oral
35-70 mg, lead intra gastric
19 days Arbor Acre
broiler chicks
30 days Fresh water fish
5 weeks of Weanling female
exposure SD rats
followed by 4
weeks of recovery
One or two times Male Buffalo rats
a wk/7 wks.
CYP Cytochrome P-450
ALAD Reduced Glutathione
GSH Aminolevulinic acid dehydratase
Dietary Pb consistently increased liver arachidonic acid, the
arachidonate/linoleate ratio and hepatic non-protein sulfhydryl concentration.
Hepatic microsomal fatty acid elongation activity was decreased by Pb. over all
these results demonstrate that changes in the precursors and mechanisms
involved with eicosanoid metabolism are not always reflected in tissue
concentrations of leukotriens and prostaglandin.
Lead accumulation in the liver and other tissue increased in a dose dependent
manner up to 5mg/L, exposure to sublethal concentration (5 ppm) of lead
reduced the total lipids, phospholipids, and cholesterol levels in the liver and
ovary. Lead nitrate may affect the fecundity of fish by altered lipid metabolism.
Effect of weight loss on body burden of lead - Weight loss increases the quantity
and concentration of lead in the liver even in the absence of continued exposure
Decrease in plasma cholesterol, & HDL fraction, increase in serum triglyceride,
atrophy of the elastic fibers in the aorta.
ZPP Zinc protoporphyrin
HMP Hexose monophosphate shunt pathway
b. wt. body weight
Knowles and
Donaldson et
al. (1990)
Tulasi et al.
(1992)
Han et al.
(1996)
Skoczynska et
al. (1993)
-------
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to
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O
>
X
Table AX5-10.3. Effect of Lead Exposure on Hepatic Cholesterol Metabolism
Concentration
100 pmol/kg body wt, i.v.
lead nitrate
100 pmol/kg body wt, i.v.
lead nitrate
0.05 mg/kg body wt/day.
lead acetate,
subcutaneous, with or
Duration
Multiple durations
0, 3, 6, 12, 24, and
48 h
Multiple durations
0,1,3,6,12,18,
24, 48, and 72 h
preexposure for
5-7 days, gestation
through lactation.
Species
Male Sprague
Dwaley (SD)
Rats.
Male Sprague
Dwaley (SD) rats
female Charles
Foster rats
Effects3
Lead nitrate, activates the expression of the SREBP-2 and CYP 51 gene with out
decreasing the serum cholesterol level.
Lead nitrate effects on hepatic enzymes involved in cholesterol homeostasis —
Demonstrated for the first time sterol independent gene regulation of cholesterol
synthesis in lead nitrate treatment
Lead and cadmium accumulated in the livers of metal treated pregnant and
lactating rats. Hepatic steroid metabolizing enzyme 17-p-hydroxy steroid
oxidoreductase and UDP glucaronyl transf erase were decreased and the hepatic
Reference
Kojimaet al.
(2002)
Kojima et al.
(2004)
Pillai and
Gupta (2004)
without cadmium acetate
0.025 mg lead acetate/kg
body wt/day
Cytochrome P-450 content was reduced by the metal exposure. Lead and cadmium
alter liver biochemical parameters, however, combined exposure had no
intensifying effect on liver parameters. When administered together on similar
concentration basis, the major effects are mediated by cadmium.
300 mg/L lead acetate,
oral
Gestation through
lactation analyses
done at day 12 and
day 21 postnatal.
Female Wistar
Rats
In neonates, decrease in liver Hb, iron, alkaline and acid phosphatase levels.
Protein, DNA and lipid total amounts were reduced and hepatic glycogen content
was reduced. Lead intoxication of mothers in gestation and lactation results in
alterations in the hepatic system in neonates and pups.
Corpas et al.
(2002)
a CYP = Cytochrome P-450
b. wt. = body weight
H
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O
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Table AX5-10.4. Lead, Oxidative Stress, and Chelation Therapy
>
X
Concentration and
Compound Duration
Lead acetate, 50 mg/kg 8 wks
b.wt, intragastric
2,000 ppm, lead acetate, 5 wks
Diet
0.1-1.0 nM
Species
Male Albino
Wistar rats
Male Fisher 344
rats
Rat liver
hepatocytes.
Normal and LAN
loaded
Effects
Lead induces accentuation of membrane lipid peroxidation in liver by the changes
(decrease) in the activities of several antioxidant enzymes such as SOD, Catalase,
GPx and Glutathione reductase. Lead exposure also caused a reduction in
GSH/GSSG ratio (reduced to oxidized Glutathione).
Effect of lead on lipid peroxidation in young vs. adult rats- Liver GSSG and
malondialdehydehyde levels were significantly higher in young rats than adult rats.
Blood lead levels were higher in young exposed animals as compared to adults.
In young, lead exposed animals, lead induced oxidative stress was more
pronounced particularly in liver tissue.
Lipid peroxidation as indicated by Malondialdehyde accumulation upon exposure
to various redox- sensitive metals in cultured rat hepatocytes and hepatocytes
loaded with a-linolenic acid indicated that - Al, Cr and Manganese, Ni, lead and
tin did not effectively induce lipid peroxidation in these cells.
- The induction was the highest in ferrous iron treated cells compared to other
metals (Cu, Cd, V, Ni).
Reference
Sandir and
Gill (1995)
Aykin-Burns
et al. (2003)
Furono et al.
(1996)
FeSO4, VC13, CuSO4,
CdCl2, CoCl2, A1C13,
CrCl3, MnCl2, NiSO4,
Pb(NO3)2, SnCl2, culture
medium
9h
H
6
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O
H
O
o
H
W
O
O
HH
H
W
LAN - bovine serum
complex 0.8 mM in
culture medium
5 mg kg-1, lead acetate,
i.p., single dose followed
by therapy with chelating
agents
Additional 12 h
incubation
Analyses after
6 days of treatment
DMSA, Mi-
ADMSA at
multiple times (0.5,
24 hr, 4th and 5th
day after lead treat
Wistar 6 day old
suckling rats
With any metal, the induction was higher in a-linolenic acid treated cells.
Iron and V induced cell injury in LAN loaded cells was prevented by addition of
DPPD. Cd was a weak inducer of lipid peroxidation under these conditions
Treatment with DMSA and Mi- ADMSA showed Mi-ADMSA to be more effective
in reducing the skeletal, kidney and brain content of lead. However there was no
difference in reducing the liver lead content between the two compounds.
Blanusha et
al. (1995)
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Table AX5-10.4 (cont'd). Lead, Oxidative Stress, and Chelation Therapy
Concentration and
Compound
Duration
Species
Effects
Reference
>
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H
6
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O
H
O
o
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W
O
O
HH
H
W
550 ppm lead acetate, oral
DMSA treatment.
Lead acetate Dose to
achieve blood lead levels
of 35-40 ng/dL.
Biweekly dose
adjustments, oral followed
by treatment with
chelator.
(A) Pb for 35+ 21
days
(B) Pb 35 days and
Pb & DMSA
for 21 days
(C) Pb 35 days and
DMSA for
21 days
(D) AcedifiedDi
H2O for 35 days
and Di water for
21 days
1 year, chelator for
two successive
19 day period
following lead
exposure.
6-7 Wk old male
Sprague-Dawley
rats
DMSA reversed the hematological effects of Pb, decreased the blood, brain , bone,
kidney and liver concentration and produced marked lead diuresis, even when
challenged with ongoing Pb exposure.
Pappas et al.
(1995)
Infant rhesus
monkeys
Specific emphasis on the beneficial effects of succimer treatment to cessation of
lead exposure. These data demonstrated that succimer efficiently reduces blood Pb
levels which does not persist beyond the completion of treatment. They also
demonstrate the relative benefit of eliminating lead exposures , which serves to
underscore the importance of primary prevention of lead exposure. Neither DMSA
treatment nor the cessation of lead exposure were beneficial in reducing skeletal
lead levels.
Smith et al.
(2000)
5 mg Pb kg-1 , i.p lead Analyses at Day 5
acetate followed by
chelators for various time
points.
50 mg/kg lead as lead 24 h
nitrate, i.p, two injections,
16h apart
50% Ethanol, 0.5 mL, two
injections, 16 h apart
0.1% lead acetate in 4 weeks
drinking water with and
without Sodium
Molybdate, i.p
Suckling Wistar Meso - DMSA is the treatment of choice for acute lead poisoning in infants
rats compared to EDTA and Rac-DMSA.
Male Albino rats S- Adenosyl methionine confers protection against alterations in several parameters
(ALAD, GSH, MDA) indicative of lipid peroxidation in blood, liver and brain in
lead and acute lead and ethanol exposed animals as well as the organ concentration
of lead.
Male Albino rats Sodium molybdate significantly protected the uptake of lead in blood, liver and
kidney. The treatment with molybdate also restored the lead induced inhibited
activity of blood 5-aminolevulinic acid dehydratase and the elevation of blood Zn
protoporphyrin , hepatic lipid peroxidation and serum ceruloplasmin.
Kostial et al.
(1999)
Flora and Seth
(1999)
Flora et al.
(1993)
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Table AX5-10.4 (cont'd). Lead, Oxidative Stress, and Chelation Therapy
Concentration and
Compound
Duration
Species
Effects
Reference
>
X
-------
o
O
to
O
O
Table AX5-10.4 (cont'd). Lead, Oxidative Stress, and Chelation Therapy
Concentration and
Compound
Duration
Species
Effects
Reference
0-500 uM lead acetate 6 h
2000 ppm of lead acetate 5 weeks
in drinking water for 5
weeks
Taurine 6th week
1.1 kg/day
CHO cells and Antioxidant Taurine reversed the abnormalities associated with lipid peroxidation Gurer et al.
parameters such as increased. Malondialdehyde formation and decreased (2001)
Fischer 344 rats. Glutathione and enhanced CHO cell survival. However, was not effective in
reducing cell and tissue lead burden in CHO cells and lead exposed Fischer rats.
>
X
I mg Pb2+/kg B.wt, i.p.
lead acetate
Lead as acetate, 400
mgPb2+/mL, drinking
water
0.5 mg/mL L-methionine
4 wks, treatment
with various
antioxidant in the
5th wk
10 days
4 wks post-lead
exposure
IVRI 2 CQ rats Lead exposure resulted in increased lipid peroxidation, with tissue specific changes Patra et al.
in liver. Treatment of exposed rats with ascorbic acid and a-tocopherol lowered the (2001)
lipid peroxidation.
Kunming mice L- methionine has an ameliorative effect on lead toxicity-Methionine reduced the Xie et al.
decrease in Hb content and depressed body growth caused by lead. Treatment with (2001)
dietary methione along with lead decreased the MDA formation as opposed to lead,
moderately reversed the decreased iron content of the organs and decreased organ
lead content.
H
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O
o
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W
O
O
HH
H
W
100 uM/kg b.wt. lead 3 and 24 h
acetate, intramuscular,
single
100 ug/ lead acetate, intra 3 days
gastric, oral and
intraperitoneal, treated
with or with out thiamin
(25, 50 mg/kg b.wt) and
or Ca EDTA ( 50 mg/kg
B.wt
Male Albino rats Lead exposure resulted in significant increases in acid and alkaline phosphatases, Othman and
serum GOT and GPT, elevated liver and kidney lipid peroxidation and decreased El Missiry
antioxidant enzymes at 3 and 24 h after exposure. Selenium administration prior to (1998)
lead exposure produced pronounced prophylactic effects against lead exposure by
enhancing endogenous anti oxidant capacity.
CD-I mice Two times more whole body lead was retained by intraperitoneal injection as Kim et al.
compared to intragastric administration. Thiamin treatment increased the whole (1992)
body retention of both intragastric and intraperitoneal lead by about 10%. Calcium
EDTA either alone or in combination with thiamin reduced the whole body
retention of lead by about 14% regardless of the route of exposure. Regardless of
the route Ca EDTA in the combined treatment reduced the relative retention of lead
in both in liver and kidney. These studies indicate the combination treatment with
thiamin and Ca EDTA alters the distribution and retention of lead in a manner
which might have therapeutic application.
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to
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Table AX5-10.4 (cont'd). Lead, Oxidative Stress, and Chelation Therapy
>
X
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6
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o
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O
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HH
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W
Concentration and
Compound
2000 ppm lead
acetate, oral
0.1% lead as acetate
in drinking water
DMSA - 50 mg/kg,
i.p./day
MiADMSASO
mg/kg, i.p./day
Vitamin E 5 mg/kg
and vitamin C
25 mg/kg/ day, i.v.
and oral
500 mg/kg lead
acetate daily, oral
treatment with
chelators
Lead as acetateO.2%
in drinking water
LA 25 mg/kg b.wt
and DMSA 20
mg/kg b.wt
b.wt.
aCYP
SOD
GSH
GSH/GSSG Ratio
MDA
Al
As
Duration Species
4 wks, 5 days of Male Wistar albino
treatment with rats
antioxidant or
chelators
3 months Male Wistar rats
5 days post-lead
exposure
Multiple durations Male Albino rats
(2, 4, and 6 wks)
5 wks followed by a Male Albino rats
6th wk administration
of LA and or DMSA
body weight
Cytochrome P-450
Super oxide dismutase
Glutathione
Reduced Glutathione/Oxidized Glutathione
Malondialdehyde
Aluminum
Arsenic
Effects
Treatment with all the chelators reduced hepatic GSH and reduced GSSG levels.
Significant beneficial role of Alpha-lipoic acid (LA), in recovering the altered
biochemical parameters, however showed no chelating properties in lessening body
lead burden either from blood, liver, or kidney. Most beneficial effects against lead
poisoning was observed with combined treatment of lipoic acid and either DMSA
(meso 2,3 - dimercaptosuccinic acid) or MiADMSA (Mono isoamyl DMSA).
Single or combined administration of vitamin C, a-tocopherol and the chelators
DMSA and Mi ADMSA against the Parameters of lead induced oxidative stress-
thiol chelators and the vitamins could bring the blood ALAD to normal levels, most
significantly by combined administration of Mi ADMSA with vitamin C. Vitamin
C and E were effective against reducing oxidized glutathione ( GSSG), and
thibarbituric acid reactive substance(TBARS) and increasing catalase activity.
MiADMSA and DMSA with vitamin C were effective in increasing hepatic GSH
levels. In summary combined treatment regimens with thiol chelators and vitamins
seem very effective in reducing the lead induced Oxidative stress.
Impact of combined administration of vitamin C and Sylimarin on lead toxicity.
Combined treatment of lead-exposed animals with vitamin C and Silymarin showed
marked improvement of the adverse biochemical, molecular and histopathological
signs associated with lead toxicity.
Lead treatment for 5 weeks resulted hepatic enzymes alanine transaminase,
aspartate transaminase, and alkaline phosphatase, increased lipid peroxidation,
and decreased hepatic anti oxidant enzymes. LA or DMSA alone, partially
abrogated these effects, however, in combination completely reversed the lipid
oxidative damage.
Cr Cromium CuSO4 Copper sulphate
V Vanadium CrCl3 Cromium chloride
Pb Lead MnCl2 Manganese chloride
NAC N acetyl cysteine NiSO4 Nickel sulphate
FeSO4 Ferrous sulphate CoCl2 Cobalt chloride
A1C13 Aluminum chloride LAN a Linolenic acid
Reference
Pande and
Flora (2002)
Flora et al.
(2003)
Shalan et al.
(2005)
Sivaprasad et
al. (2004)
VC13 Vanadium chloride DPPD DPPD^-jVDiphenyl-p-phynylene-diamine
CdCl2j Cadmium chloride
-------
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to
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O
Table AX5-10.5. Lead-induced Liver Hyperplasia: Mediators and Molecular Mechanisms
>
X
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W
Concentration
—
A. Lead nitrate, 100
HM/kg b.wt, intra-gastric
B. Diethyl nitrosoamine
200 mg/kg b.wt, i.p.
0-100 uMPb sulphate, Pb
monoxide, Pb chloride
and Pb acetate up to
1 mM, culture media.
Choline Ig/kg/day in
drinking water
Lead nitrate, 75 |iM/kg
b.wt, single i.v.
75 nmol/kg b. wt. Lead
nitrate in adult and 20
Hg/mL in the young, i.v.;
single dose
Duration Species
— Rat
3 and 15 days Male Wistar
Albino rats
Multiple time REL liver cells
points ranging from
24 h up to 7 days.
0, 20 and 24 h Male and female
rats , partial
hepatectomy
6 h - 4 wks Adult male
Albino rats
Analyses at 72 h Male Wistar
Albino Rats.
Effects3
Apoptosis plays a major role in the regressive phase of lead nitrate induced hepatic
hyperplasia as detected by the apoptotic bodies by in situ end labeling and H&E
sections of the hepatic tissue. H&E scores mostly cells in apoptosis phase II, ISEL
(in situ end labeling) scores for cells in phase I. Combination of these two methods
is suggested for the better understanding of the extent and nature of apoptotic
process in liver cells treated with chemicals.
Mitogenic stimuli (3 days lead nitrate treatment) and complete regression (15 days
after the treatment), affected the apoptosis differentially.
Influence of apoptosis Vs necrosis on the growth of hepatocytes initiated by
diethyl nitrosamine followed by lead nitrate treatment indicated that the
regenerative response elicited by a necrogenic dose of CCL4 promoted GSTP
(Placental glutathione), a pre-neoplastic marker positive cells as against the lead
nitrate that induced the apoptosis.
Lead compounds showed a dose and time related effect on REL liver cell
proliferation with varying potencies specific to the different lead salts. Pb acetate
was the most effective and Pb monoxide, the least effective. On 1 hr treatment
none of the compounds tested affected the intracellular communication.
PKC isozymes during liver cell regeneration — PKC 5 showed a pronounced
increase 20h after partial hepatectomy. a, p, and Zeta at 24 h corresponding with
S-phase. Sexual dimorphism matching with sexual differences in DNA synthesis
was evident. Administration of choline was able to modulate the protein kinase C
isozyme pattern in females in relation to DNA synthesis and c-myc expression.
Taken together the data positively implicates a, p, and Zeta in growth after partial
hepatectomy and 5 in negative regulation.
Lead induced significant increase in liver weight. Increased 3H Thymidine
incorporation. Lead induces extensive hypomethylation in treated rat livers. Site-
specific effect on methylation was confirmed at Hpa II, Msp I, Hae III.
Effect of lead nitrate on the 5- methyl deoxy cytidine (5-mdcyd) content and the
Hpall, MSPI, Hae III restriction patterns of hepatic DNA from young, middle aged
and senescent rats. The results indicated that the methylation pattern of genomic
DNA changed significantly with age and the methylation patterns were
differentially affected in all the three populations.
Reference
Nakajima et
al. (1995)
Columbano et
al. (1996)
Apostoli et al.
(2000)
Tessitore et
al. (1995)
Kanduc et al.
(1991)
Kanduc &
Frisco (1992)
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Table AX5-10.5 (cont'd). Lead-induced Liver Hyperplasia: Mediators and Molecular Mechanisms
>
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to
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o
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O
O
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Concentration
lOnmol/lOOgbody
weight lead nitrate, i.v.
100 nmol/kg, b. wt. lead
nitrate, i.v.
100 nmol/kg b. wt.
100 junol/kg b. wt, i.v.
100 |i mo I/kg b. wt., i.v.
lead nitrate
Duration
Multiple analyses
up to 40 h
Analyses at
multiple time
points 0.25- 24 h
8h
Multiple analyses
time points,
1-120 h
Analyses at
multiple time
points 8 h to 15
days
Species
Male Wistar Rats,
hepatocytes from
partial
hepatectomy and
lead nitrate
treatment.
Male Wistar
Albino Rats
Male Sprague
Dawley rats
Male Wistar rats
Male Wistar rats
Effects3
The kinetics of DNA synthesis and expression of Proto oncogenes in partially
hepatectamized liver cells and lead nitrate treated hepatic cells indicated peak
DNA synthesis after 24 h in the formal and after 36 h in the later case. Both
proliferative stimuli induced c-fos, c-myc and c-Ha Ras expression. Induced c-
myc expression persisted for up to 40h during the lead nitrate- induced liver cell
proliferation. Lead induces hepatic hyperplasia through changes in proto-
oncogene expression.
proliferative stimuli by means of lead nitrate exposure resulted in increased
expression of c-jun m-RNA where as compensatory regeneration in partially
hepatectamized cells occurred through increased expression of c-fos and c-jun.
Different mitogenic stimuli induced differential expression of these
protooncogenes, in addition had a different profile than cells from partial
hepatectomy despite the cell cycle timings being the same in some cases.
In rat liver, in addition to a few hepatocytes four types of non parenchymal cells
namely, fibroblasts, macrophages, bile ducts and periductular cells proliferate in
response to lead nitrate treatment. This growth is not related to adaptive response
secondary to parenchymal enlargement. However, such growth in parenchymal
cells seems dormant and does not play a functional role in adult liver epithelial
growth.
Both mRNA levels and enzyme activity of DNA polymerase p markedly increased
before and/or during DNA synthesis in proliferating hepatocytes in lead nitrate
treated and partially hepatectomized rats. 5 fold increase in the enzyme activity
was observed 8 h after lead nitrate administration. In the regenerative liver cells a
3 fold increase was observed 24-48h after partial hepatectomy.
Lead nitrate induced Poly (ADP-ribose) polymerase mRNA 24 hr after exposure.
A 2 fold increase in the mRNA levels of the enzyme occurred two days after the
exposure. Such changes were also observed in hepatic cells from livers of partial
hepatectomy. These changes preceded the increase in DNA synthesis and
remained high during the time of extensive DNA synthesis.
Reference
Coni et al.
(1989)
Coni et al.
(1993)
Rijhsinghani
et al. (1992)
Menegazzi et
al. (1992)
Menegazzi et
al. (1990)
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Table AX5-10.5 (cont'd). Lead-induced Liver Hyperplasia: Mediators and Molecular Mechanisms
Concentration
Duration
Species
Effects3
Reference
to
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O
>
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O
H
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o
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O
HH
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30 mg/kg b. wt. lead
nitrate
30 mg/kg b. wt. lead
nitrate
100 |imol/kg b. wt. lead
nitrate, i.v., single dose.
A. Mitosis-
Lead nitrate- 100
|iM/kg, i.v.
Ethylene dibromide 100
mg/kg , intra gastric
Cyproterone acetate, 60
mg/kg intra gastric.
B. Hepatocyte nodules
diethyl nitrosamine 200
mg/kg
Lead nitrate, single i.v.
100 nm/kgb.wt
LPS- 12.5 ng/rat, post Pb
nitrate treatment.
Multiple time Adult male and
points up to 8 days female rats
Multiple time point Adult male and
up to 60 h female rats
Multiple time point Male Wistar Rats
analyses ranging
from 12- 168 h
30' - 3 h
Adult male
Wistar rats
Multiple analyses
at 3, 6, 12, 24 and
36 h
Male Wistar rats
Lead nitrate induced liver hyperplasia exhibited sexual dimorphism where Tessitore et
mitogenic action was less effective and was delayed in females as compared with al. (1994)
males. Pre administration with choline partially filled these sexual differences.
Lead nitrate induced liver hyperplasia exhibited sexual dimorphism. Pre Tessitore et
administration with choline partially filled these sexual differences. Significant al. (1994)
down regulation of PKC p and PKC a activities occurred during lead induced
proliferation
Effect of lead nitrate on protein kinase C (PKC) activity. A single dose of lead Liuet al.
nitrate resulted in enhanced activity of PKC in the purified particulate fraction of (1997)
the rat liver, reached its peak activity by 24 h which lasted for 48 h. This was
accompanied by increased frequency of mitotic cells. These results indicate, lead
nitrate induced PKC activity may play a role in liver cell proliferation.
Liver cell proliferation by enhanced DNA synthesis was observed with the Coni (1991)
mitogens Cyproterone acetate, ethylene dibromide, and lead nitrate as early as 30
mints after treatment and persisted even after 5 days of treatment by lead nitrate
administration.
hepatocytes isolated from pre neoplastic liver nodules have also exhibited
enhanced cell proliferation.
Stimulation of hepatocyte cell proliferation by lead nitrate was not accompanied Shinozuka et
by changes in liver levels of Hepatocyte growth factor (HGF), Transforming al. (1994)
growth factor-a (TGF-a), or TGF-pl m-RNA. Lead nitrate treatment resulted in
the enhancement of Tumor necrosis factor a at a time preceding the onset of
hepatocyte DNA synthesis, indicating its role in lead induced hepatic cell
proliferation. The survival of lead nitrate treated rats decreased significantly with
an after treatment of LPS (lipopolysaccharide).
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Table AX5-10.5 (cont'd). Lead-induced Liver Hyperplasia: Mediators and Molecular Mechanisms
>
X
H
6
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O
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O
O
HH
H
W
Concentration
15 mg/kgb. wt. lead
acetate
Lead nitrate 100 uM/kg
b. wt. i.v. single dose
100 umol/kg b. wt lead
nitrate, single, i.v.
100 umol/kg b. wt. single
i.v.,
100 umol/kg b. wt. i.v.
single dose
100 u mol/kg b. wt. i.v.,
single dose
Duration Species
Pb+ LPS group Male Sprague
analyzed after 14 h Dawley rat
and the rest after
24 h after lead
administration
Multiple time Male Wistar rats
points of analyses
extending up to 48
h after treatment
Multiple time
points of analyses
up to 48 h
Multiple time Male Sprague
points of analyses Dawley rats
up to 80 h
Multiple time Male Wistar rats
points of analyses
up to 24 h
Multiple time point Male Sprague
analyses up to 96 h Dawley rats
Effects3
Lead augments the lethality of endotoxin lipopolysaccharide (LPS) in rats and
enhances liver injury, which is further enhanced by TNF. Lead + LPS treatment
increased both serum TNF concentrations and TNF area as compared to LPS
alone, simultaneous administration of lead with either LPS or TNF, serum
aspartate transaminase, alanine transaminase, alkaline phosphatase, glutamyl trans
peptidase and plasma triglyceride levels were markedly increased
Lead nitrate and ethylene bromide induce liver cell proliferation via induction of
TNFa. Dexa methasone, a known TNF inhibitor, decreases TNF expression and
liver cell proliferation by these mitogens. These studies support the fact that TNF
might mediate hepatic cell proliferation by lead nitrate and ethylene bromide.
Lead nitrate (LN) treatment resulted in increased Brdu incorporation of
hepatocytes and non parenchymal cells at 12 h after treatment and reached the
peak index at 36 h. Rats given a single iv of recombinant TNFa enhanced
proliferation in non parenchymal cells after 24 h, the labeling of hepatocytes at
36 h. NAF, Nafenopin another mitogen which does not induce liver TNFa,
increased the number of labeled hepatocytes without increasing the labeling of non
parenchymal cells indicating that only lead nitrate induced proliferation is
mediated by TNFa and these mitogens initiate proliferation in different cells based
on their capacity to stimulate TNFa production.
Lead nitrate induces liver cell proliferation in rats without accompanying liver cell
necrosis. This proliferation involves enhanced TNF mRNA and levels but not
hepatocyte growth factor. The role of TNF in lead nitrate induced liver cell
proliferation is supported by the inhibition of TNF and reduced hepatocyte
proliferation by several TNF inhibitors.
Lead nitrate induced liver cell proliferation involves TNF a production, enhanced
NF-KB activation increased hepatic levels of iNos mRNA as opposed to other
mitogens such as Cyproterone acetate or Nafenopine.
The role of neurotrophins, the nerve growth factor (NGF), the brain derived
neurotrophic factor (BDNF) and neurotrophin -3 (NT-3) in lead nitrate treated
liver cells was studied. LN, treatment resulted in increased in the levels of NGF,
BDNF and NT-3. The increase in neurotrophin receptors and the gene expression
were correlate with liver weights. This study demonstrates that lead nitrate
induced hyperplasia may be mediated by neurotrophins.
Reference
Honchelet al.
(1990)
Ledda-
Columbano et
al. (1994)
Shinozuka et
al. (1996)
Kubo et al.
(1995)
Menegazzi et
al. (1997)
Nemoto et al.
(2000 )
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Table AX5-10.5 (cont'd). Lead-induced Liver Hyperplasia: Mediators and Molecular Mechanisms
>
X
Concentration
Multiple doses 0-50 |iM,
culture medium
50 uM lead acetate,
culture medium
10 uM/HOgb. wt., single
i.v.
10 umol/100 g b. wt.
single i.v.
lOmmol/lOOg, lead
nitrate, i.v.
Duration
Multiple time
points up to 24 h
24 h
Multiple time point
analyses up to
5 days
Multiple time
points up to 9 days
Multiple time
points
Species
Hepatocytes from
Adult male
Swiss-mice,
primary
Rat hepatocyte
and Kupffer cell
and granulocyte
co-cultures
Adult male
Wistar Rats
Male Wistar rats
Male Wistar rats
Effects3
Interaction between Pb and cytokines in hepatotoxicity- Pb potentiated cytokine -
induced oxidative stress by decreasing GSH and increased efflux of Oxidized
glutathione (GSSG). Combined treatment resulted in a decline in intra cellular
ATP concentration
Lead stimulates intercellular signaling between Kupffer cells and hepatocytes
which increased synergistically at low lipopolysaccharide levels. These signals
promote proteolytic hepatocyte killing in combination with a direct cellular
interaction between the granulocytes and hepatocytes.
Lead nitrate induced hepatocyte apoptosis was prevented by pre- treatment with
gadolinium chloride, a Kupffer cell toxicant - Role for Kuffer cell in hepatocyte
apoptosis
Lead nitrate- induced liver hyperplasia in rats results in a significant increase in the
expression of aceyl glycoprotein receptor (ASGP-R) during the involutive phase of
lead nitrate induced hyperplasia in rat-liver, which coincided with the massive
death by apoptosis of the same cells. A significant rise in the galactose-specific
receptors was also observed 3 days after the treatment. These studies demonstrate
that carbohydrate receptors regulate lead nitrate induced liver cell apoptosis.
Demonstration of the expression of carbohydrate receptors on Kupffer cells. Lead
nitrate induced apoptosis in Kupffer cells and intemalization of apoptotic cells
(Phagocytes) is mediated by both Mannose and Galactose receptors.
Reference
Sieg & Billing
(1997)
Milosevic and
Maier (2000)
Pagliara, et al.
(2003a)
Dini et al.
(1993)
Ruzittuet al.
(1999)
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Table AX5-10.5 (cont'd). Lead-induced Liver Hyperplasia: Mediators and Molecular Mechanisms
>
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H
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O
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H
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O
O
HH
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W
Concentration
Pb (No3)2, , i.v.
lOOnM/HOg .b.wt
GdCl3
0.75 mg/100 g. b. wt, i.v.
Duration
1, 3, and 5 days.
2, 4, or 24 h before
lead nitrate
Species
In vivo Adult
male Wistar rats
Effects3
Hepatic apoptosis induced by lead nitrate in vivo is abolished by gadolium
chloride, a Kupffer cell toxicant that suppresses Kupffer cell activity and reduces
to half the apoptotic rate. Lead nitrate treatment also deprives the hepatic cells
from reduced glutathione and this process is reversed by Gadolium chloride. Lead
nitrate induces apoptosis in Kupffer cells, and HepG2 cells in vitro.
Reference
Pagliara
(2003b)
In vitro, 10 mM lead
nitrate
injection.
Analyses at
multiple time
points up to 24 h in
Hep G2 cells and at
24 and 48 h in
Kupffer cells
Hep G2 cells
Multiple concentrations 1 , 2, 4 and 6 days
varying from
300 nM-lOuM,
up to 100 uM in certain in
vitro expts
0-10 uM lead acetate in 24 & 48 h
the culture medium
Hepatoma cell
line, H4- II-C3
H4-IIE - C3
hepatoma cell
culture model
Acute effect of lead on glucocorticoid regulation of Tyrosine aminotransferase
(TAT) in hepatoma cells -Lead treatment does not significantly alter initial
glucocorticoid receptor number or ligand binding. Lead may perturb PKC
mediated phosphorylations in the glucocorticoid-TAT signal transduction system.
Lead also may be increasing the turnover of TAT by actions at transcription,
translation and /or post translation.
In HTC cells glucocarticoid signal transduction pathways involve calcium-
mediated events and PKC isoforms , lead exposure interferes with calcium
mediated events and aberrant modulation of PKC activities and may contribute to
the over all toxicity of lead.
Heiman and
Toner (1995)
Tonner and
Heiman,
(1997)
b. wt. = body weight
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Table AX5-10.6. Effect of Lead Exposure on Liver Heme Synthesis
>
X
Concentration
75 mg Pb/kg b. wt, i.p.
10"5 ppm lead nitrate
A. Triethyllead-3.5&8.0
mg/kg b.wt.
Lead nitrate
Duration
Multiple time
point analyses
0-30 h
Multiple
analyses up to
24 h
Multiple
analyses up to
28 days
Species
C57 BL/6 mice
RLC-GA1 Rat
liver cell line
Adult male
Fischer rats
Effects3
Lead poisoning decreases P-450 as a consequence of two different mechanisms,
a mechanism unrelated to heme where P-450 transcription is inhibited (reduces
the synthesis and activity), and a second mechanism where by inhibition of heme
synthesis occurs decreasing the heme saturation of P450 and/or apo-P450
content.
Lead increases heme synthesis in RLC-GA1 in rat liver cell line, when measured
by the amount of 59 Fe incorporated into heme fraction. Increased incorporation
of59 Fe into the heme fraction of the lead treated cells was the result of increased
uptake of iron 59 Fe into the heme fraction of lead treated cells.
Cellular degradation of lead was not significantly affected by lead.
Triethyl lead chloride has a similar potency to inorganic lead nitrate in inhibiting
ALAD both in vitro and in vivo. Liver and blood ALAD have similar
sensitivities to lead compounds. Inhibition is reduced in the presence of Zn.
Reference
Joveret al.
(1996)
Lake and
Gerschenson
(1978)
Bondy(1986)
3.5, 25 and 100 mg/kg
Single Subcutaneous
B. In vitro,
10-3-10-9Mtriethylleador
lead nitrate
30 minutes
H
6
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O
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W
O
O
HH
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W
5 uM lead acetate or lead Multiple Rat primary
diethyldithiocarbomate lead analyses from hepatocyte
uptake studies 0.33-10 uM 0-20h cultures
Per OS eqimolar doses (17 uM 5 days. Female rabbits
Me/kg)ofSnCl2orPb
(CH3COO)2 every day
Effect of lead and diethyl dithiocarbomates on rat primary hepatocytes as studied Oskarsson et al.
with lead acetate and or lead- diethyldithiocarbomate complex (Pb DTC2i) (1989)
labeled with 203Pb indicated that (Pb DTC2i) complex caused a more rapid and
stronger inhibition of ALAD activity than lead acetate.
Uptake of lead was rapid and higher with the complex than lead acetate.
The complex also inhibited the ALAD activity in vitro when incubated with
purified ALAD enzyme.
Lead decreased liver and bone marrow ALAD, but had no change in the Zareba and
Aminolevulinic acid synthetase (ALA-S) and increased erythrocyte free Chmielnicka
protoporphyrin. (1992)
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Table AX5-10.6 (cont'd). Effect of Lead Exposure on Liver Heme Synthesis
Concentration
Duration
Species
Effects3
Reference
to
O
O
>
X
CP-I in rats and exposed workers. Urinary Tomokuni
B. Lead smelt 5-hydroxy indole acetic acid was not influenced by lead exposure. (1987)
workers, males
Weanling High Zn in the diet reduces plasma copper, but not plasma ceruloplasmin activity Panemangalore
Sprague Dawley or the recovery of plasma copper or ceruloplasmin activity after oral copper and Bebe (1996)
rats sulphate of Cu-deficient rats. High dietary Zn also modifies the response of
plasma SOD activity to dietary copper , but does not influence RBC SOD
activity
H
6
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O
H
O
o
H
W
O
O
HH
H
W
1200 mg/kg b. wt. lead acetate
in diet, Sub acute toxic studies
400 mg/lead
4 wks
Broiler chickens Liver porphyrin levels increased during lead toxicosis. Concurrent Khan & Szarek
administration of selenium or monensin in the feed further enhances this process. (1994)
0- 1 00 uM lead acetate in the 1 9 h
culture medium
Primary Rat and
chick embryo
hepatocyte
cultures.
Formation of Zn protoporphyrins in cultured hepatocytes- Lead did not
specifically increase Zinc protoporphyrin accumulation or alter iron availability
in cultured hepatocytes.
Jacobs et al.
(1998)
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o
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Table AX5-10.6 (cont'd). Effect of Lead Exposure on Liver Heme Synthesis
Concentration
Duration
Species
Effects3
Reference
to
O
O
>
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H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Lead acetate, 160 mg/L, semi
liquid diet, oral
8 weeks
Male Wistar rats
Lead acetate, 0.0625 uM- 32
uM, in vitro
1, 5, or 10 mg/kg b. wt. lead
acetate or nitrate, i.p.
10'4 M Pb acetate for Hep G2
cells
10 mg lead/kg b. wt. as lead
acetate , i.p., single injection
10 and 100 uM lead acetate
1 0 minutes pre
incubation and
20 minute
incubation
3 days
Analyses at
multiple time
points up to
72 h
Rabbit
reticulocytes
A. Transgenic
mice carrying
chimeric human
TF gene
B. Hep G2 cells
Transgenic mice
and Hep G 2 cells
Rats exposed to lead had a higher blood and liver lead, increased erythrocytic Santos (1 999)
protoporphyrin. Lead exposure also resulted in hypoactivity of aminolevulinate
dehydrase.
Rats exposed to ethanol and lead had altered abnormalities in heme similar to
animals exposed to lead alone.
Hepatic levels of Zn decreased significantly only in animals exposed to both.
Hepatic GSH, urinary ALA and porphyrin levels were maintained similarly in all
the groups
Transferrin bound iron uptake by Pb was also inhibited by lead at higher
concentrations such as 4 |iM.
The effect of lead on ferrous iron transport is similar between lead chloride, Qin and Morgan
acetate, and nitrate and reversible. (1990)
Uptake of ferrous iron into all (heme, cytosolic and stromal fractions) was
inhibited by low concentrations of lead.
50% inhibition in the uptake by cytosol occurred at 1 uM lead.
These studies present evidence for the modulation of the synthesis of human Adrian et al.
transferrin by lead. In transgenic mouse with chimeric human chloromphenical (1993)
acetyl transferase lead regulates human Transferrin (TF) transgenes at the m
RNA level. Liver catalase (CAT) enzyme activity, CAT protein, and TF-CAT
m-RNA levels were all suppressed. Lead did not alter other liver proteins,
mouse TF and Albumin.
Pb suppressed synthesis of Transferrin protein in cultured human hepatoma Hep
G, cells.
Lead suppresses human transferrin synthesis by a mechanism different from Huckins et al.
acute phase response. Common proteins such as C3 and albumin associated with (1 997)
acute phase response were not altered by lead. Lead acetate suppresses 35S -
transferrin protein synthesis and m-RNA levels in Hep G2 cells and transgenic
mice, while LPS altered only protein levels.
b. wt = body weight
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Table AX5-10.7. Lead and In Vitro Cytotoxicity in Intestinal Cells
to
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O
Compound and
Concentration
Duration
Species
Effects3
Reference
>
X
HgCl2, CdCl2, Ti2 S04,
Pb(NO3)2 - concentration
not given clearly,
Butathionine, up to 1 mM
Glutathione 1 mM
N- Acetyl cysteine, 1 mM
Cell proliferation 1-407, Intestinal
assays 48 h epithelial cell
Glutathione
depletion assays
48 h
Sulphahydryl
repletion studies.
Rank order cytotoxicity of various metal salts in 1-407 intestinal epithelial cells
in terms of LC50 values-HgCl2 (32 uM)>CdC!2(53 uM), CuCl2 (156 uM)>
Ti2S04
(377 uM)>Pb (NO3)2(1.99 mM)
Role of Glutathione, in the cytotoxicity of these metals by the assessment of
GSH depletion by Butathionine sulfoxamine pretreatment at non cytotoxic
concentration increased the toxicity of HgCl2 (5.7-fold), and CuCl2 (1.44-fold).
Administration of glutathione, with either HgCl2 or CdCl2 did not protect the
cells against the toxicity.
W-acetyl cysteine reduced the cytotoxicity of mercury.
Keogh et al.
(1993)
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HH
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December 2005
Table AX5-10.8. Lead and Intestinal Uptake - Effect on Ultrastructure, Motility, Transport, and Miscellaneous
Compound and
Concentration
Lead acetate, 0. 1%, in
drinking water.
Duration Species
Multiple analyses Male Wistar rats
at 2, 30, and 60
days after lead
Effects3
Small intestinal goblet cells are involved in lead detoxification.
Lead treatment for 30 days produces characteristic goblet cells in the intestine
Authors
Tomczok et al.
(1988)
exposure.
and lead appears in conjunction with goblet cell membrane.
Prolonged exposure to lead more than 30 days caused silver sulphide deposition
(indicative of heavy metal deposition) in the mucus droplets of cytoplasmic
goblet cells.
>
X
100 mg/lead acetate/kg, b.
wt.
Multiple analyses
at 2, 30 and 60
days
Male Wistar rats
Lead poisoning changes the ultra structure of intestine.
30 day lead exposed rat intestinal enterocytes showed numerous, small rough-
membraned vesicles and prominent, dilated golgi complexes, in their cytoplasm.
By 60th day, lead-exposed rats had a vacuolated cytoplasm and prominent golgi
filled with vacuoles.
Tomczok et al.
(1991)
Added lead concentration in
the milk - 0-80 ug/ml
H
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O
o
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W
O
O
HH
H
W
Pb as lead acetate, for 0.5-
10.0 uM, Zn as Zn acetate
0, 5, 10 or 50 uM
Temperature variation
Expts, 5 uM Pb, and
incubated for 10 mints at 4,
22, or 37 °C
5, 10, 30 or 60
mints,
Simultaneously
with lead for 10
minutes
Incubation time
10 minutes
Adult & Infant
rats (16 days)
Fresh or frozen
rat or Avian milk
IEC-6 normal rat
intestinal
epithelial cells.
90% of Pb in rat and bovine milk was found associated with caseine micelles Beach and
regardless of whether the milk is labeled in vitro or in vivo with203 Pb. Similarly Henning (1988)
lead in infant milk formula was also predominantly associated with casein,
however, to a much lower extent than rat and bovine milk formulae.
Lead tracer studies indicated that in infant rats, as the milk traversed through the
intestine, in the collected luminal fluid, Pb was primarily associated with casein
curd and remained as a non precipitable, non-dialyzable fraction as it moved to
the small intestine, indicating that Pb remains with protein fraction as it traverses
through the stomach and small intestine, fraction
Pb uptake by IEC-6 cells depends on the extracellular Pb concentration. Pb Dekaney et al.
transport in IEC-6 cells is time and temperature dependent, involves (1997)
sulphahydryl groups, and is decreased by the presence of Zn.
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Table AX5-10.8 (cont'd). Lead and Intestinal Uptake - Effect on Ultrastructure, Motility, Transport, and Miscellaneous
Compound and
Concentration
Duration
Species
Effects3
Authors
>
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to
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OECD
(Organisation for Economic
Co-operation and
Development) medium was
artificially contaminated at
1, 3, 5, or 10 times the
Dutch intervention value of
530 mg/Pb/kg dry wt. Lead
containing medium was
presented at the apical
surface of the cells in 2 ml
DMEM/chyme.
Neutral red uptake studies
had DMEM/chime with low
SuMandhighSOuM lead
content
Cell viability
studies—24 h
incubation.
Lead transport
studies, 1, 3, 5
and 24 h
Transport of bioaccessible lead across the intestinal epithelium—In Coco- 2 cells
exposed to artificial chime, with in 24 hrs. App. 27% of the lead was associated
with the cells and 3% were transported across the cell monolayer. Lead
associated with cells showed a linear relationship with the lead available in the
system.
Results indicate that only a fraction of the bioavailable lead is transported across
the intestinal epithelium.
On the basis of lead speciation in chime, It could be attributed that dissociation
of labile lead species, such as lead phosphate, and lead bile complexes and
subsequent transport of the released free metal ions flow toward the intestinal
membrane.
Oomenet al.
(2003)
44 mg/kg/day lead as 53 4 weeks
mmol/L lead acetate
2.5 mg/ml lead acetate in 55 days
drinking water
100 |iM lead nitrate, in Duration not
vitro specified
Rat
Colonic segments
taken from
chronically
exposed guinea
pigs
Muscle -
myenteric plexus
preparations of
distal ileum of
controlled
animals
Lead exposure significantly decreases the amplitude of contraction in rat
duodenum.
Colonic propulsive activity as measured by the velocity of the displacement of
the balloon, from the oral to the aboral end, did not get affected significantly by
lead treatment.
Moderate decrease of electrically induced cholinergic contractions.
Karmakar and
Anand(1989)
Rizzi et al
(1989)
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Table AX5-10.8 (cont'd). Lead and Intestinal Uptake - Effect on Ultrastructure, Motility, Transport, and Miscellaneous
Compound and
Concentration
Duration
Species
Effects3
Authors
40 uM-240 uM Tri ethyl
lead added in a cumulative
manner in vitro to mid-ileal
7. 5 sec -2 Swiss mice JVI1 1 . Peristaltic contractile activity of ileum as measured as a change in period Shraideh et al.
minutes ileum duration and force amplitude indicated that tri ethyl lead (TEL) concentrations of (1999)
< 40 uM had no obvious effects on these parameters.
2. In the concentration range between 40 uM -120 uM, tri ethyl lead affected the
rhythm of contraction in a concentration dependent manner with elongation in
period and reduction in force amplitude.
3. At concentrations above 120 uM, TEL induced irreversible dramatic changes
in the ileal contractile activity.
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December 2005
Compound and
Concentration
Ca- 0.5% in diet (low
Calcium)
Table AX5-10.9.
Duration
10 days
Lead, Calcium, and Vitamin D Interactions, and Intestinal Enzymes
Species Effects3
White Leghorn Dietary lead affects intestinal Ca absorption in two different ways depending on
Cockerels the dietary Ca status.
Authors
Fullmer and
Rosen (1990)
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1.2% in diet (high calcium)
Pb - 0.8% in the diet as Pb
chloride.
Ca-0.1% or 1.2% in the
diet
with
Lead-0.1-0.8% as Lead
chloride in the diet
1 or 2 weeks
Leghorn
Cockerels
Ca-0.1-1.2%
Pb-0.8%
2 weeks
White Leghorn
Cockerels
A. In chicks fed low Ca diet (0.05%), ingested lead inhibited intestinal 47Ca
absorption, intestinal Calbindin D, and alkaline phosphatase synthesis in a
dose dependent fashion.
B. In normal calcium diets (1.2%) lead exposure had no bearing on the intestinal
Ca absorption, or Calbindin D, or Alkaline phosphatase synthesis and in fact
elevated their levels at higher lead concentrations.
These results indicate that the primary effects of lead in both cases, occur at
or prior to intestinal protein synthesis involving Cholecalciferol endocrine
system.
- Dietary Ca deficiency, initially Fullmer (1991)
(1st week) stimulates Ca absorption and Calbindin D levels regardless of dietary
Pb intake.
- At 2 weeks, this response is reversed by lead.
- Intestinal lead absorption was enhanced by Ca deficiency initially and was
inhibited by prolonged dietary lead intake.
- Intestinal Pb absorption was increased in adequate Ca situation, but only after 2
weeks at the lower levels of dietary Pb.
Interactions between dietary lead and Ca-influence on serum vitamin D levels. Fullmer (1997)
- Lead ingestion and Ca deficiency alone or in combination generally increased
serum 1,25 (OH)2 D levels over the most of the range of dietary lead and Ca.
- In severe Ca deficiency, Pb ingestion resulted in significant decreases in
hormone concentration.
- Similarities in response profiles for 1,25 ( OH)2 D, intestinal Ca absorption and
Calbindin- D suggested major interactions between lead and calcium mediated
changes via circulatingl,25(OH)2 D concentration.
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Table AX5-10.9 (cont'd). Lead, Calcium, and Vitamin D Interactions, and Intestinal Enzymes
Compound and
Concentration
Duration
Species
Effects3
Authors
Lead, Alkaline phosphatase Incubation time-
and Ca + ATPase not specified
2.0-10.0 mM
Lead, Sucrase 0.5 mM -
6.0 mM
Lead, y-glutamyl
transpeptidasel.0-10 mM
Lead, Acetyl choline
esterase 10.00-35.00 mM
Male Albino rats Lead inhibited the activity of several intestinal brush border enzymes such as Gupta et al.
Ca2+- ATPase, Sucrase, y-glutamyl - transpeptidase and acetyl choline esterase (1994)
with the exception of alkaline phosphatase. Inhibition of Ca2+- ATPase was
competitive and that of the other enzymes is by non-competitive means.
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Oral lead in Similac or
apple juice adjusted for
attainment of blood lead
levels 35-40 ng/dL.
Succimer 30 mg/kg/day
204 Pb 24.5 nM followed by
206 Pb 352 nM, Single dose
Administered Female infant Effect of oral succimer chelation on the Gastro intestinal absorption and the Cremin et al.
from 8th day post Rhesus Monkeys whole body retention of lead — (200 1 )
partum, until age .
2(, ^ Radio isotope Pb tracer technique —
T • Succimer significantly reduced Gastro intestinal absorption of lead and increased
1 \VO SUCCcSSlVc . -1-11
1 9 day s at age 53 urma^ excretlon of lead
weeks and 65 The initial decrease in whole body lead by 10% was over come when majority
weeks, of administered tracer was retained in the body after 5 days of treatment
Administered
immediately
before chelation
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CHAPTER 5 ANNEX
ANNEX TABLES AX5-11
December 2005 AX5-176 DO-NOT QUOTE OR CITE
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Source
Goyer(1968a)
Goyer(1970a,b)
Choie and Richter (1972)
Moore et al. (1973)
Moore &Goyer( 1974)
Shelton and Egle (1982)
Egle and Shelton (1986)
Oskarssonet al. (1982)
Mistry et al. (1984)
Fowler and DuVal (1991)
Organ
Kidney
Kidney
Kidney
Kidney
Kidney
Kidney
Brain
Kidney
cytosol &
brain
Kidney
cytosol
Kidney
cytosol
Table AX5-11.1. Lead-binding Proteins
Molecular
Species Weight Protein Properties
Rat Intranuclear lead inclusion
bodies
Rat Lead is concentrated in the
intranuclear inclusion body
Rat Initial inclusion bodies in
cytoplasm
Rat Protein in inclusion bodies is
acidic, with high levels of
aspartic a, glutamic a, glycine
& cystine
Rat Inclusion body
protein is 27.5
kDa
Rat Inclusion body is Namedp32/6.3
32 kDa with pi of
6.3
Rat, mouse, p32/6.3 found
dog, guinea
pig, and
chicken
Rat 11. 5 and 63 kDa
Rat 11. 5 kDa, 63 kDa, Respective Kd values: 13, 40
> 200 kDa 123 nM
Rat Cleavage product of alpha-2
microglobulin
Inducible Separation Technique
Yes
Yes
Yes
Yes
Yes Acrylamide gel electrophoresis
Yes Two-dimensional gel electrophoresis
No(?)
No 203Pb binding followed by Sephadex G-
75 or G-200 chromatography, then
SDS-PAGE
No 203Pb binding followed by Sepharose-
6B column chromatography
No Chromatography followed by reverse
phase HPLC, then production of
antibodies. Kd 10-8 M
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Table AX5-11.1 (cont'd). Lead-binding Proteins
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December 2005
Table AX5-11.1 (cont'd). Lead-binding Proteins
Source Organ Species
Church et al. (1993a) RBC Human lead
workers, one
asymptomatic
and one
symptomatic
Church et al. (1993b) RBC Human lead
workers
Xieet al. (1998) RBC Human lead
workers
Molecular
Weight
6-7 kDa
5, 7 and 12 kDa,
pi 4.7-4.9
240 -260 kDa,
< 30 kDa
Protein Properties
First pt had 67% of RBC Pb
bound to protein. Second pt
had 22% of RBC Pb in
protein
30 % cysteine Thought to be
MT on basis of greater UV
abs at 254 nm than 280 nm
High M.Wt. Peak identified
as ALAD. Low M.Wt. peak
Inducible Separation Technique
Yes RBC hemolysate filtered through
Amicon YM 30 membrane. Superose
12 column. Lead quantitated by A.A.
Yes Superose 12, Amicon YM 30, Amicon
YM 2, HPLC
Yes Bio-gel A column. Pb determined by
AA.
X
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Goering & Fowler,
(1987a)
Goering & Fowler,
(1987b)
Kidney
Kidney and
liver
Rat
Rat
seen after adding lead in vitro
Pre-treatment with zinc
before injecting 203Pb leads to
zinc-thionein binding Pb
Pre-Rx with Zn or Cd induces
Zn or Zn, Cd-MT. The MT
decreases Pb inhibition of
ALAD
No 203Pb binding, Sephadex G-75
No 203Pb binding, Sephadex G-75
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Qu et al. (2002); Waalkes Kidney MT-null
et al. (2004) phenotypic
Pb-exposed MT-null
developed no Pb inclusion
bodies, accumulated less
renal Pb than WT
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CHAPTER 6 ANNEX
ANNEX TABLES AX6-2
December 2005 AX6-1 DRAFT-DO NOT QUOTE OR CITE
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Table AX6-2.1. Analytical Methods for Determining Lead in Blood, Urine, and Hair
Sample
Matrix
Blood
Blood
Blood
Blood
Blood
Blood
Blood and
urine
Blood and
urine
Blood and
urine
Blood and
tissue
Preparation Method
Wet ashing with acid mixtures; residue dissolution in
dilute HC1O4
Wet ashing with HNO3; residue dissolution in dilute
HNO3
Dilution with Triton X-100®; addition of nitric acid
and diammonium phosphate
Dilution of sample with ammonium solution
containing Triton X-100
Dilution of sample in 0.2% Triton X-100 and water
Wet ashing, dilution
Mixing of urine sample with HNO3; filtration,
chelation of lead in whole blood or filtered urine with
APDC, extraction with MTBK
Wet ashing of sample with HNO3, complexation with
diphenylthio-carbazone, and extraction with
chloroform
206Pb addition and sample acid digestion; lead copre-
cipitation by addition of Ba(NO3)2, followed by
electrodeposition on platinum wire
Digestion of sample with HNO3/HC1O4 /H2SO4; heat
Analytical Method
ASV with mercury-
graphite electrode
(NIOSH Method 195)
GFAAS (NIOSH Method
214)
GFAAS
ICP/MS
GFAAS
ICP-MS
GFAAS
AAS
(NIOSH Method 8003)
Spectrophotometry
(NIOSH Method 102)
IDMS
ICP-AES (Method 8005)
Sample
Detection Limit
40|ig/L
100 \ig/L
2.4 ng/L
15ng/L
K15Mg/L
0.1 ppb
4ppb
0.05 jjg/g (blood);
50 |ig/L (urine)
30 ng/L (blood);
12 ng/L (urine)
No data
0.01 ng/g (blood);
0.2 |ig/g (tissue)
Accuracy
(percent recovery)
95-105
No data
93-105
96-111
97-150
94-100
90-108
99 (±10.8%)
97
97
98-99
113
Reference
NIOSH (1977b)
NIOSH (1977e)
Aguilera de Benzo
etal. (1989)
Delves and Campbell
(1988)
QueHee etal. (1985)
Zhang etal. (1997)
NIOSH (1994)
NIOSH (1977a)
Manton and Cook
(1984)
NIOSH (1984)
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Sample
Matrix
Blood
Urine
Serum,
blood, and
urine
Urine
Hair
Hair
Han-
Hair
Preparation Method
Addition of 50 uL of blood into reagent, mixing, and
transferring to sensor strip (commercial test kit)
Collect 50 mL urine sample and add 5 mL
concentrated HNO3 as preservative; filter samples
through cellulose membrane, adjust pH to 8, ash filters
and resins in low temperature oxygen plasma for 6
hours
Filtration of sample if needed; blood requires
digestion in a Parr bomb; dilution of serum or urine
with acid or water
Wet ashing of sample with acid mixture and
dissolution in dilute HC1O4
Cleaning of sample with acetone/ methanol; digestion
with acid mixture and heat; diammonium phosphate
addition as matrix modifier
Cleaning with lauryl sulfate and water; digestion with
heated nitric acid
Cleaning with water; digestion with heated nitric acid
and H2O2
Cleaning with acetone/water
Analytical Method
Gold electrode sensor
ICP-AES (Method 83 10)
ICP-AES
ASV with mercury-
graphite electrode
(Method 200)
GFAAS
ICP-AES
ET-AAS
XRF
Sample
Detection Limit
1.4ug/dL
5ug/L
10-50 ug/L
4 ug/L
0.16 ug/g
1 ug/g
O.026 ug/g
0.5 ug/g
Accuracy
(percent recovery)
No data
100
85 (serum) >80 (urine,
blood)
90-110
99
No data
>90
No data
Reference
ESA(1998)
NIOSH(1994)
Que Hee and Boyle
(1988)
NIOSH(1977c)
Wilhelmetal. (1989)
DiPietro et al. (1989)
Drashetal. (1997)
Gerhardsson et al.
(1995a)
AAS, atomic absorption spectroscopy; APDC, ammonium pyrrolidine dithiocarbamate; ASV, anode stripping voltammetry; Ba(NO3)2, barium nitrate; ET-AAS, electro-thermal
atomic absorption spectrometry; GFAAS, graphite furnace atomic absorption spectroscopy; H2O2, hydrogen peroxide; H2SO4, sulfuric acid; HC1O4, perchloric acid; HNO3,
nitric acid; ICP-AES, inductively coupled plasma/atomic emission spectroscopy; ICP-MS, inductively coupled plasma-mass spectrometry; IDMS, isotope dilution mass
spectrometry; MIBK, methyl isobutyl ketone; NIOSH, National Institute for Occupational Safety and Health; 206Pb, lead 206; XRF, X-ray fluorescence.
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Table AX6-2.2. Summary of Selected
Reference, Study
Location, and Period Study Description
United States
CDC (2005) Design: national survey (NHANES IV) stratified,
U.S. multistage probability cluster design
1999-2002 Subjects: children and adults (>1 yrs, n = 16, 915)
in general population
Biomarker measured: blood lead
Analysis: ICP-MS
Brody et al. (1994) Design: national survey (NHANES III) stratified,
Pirckle et al. (1998) multistage probability cluster design.
U.S. Subjects: children and adults (> 1 yrs, n = 29, 843)
1 988-1 994 in general population
Biomarker measured: blood lead
Analysis: GFAAS
Measurements of Blood Lead Levels in Humans
Blood Lead Measurement
Units: |ig/dL
Geometric mean (95% CI)
Age(yr) 1999-2000
1-5: 1.66(1.60,1.72)
n: 7, 970
6-11: 1.51(1.36,1.66)
n: 905
12-19: 1.10(1.04,1.17)
n: 2, 135
>20: 1.75(1.68,1.81)
n: 4, 207
Males: 2.01(1.93,2.09)
n: 3,913
Females: 1.37(1.32,1.43)
n: 4,057
Units: |ig/dL
Geometric mean (95% CI)
Age (yr) 1988-1991
1-5: 3.6(3.3,4.0)
n: 2,234
6-11: 2.5(2.2,2.7)
n: 1,587
12-19: 1.6(1.4,1.9)
n: 1,376
20-49: 2.6(2.5,2.8)
n: 4, 320
50-69 4.0(3.8,4.2)
n: 2,071
>70 4.0(3.7,4.3)
n: 1,613
Males: 3.7(3.5,3.9)
n: 6,051
Females: 2.1(2.0,2.2)
n: 6,068
2001-2002
1.45(1.39,
8,945
1.25(1.14,
1,044
0.94 (0.90,
2,231
1.56(1.49,
4,772
1.78(1.71,
4,339
1.19(1.14,
4,606
Comment
Data from NHANES IV Phase 1
(1999-2000) and 2 (2001-2002).
1.40)
1.36)
0.99)
1.62)
1.86)
1.25)
Comparison of data from NHANES III
Phase 1 (1988-1991) and Phase 2
1991-1994 (1991-1994) indicated declining blood
. _ ,. . , -. lead concentrations in children.
2,392
1.9(1.8,2
1,345
1.5(1.4,1
1,615
2.1(2.0,2
4,716
3.1 (2.9,3
2,026
3.4(3.3,3
1,548
2.8(2.6,2
6,258
1.9(1.8,2
7,384
•1)
•7)
•2)
•2)
.6)
•9)
.)
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Table AX6-2.2 (cont'd). Summary of Selected Measurements of Blood Lead Levels in Humans
Reference, Study
Location, and Period
Study Description
Blood Lead Measurement
Comment
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United States (cont'd)
Nash et al. (2003)
U.S.
1988-1994
Pirckleetal. (1994)
U.S.
1976-1980
Symanski and Hertz -
Picciotto (1995)
U.S.
1982-1984
Design: national survey (NHANES III) stratified,
multistage probability cluster design
Subjects: women(n = 2, 575), age range: 40-59
yrs, in general population
Biomarker measured: blood lead
Analysis: GFAAS
Design: national survey (NHANES II, III)
stratified, multistage probability cluster design
Subjects: children and adults (> 1 yrs, n = 29, 843)
in general population
Biomarker measured: blood lead
Analysis: GFAAS
Design: national survey (HHANES) multistage-
area probability sample
Subjects: adults, females (n = 3,137), age range
20-60 yrs, in general Hispanic population
Biomarker measured: blood lead
Analysis: GFAAS
Units: ug/dL
Geometric mean (95% CI, n)
Premenopausal: 1.9 (1.7, 2.0, 1, 222)
Surgically menopausal: 2.7 (2.4, 3.2, 139)
Naturally menopausal: 2.9 (2.5, 3.2, 653)
Units: ug/dL
Geometric mean (95% CI)
Age (yr) 1976-1980 1988-1991
1-5: 15.0(14.2,15.8) 3.6(3.3,4.0)
n: 2,271 2,234
6-19: 11.7(11.2,12.4) 1.9(1.7,2.2)
n: 2,024 2,963
20-74: 13.1(12.7,13.7) 3.0(2.8,3.2)
n: 5,537 6,922
Males: 15.0(14.5,15.5) 3.7(3.5,3.9)
n: 4,895 6,051
Females: 11.1(10.6,11.5) 2.1(2.0,2.2)
n: 4,937 6,068
Units: ug/dL
Arithmetic mean (SE, n)
All
Premenopausal: 7.5 (0.07, 1, 984)
Menopausal: 8.9 (0.11, 1, 152)
Mexican-American:
Premenopausal: 7.2(0.13,1,219)
Menopausal: 8.4 (0.20, 624)
Geometric mean blood lead
concentrations were significantly lower
in premenopausal women. Increasing
blood lead concentrations were
significantly associated with decreased
bone mineral density.
Comparison of data from NHANES II
(1976-1980) and Phase 1 of NHANES
III (1988-1991) indicated declining
blood lead concentrations in U.S.
population.
Mean difference between
premenopausal and postmenopausal
(<4 yrs) was 1.4 ug/dL
(95% CI: 0.20,2.7).
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Table AX6-2.2 (cont'd). Summary of Selected Measurements of Blood Lead Levels in Humans
Reference, Study
Location, and Period
Study Description
Blood Lead Measurement
Comments
United States (cont'd)
Yassin et al. (2004) Design: national survey (NHANES III) stratified,
U.S. multistage probability cluster design
1988-1994 Subjects: adults (n= 11, 126) in general
population, age range: 1 8-64 yr), stratified by
occupational category
Biomarker measured: blood lead
Analysis: GFAAS
Units: ng/dL
Occupation
Vehicle mechanics
Food service workers
Management, professional
technical, and sales workers
Personal service workers
Agricultural workers
Production workers: machine
operators, material movers, etc.
Laborers other than in construction
Transportation workers
Mechanics other than vehicle
mechanics
Construction trades people
Construction laborers
Health service workers
All
GM
4.80
2.00
2.13
2.48
2.76
2.88
3.47
3.49
3.50
3.66
4.44
1.76
2.42
GSD
3.88
2.69
4.05
4.52
4.02
4.24
3.36
5.19
4.91
4.64
7.84
2.24
6.93
Maximum
28.1
27.0
39.4
25.9
23.4
52.9
21.8
22.3
16.6
16.9
36.0
22.4
52.9
n
169
700
4,768
1,130
498
1,876
137
530
227
470
122
499
11,126
Mexico
Hernandez-A vila et al.
(2002)
Mexico
1993-1995
Design: cross-sectional
Subjects: adults females (n = 903) in general
population, age range: 36-70 yr)
Biomarker measured: blood lead
Analysis: GFAAS
Units: ng/dL
Arithmetic mean (SD, n)
Premenopausal: 10.63 (5.46, 463)
Menopausal: 11.39 (2.65, 437)
Surgically menopausal: 10.23 (4.92, 115)
Naturally menopausal: 11.30 (5.88, 322)
Mean difference between
premenopausal and menopausal; was
0.76 ug/dL (95% CI: 0.224, 1.48).
GFAAS, graphite furnace atomic absorption spectroscopy; ICP-MS, inductively coupled plasma-mass spectrometry; NR, not reported.
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Table AX6-2.3. Bone Lead Measurements in Cadavers
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States
Wittmersetal. (1988)
Minnesota
1976-82
Lead in tibia, skull, iliac crest, rib,
and vertebrae. 81 Caucasian males
and 53 male cadavers ranging in age
from 0 to 98 yr. Ashing, nitric acid,
AAS.
Saltzman et al. (1990)
Cincinnati, OH
1970-71
29 tissues from 55 cadavers, mean
age 50 yrs. Muffle furnace ashing.
Pb concentrations by dithazone
method.
Mean and SEM (ng/g bone ash) >75 yr: Tibia 29.0 +3.4 (n = 28), ilium
17.0 + 2.6 (n = 29), rib 20.5 + 2.4 (n = 31), vertebra 18.8 + 2.6 (n = 30),
skull26.1 + 3.2(n = 28)
51-75 yr: Tibia 24.2 + 2.3 (n = 38), ilium 19.2 + 2.4 (n = 15), rib 22.3 + 2.6
(n = 40), vertebra 22.4 + 2.6 (n = 41), skull 22.8 + 2.9 (n = 29)
36-50 yr: Tibia 16.6 +4.1 (n = 14), ilium 9.9 + 1.6 (n = 15), rib 9.7 + 1.7
(n= 15), vertebra 11.9+ 2.1 (n= 15), skull 15.2 + 3.3 (n= 15)
21-35 yr: Tibia 5.9 +1.2 (n = 18), ilium 5.3 + 1.2 (n = 16), rib 5.0 + 1.2
(n = 18), vertebra 6.3 + 1.3 (n = 17), skull 4.9 + 1.1 (n = 17)
14-20 yr: Tibia 2.3 +1.0 (n = 13), ilium 2.3 + 0.9 (n = 13), rib 2.9 + 1.4
(n = 12), vertebra 3.8 + 1.4 (n = 12), skull 3.2 + 1.7 (n = 10)
0-2 yr: Tibia 0.3 +0.2 (n = 11), ilium 0.0 + 0.0 (n = 11), rib 0.7 + 0.4
(n = 12), vertebra 0.6 + 0.6 (n = 12), skull 0.6 + 0.4 (n = 12)
Higher concentrations of Pb in tibia compared with rib and vertebrae and
higher values for males compared with females. Males (n = 46): Ribs
6.70 + 3.96 (ng/g, wet weight), tibia 12.55 + 10.65, vertebrae 4.12 + 2.49.
Females (n = 8): Ribs 3.17 + 0.91 (ng/g, wet weight), tibia 4.54 + 2.04,
vertebrae 2.01+0.72.
Ratio of lead in tibia and
skull/iliac/rib/vertebrae <1
from age 0 to 35 yrs then >1
from 36 to 75 yrs and greater
than 75 yrs. Evidence of
differential distribution
amongst bones with age; the
earliest difference is apparent
during adolescence when
trabecular bone of the vertebral
body accumulates significantly
more lead than that of the other
4 sites.
Bone Pb increased with age.
Results were similar to those of
Barry (1978) and Wittmers
etal. (1988).
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Canada
Samuels et al.
(1989)
Canada
1965-69
Ashed vertebral bones from male and
female cadavers from three Canadian
cities. AAS method.
Changes for different age ranges in Pb concentration for the period 1965 -
1969:
0-11 months: 3.98 ng/g (n = 28)
1-4 yrs: 10.02 ng/g(n = 32)
5-11 yrs: 12.91 ng/g(n = 26)
12-19 yrs 7.11 jig/g(n = 26)
>20yrs: 14.77 jig/g (n = 25)
For period 1965 to 1969 levels
vary over age groups
(p = 0.0001) but there was little
gender difference. For the
period 1980 to 1998 for
Winnipeg, values were
approximately half to one third
those prevailing earlier.
-------
o
O
to
O
O
Table AX6-2.3 (cont'd). Bone Lead Measurements in Cadavers
X
oo
H
6
o
o
H
O
O
HH
H
W
Reference, Study
Location, and Period
Europe
Draschetal. (1987)
Germany
1983-85
Drasch and Ott (1988)
Germany
1984
Hacetal. (1997)
Poland
Study Description
Bone Pb in temporal
bone, cortical part of
the mid-femur, and
pelvic bone from
120 female and 120
male adult cadavers.
AAS.
Bone Pb in temporal
bone, cortical part of
the mid femur, and
pelvic bone from
82 child cadavers.
Nitric acid digestion,
AAS.
Pb in rib bone and hair
from 59 cadavers, aged
1-87 yrs. Perchloric
acid digestion, AAS.
Lead Measurement Findings, Interpretation
Geometric means:
Males: Pelvic 1 .95 + 1 .00 (ng/g, wet weight), mid-femur 4.75 + 2.53, temporal 6.24 + 3.17.
Females: Pelvic 1 .41 + 0.74 (ng/g), mid-femur 3. 14 + 1 .89, temporal 5.00 + 2.66.
Age 0-1 yrs 1-6 yrs 10-20 yrs 0-20 yrs
Sex Male Female Male Female Male Female Male Female
n 9 16 9 9 18 16 39 42
Tempo 0.331 0.334 0.530 0.732 1.770 1.740 0.858 0.749
ral
Pelvic 0.230 0.278 0.461 0.522 0.748 0.511 0.455 0.404
bone
Mid- 0.333 0.327 0.642 0.858 1.342 1.010 0.768 0.632
femur
(values in jig/g wet weight)
Bone Pb 3.0 (+1.5) jjg/g (n = 54).
Found cortical lead >
trabecular lead. Limited
difference in Pb for younger
males and females; much
higher Pb in bones of men
>50 yr old compared with
women
Negligible difference for 0 to
1 yr olds, for pre-school
children (1-6 yrs) and for 10
to 20 yr olds; mean values for
cortical bones showed higher
Pb concentrations than
trabecular bone; mean Pb in
the mid femur and temporal
bone was not statistically
different for each of three age
groups.
Small increases to age 50 yrs
in rib bone. Number of
samples for each age group
not stated.
Asia
Nodaetal. (1993)
Japan
1976, 1981, and 1986
76 cadavers, age range
0 to 83 yrs.
Age 0 yrs (1.25 ng/g wet weight) to 59 yrs (4.5 ng/g)
after which there was a decrease (approximately 2.5 |ig/g). For the age range 10-49 yrs,
there was no significant difference in mean values of 2.8 to 3.1 ng/g.
Found no significant gender
difference but levels in 1986
were significantly lower than
in 1976.
-------
o
O
to
O
O
Table AX6-2.4. Bone Lead Measurements in Environmentally-Exposed Subjects
Reference, Study
Location, and Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
H
6
o
o
H
O
O
HH
H
W
United States
Kim etal. (1996)
Boston, MA
1989-90
Huetal. (1990)
Boston, MA
Unknown
Hu etal. (1996)
Boston, MA
1991+
Campbell et al. (2004)
New York
Unknown
Examination of the relationship between
tooth Pb in children and bone Pb levels
in young adults. Members of a cohort of
young adults (n = 63, -20 yr of age) were
reassessed 13 yr after initial examination.
Dentine Pb by anodic stripping voltammetry.
Bone K-shell XRF. LOWESS smoothing,
multiple linear regression.
To evaluate if K-shell XRF can be used to
assess low-level Pb burdens in 34 employees
(26 males, 8 females) ranging in age from 21
to 58 yr of a biomedical company with no
known history of excessive Pb exposure.
Medical environmental history
questionnaire. Multiple linear regression.
Normative Aging Study.
Subjects were middle-aged and elderly men
who had community (nonoccupational)
exposures to lead.
Cross-sectional. Backwards elimination
multivariate regression models that
considered age, race, education, retirement
status, measures of both current and
cumulative smoking, and alcohol
consumption.
Investigated the relationship between bone
mineral density_and environmental Pb
exposure in 35 African American children.
No PbB.
Tibia Pb 1.3 (+ 4.4), patella Pb 5.4 (+8.4).
Dentine Pb 13.4 (+10.7).
Approximately one-third of tibia and one-fourth
of patella estimates were negative values.
18(53%) of subjects had bone Pb levels included
0 or less within the estimate of uncertainty.
Highest bone Pb 21 + 4 ug/g bone mineral.
For 16 young adults, age and year of home
construction had a positive but statistically
insignificant effect (p > 0.05) on bone Pb.
47-59 yrs (n =116): PbB 5.8 (+3.7), tibia 14.6
(+8.3), patella 23.6 (+12.4)
60-69 yrs (n = 360): PbB 6.3 (+4.2), tibia 21.1
(+11.4), patella 30.5 (+16.9)
>70 yrs (n = 243): PbB 6.5 (+4.5), tibia 27
(+15.6), patella 38.8 (+23.5)
High Pb exposure: PbB levels (mean 23.6 ug/dL;
n = 19); lowPb exposure (mean 6.5 ug/dL;
n= 16).
A 10 ug/g increase in dentine Pb levels in
childhood was predictive of a 1 ug/g increase
in tibia Pb levels and a 5 ug/g increase in
patella PbB levels, and a 3 ug/g increase in
mean bone Pb levels among the young adults.
They concluded that Pb exposure in early life
may be used to predict elevated body burden
up to 13 yr later.
K-shell XRF may be useful for assessing low-
level Pb burdens in epidemiological studies.
Factors that remained significantly related to
higher levels of both tibia and patella Pb were
higher age and measures of cumulative
smoking, and lower levels of education.
An increase in patella Pb from the median of
the lowest to the median of the highest
quintiles (13-56 ug/g) corresponded to a rise
in PbB of 4.3 ug/dL. Bone Pb levels
comprised the major source of circulating lead
in these men.
Unexpectedly, they found that children with
high Pb exposure had a significantly higher
bone mineral density than children with low
Pb exposure. They hypothesized that this
arises from the effect of Pb on accelerating
bone maturation by inhibition of parathyroid
hormone-related peptide.
-------
o
O
to
O
O
Table AX6-2.4 (cont'd). Bone Lead Measurements in Environmentally-Exposed Subjects
Reference, Study
Location, and Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
United States (cont'd)
Rosen et al.
(1989)
Bronx, NY
Unknown
Kosnettetal. (1994)
Dickson City, PA
1991
Rosen etal. (1993)
Moosic and Throop, PA
1989-91
Stokes etal. (1998)
Bunker Hill, ID; Spokane,
WA
1994
Comparison of L-shell XRF measures
and EDTA provocation test in lead-toxic
children 1-6 yr old. Eligible if PbB 25-
55 ng/dL and erythrocyte protoporphyrin
>35 ng/dL.
Aim to determine the influence of
demographic, exposure and medical
factors on the bone Pb concentration of
subjects with environmental Pb exposure.
101 subjects (49 males, 52 females; aged
11 to 78 yrs) recruited from 49 of 123
households geographically located in a
suburban residential neighborhood.
Tibia. Multiple regression.
Suburban population (Throop, n = 269)
exposed to unusually high emissions
during 1963-81 from nearby battery
recycling/secondary smelter. Moosic
served as control community.
-9% children aged 5-12 yr, 15% 13-17
yr, 40% > 18 yr. Soil and PbB, L-shell
XRF.
Examined whether environmental
exposure to Pb during childhood was
associated with current adverse
neurobehavioral effects. K-shell XRF.
Formerly exposed as children 19-30 yr
(n= 238, age 19-30 yr).
Referents (n = 258)
Negative EDTA test results (n = 30): PbB 30 + 5
Hg/dL, tibia Pb 12 + 2 ng/g (range 7-52).
Positive EDTA test results (n = 29): PbB 39 + 8
Hg/dL, tibia Pb 37 + 3 ng/g (range 7-200).
Mean (SD) bone Pbl2.7 (14.6).
Log-transformed bone Pb highly correlated with
age (r = 0.71; p < 0.0001). Gender differences in
log-transformed bone Pb values were
insignificant up until the 6th decade.
No significant differences in tibia Pb found
among three age groups in Moosic or Throop.
Mooaic: means 5-12 yr, 6 |ig/g; 13-17 yr, 8 |ig/g;
>18yr,7ng/g
Throop: means 5-12 yr, 12+1 |ig/g; 13-17 yr,
15 + 2|ig/g; >18yr, 12+1 ng/g.
Exposed group:
PbB 2.9 ng/dL; tibia Pb 4.6 ng/g.
Referent group:
PbB 1.6 ng/dL; tibia Pb 0.6 ng/g.
From PbB and LXRF alone, 90% of Pb-toxic
children were correctly classified as being
EDTA-positive or -negative. LXRF may be
capable of replacing EDTA testing.
Bone Pb showed no significant change up to
age 20 yr, increased with the same slope in
men and women between ages 20 and 55 yrs,
and then increased at a faster rate in men older
than 55 yrs.
No change in bone Pb with age. Baseline
values for bone Pb in the environmentally
exposed population of Moosic can serve as a
reference baseline for contemporary bone Pb
levels in similar communities in the USA.
-------
o
O
to
O
O
Table AX6-2.4 (cont'd). Bone Lead Measurements in Environmentally-Exposed Subjects
Reference, Study
Location, and Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
United States (cont'd)
McNeill et al. (2000)
Idaho and Washington
1994
To determine if high Pb exposure in
childhood persisted until adulthood.
262 exposed subjects and 268 age and
sex matched controls aged 19-29 yr.
Tibia bone Pb, cumulative PbB index.
Inverse weighted group mean data,
linear regressions.
Group inverse weighted mean (SEM).
Males: Exposed 4.54 (0.31); controls 0.03 (0.31) ug
Pb/g bone mineral.
Females: Exposed 5.61 (0.43); controls 1.67 (0.43)
ug Pb/g bone mineral.
Lead from exposure in early childhood had
persisted in the bone matrix until adulthood.
Bone Pb significantly correlated with age for
exposed groups. No significant correlation in
regressions for control groups with age.
Exposed subjects had group bone Pb levels
significantly higher (p < 0.005) than control
subjects in 7 of 11 age groups. Exposed
subjects had increased current PbB
concentrations that correlated significantly
with bone Pb values. Incorporation rate of Pb
into bone 0.039 (0.003) (/j,g Pb/g bone
mineral)/ ug/dL yr).
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Mexico
Farias etal. (1998)
Mexico City and suburbs
1995-96
Examined the relation of blood and
tibia bone Pb levels to Pb
determinants in 100 adolescents aged
11 to 21 yr. LOWESS smoothing,
multivariate regressions.
Females (n = 62): PbB 6.4 (+3.2), tibia 5.5(+8.6).
Males (n = 36): PbB 9.1 (+5.5), tibia 3.8 (+5.5).
25 subjects had bone Pb < 0.
Bone Pb accounted for 4.1% of variation in PbB.
Increase in bone Pb of 21.6 ug/g was associated with
an increase in PbB of 1.2 ug/dL.
Predictors of bone Pb included higher traffic
density near the home, mother's smoking
history, and time spent outdoors. Predictors
of log-transformed PbB included bone Pb
levels, male sex, use of Pb-glazed ceramics,
and living in Mexico City. BonePb
accumulated over time constitutes a moderate
source of circulating Pb during adolescence
-------
o
O
to
O
O
Table AX6-2.5. Bone Lead Measurements in Occupationally-Exposed Subjects
Reference, Study
Location, and Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
to
United States
Huetal. (1994)
U.S.
1991
Schwartz et al. (2000)
U.S.
1995
Popovich et al. (2005)
Idaho
Construction workers aged 23 to 67 yr
(n=19). Examination of Bone Pb
and PbB as predictors of blood
pressure in construction workers.
Multivariate linear regression,
LOWESS smoothing.
Retired organolead employees (n =
543). Aim to determine influence of
PbB, chelatable Pb, and tibial Pb on
systolic and diastolic blood pressure.
108 former female smelter employees
and 99 referents to assess the PbB
versus bone Pb relationship.
PbB8.3(+4.0),tibiaPb9.£
13.9 (+13.6).
(+9.5), patella Pb
PbB 4.6 (+2.6), tibia Pbl4.4 (+9.3).
Exposed: PbB 2.73 (+2.39), tibia 14.4 (+0.5)
Referents: PbB 1.25 (+2.10), tibia 3.22 (+0.50)
Pb concentrations in tibia and blood significantly
higher in the exposed group. Endogenous release
rate (ug Pb per dL blood/ug Pb/g bone) in
postmenopausal women was double the rate found in
premenopausal women (0.132 + 0.019 vs. 0.067 +
0.014).
Tibia Pb was not associated with any blood
pressure measures.
Higher tibia bone Pb (and PbB) was
associated with use of estrogen (present or
former) in both the whole referent group and
postmenopausal women in the referent group.
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Canada
Fleming etal. (1997)
Canada
1994
Primary smelter workers, 367 active
and 14 retired.
PbB in 204 workers returning after a
10-mo strike ended in 1991.
Cumulative PbB index, K-shell
measures with 109Cd source.
Active (1975-81) median PbB 16.0, (1987-92)
median PbB 8.0, tibia range 0-150, calcaneus 0-250.
Retired tibia range 20-120, calcaneus 40-220.
Bone Pb-cumulative PbB index slopes larger for
retired compared with active workers, but not
significant.
Nonlinearities in cumulative PbB index and
tibia and calcaneus Pb suggest differences in
Pb transfer from whole blood to bone among
smelter employees. Contribution to PbB from
bone stores at any instant in time is similar for
all occupationally exposed populations, active
or retired.
Age-related variations in bone turnover are
not a dominant factor in endogenous exposure
of male lead workers. More rapid absorption
of Pb in calcaneus than tibia.
-------
o
O
to
O
O
Table AX6-2.5 (cont'd). Bone Lead Measurements in Occupationally-Exposed Subjects
Reference, Study
Location, and Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
X
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Canada (cont'd)
Fleming et al. (1998)
Canada
1994
Primary smelter.
ALAD 1-1 (n = 303) and ALAD1-2, 2-2
(n=65).
PbB, serum Pb, cumulative PbB index,
ALAD genotype, K-shell measures with
109Cd source.
Brito et al. (2000) Aims were to: (i) investigate the long term
Canada human Pb metabolism by measuring the
1993-98 change of Pb concentration in the tibia and
calcaneus between 1993 and 1998; and (ii)
assess whether improved industrial hygiene
was resulting in a slow accumulation of Pb
in an exposed workforce. 101 workers in a
secondary lead smelter, 51 subjects had
similar bone Pb measurements in 1993.
Most other subjects had been hired since
1993. Cumulative PbB index. Linear
regressions.
1-1: PbB 22.9, tibia 41.2, calcaneus 71.6
1-2, 2-2: PbB 25.2, tibia 42.7, calcaneus 72.3.
Slopes of linear relations of bone Pb to cumulative
PbB index were greater for workers homoallelic for
ALAD 1, indicating more efficient uptake of lead
from blood into bone; effect most significant in
calcaneus bone and for workers hired since improved
safety measures enacted in 1977 [ALAD1-1: 0.0528
+ 0.0028 and ALAD1-2 or 2-2: 0.0355 + 0.0031
(p< 0.001)].
Repeats (n= 51)
1993: Tibia 39 (±19), calcaneus 64 (±36).
1998: Tibia 33 (±18), calcaneus 65 (±38).
Non-repeats (n = 50)
1998: Tibia 15 (±16), calcaneus 13 (±18).
Tibia Pb decreased significantly (p < 0.001) in the
51 subjects with repeated bone Pb measurements.
Tibia Pb in 1993 and changes in cumulative PbB index
were significant predictors of changes in tibia Pb.
An overall half-life of 15 yr (95% CI: 9, 55 yr) was
estimated. Adding continuing lead exposure and
recirculation of bone lead stores to the regression
models produced half-life estimates of 12 and 9 yr,
respectively, for release of lead from the tibia. Repeat
subjects showed no net change in calcaneus Pb after
Syr.
Decreased transfer of blood lead into bone
in individuals expressing the ALAD2 allele
contrasted with increased blood lead.
ALAD genotype affected lead metabolism
and potentially modified lead delivery to
target organs including the brain but
ALAD genotype did not significantly affect
the net accumulation of lead in bone.
The decrease in new exposure coupled to
release of previously stored bone Pb resulted
in a significant decrease in tibia Pb in the
repeat subjects. The rate of clearance of Pb
from the tibia of 9 to 15 yr is towards the
more rapid end of previous estimates. The
lack of a significant change in the calcaneus
Pb was surprising and if confirmed would
have implications for models of Pb
metabolism.
-------
o
O
to
O
O
Table AX6-2.5 (cont'd). Bone Lead Measurements in Occupationally-Exposed Subjects
Reference, Study
Location, and Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
£
Canada (cont'd)
Brito et al. (2002) Evaluated endogenous release of Pb from
Canada bone to blood in 204 exposed subjects
1994, 1999 resuming their duties after a 10-mo strike
in a primary lead smelter in 1991. Bone
Pb (109Cd source) measured in the tibia and
calcaneus in 1994 (Fleming etal., 1997)
and 1999. A linear model used to predict
the current PbB upon the level of lead in
bone. 327 subjects available on both
occasions. Group H higher PbB and
Group L lower PbB.
Group H: PbB 22.0, tibia 19.2 (n = 120)
Group L: PbB 20.6, tibia 82.8 (n = 45)
Group H: PbB 24.2, calcaneus 41.4 (n = 90)
Group L: PbB 20.2,calcaneus 138.2 (n = 45)
Structural analysis of data gave slopes for tibia
(2.0, 95% CI: 1.66-2.54) and calcaneus (0.19, 95%
CI: 0.16-0.23) that were significantly higher than
those predicted by the commonly used simple linear
regression method, for tibia (0.73, 95%, CI:
0.58-0.88) and calcaneus (0.08, 95% CI: 0.06-0.09).
Suggested that more Pb than previously
predicted by regression analysis is released
from bone to blood.
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Europe
Somervaille et al. (1988)
England
Christoffersson et al.
(1984)
Sweden
Unknown
Christoffersson et al.
(1986)
Sweden
1978-84
K-shell measures with 109Cd source on
diverse Pb workers and controls
Crystal glass (n = 87); Battery plant
(n = 88); Precious metals (n = 15);
Laboratory (n = 20).
Cumulative PbB index.
Lead smelter employees
Active (n = 75); Former plant (n = 32)
Finger bone measurement with 57Co
source.
Retired lead workers.
Group 1: 7 smelter, 1 storage battery
monitored for 2-5 yr directly after end of
exposure.
Group 2: 6 battery, bone Pb measured 7-
13 yr after end of exposure. Finger bone
measurement with 57Co source from 4 to
9 times.
Crystal glass: PbB 48.1, tibia 31.0
Battery plant: PbB 32.3, tibia 32.3
Precious metals: PbB 51.4, tibia 54.5
Laboratory: PbB 13.1, tibia 16.7
Active: median PbB 53.8 (15.5), mean tibia 43
(<20, 122)
Former: median PbB 24.9 (7.0), mean tibia 59.0
(<20,135)
Group 1: mean initial bone Pb 97 (61, 131),
decreasing bone Pb with time half-life 6.7 yr (3.4, 15)
Group 2: mean initial bone Pb 72 (37, 96), mean
half-life 8.2 yr (2.4,oo)
Correlation coefficients between tibia lead
and duration of employment were
consistently higher at all three factories
respectively (r = 0.86, p < 0.0001; r = 0.61,
p < 0.0001; r= 0.80, p< 0.0001). Strong
relation between tibia Pb and cumulative
PbB index among workers in factories
from which PbB histories were available.
Increase of bone Pb with time of
employment, no association between bone
Pb and current PbB in active workers, in
retired workers PbB rose with increasing
bone Pb.
Decrease of lead in bone after the end of
exposure considerably faster than estimated
earlier from various data on lead
metabolism.
-------
o
O
to
O
O
Table AX6-2.5 (cont'd). Bone Lead Measurements in Occupationally-Exposed Subjects
Reference, Study
Location, and Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Europe (cont'd)
Hanninenetal. (1998)
Finland
Unknown
Erkkilaetal. (1992)
Finland
Unknown
Nilssonetal. (1991)
Sweden
1980s
Storage battery workers
Grouped into those whose PbB exceeded
50 jig/dL [High PbB (n = 28; 21 males)],
and never [Low PbB (n = 26; 22 males)].
Evaluation of neuropsychological
dysfunction.
K-shell measures with 109Cd source on acid
battery employees and controls
Active (n = 91); Former plant (n = 16);
Office (n = 38); Laboratory (n = 26). K-
shell XRF.
Group A: 7 retired smelter workers and
1 battery worker monitored for —10 yr with
11-17 finger bone measurements with
57Co.
Group B: 6 retired battery workers
monitored for up to 18.5 yr with 7-13
finger bone measurements.
High PbB: average PbB 39.3 (+8.3), tibia 35.3
(+16.6), calcaneus 100.4 (+43.1)
Low PbB: average PbB 29.0 (+6.2), tibia 19.8
(+13.7), calcaneus 78.6(+62.4)
Active: PbB 30.0 (9.5), tibia 21.1 (17), calcaneus 76.6
(55.3)
Former plant: PbB 12.2 (6.2), tibia 32.4 (34.9),
calcaneus 73.5 (57.7)
Office: PbB 6.4 (3.3), tibia 7.7 (11.3), calcaneus 14.2
(15.6)
Laboratory: PbB 3.7 (1.7), tibia 3.5 (10.S
1.2(10.6)
, calcaneus
Bone Pb values decreased over time.
A mono-exponential retention model was used.
Group A: estimated half-life for bone Pb was
6.2-27 yr.
Group B: half-life was 11-470 yr.
No relation was found between the
neuropsychological test battery and tibial
Pb.
Tibia Pb concentration increased
consistently both as a function of intensity
of exposure and duration of exposure.
Calcaneal Pb concentration strongly
dependent on the intensity rather than
duration of exposure. Biological half life
of Pb in calcaneus <7-8 yr periods into
which the duration of exposure was split.
Retired workers: endogenous exposure to
Pb arising from skeletal burdens
accumulated over a working lifetime can
easily produce the dominant contribution to
systemic Pb concentrations once
occupational exposure has ceased.
The "shared" half-life for bone Pb was 16
(CI: 12,23) yr. These values are longer
than ones of Christoffersson et al. (1986)
for the same two groups; no "background"
values were subtracted in the latter case.
-------
o
O
to
O
O
Reference, Study
Location, and Period
Table AX6-2.5 (cont'd). Bone Lead Measurements in Occupationally-Exposed Subjects
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
Europe (cont'd)
X
Oi
Oi
Gerhardsson et al.
(1993)
Sweden
Unknown
Pb smelter and truck assembly (referent)
workers; Active smelter (n = 70); Retired
smelter (n = 30); Truck assembly (n = 31);
Retired truck assembly (n = 10). K-shell
measures with 109Cd source.
Median values presented.
Active smelter: PbB 31.9 (5.0, 47.4), tibia 13.0
(-4.1, 72.8), calcaneus 48.6 (0.4, 217.8)
Retired smelter: PbB 9.9 (3.3, 21), tibia 39.3
(2.9, 73.4), calcaneus 100.2 (34.8, 188.9)
Truck: PbB 4.1 (1.7, 12.4), tibia 3.4
(-9.4, 13.3), calcaneus 12.2 (-12.7, 43.0)
Retired truck: PbB 3.5 (2.2, 12.2), tibia 12.0
(-6.7, 23.7), calcaneus 30.2 (-7.1, 56.7)
Higher calcaneus Pb than tibia Pb in active
lead workers suggested more rapid
absorption over time in this mainly
trabecular bone. Estimated biological half-
times were 16 yr in calcaneus (95% CI:
11, 29 yr) and 27 yr in tibia (95% CI: 16,
98 yr). Strong positive correlation between
bone Pb and cumulative PbB index.
Borjesson et al. (1997)
Sweden
1992
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Bergdahl et al. (1998)
Sweden
1986
Erfurthetal. (2001)
Sweden
Pb smelter and referent male metal
workers Active smelter (n = 71); Retired
smelter (n = 18); Referent active (n = 27);
Referent retired (n = 8). Similar cohort to
Gerhardsson et al. (1993). Finger bone
measurement with 57Co source.
Cumulative PbB index.
Secondary Pb smelter
Exposed (n = 77); Referents (n = 24). K-
shell measures with 109Cd source.
Cumulative PbB index and (calculated)
plasma Pb.
Secondary smelter
Active (n = 62); Retired (n = 15);
Referents (n = 26).
Evaluation of effects of Pb on the
endocrine system.
Finger bone measures with 57Co source.
Median values presented.
Active smelter: PbB 33.1 (8.3, 93),
bone Pb 23.0 (-13, 99)
Retired smelter: PbB 17.2 (8.9, 33.1),
bone Pb 55 (3, 88)
Active referent: PbB 3.7 (0.8, 7.0),
bone Pb 3 (-21, 16)
Retired referent: PbB 3.9 (3.1, 6.2),
bone Pb 1.5 (-3, 12)
Exposed: PbB 35.0 (14, 57), tibia 25 (5, 193),
calcaneus 52 (-20,458)
Referents: PbB 5.0 (2.9, 16). tibia 10 (-6, 36),
calcaneus 11 (-12, 61)
Median values presented.
Active: PbB 33.2 (8.3, 93.2), tibia 21 (-13,99)
Retired: PbB 18.6 (10.4, 49.7), tibia 55 (3, 88)
Referents: PbB 4.1 (0.8, 6.2), tibia 2 (-21, 14)
Multiple regression analyses showed bone
Pb was best described by the cumulative
PbB index, which explained 29% of the
observed variance (multiple r2) in bone Pb
in active workers and about 39% in retired
workers. Estimated biological half-life of
bone Pb among active lead workers was
5.2yr(95%CI: 3.3-13.0 yr).
Strong relationships between the tibia Pb
(r2 = 0.78) and calcaneus (r2 = 0.80) and
cumulative PbB index. Half-lives of Pb in
tibia 13-24 yr and calcaneus 12-19.
No significant associations between bone
Pb and pituitary and thyroid hormones,
serum testosterone, gonadotropin-releasing
hormone and thyroid releasing hormone.
-------
o
O
to
O
O
Table AX6-2.5 (cont'd). Bone Lead Measurements in Occupationally-Exposed Subjects
Reference, Study
Location, and Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
Europe (cont'd)
Rods etal. (1995)
Belgium
Pb smelter and others.
Active production (n = 73); Other
departments (n = 50). K-shell measures
with 109Cd source. Cumulative PbB index.
Active: PbB 42.0, tibia 66.5
Others: PbB 14.5, tibia 31.4
Strong relationship between bone Pb and
cumulative PbB index in smelter
populations (r = 0.80, p < 0.0001; age
explained < 9.5% of variance). Slope of
regression equation of log bone Pb versus
log cumulative PbB index showed that
doubling of cumulative PbB index
corresponds to doubling of bone Pb.
Mexico
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Juarez-Perez et al. Lithographic print shop workers; Males,
(2004) n = 59, 10 females; mean age 47 yrs
Mexico City Plasma Pb by ultraclean ICP-MS methods.
1996-7 K-shell measures with 109Cd source.
PbB 11.9 (+5.8), tibia 27.6 (+18.1; ND-73.1
patella 46.8 (+29.3; ND-139)
Statistically significant associations
between: plasma Pb and PbB, patella Pb,
tibia Pb, age, education, use of Pb-glazed
ceramics but not air Pb, hand Pb or hygiene
index at work. Multiple linear regression
models with patella and tibia Pb as main
predictors and adjusting for PbB and
hygiene index explained 57% of variability
in plasma Pb. Negative association
between plasma Pb and hygiene index
suggest oral exposure and gastrointestinal
uptake of Pb predominant source of Pb
exposure in these subjects.
Asia
Schwartz etal. (2001)
Korea
1997-99
Korean Pb workers (798, 639 male,
164 female) and controls (135, 124 male,
1 female). Evaluation of associations
between PbB, tibia Pb, chelatable Pb, and
neurobehavioral functions. K-shell
measures with 109Cd source.
Active: PbB 32 (+15), tibia 37.2 (+40.4)
Controls: PbB 5.3 (+1.8), tibia 5.8 (+7.0).
After adjustment for covariates, tibia Pb
was not associated with neurobehavioral
test scores.
-------
o
O
to
O
O
Table AX6-2.5 (cont'd). Bone Lead Measurements in Occupationally-Exposed Subjects
Reference, Study
Location, and Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
oo
Asia (cont'd)
Toddetal. (2001)
Korea
Korean Pb workers active (n = 723),
retired (n = 79), controls (n = 135).
Evaluation of associations between PbB,
tibia Pb, chelatable Pb.
K-shell measures with 109Cd source.
Active: median PbB 31.7, tibia 24.4
(-7.4, 337.6)
Retired: median PbB 13.5, tibia 26.4
(-6.7, 196.7)
Controls: median PbB 5.1, tibia 5.0
(-10.9,26.6)
Control women higher bone Pb than men.
Job duration, body mass index, and age
were positive predictors of tibial Pb. Rate
of increase in tibia Pb with age itself
increased with increasing age. Tibial Pb
stores in older subjects are less bioavailable
and may contribute less to PbB than tibial
stores in younger subjects.
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
-------
o
O
to
O
O
Table AX6-2.6. Bone Lead Contribution to Blood Lead
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
X
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
United States
Korrick et al.
(2002)
Boston, MA
1990-95
Popovich et al.
(2005)
Bunker Hill, ID
1994
Nurses' Health Study. Cross-
sectional study of 264 elderly
women; 46-54 yr (n = 80) 55-64
yr (n = 102), 65-74 yr (n = 82).
Tibia and patella Pb. Multivariate
linear regression models.
108 former female smelter
employees and 99 referents to
assess the PbB versus bone Pb
relationship
46-54 yr: PbB 2.7 (SE +0.3), tibia 10.5 (+1.0), patella
14.9 (+1.2)
55-64 yr: PbB 3.4 (+0.2), tibia 12.7 (+0.9), patella 17.0 (+1.1)
65-74 yr: PbB 3.3 (+0.3), tibia 16.4 (+0.9), patella 19.8 (+1.2).
An increase from the first to the fifth quintile of tibia Pb level
(19 ug/g) was associated with a 1.7 ug/dL increase in PbB
(p 0.0001).
Exposed: PbB 2.73 (+2.39), tibia 14.4 (+0.5)
Referents: PbB 1.25 (+2.10), tibia 3.22 (+0.50)
Pb concentrations in tibia and blood significantly higher in the
exposed group. Endogenous release rate (ug Pb per dL blood/u
Pb/g bone) in postmenopausal women was double the rate found
in premenopausal women (0.132 + 0.019 vs. 0.067 + 0.014).
Tibia and patella Pb values were significantly
and positively associated with PbB but only
among postmenopausal women who were not
using estrogens. Older age and lower parity
were associated with higher tibia Pb; only age
was associated with patella Pb. They
suggested the observed interaction of bone Pb
with estrogen status in determining PbB
supports the hypothesis that increased bone
resorption, as occurs postmenopausally
because of decreased estrogen production,
results in heightened release of bone Pb stores
into blood.
Higher tibia bone Pb (and PbB) was associated
with use of estrogen (present or former) in
both the whole referent group and
postmenopausal women in the referent group.
-------
o
O
to
O
O
Table AX6-2.6 (cont'd). Bone Lead Contribution to Blood Lead
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
X
to
O
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Canada
Brito et al. (2000)
Canada
1993-98
Brito et al. (2002)
Canada
1994, 1999
Aims were to: (i) investigate the
long term human Pb metabolism by
measuring the change of Pb
concentration in the tibia and
calcaneus between 1993 and 1998;
and (ii) assess whether improved
industrial hygiene was resulting in a
slow accumulation of Pb in an
exposed workforce. 101 workers in a
secondary lead smelter, 51 subjects
had similar bone Pb measurements in
1993. Most other subjects had been
hired since 1993. Cumulative PbB
index. Linear regressions.
Evaluated endogenous release of Pb
from bone to blood in 204 exposed
subjects resuming their duties after a
10-mo strike in a primary lead
smelter in 1991. Bone Pb (109Cd
source) measured in the tibia and
calcaneus in 1994 (Fleming et al.,
1997) and 1999. A linear model
used to predict the current PbB upon
the level of lead in bone.
327 subjects available on both
occasions. Group H higher PbB and
Group L lower PbB.
Repeats (n = 51)
1993: Tibia 39 (±19), calcaneus 64 (±36).
1998: Tibia 33 (±18), calcaneus 65 (±38).
Non-repeats (n = 50)
1998: Tibia 15 (±16), calcaneus 13 (±18).
Tibia Pb decreased significantly (p <0.001) in the 51 subjects with
repeated bone Pb measurements. Tibia Pb in 1993 and changes in
cumulative PbB index were significant predictors of changes in
tibia Pb. An overall half-life of 15 yr (95% CI: 9, 55 yr) was
estimated. Adding continuing lead exposure and recirculation of
bone lead stores to the regression models produced half-life
estimates of 12 and 9 yr, respectively, for release of lead from the
tibia. Repeat subjects showed no net change in calcaneus Pb after
Syr.
Group H: PbB 22.0, tibia 19.2 (n = 120)
Group L: PbB 20.6, tibia 82.8 (n = 45)
Group H: PbB 24.2, calcaneus 41.4 (n = 90)
Group L: PbB 20.2,calcaneus 138.2 (n = 45)
Structural analysis of data gave slopes for tibia (2.0, 95% CI:
1.66, 2.54) and calcaneus (0.19, 95% CI: 0.16, 0.23) that were
significantly higher than those predicted by the commonly used
simple linear regression method, for tibia (0.73, 95% CI: 0.58,
0.88) and calcaneus (0.08, 95% CI: 0.06, 0.09).
The decrease in new exposure coupled to
release of previously stored bone Pb resulted in
a significant decrease in tibia Pb in the repeat
subjects. The rate of clearance of Pb from the
tibia of 9 to 15 yr is towards the more rapid end
of previous estimates. The lack of a significant
change in the calcaneus Pb was surprising and
if confirmed would have implications for
models of Pb metabolism.
Suggested that more Pb than previously
predicted by regression analysis is released
from bone to blood.
Mexico
Brown et al.
(2000)
Mexico City
1994-5
Investigated determinants of bone
Pb and PbB of 430 lactating
Mexican women during the early
postpartum period and contribution
of bone Pb to PbB. Linear
regression analyses.
PbB 9.5 (±4.5), tibia 10.2 (±10.1), patella 15.2 (±15.1).
Older age, use of Pb glazed pottery, and higher
proportion of life spent in Mexico City were
main predictors of higher tibia and patella Pb.
Women in the 90th percentile for patella Pb
had an untransformed predicted mean PbB 3.6
Hg/dL higher than those in the 10th percentile.
-------
o
O
to
O
O
Table AX6-2.6 (cont'd). Bone Lead Contribution to Blood Lead
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
X
to
Mexico (cont'd)
Tellez-Rojo et al.
(2002)
Mexico City
1994-95
Evaluated the hypothesis that
lactation stimulates Pb release from
bone to blood. Cross-sectional
examination of breastfeeding patterns
and bone Pb as determinants of PbB
among 425 lactating women (mean
age 24.8 ± 5.3 yr) for 7 mo after
delivery. Bone Pb at 1 mo
postpartum. Maternal blood samples
and questionnaire information
collected at delivery and at 1, 4, and
7 mo postpartum. Generalized
estimating equations.
Mean PbB decreased with time postpartum: 1 mo 9.4 (±4.4),
4 mo 8.9 (±4.0), 7 mo 7.9 (±3.3).
Tibia 10.6 (11.6 after correction for negative values), patella
15.3 (16.9 after correction). After adjustment for bone Pb and
environmental exposure, women who exclusively breastfed
their infants had PbB levels that were increased by 1.4 ug/dL
and women who practiced mixed feeding had levels increased
by 1.0 ug/dL, in relation to those who had stopped lactation.
A 10 ug Pb/g increment in patella and tibia bone Pb increased
PbB by 6.1% (95% CI: 4.2, 8.1) and 8.1% (95% CI: 5.2,
11.1), respectively.
They concluded that their results support the
hypothesis that lactation is directly related to
the amount of Pb released from bone.
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Garrido-Latorre Aim was to examine the relationship
et al. (2003) of blood lead levels to menopause
Mexico City and bone lead levels in 232
1995 perimenopausal and postmenopausal
women from Mexico City.
Measured bone mineral density in
addition to bone Pb. Information
regarding reproductive characteristics
and known risk factors for PbB was
obtained using a standard
questionnaire by direct interview.
Mean age of the population was
54.7 yrs (±9.8). Linear regression
analyses.
PbB 9.2 (±4.7), tibia 14.85 (±10.1), patella 22.73 (±14.9).
A change of 10 ug Pb/g bone mineral in postmenopausal
subjects was associated with an increase in blood lead of
1.4 ug/dL, whereas a similar change in bone lead among
premenopausal women was associated with an increase in
blood lead of 0.8 ug/dL.
Found that postmenopausal women using
hormone replacement therapy had lower PbB
levels and higher tibia and patella bone Pb
levels than non-users; patella Pb explained the
greatest part of variations in PbB. Found no
association with PbB levels and did not
describe any relationships between bone lead
and bone density
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o
O
to
O
O
Table AX6-2.7. Bone Lead Studies in Pregnant and Lactating Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
United States
Huetal. (1996)
Boston, MA
1990
Cord blood PbB measured in
223 women, 41 bone Pb measured
at l-4postpartum. ANOVA.
X
to
to
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Rothenberg et al
(2000)
Los Angeles, CA
1995-98
Rothenberg et al.
(2002)
Los Angeles, CA
1995-2001
Examined bone Pb contribution to
PbB in a group of 311 immigrant
women (mean age 27.8 ±7.5 yr),
99% from Latin America, during
the 3rd trimester of pregnancy, and
1 to 2 mo after delivery. Multiple
regression, variance-weighted
least squares regression, structural
equation modeling.
Examined the effects of blood and
bone PbB on hypertension and
elevated blood pressure in the 3rd
trimester and postpartum among
1,006 mostly Latina and Afro-
American women. Multiple and
logistic regression.
Values omitted if measurement uncertainty was >10 ug/g for tibia and
15 ug/g for patella.
Cord PbB 1.19 (±1.32), maternal PbB 2.9 (±2.6), tibia 4.5 (±4.0) patella 5.8
(±4.5).
Maternal age was the only factor marginally associated with combined bone
Pb (p = 0.08) but not individually with tibia or patella Pb.
Prenatal PbB 2.2 (+4.87-1.0, geometric mean), postnatal PbB 2.8
(+4.97-1.2) (p < 0.0001), tibia 6.7(±12.5), calcaneus 8.4 (±13.2). Variance-
weighted multiple regression and structural equation models showed that
both calcaneus and tibia Pb were directly associated with prenatal PbB but
only calcaneus Pb was associated with postnatal PbB. Increasing natural log
yrs in the United States independently predicted decreasing calcaneus and
3rd trimester PbB.
Returned and eligible: 3rd trimester PbB (n = 720) 1.9 (+3.67-1.0),
postpartum PbB (n = 704) 2.3 (+4.37-1.2), tibia (n = 700) 8.0 (±11.4),
calcaneus (n = 700) 10.7 (±11.9). Returned but ineligible: 3rd trimester
PbB (n = 279) 1.9 (+4.27-0.8), postpartum PbB (n = 274) 2.3 (+4.77-1.1),
tibia (n = 263) 8.7 (±13.9), calcaneus (n = 262) 11.2 (±15.1). For each
10 ug/g increase in calcaneus Pb level, the odds ratio for 3rd trimester
hypertension (systolic blood pressure > 140 mmHg or diastolic blood
pressure >90 mmHg) was 1.86 (95% CI: 1.04, 3.32). In normotensive
subjects, each 10 ug/g increase in calcaneus Pb level was associated with a
0.70 mmHg (95% CI: 0.04, 1.36) increase in 3rd trimester systolic blood
pressure and a 0.54 mmHg (95% CI: 0.01,1.08) increase in diastolic blood
pressure after adjusting for postpartum hypertension, education,
immigration status, current smoking, current alcohol use, parity, age, and
body mass index. Tibia bone Pb was not related to hypertension or elevated
blood pressure either in the 3rd trimester or postpartum, nor was calcaneus
Pb related to postpartum hypertension or elevated blood pressure.
Umbilical cord blood Pb among
women served by this Boston
hospital declined dramatically
from 1980 to 1990.
Suggest that while some
exogenous Pb sources and
modulators of PbB, such as use
of Pb-glazed pottery and calcium
in the diet, control Pb exposure
during and after pregnancy,
endogenous Pb sources from past
exposure before immigration
continue to influence PbB levels
in this cohort.
The authors concluded that past
Pb exposure influences
hypertension and elevated blood
pressure during pregnancy and
controlling blood pressure may
require reduction of Pb exposure
long before pregnancy.
-------
o
O
to
O
O
Table AX6-2.7 (cont'd). Bone Lead Studies in Pregnant and Lactating Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
Mexico
X
to
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Hemandez-Avila
etal. (1996)
Mexico City
Gonzales-Cossio
etal. (1997)
Mexico City
Unknown
Cross-sectional investigation of
the interrelationships between
environmental, dietary, and
lifestyle histories, blood and bone
Pb levels, among 98 recently
postpartum women. Multivariate
linear regression. Age 25.6
(±6.8) yr.
Examined relationship of Pb levels
in cord blood and maternal bone to
birth weight. Umbilical cord and
maternal venous blood samples
and anthropometric and
sociodemographic data were
obtained at delivery and 1 mo
postpartum. Bone Pb at 1 mo
postpartum. Multiple regression,
LOWESS.
Background information for
calcium supplementation study
Hemandez-Avila et al. (2003).
Mother-infant pairs (n = 272).
14-20 yr (n = 24): PbB 10.4 (±4.1), tibia 11.8 (±14.9), patella 14.1 (±13.3).
21-29 yr (n = 44): PbB 10.3 (±4.8), tibia 10.7 (± 10.9), patella 17.1 (±13.4)
30-43 yr (n = 27): PbB 7.8 (± 3.7), tibia 16.3 (±8.4), patella 18.1 (±12.7).
A 34 ug/g increase in patella Pb (from the medians of the lowest to the
highest quartiles) was associated with an increase in PbB of 2.4 ug/dL.
Significant predictors of bone Pb included years living in Mexico City,
lower consumption of high calcium content foods, and nonuse of calcium
supplements for the patella and years living in Mexico City, older age, and
lower calcium intake for tibia bone. Low consumption of milk and cheese,
as compared to the highest consumption category (every day), was
associated with an increase in tibia Pb of 9.7 ug/g.
Maternal PbB 8.9 (±4.1), cord PbB 7.1 (±3.5), tibia 9.8 (±8.9), patella 14.2
(±13.2).
After adjustment for other determinants of birth weight, tibia Pb was the
only Pb biomarker clearly related to birth weight. The decline in birth
weight associated with increments in tibia Pb was nonlinear and accelerated
at the highest tibia Pb quartile. In the upper quartile, neonates were on
average, 156 g lighter than those in the lowest quartile.
Suggest that patella bone is a
significant contributor to PbB
during lactation and that
consumption of high calcium
content foods may protect
against the accumulation of Pb
in one.
Bone-lead burden is inversely
related to birth weight.
-------
o
O
to
O
O
Table AX6-2.7 (cont'd). Bone Lead Studies in Pregnant and Lactating Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
to
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Mexico (cont'd)
Brown et al. (2000)
Mexico City
1994-5
Chuangetal. (2001)
Mexico City
1994-95
Ettinger et al. (2004)
Mexico City
1994-95
Investigated determinants of bone
Pb and PbB of 430 lactating
Mexican women during the early
postpartum period and
contribution of bone Pb to PbB.
Linear regression analyses.
Aim to estimate the contribution
of maternal whole PbB and bone
Pb, and environmental Pb to
umbilical cord PbB (as a measure
of fetal Pb exposure). Maternal
and umbilical cord blood samples
within 12 hr of each infant's
delivery. Structural equation
modeling.
Aim to quantify the relation
between maternal blood and bone
Pb and breast-feeding status
among 310 lactating women in
Mexico City, Mexico, at 1 mo
postpartum. Breast milk
measured. Multiple linear
regression, LOWESS smoothing.
PbB 9.5 (±4.5), tibia 10.2 (±10.1), patella 15.2 (±15.1).
Bone Pb measured within 1 mo after delivery. PbB 8.45 (±3.94, n = 608),
tibia 9.67 (±9.21, n = 603), patella 14.24 (±14.19, n = 575).
Tibia and patella Pb, use of Pb glazed ceramics, and mean air Pb level
contributed significantly to plasma Pb. An increase in patella Pb and tibia
Pb was associated with increases in cord PbB of 0.65 and 0.25 ug/dL,
respectively.
Breastfeeding: PbB 9.3 (±4.4, n = 310), tibia 9.6 (±10.1, n = 303), patella
14.5 (±14.9, n = 294).
Non breastfeeding: PbB 9.3 (±4.9, n = 319), tibia 10.5 (±10.2, n = 306),
patella 15.2 (±16.1, n = 289). Breast milk geometric mean 1.1 (range
0.21-8.02) ug/L. Breast milk Pb significantly correlated with umbilical cord
Pb and maternal PbB at delivery and with maternal PbB and patella Pb at
1 mo postpartum. An interquartile range increase in patella Pb (20 ug/g)
was associated with a 14% increase in breast milk lead (95% CI: 5,25%).
An IQR increase in tibia Pb (12.0 ug/g) was associated with a 5% increase
in breast milk lead (95% CI: - 3, 14).
Older age, use of Pb glazed
pottery, and higher proportion of
life spent in Mexico City were
main predictors of higher tibia
and patella Pb. Women in the
90th percentile for patella Pb had
an untransformed predicted
mean PbB 3.6 ug/dL higher than
those in the 10th percentile.
Suggested that maternal plasma
Pb varies independently from
maternal whole PbB.
Contributions from endogenous
(bone) and exogenous
(environmental) sources were
approximately the same.
(Plasma Pb not measured).
Suggest that even among a
population of women with
relatively high lifetime Pb
exposure, breast milk Pb levels
are low, influenced both by
current Pb exposure and by
redistribution of bone Pb
accumulated from past
environmental exposures.
-------
o
O
to
O
O
Table AX6-2.7 (cont'd). Bone Lead Studies in Pregnant and Lactating Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
X
to
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Mexico (cont'd)
Saninetal. (2001)
Mexico City
1994-95
Gomaa et al. (2002)
Mexico City
Unknown
Examined early postnatal growth
in a cohort of healthy breastfed
newborns in relation to maternal
bone Pb burden. 329 mother-
infant pairs sampled for umbilical
cord blood at birth and maternal
and infant venous blood at 1 mo
postpartum. Maternal evaluations
at 1 mo postpartum included Pb
measures in blood and bone.
Primary endpoints were attained
weight 1 mo of age, and weight
gain from birth to 1 mo of age.
Linear regression.
Aim to compare umbilical cord
PbB and maternal bone Pb as
independent predictors of infant
mental development (n = 197).
Prospective design. At 24 mo of
age, each infant was assessed
using the Bay ley Scales of Infant
Development-II (Spanish
Version). Multiple linear
regression.
Included in analyses (n = 329):
Infant: cord PbB 6.8 (±3.9), PbB 1 mo 5.7 (±3.0)
Maternal: PbB 9.7 (±5.2), tibia Pb 10.1 (±10.3), patella Pb 15.2 (±15.2)
Excluded from analyses (n = 276):
Infant: cord PbB 6.3 (±3.0), PbB 1 mo 5.5 (±3.3)
Maternal: PbB 8.8 (±3.9), tibia Pb 9.75 (±10.3), patella Pb 14.2 (±17.3).
Infant PbB were inversely associated with weight gain, with an estimated
decline of 15.1 g/jig/dL of PbB. Children who were exclusively breastfed
had significantly higher weight gains; however, this gain decreased
significantly with increasing levels of patella Pb. Multivariate regression
analysis predicted a 3.6 g decrease in weight at 1 mo of age/jig Pb/g bone
mineral increase in maternal patella Pb levels.
Cord PbB 6.7 (±3.4), tibia 11.5 (±11.0), patella 17.9 (±15.2). After
adjustment for confounders, Pb levels in umbilical cord blood and patella
bone were significantly, independently, and inversely associated with the
Mental Development Index (MDI) scores of the Bailey Scale. In relation to
the lowest quartile of patella Pb, the 2nd, 3rd, and 4th quartiles were
associated with 5.4-, 7.2-, and 6.5-point decrements in adjusted MDI scores.
A 2-fold increase in cord PbB (e.g., from 5-10 |ig/dL) was associated with a
3.1-point decrement in MDI score.
The authors concluded that
maternal Pb burden is negatively
associated with infant attained
weight at 1 mo of age and to
postnatal weight gain from birth
to 1 mo of age.
Suggest that higher maternal
patella bone Pb levels constitute
an independent risk factor for
impaired mental development in
infants at 24 mo of age. This
effect is probably attributable to
mobilization of maternal bone Pb
stores.
-------
o
O
to
O
O
Table AX6-2.7 (cont'd). Bone Lead Studies in Pregnant and Lactating Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
Mexico (cont'd)
X
Oi
to
Oi
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Hernandez-A vila
et al. (2002)
Mexico City
1994
Tellez-Rojo et al.
(2002)
Mexico City
1994-95
Aim to evaluate the effects of
maternal bone Pb stores on
anthropometry at birth in 223
mother-infant pairs.
Anthropometric data were
collected within the first 12 hr
following delivery. Maternal
information was obtained 1 mo
after delivery (mean age 24.4 ± 5.4
yr). Transformed anthropometric
measurements to an ordinal 5-
category scale, and association of
measurements with other factors
evaluated with ordinal logistic-
regression models. Cumulative
Odds Model.
Evaluated the hypothesis that
lactation stimulates Pb release
from bone to blood.
Cross-sectional examination of
breastfeeding patterns and bone Pb
as determinants of PbB among 425
lactating women (mean age 24.8
±5.3 yr) for 7 mo after delivery.
Bone Pb at 1 mo postpartum.
Maternal blood samples and
questionnaire information
collected at delivery and at 1, 4,
and 7 mo postpartum. Generalized
estimating equations.
Cord blood 7.01 (±3.5), maternal PbB 8.82 (± 4.0), tibia 10.70 (±7.58,
adjusted for negative values), patella 15.39 (±11.18, adjusted for negative
values). Maternal PbB increased linearly by 0.096/ug of tibia Pb and
0.078/ng patella Pb. Umbilical cord PbB increased by 0.111/ng tibia Pb
and 0.061/ug patella Pb. Birth length of newborns decreased as tibia Pb
levels increased (odds ratio of 1.03/ug/g bone mineral [95% CI: 1.01,
1.06]).
Mean PbB decreased with time postpartum: 1 mo 9.4 (±4.4), 4 mo 8.9
(±4.0), 7 mo 7.9 (±3.3).
Tibia 10.6 (11.6 after correction for negative values), patella 15.3 (16.9 after
correction). After adjustment for bone Pb and environmental exposure,
women who exclusively breastfed their infants had PbB levels that were
increased by 1.4 ug/dL and women who practiced mixed feeding had levels
increased by 1.0 ug/dL, in relation to those who had stopped lactation.
A 10 ug Pb/g increment in patella and tibia bone Pb increased PbB by 6.1%
(95% CI: 4.2, 8.1) and 8.1% (95% CI: 5.2, 11.1), respectively.
Compared with women in the
lower quintiles of the distribution
of tibia Pb, those in the upper
quintile had a 79% increase in
risk of having a lower birth
length newborn (OR ratio 1.79;
95%CI: 1.10,3.22). PatellaPb
was positively related to the risk
of a low head circumference
score; this score remained
unaffected by inclusion of birth
weight. The increased risk was
1.027 Mg Pb/g bone mineral (95%
CI: 1.01,1.04). Odds ratios did
not vary substantially after the
authors adjusted for birth weight
and other important determinants
of head circumference.
They concluded that their results
support the hypothesis that
lactation is directly related to the
amount of Pb released from
bone.
-------
o
O
to
O
O
Table AX6-2.7 (cont'd). Bone Lead Studies in Pregnant and Lactating Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
Mexico (cont'd)
Hemandez-Avila
et al. (2002)
Mexico City
1994
X
to
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Hemandez-Avila
etal. (2003)
Mexico City
1994-95
Evaluated the effects that maternal
bone Pb has on anthropometry at
birth in 223 mother-infant pairs.
Anthropometric data (birth length,
head circumference) collected
within the first 12 hr following
delivery. Maternal information
was obtained 1 mo postpartum.
Transformed anthropometric
measurements to an ordinal 5-
category scale, ordinal logistic-
regression models.
Tested the hypothesis that in a
randomized trial of lactating
women a dietary calcium
supplement will lower blood lead
levels. Lactating women (mean
age 24 yr) were randomly assigned
to receive either calcium carbonate
(1200 mg of elemental calcium
daily) or placebo in a double-blind
trial. Blood samples were
obtained at baseline, and 3 and
6 mo after the trial began. Primary
endpoint was change in maternal
PbB in relation to supplement use
and other covariates with
multivariate generalized linear
models for longitudinal
observations.
Participants (n = 223) Cord blood 7.01 (±3.5), maternal PbB 8.82 (±4.0),
tibia 9.83 (±8.9), patella 14.14 (±13.0).
Nonparticipants (n = 494): Cord blood 6.75 (±3.50), PbB 8.47 (±4.19).
Birth length of newboms decreased as tibia Pb levels increased. Compared
with women in the lower quintiles of the distribution of tibia Pb, those in the
upper quintile had a 79% increase in risk of having a lower birth length
newborn (odds ratio 1.79; 95% CI: 1.10, 3.22). The effect was attenuated-
but nonetheless significant- even after adjustment for birth weight. Patella
Pb was positively and significantly related to the risk of a low head
circumference score; this score remained unaffected by inclusion of birth
weight.
Lactating calcium group (n = 296): PbB 9.2 (±4.2), tibia 10.7 (±9.8), patella
16.2 (±15.7)
Lactating placebo (n = 321): PbB 9.4 (± 5.0), tibia 9.6 (±10.3), patella 13.5
(±15.1)
Women randomized to the calcium supplements experienced a small decline
in PbB of 0.29 ng/dL (95% CI: -0.85,-0.26). The effect was more
apparent among women who were compliant with supplement use and had
high patella Pb of >5 ng/g. Among this subgroup, supplement use was
associated with an estimated reduction in mean PbB of 1.16 ng/dL
(95% CI: -2.08, -0.23), an overall reduction of 16.4%.
The authors estimated the
increased risk of having a low
head-circumference score to be
1.027 ng Pb/g bone mineral (95%
CI: 1.01,1.04). Odds ratios did
not vary substantially after the
authors adjusted for birth weight
and other important determinants
of head circumference.
Among lactating women with
relatively high Pb burden,
calcium supplementation was
associated with a modest
reduction in PbB levels.
-------
o
O
to
O
O
Table AX6-2.7 (cont'd). Bone Lead Studies in Pregnant and Lactating Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in ug/dL, Bone Pb in ug/g Bone Mineral
Findings, Interpretation
Mexico (cont'd)
X
to
oo
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Tellez-Rojo et al.
(2004)
Mexico City
1997-99
Tested the hypotheses that
maternal bone Pb burden is
associated with increasing
maternal whole PbB and plasma
Pb over the 3 trimesters of
pregnancy and that this association
is modified by rates of maternal
bone resorption. Urine was
analyzed for cross-linked N-
telopeptides (NTx) of type I
collagen, a biomarker of bone
resorption. Patella and tibia Pb at
1 mo postpartum. Mixed models.
Participants (n = 193):
PbB (ng/dL): initial 7.10 (±1.72), 1st trimester 6.47 (± 0.17), 2nd
trimesters.80 (± 0.17), 3rd trimester 6.05 (± 0.17).
Plasma (ug/L): 1st trimester 0.13 (±1.88), 2nd trimester 0.12 (± 1.95), 3rd
trimester 0.12 (± 1.88) (geometric means and SD)
Bone Pb during pregnancy:
Tibia 11.35 (±8.82, adjusted for negative values), patella 13.82 (±10.97,
adjusted for negative values).
Nonparticipants (n = 134):
PbB 6.82 (±1.75), tibia 13.71 (±9.17, adjusted for negative values), patella
11.79 (±9.75, adjusted for negative values).
Found an increasing trend for plasma Pb among women with the highest
bone Pb (>median level of 12.1 ug/g) but a decreasing trend among less-
exposed women(below the median level). The observed increase reached its
maximum among women with both the highest bone Pb and the highest
bone resorption. In comparison with women with a low bone Pb and a high
NTx level, those with a high bone Pb and a high NTx level had, on average,
an 80% higher mean plasma Pb. In the cross-sectional analyses for each
trimester of pregnancy, there was an increasingly stronger association
between bone Pb and plasma Pb (log-transformed) as pregnancy progressed.
An increase in patella lead of 10 ug/g would be associated with 9% (p =
0.07), 24% (p < 0.01), and 25% (p < 0.01) increases in plasma Pb in the 1st,
2nd, and 3rd trimesters of pregnancy, respectively. The corresponding
values for tibia lead were 8% (p = 0.16), 19% (p< 0.01), and 13% (p =
0.01), respectively. Dietary calcium intake was inversely associated with
plasma lead.
They concluded that the results
support the hypothesis of a
biologic interaction between
bone Pb burden and bone
resorption. They also suggest
that as pregnancy progresses,
bone Pb may be mobilized
increasingly into plasma.
-------
o
O
to
O
O
X
to
VO
Table AX6-2.7 (cont'd). Bone Lead Studies in Pregnant and Lactating Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
Mexico (cont'd)
Moline et al. (2000)
Morelos, Mexico
1999
Pilot study to assess the body
burden of lead in 24 Mexican
women (age 21-34 yr) who were
lactating. Demographic and
reproductive characteristics of
women and potential sources of
lead exposure were gathered by a
direct interview. Multiple
regression. Average time of
lactation 22 (±17) months.
PbB 4.6 (± 2.0, geometric mean), tibia 9.2 (±4.2), patella 14.8 (±8.0),
calcaneus 11.7 (±11.2). An inverse relationship was noted between months
of lactation and age-adjusted calcaneus lead level (p = 0.001).
No association was observed between age-adjusted patella or tibia lead level
and months of lactation (p = 0.15).
This pilot study provides further
limited evidence for the
hypothesis that Pb mobilization
occurs during lactation.
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
-------
o
O
to
O
O
Reference, Study
Location, and
Period
Table AX6-2.8. Bone Lead Studies of Menopausal and Middle-aged to Elderly Subjects
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
United States
Huetal. (1996)
Boston, MA
1991+
X
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Kim et al. (1997)
Boston, MA
1991-95
Cheng etal. (1998)
Boston, MA
1991-95
Normative Aging Study.
Subjects were middle-aged and
elderly men who had community
(nonoccupational) exposures to lead.
Cross-sectional. Backwards
elimination multivariate regression
models that considered age, race,
education, retirement status, measures
of both current and cumulative
smoking, and alcohol consumption.
Normative Aging Study (n = 70).
Aim to examine age and secular
trends in bone and blood lead levels
of community-exposed men aged 52-
83 yr. Bone and blood lead levels
measured twice, with a 3-yr interval.
Normative Aging Study (n = 747).
Aim to examine relationships of
nutritional factors to body Pb burden.
Cross-sectional.
Multiple regression models adjusting
for age, education level, smoking, and
alcohol consumption.
47-59 yr: (n = 116): PbB 5.8 (+3.7), tibia 14.6 (+8.3),
patella 23.6 (+12.4)
60-69yr: (n=360): PbB 6.3 (+4.2), tibia21.1
(+11.4), patella 30.5 (+16.9)
>70yr: (n = 243): PbB 6.5 (+4.5), tibia 27 (+15.6),
patella 38.8 (+23.5)
PbB 6.7 (+1.8), tibia 17.5 (+2.0), patella 29.1 (+1.8)
3 yr later: PbB 5.1 (+1.4), tibia 17.9 (+1.7), patella
22.2 (+1.8)
PbB 6.2 (± 4.1), tibia 21.9 (± 13.3), patella
32.0 (±19.5).
Multiple regression models men in the lowest quintile
of total dietary intake levels of vitamin D (including
vitamin supplements) (<179 i.u./day) had mean tibia
and patella Pb levels 5.6 ug/g and 6.0 ug/g/ higher
than men with intake in the highest quintile (>589
i.u./day). Higher calcium intake was associated with
lower bone Pb levels, but this relation became
insignificant when adjustment was made for vitamin
D. Subjects in the lowest vitamin C intake quintile
(<109 mg/day) had a mean PbB level 1.7 ug/dL higher
than men in the highest quintile (>339 mg/day), while
men in the lowest iron intake quintile (<10.9 mg/day)
had a mean blood lead level 1.1 ug/dL higher than
men in the highest quintile (>23.5 mg/day).
Factors that remained significantly related to higher
levels of both tibia and patella Pb were higher age
and measures of cumulative smoking, and lower
levels of education. An increase in patella Pb from
the median of the lowest to the median of the
highest quintiles (13-56 ug/g) corresponded to a
rise in PbB of 4.3 ug/dL. Bone Pb levels
comprised the major source of circulating lead in
these men.
Cross-sectional analysis of each set of
measurements indicated that, on average, a 1-year-
older individual would have 2.7% and 2.4-3.2%
higher levels of Pb in patella and tibia,
respectively. Secular trend over time was
decreasing for patella Pb levels and stable for tibia
Pb levels.
Also observed inverse associations of blood lead
levels with total dietary intake of vitamin C and
iron. Suggested that low dietary intake of vitamin
D may increase Pb accumulation in bones, while
lower dietary intake of vitamin C and iron may
increase PbB.
-------
o
O
to
O
O
Table AX6-2.8 (cont'd). Bone Lead Studies of Menopausal and Middle-aged to Elderly Subjects
Reference, Study
Location, and
Period Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
United States (cont'd)
X
Hu et al. (2001) Normative Aging Study. Aim to
Boston, MA determine if ALAD polymorphism is
1991+ associated with altered levels of lead
in bone and blood. Multivariate
linear regression models controlling
for age, education, smoking, alcohol
ingestion, and vitamin D intake.
ALAD 1-1 (n = 608): PbB 6.3(+4.1), tibia 22.2
(+13.9), patella 32.2 (+19.9)
ALAD 1-2/2-2 (n = 118): PbB 5.7 (+4.2), tibia 21.2
(+10.9), patella 30.4 (+17.2)
ALAD 1-1 genotype was associated with cortical
bone lead levels that were 2.55 ug/g (95% CI: 0.05,
5.05) higher than those of the variant allele carriers.
No significant differences by genotype with respect
to Pb levels in trabecular bone or blood. In
stratified analyses and a multivariate regression
model that tested for interaction, the relationship of
trabecular bone Pb to PbB appeared to be
significantly modified by ALAD genotype, with
variant allele carriers having higher PbB levels, but
only when trabecular bone Pb levels >60 ug/g.
The authors suggest that the variant ALAD-2 allele
modifies lead kinetics possibly by decreasing lead
uptake into cortical bone and increasing the
mobilization of lead from trabecular bone.
fe
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Oliveira et al. (2002)
Boston, MA
1991-98
Normative Aging Study.
To determine if seasonal fluctuations
in PbB levels are related to increased
mobilization of bone Pb stores during
the winter months. Measurements of
blood and bone Pb during the high
sun exposure months of May-August
(summer; n = 290); the intermediate
sun exposure months of March, April,
September, and October (spring/fall;
n = 283); and the low sun exposure
months of November-February
(winter; n= 191).
Mean PbB levels were slightly lower in summer
(5.8 ±3.4 ug/dL) compared with winter (6.6 ± 4.7
ug/dL). Mean bone Pb levels were higher during the
summer than the winter months: 23.9 (±15.2) and
20.3 (±11.3) ug/g respectively for the tibia and
34.3 (±22.8) and 29.0 (±16.2) ug/g respectively for
patella.
Found a significant interaction between season and
bone Pb with bone Pb during the winter months
exerting an almost 2-fold greater influence on PbB
levels than during the summer months. The
authors attributed this to increased mobilization of
endogenous bone Pb stores arising potentially from
decreased exposure to sunlight, lower levels of
activated vitamin D and enhanced bone resorption.
-------
o
O
to
O
O
Table AX6-2.8 (cont'd). Bone Lead Studies of Menopausal and Middle-aged to Elderly Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
United States (cont'd)
X
to
Korrick et al. (2002)
Boston, MA
1990-95
Nurses' Health Study.
Cross-sectional study of 264 elderly
women; 46-54 yr (80) 55-64 yr (102),
65-74 yr (82). Tibia and patella Pb.
Multivariate linear regression models.
46-54 yr: PbB 2.7 (SE +0.3), tibia 10.5 (+1.0), patella
14.9 (+1.2)
55-64 yr: PbB 3.4 (+0.2), tibia 12.7 (+0.9), patella
17.0 (+1.1)
65-74 yr: PbB 3.3 (+0.3), tibia 16.4 (+0.9), patella
19.8 (+1.2).
An increase from the first to the fifth quintile of tibia
Pb level (19 ug/g) was associated with a 1.7 ug/dL
increase in PbB (p = 0.0001).
Tibia and patella Pb values were significantly and
positively associated with PbB but only among
postmenopausal women who were not using
estrogens. Older age and lower parity were
associated with higher tibia Pb; only age was
associated with patella Pb. They suggested the
observed interaction of bone Pb with estrogen
status in determining PbB supports the hypothesis
that increased bone resorption, as occurs
postmenopausally because of decreased estrogen
production, results in heightened release of bone Pb
stores into blood.
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
Tsaihetal. (1999)
Boston, MA
1991-97
Wright et al. (2004)
Boston, MA
1991-97
Normative Aging Study.
Aim to evaluate hypothesis that bone
and erythrocyte Pb make independent
contributions to urine Pb excreted
over 24 hour. Urine used as a proxy
for plasma Pb.
Age range 53-82 yr (n = 71).
Generalized additive model.
Normative Aging Study. Aim to
evaluate if hemochromatosis gene
(HFE) was associated with body lead
burden. Tibia and patella bone Pb.
DNA samples genotyped.
Multivariate linear regression
analyses.
PbB: 5.94 (±3.0), tibia 21.7 (±10.9), patella 31.1
(±15.1), urinary Pb 5.69 (±1.9) ^g/day. Both
erythrocyte Pb and bone Pb variables remained
independently and significantly associated with
urinary Pb.
Of 730 subjects, 94 (13%) carried the C282Y
variant and 183 (25%) carried the H63D variant.
In multivariate analyses that adjusted for age,
smoking, and education, having an HFE variant allele
was an independent predictor of significantly lower
patella Pb levels (p< 0.05).
Finding suggests that bone influences plasma Pb in
a manner that is independent of the influence of
erythrocytic lead on plasma Pb. Reinforces
superiority of bone Pb over PbB in predicting some
chronic forms of toxicity may be mediated through
bone's influence on plasma Pb. Urinary lead might
be useful as a proxy for plasma Pb.
Suggested that HFE variants have altered kinetics
of Pb accumulation after exposure and these effects
may be mediated by alterations in Pb toxicokinetics
via iron metabolic pathways regulated by the HFE
gene product and body iron stores.
-------
o
O
to
O
O
Table AX6-2.8 (cont'd). Bone Lead Studies of Menopausal and Middle-aged to Elderly Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
United States (cont'd)
Lin et al. (2004) Community Lead Study. Measured PbB
Boston, MA and bone Pb levels among minority
1999-2000 individuals from Boston. Compared with
earlier studies of predominantly white
subjects, the 84 volunteers in this study
(33:67 male to female ratio; 31-72 yrs of
age) had similar educational,
occupational, and smoking profiles and
mean blood, tibia, and patella Pb levels.
LOWESS smoothing curves. Multiple
linear regression analyses to predict
blood, tibia and patella Pb.
Berkowitz et al. Longitudinal study of 91 premenopausal
(2004) and perimenopausal women aged
New York > 30 yrs of age from New York who
1994-99 were undergoing surgical menopause
(baseline; n 84) to determine if bone Pb
values decrease and PbB values increase
during menopause. Tibia Pb
concentrations measured at baseline, 6
mo (70) and 18 mo (62) postsurgery.
Schafer et al. Evaluated the relations among PbB, tibia
(2005) Pb, and homocysteine levels by cross-
Baltimore, MD sectional analysis among subjects in the
Baltimore Memory Study, a longitudinal
study of 1, 140 randomly selected
residents in Baltimore, MD, aged 50-70
yr and 66.0% female, 53.9% white, and
41.4% black or African American.
Multiple linear regression analyses.
<45 yr (n = 28): PbB 2.0 (±1.2), tibia 8.3 (±8.4),
patella 8.9 (±14.3)
46-60 yr (n = 41): PbB 2.8 (±1.7), tibia 10.8 (±11.5),
patella 11.8 (±11.4)
61-75 yr(n= 15): PbB 5.3 (±3.2),tibia 21.7 (±8.6),
patella 30.9 (±15.7)
Slopes of the univariate regressions of blood, tibia, and
patella lead versus age were 0.10 ug/dL/yr (p < 0.001),
0.45 ug/g/yr (p O.001), and 0.73 ug/g/yr (p < 0.001),
respectively.
Baseline: Median PbB 2.5 (0.3, 11.7), tibia 6.1
(-22.2, 36.4)
6 mo: PbB 3.2 (0.4, 12.0), tibia 6.8 (-14.2, 29.0)
18 mo: PbB 3.1 (0.5, 9.1), tibia 5.8 (-15.4, 24.2)
PbB 3.5 (±2.4) ug/dL, tibia 18.9 (±12.5) ug/g,
homocysteine 10.0 (±4.1) /jmo\/L. Tibia lead was
modestly correlated with PbB (Pearson r = 0.12,
p < 0.01) but was not associated with homocysteine
levels.
Analyses of smoothing curves and regression lines
for tibia and patella Pb suggested an inflection
point at 55 yr of age, with slopes for subjects >55
yr of age that were not only steeper than those of
younger subjects but also substantially steeper than
those observed for individuals >55 yr of age in
studies of predominantly white participants.
Marginal decline in tibia Pb values between 6 and
18 mo post surgery for women who took estrogen
replacement therapy (ERT) but not for those who
did not take ERT. They concluded that there was
no substantial mobilization of Pb (from the tibia)
during menopause but common ERT use may have
masked this effect, the amounts of Pb released
were too low to detect in blood, or the numbers of
subjects was too small to detect an effect.
Suggested that homocysteine could be a
mechanism that underlies the effects of lead on the
cardiovascular and central nervous systems,
possibly offering new targets for intervention to
prevent the long-term consequences of lead
exposure.
-------
o
O
to
O
O
Table AX6-2.8 (cont'd). Bone Lead Studies of Menopausal and Middle-aged to Elderly Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
X
fe
H
6
o
o
H
O
O
H
W
O
O
HH
H
W
United States (cont'd)
Kosnett et al. Aim to determine the influence of
(1994) demographic, exposure and medical
Dickson City, PA factors on the bone Pb concentration of
subjects with environmental Pb exposure.
101 subjects (49 males, 52 females; aged
11 to 78 yrs) recruited from 49 of 123
households geographically located in a
suburban residential neighborhood.
Log-transformed bone Pb highly correlated with age
(r= 0.71; ps 0.0001).
Popovich et al.
(2005)
Bunker Hill, ID
1994
Bone Pb showed no significant change up to age 20
yr, increased with the same slope in men and
women between ages 20 and 55 yr, and then
increased at a faster rate in men older than 55 yr.
108 former female smelter employees
and 99 referents to assess the PbB versus
bone Pb relationship.
Exposed: PbB 2.73 (+2.39), tibia 14.4 (+0.5)
Referents: PbB 1.25 (+2.10), tibia 3.22 (+0.50)
Pb concentrations in tibia and blood significantly
higher in the exposed group. Endogenous release rate
(Hg Pb per dL blood/ |ig Pb/g bone) in
postmenopausal women was double the rate found
in premenopausal women (0.132 + 0.019 versus
0.067 + 0.014).
Higher tibia bone Pb (and PbB) was associated
with use of estrogen (present or former) in both the
whole referent group and postmenopausal women
in the referent group.
Canada
Webber et al.
(1995)
Canada
Unknown
Tested hypothesis that women on
hormone replacement therapy should
have higher bone Pb content and lower
plasma Pb as hormone replacement
therapy would suppress the transfer of
endogenous Pb to the circulation.
56 women, some using hormone
replacement therapy over approximately
4 yrs.
Low dose hormone replacement therapy (n = 15):
PbB 4.08 (±1.60), tibia 19.37 (±8.62), calcaneus 24.02
(±10.88)
Moderate dose hormone replacement therapy (n = 11):
PbB 5.22 (±3.36), tibia 16.80 (±11.68), calcaneus
23.83 (±14.18)
Calcium only (n = 22): PbB 4.6 (±1.59), tibia 11.13
(±6.22), calcaneus 21.12 (±13.55)
Women not taking hormones had significantly
lower Pb values in cortical bone compared to all
women on hormone replacement therapy (p =
0.007). Showed higher tibia Pb levels but no
increase in calcaneus Pb level or decrease in PbB.
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Table AX6-2.8 (cont'd). Bone Lead Studies of Menopausal and Middle-aged to Elderly Subjects
Reference, Study
Location, and
Period
Study Description
Lead Measurement (SD or range)
PbB in u,g/dL, Bone Pb in u,g/g Bone Mineral
Findings, Interpretation
Mexico
X
Garrido-Latorre Aim was to examine the relationship of
et al. (2003) blood lead levels to menopause and bone
Mexico City lead levels in 232 perimenopausal and
1995 postmenopausal women from Mexico
City. Measured bone mineral density in
addition to bone Pb. Information
regarding reproductive characteristics
and known risk factors for PbB was
obtained using a standard questionnaire
by direct interview. Mean age of the
population was 54.7 yrs (±9.8). Linear
regression analyses.
PbB 9.2 (±4.7), tibia 14.85 (±10.1), patella 22.73
(±14.9).
A change of 10 ng Pb/g bone mineral in
postmenopausal subjects was associated with an
increase in blood lead of 1.4 ng/dL, whereas a similar
change in bone lead among premenopausal women
was associated with an increase in blood lead of
0.8 ng/dL.
Found that postmenopausal women using hormone
replacement therapy had lower PbB levels and
higher tibia and patella bone Pb levels than non-
users; patella Pb explained the greatest part of
variations in PbB. Found no association with PbB
levels and did not describe any relationships
between bone lead and bone density.
Australia
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Gulson et al. Environmentally exposed females (n = 7)
(2002) and males (n = 3) aged 44-70 yr. Treated
Sydney, Australia for 6 mo with the bisphosphonate
2000 alendronate. PbB and isotopic ratios
measured by TIMS for 6 mo prior to
treatment and 12 mo post-treatment.
Bone mineral density and bone markers
including NTX measured.
Found a decrease in PbB concentrations and changing
blood lead isotopic composition in the direction
predicted during treatment. Upon cessation of
treatment, PbB increased and the isotopic
compositions changed.
Results consistent with changes in bone remodeling
associated with bisphosphonate use.
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Table AX6-2.9. Lead in Deciduous Teeth from Urban and Remote Environments
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Canada
Tsujietal. (2001)
Ontario, Canada
Dentine chips from schoolchildren living
in a remote area.
Mean value of 9.2 ug/g dry weight (n = 6 1 )
Attributed the high values to consumption of
lead contaminated game meat.
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Europe
Tvinnereim et al.
(1997)
Norway
1990-94
Lyngbyeetal. (1991)
Denmark
2,746 deciduous whole teeth.
In 2,033 teeth from 1, 848 children.
Mean 1.27 ± 1.87 ug/g of dry tooth substance
Geometric mean for the largest group from Arhus to
be 8.4 ug/g (wet weight) with similar values from
Copenhagen suburbs with a secondary lead smelter
(9.6 ug/g) and a lead battery factory (9.9 ug/g).
Observed an -50% reduction in lead
concentrations since the 1970s.
Concluded that automobile exhausts and
indirect occupational exposure were important
sources for the lead in dentine.
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Gil et al. (1996) 220 whole deciduous and permanent teeth
Coruna, Spain (one per subject).
Nowak and
Chmielnicka (2000)
Poland
Compared permanent teeth from two
cohorts, one from the highly polluted
Katowice district and a control town of
Beskid.
Permanent teeth showed higher mean values
(13.1 ±1.1 ug/g) than deciduous teeth (4.0 ± 1.1 ug/g)
In the control teeth they observed decreases in lead
for incisors (41.8 ug/g) to canines (37.5 ug/g) to
molars (35.3 ug/g) to premolars (32.0 ug/g).
However, there was no difference in the mean values
for the two centers: Katowice 36.5 ± 16.3 ug/g and
Beskid 36.3 ± 11.5 ug/g.
Found no gender differences.
These values are very high compared with
most other studies.
Mexico
Hernandez-Guerrero
et al. (2004)
Mexico City
100 healthy deciduous teeth collected
from 2 to 13 yr old children.
Higher mean concentrations of lead in the 10-13 yr
old group (7.7 ug/g) than in other age groups and the
mean concentrations were higher in girls (7.3 ug/g)
than boys (6.3 ug/g).
No association between pollution intensity
and tooth lead.
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Table AX6-2.9 (cont'd). Lead in Deciduous Teeth from Urban and Remote Environments
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Mexico (cont'd)
Frank etal. (1990)
Alsace, Mexico
Circular biopsies 500 fj.m in diameter
punched in the vertical sections of the
crown and cervical third of each root. The
age of the European subjects ranged from
10 to 80 yrs in Europe and 12 to 29 yrs in
Mexico City. Energy-dispersive X-ray
fluorescence method to compare lead in
enamel and dentine of premolars and
permanent molars.
Compared with the European values, there were
approximately 6 times higher inner coronal dentine
and 7 to 9 times higher pulpal root dentine
concentrations for samples from Mexico City.
The authors found no significant difference in
the relationship between traffic and mean lead
values for enamel and dentine in the European
communities but a significantly higher lead
concentration in relation to age. The
differences were attributed to traffic exposure.
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Asia
Karakayaetal. (1996)
Ankara, Turkey
103 whole deciduous teeth from primary
school aged children aged 7 to 12 yrs.
Significant differences in lead for urban (4.99 ± 0.46
Hg/g dry weight) compared with suburban children
(1.69±0.25ng/g).
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Table AX6-2.10. Lead In Deciduous Teeth from Polluted Environments
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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Europe
Begerowetal. (1994)
Germany
1991
790 children aged 6 yrs old living in
urban and rural areas in western and
eastern Germany. Incisors sampled.
Cikrt et al. (1997) Compared tooth (n = 162) and blood lead
Czech Republic levels in children living at various
distances from a lead smelter.
Lead levels of 1.50 to 1.74 ng/g from the western sector
and from 1.51 to 2.72 jig/g in the eastern sector.
Significant difference in the mean tooth lead for children
from the most contaminated zone less than 0.5 km from the
smelter (6.44 ng/g; n = 13) and those >5 km from the
smelter (1.45 ng/g; n = 36). Blood lead levels varied from
15.42 ng Pb/100 ml (n = 6; 95% CI: 7.17, 33.17) close to
the smelter to 4.66 ng/100 ml (n = 165, 95% CI: 4.30,
5.04) at larger distances.
Major decrease (40-50%) since 1976.
No descriptions of the teeth type were
available.
Australia
Gulson(1996)
Broken Hill, Australia
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Gulson et al. (2004)
Lake Macquarie,
Australia
36 exposed and nonexposed children
from Broken Hill lead-zinc mining
community. Sectioned teeth into mainly
enamel (incisal section) and mainly
dentine (cervical section). Lead isotope
ratios and lead concentrations by TIMS
with isotope dilution.
10 children from six houses in a primary
zinc-lead smelter community at North
Lake Macquarie, New South Wales,
Australia. Sectioned deciduous teeth
compared with environmental samples.
Lead isotope ratios and lead
concentrations by TIMS with isotope
dilution.
For subjects with low exposure (n = 13), lead
concentrations in the incisal section ranged from 0.4 to 3.5
Hg/g with a mean and standard deviation of 1 .2 ± 0.8 ng/g
(n = 13). For the cervical sections in low exposure children
the values ranged from 0.8 to 8.3 and mean 3.7 ± 2.4 ng/g.
For subjects with high exposure (n = 23), lead
concentrations in the incisal section ranged from 1.0 to 8.9
Hg/g with a mean and standard deviation of 2.6 ±1.8 ng/g.
For the cervical sections in high exposure children the
values ranged from 1.5 to 31.5 ng/g and mean 13. 7 ± 8.0
Blood lead levels in the children ranged from 10 to
42 ng/dL and remained elevated for a number of years.
Median lead level in the enamel section of the teeth was
2.3 ng/g with a range from 0.6 to 7.4 ng/g; in dentine the
median value was 5.3 ng/g with a range from 1 .4 to
19.9 ng/g.
The isotopic results in dentine were
interpreted to reflect an increased lead
exposure from the lead-zinc-silver
orebody during early childhood, probably
associated with hand-to-mouth activity.
Approximately 55 to 100% of lead could
be derived from the smelter.
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Table AX6-2.11. Summary of Selected Measurements of Urine Lead Levels in Humans
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Reference, Study
Location, and Period Study Description
United States
CDC (2005) Design: national survey (NHANES IV)
U.S. stratified, multistage probability cluster design
1 999-2002 Subjects: children and adults (>6 yrs, n = 5 140)
in general population
Biomarker measured: urine lead
Analysis: ICP-MS
Urine Lead Measurement Comment
Units: ug/j
Geometric
Age (yr)
>6:
n:
6-11:
n:
12-19:
n:
>20:
n:
Males:
n:
Females
n:
2, creatinine
mean (95% CI)
1999-2000
0.72 (0.70, 0.74)
2465
1.17(0.98,1.41)
340
0.50 (0.46, 0.54)
719
0.72 (0.68, 0.76)
1406
0.72 (0.68, 0.76)
1227
: 0.72 (0.68, 0.76)
1238
Geometric mean blood lead
concentrations in age strata ranged
200 1 -2002 from 0 . 94 to 1 . 5 1 ug/dL .
0.64 (0.60, 0.68)
2689
0.92(0.84,1.00)
368
0.40 (0.38, 0.43)
762
0.66(0.621,0.70)
1559
0.64(0.61,0.67)
1334
0.64 (0.59, 0.69)
1355
Schwartz et al.
(1999,2000b)
U.S.
1993-1997
Rabinowitz et al.
(1976)
New York
NR
Design: prospective
Subjects: adult male (n= 543) former TEL
manufacture workers (age range: 42-74 yrs)
Biomarker measured: DMSA (10 mg/kg)-
provoked urine lead
Analysis: GFAAS
Units: ug/4 hr
Arithmetic mean (SD):
>2 yr exposure: 17.1(15.7)
<2 yr exposure: 20.4(17.9)
Design: experimental study
Subjects: adult (n:5) males, age range 25-53 yrs,
ingested 300 ug Pb/day (approximately 50% as
204Pb) for 10-210 days
Biomarker measured: urine lead
Analysis: MS
Units: ug/day
Arithmetic mean (range): 36(36-41)
Arithmetic mean (SD) blood lead
(ug/dL) was 5.0 (2.8) for workers
exposed >2 yr and 2.8 (1.9) for
workers exposed <2yr. Blood lead
was strongest predictor or DMSA-
provoked urine lead.
Arithmetic mean (SD) tibia lead (ug/g,
XRF) was 15.6 (9.8) for workers
exposed >2 yr and 12.1 (7.7) for
workers exposed <2yr.
Arithmetic mean (range) blood lead
(ug/dL) was 19.4 (16.7-25.1).
Blood-to urine clearance estimate was
0.19 (range 0.15-0.23) L/day (from
Diamond, 1992).
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Table AX6-2.11 (cont'd). Summary of Selected Measurements of Urine Lead Levels in Humans
Reference, Study
Location, and Period
Study Description
Urine Lead Measurement
Comment
United States (cont'd)
Bergeretal. (1990)
Ohio
1983-1986
Design: cross-sectional, convenience sample
Subjects: children (n = 39), age range not reported.
Biomarker measured: timed urine lead
Analysis: AAS
ug/day
5-70
Blood lead range was 22-55 ug/dL.
Blood-to urine clearance estimate was
0.07 L/day (from Diamond, 1992).
Europe
^ Chamberlain et al. Design: experimental
^ (1978) Subjects: adult males (n = 6), intravenous injection
Oi United Kingdom of 203Pb tracer
^ 1975-1976 Biomarker: urinary lead clearance
Analysis: gamma spectrometer (203Pb)
Units: L/day
Arithmetic mean (range)
Blood-to-urine: 0.09(0.08-0.10)
Pplasma-to-urine: 20
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Brockhaus et al. (1988)
Germany
1982-1986
Kosteretal. (1989)
Germany
NR
Design: cross-sectional
Subjects: children (n = 184), age range 4-11 yrs
residing in 2 areas impacted by smelting operations
Biomarker measured: urine lead
Analysis: GFAAS
Design: cross-sectional
Subjects: adult (n = 46,40 males) hospital
workers, age range 20-78 yr.
Biomarker measured: urine lead
Analysis: GFAAS
Units: ug/g creatinine
Geometric mean (GSD, range)
Stolberg (n = 106): 9.6 (2.3, 0.2-43.0)
Dortmund (n = 78): 6.7 (2.0, 1.6-41.0)
Units: ug/24 hr-1.73 m2 (adult body surface area)
Arithmetic mean (range): 6.8 (2.3-18.9)
Geometric mean blood lead levels were
approximately 7 ug/dL.
Arithmetic mean (range) blood lead
(Hg/dL) was 7.6 (2.6-18.7).
Blood-to urine clearance estimate was
0.15 L/day (from Diamond, 1992).
Australia
Gulson et al. (2000)
Australia
Design: longitudinal
Subjects: women (n = 58) during pregnancy,
age range 18-35 yrs
Biomarker measured: blood-to-urine clearance
Analysis: TIMS
Units: ug/h
Arithmetic mean (SD, range): 3.2 (0.8-10.2)
Geometric mean: 2.7
Reported blood-to-urine clearance
corresponds to approximately 0.08
L/day.
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Table AX6-2.11 (cont'd). Summary of Selected Measurements of Urine Lead Levels in Humans
Reference, Study
Location, and Period
Study Description
Urine Lead Measurement
Comment
Asia
Arakietal. (1986,
1990)
Japan
NR
Design: cross-sectional
Subjects: adult (n = 19) male, gun metal foundry
workers, age range 34-59 yr.
Biomarker measured: urine lead
Analysis: AAS
j> Lee etal. (1990) Design: cross-sectional
X Korea Subjects: adults (n = 95) male workers in lead
i NR smelting, battery manufacture, PVC-stabilizer
^ manufacture facilities, age range: 19-64 yrs;
reference subjects (n = 13), age range 22-54 yr.
Biomarker measured: DMSA (10 mg/kg)-
provoked urine lead
Analysis: GFAAS
Units: ug/24 hr
Arithmetic mean (range): 94(37-171)
Units: ug/4 hr
Arithmetic mean (SD, range)
Lead workers: 288.7(167.7, 32.4-789)
Reference: 23.7(11.5,10.5-43.5)
Arithmetic mean plasma concentration
was 0.67 ug/dL (range 0.37-0.92).
Plasma-to urine clearance estimate was
22 L/day.
Blood-to urine clearance estimate was
0.33 L/day (from Diamond, 1992).
Arithmetic mean (SD, range) blood
lead concentration (ug/dL) was 44.6
(12.6,21.4-78.4) in lead workers and
5.9 (1.2, 4.0-7.2) in reference subjects.
Blood lead was strongest predictor or
DMSA-provoked urine lead.
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Schwartz et al.
(2000a), Lee et al.
(2001)
Korea
1997-1999
Design: cross-sectional
Subjects: adult lead (inorganic) workers (n = 798,
634 males), age range 18-65 yrs.
Biomarker measured: DMSA (10 mg/kg)-provoked
urine lead
Analysis: GFAAS
Units: ug/4 hr
Arithmetic mean (SD, range)
186(208,4.8-2100)
Arithmetic mean (SD, range) blood lead
(ug/dL) was 32.0 (15, 4-86). Blood
lead was strongest predictor or DMSA-
provoked urine lead
Arithmetic mean (SD, range) tibia lead
(ug/g, XRF) was 37.1 (40.4, -7 to 338).
AAS - atomic absorption spectroscopy; ET-AAS - electro-thermal atomic absorption spectrometry; GFAAS - graphite furnace atomic absorption spectroscopy; ICP-AES -
inductively coupled plasma/atomic emission spectroscopy; ICP-MS - inductively coupled plasma-mass spectrometry; MS - mass spectrometry; NR - not reported; Pet -
percentile; TEL -tetraethyl lead; TIMS - thermal ionization mass spectrometry.
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Reference, Study
Location, and
Period
Table AX6-2.12. Summary of Selected Measurements of Hair Lead Levels in Humans
Study Description
Hair Lead Measurement
Comment
United States
DePietro et al. Design: cross-sectional (random sample from NHANES
(1989) II, HHANES Stands)
GA, SC, TX, VA Subjects: adults (n = 270, 200 males; age range: 20-73
1976-1980 yrs) from general population
Biomarker measured: hair lead
Analysis: ICP-AES
Units: ug/g
Geometric mean (10-90* Pet range)
2.42 (<1.0-10.8)
Hair lead level varied with hair treatment (e.g..
shampoo, coloring).
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to
Tuthill (1996) Design: cross-sectional
MA Subjects: children (n = 277, 141 males, age range 6.5-7.5
NR yrs)
Biomarker measured: hair lead
Analysis: ICP-AES
Units: ug/g
O.1-0.9: 13.5%
1-1.9:40.8%
2-2.9: 25.6%
3-3.9: 9.0%
>4: 11.1%
Study examined associations between hair lead
levels and attention-deficit behaviors.
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Europe
Annesi-Maesano
etal. (2003)
France
1985,1991-1992
Draschetal. (1997)
Germany
1993-1994
Gerhardsson et al.
(1995)
Sweden
NR
Design: cross-sectional
Subjects: mother (mean age 29 yr)-infant pairs (n:374)
Biomarker measured: hair lead
Analysis: ICP-AES
Design: cross-sectional
Subjects: adults (n= 150, 75 males; age range: 16-93
yrs) from general population with no known occupational
exposure
Biomarker measured: hair lead (post-mortem)
Analysis: ET-AAS
Design: cross-sectional
Subjects: adult male smelter workers (n = 32) and
referents (n= 10)
Biomarker measured: hair lead (post-mortem)
Analysis: XRF
Units: ug/g
Arithmetic mean (SD):
Infant: 1.38(1.26)
Mother: 5.16(6.08)
Units: ug/g
Median (range): 0.76 (0.026-20.6)
25-75* Pet range: 0.45-1.48
Units: ug/g
Median (range):
Active workers: 8.0(1.5-29,000)
Retired workers: 2.6(0.6-9.3)
Reference: 2.05 (0.3-96)
Mean blood lead concentrations were 96 ug/dL
(SD 58) in mothers and 67 (SD 48) in infant cord
blood. Infant hair-cord blood lead correlation
(Spearman, r) was 0.21 (p < 0.01).
Median blood lead (ug/dL) was 2.8 (range <0.9-
16.1). Median temporal bone lead was 2.84 ug/g
(range 0.25-22.3), Hair lead correlation (Spearman
r) was 0.35 (p < 0.001) for blood, 0.10 (p > 0.05)
for temporal bone, and 0.16 (p > 0.05) for body
burden.0.512 for liver (p = 0.003) and 0.57 (p =
0.001) for kidney.
Based on reported a cumulative annual blood lead
index of 1,374 ug/dL and average duration of
employment of 31.4 yrs, average blood lead may
have been approximately 44 ug/dL in workers.
Hair lead correlation (Spearman, r).
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Table AX6-2.12 (cont'd). Summary of Selected Measurements of Hair Lead Levels in Humans
Reference, Study
Location, and
Period
Study Description
Hair Lead Measurement
Comment
Europe (cont'd)
Esteban et al.
(1999)
Russia
1996
Design: cross-sectional
Subjects: children (n = 189, 110 females; age rage
1.9-10.6 yr) living in the vicinity of lead battery and
leaded glass manufacture facilities.
Biomarker measured: hair lead
Analysis: ICP-AES
Units: ng/g
Geometric mean (range):
5.4(1-39.2)
90th Pet: -15
Geometric mean blood lead was 8.5 ng/dL
(range 3. 1-35.7)
log blood lead = 1 .44 + 0.35 (log hair) + 0.24
(gender), r2 = 0.20.
X
AAS - atomic absorption spectroscopy; ET-AAS - electro-thermal atomic absorption spectrometry; GFAAS - graphite furnace atomic absorption spectroscopy; HHANES -
Hispanic Health and Nutrition Examination Survey; ICP-AES - inductively coupled plasma/atomic emission spectroscopy; ICP-MS - inductively coupled plasma-mass
spectrometry; NR - not reported; Pet - percentile.
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CHAPTER 6 ANNEX
ANNEX TABLES AX6-3
December 2005 AX6-44 DRAFT-DO NOT QUOTE OR CITE
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Table AX6-3.1. Prospective Longitudinal Cohort Studies of Neurocognitive Ability in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States
Bellinger etal. (1992)
U.S.
Dietrich et al.
(1991, 1992, 1993);
Ris et al. (2004)
U.S.
Canfield et al. (2003)
U.S.
148 subjects from the Boston Prospective Study
were re-evaluated at 10 years of age. The WISCR
was used to index intellectual status. Extensive
assessment of medical and sociodemographic
covariates.
253-260 children followed since birth in the
Cincinnati Lead Study were re-evaluated at 4, 5,
and 6.5 years of age. At 4 and 5 years the KABC,
was used to index intellectual status. At 6.5 years,
the WISCR was administered. At 15-17 years of
age, 195 Cincinnati Lead Study subjects were re-
evaluated with a comprehensive
neuropsychological battery that yielded a
"Learning/IQ" factor in a principal components
analysis. Extensive assessment of medical and
sociodemographic covariates.
172 predominantly African-American, lower
socioeconomic status children in Rochester, NY
followed since they were 5 to 7 months were
evaluated at 3 and 5 years. An abbreviated form of
the Stanford-Binet Intelligence Scale-4 (SBIS-4)
was used to index intellectual status. Extensive
assessment of medical and sociodemographic
covariates.
Cord and serial postnatal
blood lead assessments.
Cord blood lead grouping
<3,
6-7, >10 ug/dL.
Blood lead at 2 years 6.5
(SD 4.9) ug/dL
Prenatal (maternal) and serial
postnatal blood lead
assessments.
Prenatal blood lead 8.3
(SD 3.7) ug/dL
Blood lead at 2 years 17.4
(SD 8.8) ug/dL
Serial postnatal blood lead
Blood lead at 2 years
9.7 ug/dL
Increase of 10 ug/dL in blood lead level at age two was
associated with a decrement of approximately 6 IQ points.
Relationship was stronger for verbal compared to
performance IQ. Prenatal exposure to lead as indexed by
cord blood lead levels was unrelated to psychometric
intelligence.
Few statistically significant relationships between blood
lead indices and covariate-adjusted KABC scales at 4 and
5 years of age. One KABC subscale that assesses visual-
spatial skills was associated with late postnatal blood lead
levels following covariate adjustment. After covariate
adjustment, average postnatal blood lead level was
significantly associated with WISCR performance IQ at
6.5 years. Blood lead concentrations in excess of 20 ug/dL
were associated with deficits in performance IQ on the
order of 7 points compared with children with mean blood
lead concentrations of less than 10 ug/dL. At 15-17 years,
late childhood blood lead levels were significantly
associated with lower covariate-adjusted Learning/IQ
factor scores.
Following covariate adjustment, there was a significant
inverse relationship between blood lead indices and IQ at
all ages. Overall estimate indicated that an increase in
average lifetime blood lead concentration of 1 ug/dL was
associated with a loss of 1A IQ point. Effects were stronger
for subjects whose blood lead levels never exceeded 10
ug/dL. Semiparametric analysis indicated a decline in IQ
of 7.4 points for a lifetime average blood lead
concentration up to 10 ug/dL while for levels between 10
and 30 ug/dL a more gradual decrease in IQ was
estimated. Authors concluded that the most important
aspect of their findings was that effects below 10 ug/dL
that have been observed in previous cross-sectional studies
have been confirmed in a rigorous prospective
investigation.
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Table AX6-3.1 (cont'd). Prospective Longitudinal Cohort Studies of Neurocognitive Ability in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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O
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United States (cont'd)
Bellinger and
Needleman (2003)
U.S.
Chen et al. (2005)
U.S.
Reanalysis of data from the Boston Prospective
Study focusing on 48 subjects at 10 years of age
whose blood lead levels never exceeded 10 ug/dL.
WISCR was used to index intellectual status, (see
Bellinger, etal. (1992)
Repeat measure psychometric data on 780 children
enrolled in the Treatment of Lead-Exposed
Children (TLC) clinical trial for were analyzed to
determine if blood lead concentrations at 2 years of
age constitute a critical period of exposure for the
expression of later neurodevelopmental deficits.
Data for placebo and active drug groups were
combined in these analyses, which spanned the
ages of approximately 2 to 7 years of age.
Measures of intellectual status included the Bayley
Mental Development Index (MDI), and full scale
IQ derived from age-appropriate Wechsler scales.
Serial postnatal blood lead
Blood lead at 2 years 6.5
(SD 4.9) ug/dL
Blood lead
Range 20-44 ug/dL
Baseline blood lead 26
(SD 26.5) ug/dL in both drug
and placebo groups.
Blood lead at 7 years 8.0
(SD 4.0) ug/dL
IQ was inversely related to two-year blood lead levels
following covariate adjustment. Blood lead coefficient (-
1.56) was greater than that derived from analyses including
children with concentrations above 10 ug/dL (-0.58).
Authors conclude that children's IQ scores are reduced at
lead levels still prevalent in US
Association between blood lead and psychometric
intelligence increased in strength as children became older,
whereas the relation between baseline (2 year) blood lead
and IQ attenuated. Peak blood lead concentration thus
does not fully account for the observed association in older
children between their lower blood lead concentrations and
IQ. The effect of concurrent blood lead on IQ may
therefore be greater than currently believed. Authors
conclude that these data support the idea that lead exposure
continues to be toxic to children as they reach school age,
and does not lend support to the interpretation that
majority of the damage is done by the time the child
reaches 2 to 3 years of age.
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Table AX6-3.1 (cont'd). Prospective Longitudinal Cohort Studies of Neurocognitive Ability in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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6
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H
O
O
H
W
O
O
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W
Europe
Wasserman et al. (1992,
1994, 2003); Factor-
Litvaketal. (1999)
Yugoslavia
Birth cohort of approximately 300-400 infants
followed since birth residing in two towns in
Kosovo, Yugoslavia, one group near a
longstanding lead smelter and battery
manufacturing facility and another in a relatively
unexposed location 25 miles away. Intellectual
status was monitored from 2 to 10-12 years of age
with the Bay ley Scales of Infant Development,
McCarthy Scales of Children's Abilities, and
WISCIII. Extensive assessment of medical and
sociodemographic covariates.
Maternal prenatal, umbilical
cord and serial postnatal blood
lead
Maternal blood lead in:
exposed area 19.9 (SD 7.7)
ug/dL, unexposed area 5.6
(SD 2.0) ug/dL
Umbilical cord blood lead in:
exposed area 22.2 (SD 8.1)
ug/dL, unexposed area 5.5
(SD 3.3) ug/dL
Blood lead at 2 years in:
exposed area 35.4 ug/dL,
unexposed area 8.5 ug/dL
Rise in postnatal blood lead from 10 to 30 ug/dL at two
years of age associated with a covariate-adjusted decline of
2.5 points in Bay ley MDI. Maternal and cord blood lead
not consistently associated with Bayley outcomes. Higher
prenatal and cord blood lead concentrations associated
with lower McCarthy General Cognitive Index (GCI)
scores at 4 years. Scores on the Perceptual-Performance
subscale particularly affected. After covariate-adjustment,
children of mothers with prenatal blood lead levels >20
ug/dL scored a full standard deviation below children in
the lowest exposure group (<5 ug/dL prenatal blood lead).
Postnatal blood lead also associated with poorer
performance. Increase in blood lead level from 10-25
ug/dL was associated with a reduction of 3.8 points in GCI
after covariate-adjustment. Effects even more pronounced
on the Perceptual-Performance subscale. At 7 years,
significant inverse associations between lifetime average
blood lead and WISCIII IQ were observed, with
consistently stronger associations with Performance IQ and
later blood lead measures. Adjusted intellectual loss
associated with an increase in lifetime average blood lead
from 10-30 ug/dL was over 4 points in WISCIII Full-Scale
and Performance IQ. At 10-12 years, subjects were again
assessed with the WISCIII. Following covariate-
adjustment, average lifetime blood lead was associated
with all components of the WISCIII with effect sizes
similar to those observed at 7 years. In most instances,
bone lead-IQ relationships were stronger than those for
blood lead among subjects residing near the lead smelter.
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Table AX6-3.1 (cont'd). Prospective Longitudinal Cohort Studies of Neurocognitive Ability in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
oo
H
6
o
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H
O
O
H
W
O
O
HH
H
W
Latin America
Schnaas et al. (2000)
Mexico
Gomaa et al. (2002)
Mexico
112 children followed since birth with complete
psychometric data from the Mexico City
Prospective Study were examined. Intellectual
status was indexed with the General Cognitive
Index (GCI) from the McCarthy Scales of
Children's Abilities (MSCA). Purpose of the study
was to determine if the magnitude of the effect of
postnatal blood lead levels on cognition varies with
the time between blood lead and cognitive
assessments.
197 two year-olds residing in Mexico City
followed since birth. The Bay ley Scales of Infant
Development Mental Development Index (MDI)
was used to index intellectual status. Extensive
assessment of medical and sociodemographic
covariates.
Serial postnatal blood lead
Average blood lead
24-36 months 9.7
(range 3-48) ug/dL.
Umbilical cord and serial
postnatal blood lead
Umbilical cord blood
lead 6.7
(SD 3.4) ug/dL
Blood lead at 2 years 8.4
(SD 4.6) ug/dL.
Maternal tibial and patellar
bone lead
Patellar (trabecular)
bone lead
17.9 (SD 15.2) ug/g
A number of significant interactions observed between
blood lead levels and age of assessment. Greatest effect
observed at 48 months where a 5.8 deficit in adjusted GCI
scores was observed for each natural log increment in
blood lead. Authors concluded that four to five years of
age appears to be a critical period for the manifestation of
earlier postnatal blood lead level effects on cognition.
Umbilical cord blood lead and patellar (trabecular) bone
lead were significantly associated with lower scores on the
Bayley MDI. Maternal trabecular bone lead levels
predicted poorer sensorimotor functioning at two years
independent of the concentration of lead measured in cord
blood. Increase in cord blood lead level from 5-10 ug/dL
was associated with a 3.1 point decrement in adjusted MDI
scores. In relation to lowest quartile of trabecular bone
lead, the second, third, and fourth quartiles were associated
with 5.4, 7.2, and 6.5 decrement in MDI following
covariate adjustment. Authors concluded that higher
maternal trabecular bone lead concentrations constitute an
independent risk factor for impaired mental development
in infancy, likely due to the mobilization of maternal bone
lead stores over gestation.
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Table AX6-3.1 (cont'd). Prospective Longitudinal Cohort Studies of Neurocognitive Ability in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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Australia
Baghurstetal. (1992);
McMichael et al.
(1994); long etal.
(1996)
Australia
400-500 subjects residing in and near Port Pirie,
Australia and followed since birth were re-evaluated
at 7 to 8 and 11-13 years of age. WISCR was used
to index intellectual status at both ages. Extensive
assessment of medical and sociodemographic
covariates.
Cooney etal. (1991)
Australia
175 subjects from the Sydney, Australia Prospective
Study were assessed at 7 years of age. The WISCR
was used to index intellectual status. Extensive
assessment of medical and sociodemographic
characteristics.
Maternal prenatal, umbilical
cord and serial postnatal blood
lead
Antenatal average blood lead
10.1 (SD 3.9) ug/dL
Umbilical cord blood lead
9.4 (SD 3.9) ug/dL
Blood lead at 2 years
geometric mean 21.3
(SD 1.2) ug/dL
Deciduous central incisor
whole tooth lead
Tooth lead geometric 8.8
(SD1.9)ug/g
Maternal and cord blood lead
Cord blood lead 8.4 ug/dL
(SD not given)
Blood lead at 2 year 15.8
ug/dL (SD not given)
Significant decrements in covariate-adjusted full scale IQ
were observed in relationship to postnatal blood lead levels
at both ages. At seven to eight years a loss of 5.3 points
was associated with an increase in blood lead from 10 to
30 ug/dL. At 11-13 years mean full scale IQ declined by
3.0 points for an increase in lifetime average blood lead
concentrations from 10 to 20 ug/dL. Lead levels in central
upper incisors were also associated with lower 7-8 year IQ
following covariate adjustment. Adjusted estimated
decline in IQ across the range of tooth lead from 3 to
22 ppm was 5.1 points.
Blood indices of lead exposure were not associated with
any measure of psychometric intelligence. Authors
conclude that the evidence from their study indicates that if
developmental deficits do occur at blood lead levels
<25 ug/dL, the effect size is likely to be small (<5%).
Sydney results are difficult to interpret from the statistical
presentation in their report. It is not clear which covariates
were entered into regression analyses nor is the empirical
or substantive basis for their conclusion.
Asia
Shenetal. (1998)
China
Pregnant women and newborns in Shanghai, China
recruited from health care facilities in the community
on the basis of cord blood lead concentration
percentiles (30th and 70th) yielding a total N of 173
subjects. TheBayley Scales of Infant Development
Mental Development Index (MDI) and Psychomotor
Development Index (PDI) were used to index
sensorimotor/intellectual status at 3, 6, and 12
months. Extensive assessment of medical and
sociodemographic characteristics.
Cord blood lead
Cord blood lead "high
group" 13.4 (SD 2.0) ug/dL
"low group" 5.3 (SD 1.4)
ug/dL
Blood lead at 1 year
"high group" 14.9
(SD 8.7) ug/dL
"low group" 14.4
(SD 7.7) ug/dL
At all ages the Bayley MDI was associated with cord
blood lead groupings following adjustment for covariates.
Postnatal blood lead unrelated to any Bayley measures.
Differences in MDI between prenatal blood lead exposure
groupings generally in accord with similar investigations
in Boston, Cincinnati, and Cleveland. Authors conclude
that the adverse effects of prenatal lead exposure are
readily discernible and stable over the first year of life.
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Table AX6-3.2. Meta- and Pooled-Analyses of Neurocognitive Ability in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
H
6
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O
O
H
W
O
O
HH
H
W
United States
Lanphear et al. (2005)
International
Needleman and
Gatsonis(1990)
International
Schwartz (1994)
International
Pooled analysis of seven international prospective
studies involving 1,333 school-age children.
Primary outcome measure was full-scale IQ as
assessed by age-appropriate Wechsler scale.
Measures of exposure were concurrent, peak,
average lifetime and "early" blood lead (i.e. mean
blood lead from 6-24 months). Cord blood lead was
also investigated for those studies that collected
these samples at birth. Multivariate regression
models were developed adjusting for site as well as
10 common covariates. Blood lead measure with the
largest adjusted R2 was nominated a priori as the
preferred index related lead exposure to IQ in
subsequent analyses. Results evaluated by applying
a random-effects model.
Meta analysis of 12 studies chosen on the basis of
quality—covariate assessment and application of
multiple regression techniques. Studies weighted on
basis of sample size. Studies divided according to
tissue analyzed (blood or teeth). Joint p-values and
average effect sizes calculated using two different
methods.
Meta analysis of 7 recent studies relating blood lead
to IQ were reviewed, three longitudinal and four
cross-sectional. Measure of effect was estimated
decrease in IQ for an increase in blood lead from
10-20 ug/dL. Studies were weighted by the inverse
of the variances using random
Umbilical cord blood lead
Serial postnatal blood lead
Lifetime average blood lead
12.4 (range 4.1-34.8) ug/dL
Blood lead
Tooth lead
Blood lead
Concurrent blood lead level exhibited the strongest
relationship with IQ, although results of regression analyses
for all blood lead variables were similar. Steepest declines
in IQ were at blood lead concentrations below 10 ug/dL.
For the entire pooled data set, a decline of 6.2 IQ points
(95% CI: 3.8-8.6) was observed for an increase in blood
lead from 1-10 ug/dL.
Joint p-values for blood lead studies were <0.0001 for both
methods while for teeth joint p-values of <0.0006 and
<0.004 were obtained. Partial correlations ranged from -
0.27 to -0.0003. No single study was responsible for the
significance of the final findings. Authors concluded that
the hypothesis that lead lowers children's IQ at relatively
low dose is strongly supported by results of this quantitative
review.
Estimated decrease in IQ for increase in blood lead from
10-20 ug/dL was -2.6 points (SE 0.41). Results were not
determined by any individual study. Effect estimates
similar for longitudinal and cross-sectional studies.
For studies with mean blood lead concentrations below
15 ug/dL estimated effect sizes were larger. When the
study with the lowest exposures was examined alone using
nonparametric smoothing (Boston), no evidence of a
threshold was observed down to a blood lead level of
1 ug/dL. Author concludes that these data provide further
evidence of lead effects on cognition at levels below
10 ug/dL.
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Table AX6-3.2 (cont'd). Meta- and Pooled-Analyses of Neurocognitive Ability in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
United States (cont'd)
Pococketal. (1994)
International
Meta-analysis of five prospective and fourteen cross-
sectional studies (including tooth and blood tissues)
were included. The fixed effect method of
Thompson and Pocock (1992) was employed.
Only blood lead at or near two years of age was
considered for the prospective studies.
Blood lead
Tooth lead
Overall conclusion was that a doubling of blood lead levels
from 10-20 ug/dL, or tooth lead from 5-10 ug/g was
associated with an average estimated deficit in IQ of
around 1-2 points. Authors caution interpretation of these
results and lead literature in general citing questions
surrounding the representativeness of the samples, residual
confounding, selection bias, and reverse causality.
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Table AX6-3.3. Cross-sectional Studies of Neurocognitive Ability in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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O
O
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W
O
O
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W
United States
Lanphear et al. (2000)
U.S.
Emory et al. (2003)
U.S.
Chiodo et al. (2004)
U.S.
4,853 US children ages six to 16 years enrolled in
NHANES-III. Two subtests of the WISC-R (Block
Design and Digit Span) used to assess intellectual
status. Medical and sociodemographic covariates were
assessed
77 healthy, lower-risk African-American infants age 7
months. The Fagan Test of Infant Intelligence (FTII)
was administered to assess intellectual status. Birth
weight and gestational age examined as potential
covariates/confounders.
237 African-American inner-city children assessed at
7.5 years of age. Cohort was derived from a larger
study of the effects of prenatal ETOH exposure on
child development. 83% of children in lead study had
little or no gestational exposure to ETOH. WISC-III
was administered to assess intellectual status. Medical
and sociodemographic covariates were assessed.
Blood lead at time of testing
Geometric blood Lead 1.9
(SE 0.1) ug/dL 2.1%
with blood lead > 10 ug/dL
Maternal blood lead
Blood lead 0.72
(SD 0.86) ug/dL
Blood lead at time of testing
Blood lead 5.4
(SD 3.3) ug/dL
Multivariate analyses revealed a significant association
between blood lead levels and both WISC-R subtests.
Associations remained statistically significant when
analyses were restricted to children with blood lead levels
below 10 ug/dL. Authors caution that lack of control for
parental intelligence and variables like the HOME scale
should temper any conclusions regarding observed effects.
Infants scoring in the upper 5th to 15th percentiles for the
FTII had mother with significantly lower maternal blood
lead levels when compared to those scoring in the lower
5th or 15th percentile. Findings of this study should be
considered preliminary due to small sample size and lack
of covariate assessment or control.
Following covariate adjustment statistically significant
relationships between blood lead and full-scale, verbal and
performance IQ were observed. Significant effects of lead
on full-scale and performance IQ was evident at blood lead
concentrations below 7.5 ug/dL.
Europe
Walkowiak et al.
(1998)
Germany
Prpic-Majic et al.
(2000)
Croatia
384 six-year-old children in three German cities. Two
subtests of the WISC (Vocabulary and Block Design)
used to estimate IQ. Both subscales were combined to
form a "WISC Index." Medical and sociodemographic
covariate covariates were assessed.
275 third and fourth grade students in Zagreb, Croatia.
WISC-R was administered to assess intellectual status.
Covariate factors limited to parents' educational status
and gender of child.
Blood lead at time of testing
Blood lead 4.2 ug/dL
95th percentile 8.9 ug/dL
Blood lead at time of testing
Blood lead 7.1
(SD 1.8) ug/dL
Following covariate-adjustment, WISC Vocabulary was
significantly associated with blood lead but combined
WISC index was borderline. Authors conclude that
findings roughly correspond with those of other studies
that find effects below 10 ug/dL but caution that
potentially important covariates such as HOME scores
were not controlled.
Following covariate adjustment, no statistically significant
associations were observed for lead or other indicators of
toxicity (ALAD, EP) on WISC-R. Authors argue that
study had sufficient power and that the "no-effect"
threshold for lead must be in the upper part or above the
study's range of exposures.
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Table AX6-3.3 (cont'd). Cross-sectional Studies of Neurocognitive Ability in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Latin America
Kordas et al. (2004)
Mexico
Counter etal. (1998)
Ecuador
602 first grade children in public schools in a highly
industrialized area of northern Mexico. Premise of
study was that effects of lead could be explained by
correlated nutritional factors such as iron status,
anemia, and growth. Peabody Picture Vocabulary
Test-Revised (PPVT-R), Cognitive Abilities Test
(CAT), and an abbreviated form of the WISC-R were
administered to assess intellectual status. Medical and
sociodemographic covariates were assessed.
77 chronically lead-exposed children living in
Ecuadorian villages where lead is used extensively in
commercial ceramics production. Ravens Colored
Progressive Matrices (RCPM) used to index
intellectual status. Only half of the sample was
assessed. No assessment of medical or
sociodemographic covariates.
Blood lead at time of testing
Blood lead 11.5
(SD 6.1) ug/dL
Blood lead at time of testing
Blood lead 47.4
(SD 22) ug/dL
Following covariate adjustment blood lead levels were
significantly associated with poorer performance on the
PPVT-R, WISC-R Coding, and Number and Letter
Sequencing. Authors concluded that lead's association
with iron deficiency anemia or growth retardation could
not explain relationship between lead and cognitive
performance. Authors acknowledge study's limitations in
that parental intelligence and quality of caretaking in home
were not directly assessed as potentially confounding
variables.
Simple regression analysis revealed a correlation between
blood lead and RCMP of only borderline significance.
Results difficult to interpret because there was no attempt
to age-adjust. When analysis restricted to children 9-11
years of age, a highly significant negative correlation was
obtained. Study has little relevance to the question of lead
hazards in the US because of unusually high levels of
exposure.
H
6
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H
W
O
O
HH
H
W
Asia
Rabinowitz et al.
(1991)
Taiwan
Bellinger et al. (2005)
India
443 children in grades one to three in Taipei City and
three schools near lead smelters. Ravens Colored
Progressive Matrices (RCMP) used to index
intellectual status. Medical and sociodemographic
covariate factors were assessed.
74 four to fourteen year-old children residing in
Chennai, India were enrolled in the study, 31 of which
were assessed with the Binet-Kamath Intelligence test.
Data were collected on sociodemographic features of
subjects' families.
Dentin tooth lead
Taipei City 4.3
(SD 3.7) ug/g
Smelter areas 6.3
(SD 3.3) ug/g
Blood lead at time of testing
Blood lead 11.1
(SD 5.6) ug/dL
Scores on the RCMP were negatively correlated with tooth
lead concentrations. In multivariate analyses, parental
education was the most important predictor of RCMP
scores, but tooth lead concentrations still significantly
predicted lower scores in females residing in low-income
families.
Covariate-adjusted blood lead coefficient was negative but
nonsignificant, perhaps due to small sample size and
highly variable performance of subjects with the least
elevated blood lead concentrations.
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Table AX6-3.4. Effects of Lead on Academic Achievement in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
H
6
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H
O
O
H
W
O
O
HH
H
W
United States
Lanphear et al. (2000)
U.S.
Design: Cross-sectional. 4,853 US children ages six
to 16 years enrolled in NHANES-III. Subjects were
administered the Arithmetic and Reading subtests of
the Wide Range Achievement Test-Revised
(WRATR). A number of medical and
sociodemographic covariates were assessed and
entered into multivariable models.
Blood lead at time of testing
Geometric blood lead 1.9
(SE0.1)ng/dL. 2.1%
with blood lead > 10 ng/dL
Following covariate adjustment, a statistically significant
relationship between blood lead and WRATR performance
was found. A 0.70 point decrement in Arithmetic scores
and a 1 point decrement in Reading scores for each 1
Hg/dL increase in blood lead concentration was observed.
Statistically significant inverse relationships between blood
lead levels and performance for both Reading and
Arithmetic subtests were found for children with blood
lead concentrations < 5 ng/dL. Authors concluded that
results of these analyses suggest that deficits in academic
skills are associated with blood lead concentrations lower
than 5 ng/dL. They cautioned, however, that two
covariates that have been shown to be important in other
lead studies (i.e., parental IQ and HOME scores) were not
available. This may have over or under estimated deficits
in academic skills related to lead. They further caution
that, as with all cross-sectional studies utilizing blood lead
as the index of dose it is not clear whether deficits in
academic skills were due to lead exposure that occurred
sometime during early childhood or due to concurrent
exposure. Nevertheless, concurrent blood lead levels
reflect both ongoing exposure and preexisting body
burden.
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Table AX6-3.4 (cont'd). Effects of Lead on Academic Achievement in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
H
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O
O
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W
O
O
HH
H
W
United States (cont'd)
Needleman et al. (1990)
U.S.
Bellinger etal. (1992)
U.S.
Levitonetal. (1993)
U.S.
Design: Prospective cohort. Re-examination of the
Chelsea and Somerville cohort recruited in the
1970's (Needleman et al., 1979). 132 adolescents
were recalled. Large battery of tests was
administered to examine neurobehavioral deficits
and academic achievement in high school and shortly
following graduation. Extensive assessment of
medical and sociodemographic covariates.
Design: Prospective longitudinal. 148 children in
the Boston Lead Study cohort were examined at
10 years of age. The short-form of the Kaufman Test
of Educational Achievement (KTEA) was used to
assess academic achievement. Primary outcome was
the Battery Composite Score. Extensive assessment
of medical and sociodemographic covariates.
Design: Prospective cohort. Teachers of
approximately 2000 eight year-old children born in
1 hospital in Boston between 1979 and 1980 filled
out the Boston Teachers Questionnaire (BTQ) to
assess academic performance and behavior. Limited
information is provided on the assessment of
covariate factors but a number were considered and
controlled for in multivariable analyses.
Tooth (dentin) lead
Tooth lead median
8.2 ug/g
Cord and serial postnatal
blood lead assessments.
Cord blood lead grouping
<3, 6-7, >10 ug/dL.
Blood lead at 2 years 6.5
(SD 4.9) ug/dL
Cord blood lead
Cord blood lead 6.8 ug/dL
Tooth (dentin) lead
Tooth lead 2.8 ug/g
Subjects with dentin lead levels >20 ppm were at higher
risk of dropping out of high school (adjusted OR = 5.8,
95% CI: 1.4-40.7) and of having a reading disability
(adjusted OR: 5.8, 95% CI: 1.7-19.7). Higher dentin lead
levels were also significantly associated with lower class
standing, increased absenteeism, and lower vocabulary and
grammatical reasoning scores on the Neurobehavioral
Evaluation System (NES). Authors conclude that undue
exposure to lead has enduring and important effects on
objective parameters of success in life.
After covariate-adjustment, blood lead levels at 24 months
were significantly predictive of lower academic
achievement ((3 = -0.51, SE 0.20). Battery Composite
Scores declined by 8.9 points for each 10 ug/dL increase in
blood lead. This association was significant after
adjustment for IQ. Authors conclude that lead-sensitive
neuropsychological processing and learning factors not
reflected in measures of global intelligence may contribute
to deficits in academic achievement.
Following adjustment for potential confounding variables,
elevated dentin lead concentrations were associated with
statistically significant reading and spelling difficulties as
assessed by the BTQ among girls in the sample. Authors
conclude that their findings support the case for lead-
associated learning problems at levels that were prevalent
at that time in the general population. However, authors
add that the inability to assess child-rearing quality in this
study conducted by mail limits the inferences that can be
drawn.
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Table AX6-3.4 (cont'd). Effects of Lead on Academic Achievement in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
(^
Oi
Australia
Fergusson et al. (1993,
1997); Fergusson and
Horwood(1993)
New Zealand
Design: Prospective cohort. Academic performance
was examined in a birth cohort of 1200 New Zealand
children enrolled in the Christchurch Health and
Development Study. Measures of academic
performance at 12-13 years included the Brut
Reading Test, Progressive Achievement Test, Test of
Scholastic Abilities, and teacher ratings of classroom
performance in the areas of reading, writing, and
mathematics. The growth of word recognition skills
from 8 to 12 years was also examined using growth
curve modeling methods. Academic achievement in
relationship to lead was re-examined in this cohort at
18 years. Measures of academic achievement
included the Burt Reading Test, number of years of
secondary education, number of certificates passed
(based on national examinations), and leaving school
without formal qualifications (failing to graduate).
Extensive assessment of medical and social
covariates.
Tooth (dentin) lead
Tooth lead 6.2
(SD 6.2) ug/g
Following covariate adjustment, dentin lead levels were
significantly associated with virtually every formal index
of academic skills and teacher ratings of classroom
performance in 12-13 year-olds. After adjustment for
covariates, tooth lead levels greater than 8 ug/g were
associated with significantly slow growth in word
recognition abilities with no evidence of catch up.
At 18 years, tooth lead levels were significantly associated
with lower reading test scores, having a reading level of
less than 12 years, failing to complete three years of high
school, leaving school without qualifications, and mean
number of School Certificates passed. Authors conclude
that early exposure to lead is independently associated with
detectable and enduring deficits in children's academic
abilities. They further conclude that their findings are
particularly significant in that they confirm the findings of
Needleman (1990), albeit in a cohort with lower levels of
exposure to environmental lead.
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Table AX6-3.4 (cont'd). Effects of Lead on Academic Achievement in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia
Wang et al. (2002)
Taiwan
Rabinowitz et al. (1992)
Taiwan
Design: Cross-sectional. 934 third graders living in
an urban industrial area of Taiwan. Outcome
variables were grades for Chinese (reading, writing),
mathematics, history, and natural science. Grades
were converted into individual class rankings to
avoid teacher bias. Limited data on medical and
sociodemographic covariates.
Design: Cross-sectional. Teachers of 493 children
in grades 1-3 filled out the Boston Teachers
Questionnaire (BTQ) to assess academic
performance and behavior. Sociodemographic and
medical covariate factors were assessed.
Blood lead at time of
evaluation
Blood lead 5.5
(SD1.9)ug/dL
Tooth (dentin) lead
Tooth lead 4.6
(SD 3.5) ug/g
Following covariate adjustment, blood lead was
significantly associated with lower class ranking in all
academic subjects. Major shortcoming of this study is lack
of control for potentially important covariates such as
parental IQ. However, the relatively low levels of
exposure in this sample and strength and consistency of the
reported relationships suggest that lead may be playing
some role in lowering academic performance.
Prior to adjustment for covariates, girls with higher
exposures to lead evinced a borderline significant trend for
reading difficulties while byes displayed significantly
increased difficulties with respect to activity levels and
task attentiveness. In logistic regression models that
include significant covariate factors, the tooth lead terms
failed to achieve statistical significance. Authors conclude
that lead levels found in the teeth of children in this
Taiwanese sample are not associated with learning
problems as assessed by the BTQ.
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Table AX6-3.5. Effects of Lead on Specific Cognitive Abilities in Children — Attention/Executive Functions, Learning, and
Visual-Spatial Skills
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States
Bellinger etal. (1994)
U.S.
Stiles and Bellinger
(1993) U.S.
Canfield et al. (2003,
2004)
U.S.
Design: Prospective cohort. 79 subjects from the
original Chelsea and Somerville, MA lead study
were re-evaluated at 19-20 years of age with the
Mirsky battery of attentional measures. Extensive
measures of medical and sociodemographic
covariates.
Design: Prospective longitudinal. 148 subjects from
the Boston Lead Study were re-evaluated at 10 years
of age with an extensive neuropsychological battery.
Tests included the California Verbal Learning Test,
Wisconsin Card Sorting Test, Test of Visual-Motor
Integration, Rey-Osterieth Complex Figure, Story
Recall, Finger Tapping, and Grooved Pegboard.
Extensive measures of medical and
sociodemographic covariates.
Design: Prospective longitudinal. 170-174 children
from the Rochester Lead Study were administered a
number of learning and neuropsychological
functioning at 48, 54, and 66 months of age. At 48
and 54 months the Espy Shape School Task was
administered while at 66 months the Working
Memory and Planning assessment protocols of the
Cambridge Neuropsychological Test Automated
Battery (CANTAB) was given. Extensive measures
on medical and sociodemographic covariates.
Tooth (dentin) lead
Tooth lead 13.7
(SD11.2 ug/g)
KXRF Bone lead
Tibial bone lead
(range <1 ->10 ug/g)
Patellar bone lead
(range <1 -> 15 ug/g)
Cord and serial postnatal
blood lead assessments.
Cord blood lead grouping
<3, 6-7, >10 ug/dL.
Blood lead at 2 years 6.5
(SD 4.9) ug/dL
Serial postnatal blood lead
Blood lead at 2 years
9.7 ug/dL
Lifetime average blood
lead 7.2 ug/dL
(range 0-20 ug/dL)
Higher tooth lead concentrations were significantly
associated with poorer scores on the Focus-Execute and
Shift factors of the Mirsky battery. Few significant
associations were observed between bone lead levels and
performance. Authors conclude that early lead exposure
may be associated with poorer performance on
executive/regulatory functions, which are thought to
depend on the frontal or prefrontal regions of the brain.
Authors point out that the number of significant
associations was about equal to those that would be
expected by chance. However, tasks that assess attentional
behaviors and executive functions tended to among those
for which lead was a significant predictor of performance.
Following covariate adjustment, higher blood lead
concentrations at two year were significantly associated
with lower scores on Freedom from Distractibility factor of
the Wechsler scales, increase in percentage of
perseverative errors on the Wisconsin Card Sorting Test
and the California Verbal Learning Test.
Following covariate adjustment, blood lead level at
48 months was negatively associated with children's
focused attention while performing the Shape School
Tasks, efficiency at naming colors, and inhibition of
automatic responding. Children with higher blood lead
concentrations also completed fewer phases of the Espy
tasks and knew fewer color and shape names. On the
CANTAB battery, children with higher lifetime average
blood lead levels showed impaired performance on spatial
working memory, spatial memory span, and cognitive
flexibility and planning. Authors conclude that the effects
of pediatric lead exposure are not restricted to global
measures of intellectual functioning and executive
processes may be at particular risk.
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Table AX6-3.5 (cont'd). Effects of Lead on Specific Cognitive Abilities in Children — Attention/Executive Functions,
Learning, and Visual-Spatial Skills
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
vo
United States (cont'd)
Ris et al. (2005)
U.S.
Design: Prospective longitudinal. 195 subjects from
the Cincinnati Lead Study were administered an
extensive and comprehensive neuropsychological
battery at 16-17 years of age. Domains assessed
included Executive Functions, Attention, Memory,
Achievement, Verbal Skills, Visuoconstructional,
and Fine Motor. Factor scores transformed to ranks
derived from a principal components factor analysis
of the neuropsychological test scores were the
primary outcome variables. Extensive measures on
medical and sociodemographic covariates.
Prenatal (maternal) and
serial postnatal blood lead
assessments.
Prenatal blood lead 8.3
(SD 3.7) ug/dL
Blood lead at 2 years 17.4
(SD 8.8) ug/dL
Following covariate adjustment, strongest associations
between lead exposure and performance were observed for
factor scores derived from the Attention component, which
included high loadings on variables from the Conners
Continuous Performance Test. This relationship was
strongest in males. Authors speculate that since the
incidence of Attention Deficit/Hyperactivity Disorder is
greater in males in general, early exposure to lead may
exacerbate a latent potential for such problems.
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Table AX6-3.6. Effects of Lead on Disturbances in Behavior, Mood, and Social Conduct in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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United States
Sciarillo et al. (1992)
U.S.
Bellinger etal. (1994)
U.S.
Demo (1990)
U.S.
Design: Cross-sectional. 150 2-5 year-old children
in Baltimore separated into "high" (2 consecutive
blood lead levels >15 ug/dL) and "low" groups.
Mothers filled out the Achenbach Child Behavior
Checklist (CBCL). The Center for Epidemiologic
Studies Depression Scale (CESD) was administered
to mothers as a control measure.
Design: Prospective cohort: 1782 children bom
within a 1-year period at a single Boston hospital
were examined at 8 years of age. Teachers filled out
the Achenbach Child Behavior Profile (ACBP).
Medical and sociodemographic characteristics
assessed by questionnaire and chart review.
Design: Prospective cohort. Survey of 987
Philadelphia African-American youths enrolled in
the Collaborative Perinatal Project. Data available
from birth through 22 years of age. Analysis
considered 100 predictors of violent and chronic
delinquent behavior.
Screening Blood leads at
various times before
assessment.
Blood lead high group 28.6
(SD 9.3) ug/dL, blood
lead low group 11.3
(SD 4.3) ug/dL
Umbilical cord blood lead
Cord blood lead 6.8
(SD 3.1) ug/dL
Tooth (dentin) lead 3.4
(SD2.4)ug/g
Blood lead
Values not provided
When compared to lower exposed group, children in the
high group had a significantly higher CBCL Total
Behavior Problems Score (TBPS) and Internalizing and
Externalizing scores. After adjustment for maternal
depression, blood lead concentrations were still
significantly associated with an increase in the TBPS.
Children in high group were nearly 3 times more likely to
have a TBPS in the clinical range. A significantly higher
percentage of children in the high group scored in the
clinical range for CBCL subscales measuring aggressive
and destructive behavioral tendencies.
Cord blood lead levels were not associated with the
prevalence or nature of behavioral problems reported by
teachers. Tooth lead levels were significantly associated
with ACBP Total Problem Behavior Scores (TPBS).
Statistically significant tooth lead-associated increases in
both Externalizing and Internalizing scores were observed.
Each log unit increase in tooth lead was associated with a
1.5-point increase in T scores for these scales. Authors
caution that residual confounding cannot be ruled out
because of the lack of information on parental
psychopathology or observations of the family
environment. However, these results are in accord with
other studies that social and emotional dysfunction may be
an important expression of elevated lead levels during
early childhood.
Repeat offenders presented consistent features such as low
maternal education, prolonged male-provider
unemployment, frequent moves, and higher lead
intoxication. In male subjects, a history of lead poisoning
was among the most significant predictors of delinquency
and adult criminality.
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Table AX6-3.6 (cont'd). Effects of Lead on Disturbances in Behavior, Mood, and Social Conduct in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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United States (cont'd)
Needleman et al.
(1996)
U.S.
Dietrich et al. (2001)
U.S.
Needleman et al.
(2000)
U.S.
Design: Prospective cohort. 850 boys enrolled in the
Pittsburgh Youth Study were prescreened to assess
delinquent behavioral tendencies. Subjects who
scored in the 30th percentile on the risk score and an
equal number randomly selected from the remainder
form the sample of 530 subjects. Measures of
antisocial behavior were administered at 7 and 11
years of age including the Self Reported Antisocial
Behavior scale (SRA), Self Report of Delinquent
Behavior (SRD), and parents' and teachers' versions
of the Achenbach Child Behavior Profile (CBCL).
Extensive assessment of medical and
sociodemographic covariates.
Design: Prospective longitudinal. 195 subjects from
the Cincinnati Lead Study were examined at 16-17
years of age. Parents were administered a
questionnaire developed specifically for the study
while CLS subjects were given the Self Report of
Delinquent Behavior. Extensive assessment of
medical and sociodemographic covariates.
Design: Case-control. 194 adjudicated delinquents
and 146 non-delinquent controls recruited from high
schools in the City of Pittsburgh and Allegheny
County, PA. Covariate assessments were not
extensive but did include race, parental
sociodemographic factors, and neighborhood crime
rates.
Bone lead by K-XRF
Bone lead (exact
concentrations not reported)
Negative values treated
categorically as 1 and
positive values grouped into
quintiles.
Prenatal (maternal) and
serial postnatal blood lead
assessments.
Prenatal blood lead 8.3
(SD 3.7) ug/dL
Blood lead at 2 years 17.4
(SD 8.8) ug/dL
Bone lead by KXRF
Bone lead Cases 11.0
(SD 32.7 ug/g),
Controls 1.5
(SD 32.1 ug/g)
Following covariate-adjustment, parents of subjects with
higher lead levels in bone reported significantly more
somatic complaints, more delinquent and aggressive
behavior, and higher Internalizing and Externalizing
scores. Teachers reported significant increase in scores on
somatic complaints, anxious/depressed, social problems,
attention problems, delinquent behavior, aggressive
behavior, internalizing and externalizing problems in the
higher bone lead subjects. At 11 years, subject's SRD
scores were also significantly related to bone lead levels.
More high lead subjects had CBCL T scores in the clinical
range for attention, aggression, and delinquency. Authors
conclude that lead exposure is associated with increased
risk for antisocial and delinquent behavior.
Prenatal (maternal) blood lead was significantly associated
with a covariate-adjusted increase in the frequency of
parent-reported delinquent and antisocial acts. Prenatal
and measures of postnatal lead exposure were significantly
associated with self-reported delinquent and antisocial
behaviors. Authors concluded that lead might play a
measurable role in the development of behavioral problems
in inner-city children independent of other important social
and biomedical cofactors.
Cases had significantly higher average concentrations of
lead in tibia than controls. Following covariate adjustment,
adjudicated delinquents were 4 times more likely to have
bone lead concentration >25 ug/g then controls. Bone lead
level was the second strongest factor in the logistic
regression models, exceeded only by race. In models
stratified by race, bone lead was exceeded as a risk factor
only by single parent status. Authors conclude that
elevated body lead burdens are associated with increased
risk for adjudicated delinquency.
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Table AX6-3.6 (cont'd). Effects of Lead on Disturbances in Behavior, Mood, and Social Conduct in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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ON
to
Europe
Wasserman et al.
(1993)
Yugoslavia
Design: Prospective longitudinal. Birth cohort of
approximately 300-400 infants followed since birth
residing in two towns in Kosovo, Yugoslavia, one
group near a longstanding lead smelter and battery
manufacturing facility and another in a relatively
unexposed location 25 miles away. 379 children at
3 years of age were examined. Parents were
interviewed with the Achenbach Child Behavior
Checklist (CBCL). Extensive assessment of medical
and sociodemographic covariates.
Maternal prenatal, umbilical
cord and serial postnatal
blood lead
Maternal blood lead in:
exposed area 19.9 (SD 7.7)
ug/dL, unexposed area 5.6
(SD 2.0) ug/dL
Umbilical cord blood lead
in: exposed area 22.2 (SD
8.1) ug/dL, unexposed area
5.5 (SD 3.3) ug/dL.
Blood lead at 2 years in:
exposed area 35.4 ug/dL,
unexposed area 8.5 ug/dL.
Following covariate adjustment, concurrent blood lead levels
were associated with increased Destructive Behaviors on the
CBCL subscale, although the variance accounted for by lead
was small compared to sociodemographic factors. As blood
lead increased from 10 to 20 ug/dL, subscale scores
increased by 0.5 points. The authors conclude that while
statistically significant, the contribution of lead to social
behavioral problems in this cohort was small compared to the
effects of correlated social factors.
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Australia
Burns etal. (1999)
Australia
Fergusson et al. (1993)
New Zealand
Design: Prospective longitudinal. 322 subjects
residing in and near Port Pirie, Australia and
followed since birth were re-evaluated at 11-13 years
of age. Parents completed the Achenbach Child
Behavior Checklist. Extensive assessment of
medical and sociodemographic characteristics.
Design: Prospective cohort. 690-891 children ages
12 and 13 years from the Christchurch Child and
Health Study, New Zealand were examined.
Mothers and teachers were asked to respond to a
series of items derived from the Rutter and Conners
parental and teacher questionnaires. Extensive
assessment of sociodemographic and medical
covariates.
Maternal prenatal, umbilical
cord and serial postnatal
blood lead
Antenatal average blood
lead 10.1(SD 3.9) ug/dL
Umbilical cord blood lead
9.4 (SD 3.9) ug/dL
Blood lead at 2 years
geometric mean 21.3
(SD 1.2) ug/dL
Tooth (dentine) lead
Tooth lead
(range 3-12 ug/g)
After adjustment for covariates, regression models revealed
that for an increase in average lifetime blood lead
concentrations from 10 to 30 ug/dL, the Externalizing
behavior problem T score increased by 3.5 points in boys
(95% CI: 1.6, 5.4), but only 1.8 points (95% CI: -0.1, 11.1)
in girls. Internalizing behavior problems were predicted to
rise by 2.1 points (95% CI: 0.0, 4.2) in girls by only 0.8
(95% CI: - 0.9, 2.4) in boys. Authors concluded that lead
exposure is associated with an increase in externalizing
(undercontrolled) behaviors in boys.
Statistically significant dose-effect relationships were
observed between tooth lead levels and the
inattention/restlessness variable at each age. Authors
conclude that this evidence is consistent with the view that
mildly elevated lead levels are associated with small but long
term deficits in attentional behaviors.
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Table AX6-3.7. Effects of Lead on Sensory Acuities in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States
Schwartz and Otto
(1991)
U.S.
Design: Cross-sectional. 3545 subjects 6-19 years old who
participated in the Hispanic Health and Nutrition Examination
Survey. Pure tone audiometric evaluations were performed at
500 Hz, 2000 Hz, and 4000 Hz. Extensive measures on
medical and sociodemographic covariates.
Blood lead at the time of
testing.
Blood lead 50th
percentile
8 ng/dL
Dietrich etal. (1992)
U.S.
Design: Prospective/longitudinal. 215 subjects drawn from
the Cincinnati Lead Study at the age of 5 years. Children were
administered the SCAN-a standardized test of central auditory
processing. Extensive measurement of medical and
sociodemographic covariates
Prenatal (maternal) and
serial postnatal blood lead
assessments.
Prenatal blood lead 8.3
(SD 3.7) ng/dL
Blood lead at 2 years
17.4
(SD 8.8) ng/dL
Following covariate adjustment, higher blood lead
concentrations were associated with an increased risk
of hearing thresholds that were elevated above the
standard reference level at all four frequencies.
Blood lead was also associated higher hearing
threshold when treated as a continuous outcome.
These relationships extended to blood lead levels
below 10 ng/dL. An increase in blood lead from 6 to
18 ng/dL was associated with a 2-dB loss at all
frequencies. Authors conclude that HHANES results
those reported earlier for NHANES-II.
Higher prenatal (maternal), neonatal and postnatal
blood lead concentrations were associated with more
incorrect identification of common monosyllabic
words presented under conditions of muffling.
Following covariate adjustment, average childhood
blood lead level remained significantly associated
with impaired performance on the SCAN subtest.
Authors conclude that lead-related deficits in hearing
and auditory processing may be one plausible
mechanism by which an increased lead burden might
impede a child's learning.
Europe
Osmanetal. (1999)
Poland
Design: Cross-sectional. 155 children 4-14 year-old living in Blood lead at the time
an industrial region of Poland. Pure tone audiometric
evaluations were performed at 500 Hz, 1000 Hz, 2000 Hz,
4000 Hz, 6000Hz, and 8000 Hz. Basic data on medical
history, limited information on sociodemographic covariates
such as family structure and income.
of testing
Blood lead median
7.2 ng/dL
(range 1.9-28 ng/dL)
Higher blood lead concentrations were significantly
associated with increased hearing thresholds at all
frequencies studied. This relationship remained
significant when analyses were limited to subjects
with blood lead levels below 10 ng/dL. Authors
conclude that auditory function in children is
impaired at blood lead concentrations below 10
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Table AX6-3.8. Effects of Lead on Neuromotor Function in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
United States
Dietrich et al. (1993);
Bhattacharya et al.
(1995);Risetal.
(2005)
U.S.
Design: Prospective longitudinal. Relationship
between lead exposure and neuromotor function has
been examined in several studies on the Cincinnati
Lead Study Cohort from 6 to 17 years of age.
At 6 years of age 245 subjects were administered the
Bruininks-Oseretsky Test of Motor Proficiency
(BOTMP); at 6-10 years of age subjects were
assessed for postural instability using a
microprocessor-based strain gauge platform system
and at 16-17 years of age the fine-motor skills of
study subjects were assessed with the grooved
pegboard and linger tapping tasks (part of a
comprehensive neuropsychological battery).
Extensive measurement of medical and
sociodemographic factors.
Prenatal (maternal) and
serial postnatal blood lead
assessments.
Prenatal blood lead 8.3
(SD 3.7) ug/dL
Blood lead at 2 years 17.4
(SD 8.8) ug/dL
Following covariate adjustment, postnatal lead exposure was
significantly associated with poorer scores on BOTMP
measures of bilateral coordination, visual-motor control,
upper-limb speed and dexterity and the Fine Motor
Composite score. Low-level neonatal blood lead
concentrations were also significantly associated with poorer
scores on the aforementioned subtests, as well as measures
of visual-motor control. Postnatal lead exposure was
significantly associated with greater postural instability in 6-
10 year-old subjects and poorer fine-motor coordination
when examined at 16-17 years.
Authors conclude that effects of early lead exposure extend
into a number of dimensions of neuromotor development.
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Europe
Wasserman et al.
(2000)
Yugoslavia
Design: Prospective longitudinal. Birth cohort of
approximately 300-400 infants followed since birth
residing in two towns in Kosovo, Yugoslavia, one
group near a longstanding lead smelter and battery
manufacturing facility and another in a relatively
unexposed location 25 miles away. 283 children at
age 54 months were administered the Beery
Developmental Test of Visual-Motor Integration
(VMI) and the Bruininks-Oseretsky Test of Motor
Proficiency (BOTMP). Extensive measurement of
medical and sociodemographic factors.
Maternal prenatal, umbilical
cord and serial postnatal
blood lead
Maternal blood lead in:
exposed area 19.9 (SD 7.7)
ug/dL, unexposed area
5.6 (SD 2.0) ug/dL
Umbilical cord blood lead
in: exposed area 22.2
(SD 8.1) ug/dL, unexposed
area 5.5
(SD 3.3) ug/dL.
Blood lead at 2 years in:
exposed area 35.4 ug/dL,
unexposed area 8.5 ug/dL.
Following covariate-adjustment, the log average of serial
blood lead assessments to 54 months was associated with
lower Fine Motor Composite and VMI scores. Lead
exposure was unrelated to gross motor performance. With
covariate adjustment, an increase in average blood lead from
10 to 20 ug/dL was associated with a loss of 0.62 and 0.42
points respectively, in Fine Motor Composite and VMI.
Authors noted that other factors such as indicators of greater
stimulation in the home make a larger contribution to motor
development than lead.
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Table AX6-3.9. Effects of Lead on Direct Measures of Brain Anatomical Development and Activity in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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United States
Trope and Lopez
Villegas(1998)
U.S.
Trope etal. (2001) U.S.
Cecil et al. (2005)
U.S.
Design: Case-control. One 10 year-old subject
with history of lead poisoning and unexposed 9
year-old cousin. Magnetic Resonance Imaging
(MRI) and Magnetic Resonance Spectroscopy
(MRS) were used to assess differences in cortical
structures and evidence of neuronal loss. This was
the first study to attempt to determine in vivo
structural and/or metabolic differences in the brain
of a child exposed to lead compared with a healthy
control.
Design: Case-control. 16 subjects with a history of
elevated blood lead levels before 5 years of age and
5 age-matched siblings or cousins were evaluated.
Average age at time of evaluation was 8 years.
Magnetic Resonance Imaging (MRI) and Magnetic
Resonance Spectroscopy (MRS) were used to
assess differences in cortical structures and
evidence of neuronal loss.
Design: Prospective/longitudinal. 48 young adults
ages 20 to 23 years were re-examined. Functional
MRI (fMRI) was used to examine the influence of
childhood lead exposure on language function.
Subjects performed a verb generation/finger-
tapping paradigm. Extensive measurement of
medical and sociodemographic covariates
Blood lead
lead poisoned case
51 ug/dL
at 38 mos.
Unexposed control
not reported.
Blood lead range in lead-
exposed 23 to 65 ug/dL
Controls <10 ug/dL
Blood lead
Average childhood blood
lead 13.9 (SD 6.6 ug/dL
(range 4.8-31.1 ug/dL)
Both children presented with normal volumetric MRI. MRS
revealed a significant alteration in brain metabolites, with a
reduction in N-acetylaspartate:creatine ratio for both gray
and white matter compared to the subject's cousin. Authors
conclude that results suggest neuronal loss related to earlier
lead exposure.
All children had normal MRI examinations, but lead-
exposed subjects exhibited a significant reduction in
N-acetylaspartate:creatine and pohosphocreatine ratios in
frontal gray matter compared to controls. Authors conclude
that lead has an effect on brain metabolites in cortical gray
matter suggestive of neuronal loss.
Higher average childhood blood lead levels was significantly
associated with reduced activation in Broca's area in the left
hemisphere and increased activation in the right temporal
lobe, the homologue of Wemicke'a area in the left
hemisphere. Authors conclude that elevated childhood lead
exposure strongly influences neural substrates of semantic
language function on normal language areas with
concomitant recruitment of contra-lateral regions resulting in
a striking dose-dependent atypical organization of language
function.
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Table AX6-3.9 (cont'd). Effects of Lead on Direct Measures of Brain Anatomical Development and Activity in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Latin America
Rothenberg et al. (2000)
Mexico
Design: Prospective/longitudinal. 113 5-7 year-
old children from the Mexico City Prospective
Study were re-examined. Brain stem auditory
evoked potentials were recorded to assess the
impact of prenatal and postnatal lead exposure on
development of auditory pathways. Results
adjusted for gender and head circumference.
Blood lead
Prenatal (20 wks) 8.1
(SD 4.1) ug/dL
Cord 8.7 (SD 4.3) ug/dL
Postnatal 18 mos. 10.8
(SD 5.2) ug/dL
Prenatal blood lead at 20 weeks was associated with
decreased interpeak intervals. After fitting a nonlinear
model to these data, I-V and III-V interpeak intervals
decreased as blood lead rose from 1 to 8 ug/dL and
increased as blood lead rose from 8 to 30 ug/dL. Increased
blood lead at 12 and 48 months was related to decreased
conduction intervals for I-V and II-V across the entire blood
lead range suggesting pathway length effects.
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Asia
Meng et al. (2005)
China
Design: Case-control. 6 subjects with blood lead
concentrations >27 ug/dL and 6 controls with
blood lead concentrations < 10 ug/dL were
evaluated with Magnetic Resonance Imaging
(MRI) and Magnetic Resonance Spectroscopy to
evaluate structural abnormalities and differences in
N-acetylaspartate, creatine, and choline in frontal
lobes and hippocampus of cases and controls.
Blood lead
Blood lead cases 37.7
(SD 5.7) ug/dL
Blood lead controls 5.4
(SD 1.5) ug/dL
All children presented with normal MRI. Peak values of N-
acetylaspartate, choline, and creatine in all four brain regions
were reduced in lead exposed children relative to controls.
Authors conclude that reduced brain N-acetylaspartate in
cases may be related to decreased neuronal density or loss.
Reduced choline signal may indicate decreased cell
membrane turnover or myelin alterations while lower
creatine may indicate reduced neuronal cell viability.
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Table AX6-3.10. Effects of Lead on Reversibility of Lead-Related Deficits in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States
Ruff etal. (1993)
U.S.
Roganetal. (2001);
Dietrich et al. (2004)
U.S.
Design: Intervention study, non-randomized.
126 children with complete data age 13 to 87
months and with blood lead levels between 25 and
55 ug/dL were given chelation with ETDA and/or
therapeutic iron where indicated. At baseline and
follow-up, patients were evaluated with the Bayley
Scales of Infant Development, Mental
Development Index, or Stanford Binet Scales of
Intelligence depending upon age.
Design: Double blind, placebo-controlled
randomized clinical trial. The Treatment of Lead-
Exposed Children (TLC) clinical trial of 780
children in 4 centers was designed to determine if
children with moderately elevated blood lead
concentrations given succimer would have better
neuropsychological outcomes than children given
placebo. Children between 12 and 33 months of
age were evaluated 3 years following treatments
and again at 7 and 7.5 years of age. A wide range
of neurological, neuropsychological, and
behavioral tests was administered. Assessment of
potentially confounding factors included
sociodemographics and parental IQ.
Blood lead at time of
treatment 31.2 (SD 6.5)
ug/dL.
Blood lead
Range 20-44 ug/dL
Baseline blood lead 26
(SD 26.5) ug/dL in both
drug and placebo groups.
Without respect to treatment regimen, changes in
performance on cognitive measures after 6 months were
significantly related to changes in blood lead levels after
control for confounding factors. Standardized scores on tests
increased 1 point for every 3 ug/dL decrement in blood lead.
Succimer was effective in lowering blood lead levels in
subjects on active drug during the first 6 months of the trial.
However, after 1 year differences in the blood lead levels of
succimer and placebo groups had virtually disappears.
3 years following treatment, no statistically
significant differences between active drug and placebo
groups were observed for IQ or other more focused
neuropsychological and behavioral measures. When
evaluated at 7 and 7.5 years of age, TLC could demonstrate
no benefits of earlier treatment on an extensive battery of
cognitive, neurological, behavioral and neuromotor
endpoints. Authors conclude that the TLC regimen of
chelation therapy is not associated with neurodevelopmental
benefits in children with blood lead levels between 20 and
44 ug/dL and that these results emphasize the importance of
taking environmental measures to prevent exposure to lead in
light of the apparent irreversibility of lead-associated
neurodevelopmental deficits.
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Table AX6-3.10 (cont'd). Effects of Lead on Reversibility of Lead-Related Deficits in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States (cont'd)
Liu et al. (2002)
U.S.
Design: Prospective longitudinal clinical trial.
Data from the Treatment of Lead-Exposed Children
(TLC) used to examine prospective relationships
between falling blood lead levels and changes in
cognitive functioning. 741 children recruited
between 13 and 33 months of age were assessed at
baseline and 6 months later with the Bayley Mental
Development Index (MDI) and 36 months post-
randomization with the Wechsler Preschool and
Primary Scales of Intelligence-Revised to obtain
IQ.
Blood lead
Baseline blood lead 26.2
(SD5.1)ng/dL
36 months post-
randomization blood lead
12.2
(SD 5.2) ug/dL
TLC found no overall effect of changing blood lead level on
change in cognitive test scores from baseline to 6 months.
Slope estimated to be 0.0 points per 10 ug/dL change in
blood lead. From baseline to 36 months and 6 months to 36
months, falling blood lead levels were significantly
associated with increased cognitive test scores, but only
because of an association in the placebo group. Authors
conclude that because improvements were not observed in
all children, the data do not provide support that lead-
induced cognitive impairments are reversible. Although the
possible neurotoxicity of succimer cannot be ruled out.
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Latin America
Kordasetal. (2005);
Rico et al. (2005)
Torreon, Mexico
Design: Double-blind, placebo-controlled
nutritional supplementation clinical trial conducted
among 602 first grade children ages 6-8 years in
Torreon, Mexico. Subjects received iron, zinc,
both or placebo for 6 months. Parents and teachers
filled out the Conners Rating Scales at baseline and
follow up six months following the end of
supplementation to index behavioral changes
following therapy. In addition, 11 cognitive tests
of memory, attention, visual-spatial abilities, and
learning were administered, including WISCR-M at
baseline and follow-up 6 months later.
Blood lead
Baseline blood lead 11.5
(SD 6.1) ug/dL
No significant effects of treatment on behavior or cognition
could be detected with any consistency. Authors conclude
that this regimen of supplementation does not result in
improvements in ratings of behavior or cognitive
performance.
Australia
Tongetal. (1998)
Australia
Design: Prospective longitudinal. 375 children
from the Port Pirie Prospective Study were
followed from birth to the age of 11-13 years.
Bayley Mental Development Index (MDI) at
2 years, the McCarthy Scales General Cognitive
Index (GCI) and IQs from the Wechsler
Intelligence Scale served as the primary indicators
of intellectual status. The purpose of the study was
to assess the reversibility of lead effects on
cognition in relationship to declines in blood lead
over time.
Postnatal Blood lead
Average Blood lead at
2 years 21.2 ug/dL declining
to 7.9 ug/dL at 11-13 years.
Although blood lead levels declined substantially, covariate
adjusted scores on standardized measures of intellectual
attainment administered at 2, 4, 7, and 11-13 years of age
were unrelated to declining body burden. Authors conclude
that effects of early exposure to lead during childhood are
not reversed by a subsequent decline in blood lead
concentration.
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Table AX6-3.11. Neurobehavioral Effects Associated with Environmental Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States
Muldoonetal. (1996)
Paytonetal. (1998)
325 women from rural location (mean age
71) and 205 women from a city location
(mean age 69) participants in the Study for
Osteoporotic Fractures had the association
of nonoccupational lead exposure and
cognitive function examined. Logistic
regression determined effect of blood lead
on neuropsychological performance.
141healthy men in VA normal aging study
evaluated every 3 to 5 years with cognitive
battery and blood lead and once a
measurement of patella and tibia bone lead.
Statistics are confusing as it is not clear
when ANCOVA is used and how the
groups are created.
Rural group
Blood lead 5 ug/dL
Urban group
Blood lead 5 ug/dL
Mean blood lead 6 ug/dL,
patella bone lead 32 and
tibia bone lead 23 ug/g
bone mineral
Groups were significantly different with the urban group more educated
and smoked and drank more. Performance in each group stratified by
exposure into three groups (low <4 ug/dL, medium 4-7 ug/dL, high >7
ug/dL rural and >8 ug/dL) - no significant associations were present in
the urban group but the rural group had significantly poorer
performance with increasing blood lead for Trails B (OR = 2.6, 95%
CI: 1.04, 6.49), Digit Symbol (OR 3.73, 95% CI: 1.57, 8.84),and
Reaction Time in the lower (OR 2.84, 95% CI: 1.19, 6.74) and upper
extremities (OR 2.43, 95% CI: 1.01,5.83). The fact that marked
differences exist between the low lead groups for rural and urban (the
lowest 15th percentile) suggests the differences between the two groups
are unrelated to lead. Response time for reaction time across lead
groups increased for the rural group and decreased or remained the
same for the urban group. As response time is sensitive to lead effect,
this raises question whether factors not measured accounted for
difference. Namely MMSE for the whole population was 25 (15-26)
with poorer performance in the rural group. The clinical cutoff score
for MMSE is 24 suggesting the presence of clinical cognitive disorders.
Even though this is a simple neuropsychological battery up to 9 were
unable to perform some of the tests including 3 on the MMSE.
Regressions adjusted for age and education found significant
relationship of blood lead with Pattern Comparison (perceptual speed),
Vocabulary, Word List Memory, Constructional Praxis, Boston
Naming Test, and Verbal Fluency Test. Only for Constructional Praxis
were bone lead and blood lead significantly associated. Mechanism
most sensitive to low levels lead exposure believed to be response
speed. It is unusual that Vocabulary, a test resistant to neurotoxic insult
is significantly associated with blood lead. This may be related to the
significant negative correlation of bone lead with education, a similar
trend is present for blood lead. It is not clear how multiple comparisons
were handled.
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Table AX6-3.11 (cont'd). Neurobehavioral Effects Associated with Environmental Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States (cont'd)
Rhodes et al. (2003)
Wright et al. (2003)
526 participants with mean age 67 years,
47% had education level of high school or
less. Mood symptoms evaluated with Brief
Symptom Inventory (BSI). Use of logistic
regression adjusting for covariates
examined association of BSI scales and
blood lead and bone lead levels.
736 healthy men (mean age 68) in
Normative Aging Study examined every 3
to 5 years were administered the Mini-
Mental State Exam (MMSE). Linear
regression examined relationship of
MMSE and blood lead, Patella and Tibia
bone lead measurements after adjusting for
covariates.
Mean blood lead 6 ug/dL
Mean tibia Pb 22 ug/g
Mean patella Pb 32 ug/g
Mean blood lead 5 ug/dL,
patella bone lead 30 and
tibia bone lead 22 ug/g
bone mineral
BSI found mood symptoms for anxiety and depression were potentially
associated with bone lead levels. However education was inversely
related to bone lead and high school graduates had significantly higher
odds of Global Severity Index and Positive Symptom Total. BSI
appears to be detecting general stress related to socioeconomic status.
Mean MMSE score 27. Relation of MMSE scores <24 (n = 41) and
blood lead by logistic regression found OR 1.21 (95% CI: 1.07,1.36)
and for patella lead OR 1.21 (95% CI: 1.00, 1.03) and tibia lead OR
1.02 (95% CI: 1.00, 1.04). Risk of MMSE <24 when comparing the
lowest and highest quartiles of patella lead was 2.1 (95% CI: 1.1,4.1),
for tibia lead was 2.2 (95% CI: 1.1, 3.8) and blood lead was 3.4 (95%
CI: 1.6,7.2). Interaction between patella lead and age, and blood lead
and age in predicting MMSE found steeper decrease in MMSE score
relative to age in the higher quartiles of patella lead and blood lead.
MMSE very sensitive to years of education below 8 years. In this study
213 subjects had less than high school education. If the community
dwelling population had older individuals with less education living in
areas with higher past pollution the confounding may be impossible to
sort out. Initially at beginning of NAS subjects were eliminated with
chronic medical problems or blood pressure > 140/90. It is not
addressed how the development of medical conditions during the
duration of the study are handled.
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Table AX6-3.11 (cont'd). Neurobehavioral Effects Associated with Environmental Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
United States (cont'd)
Weisskopfetal. (2004)
466 men, mean age 70 years, in the VA
Normative Aging Study had 2 MMSE tests
3.5 years apart.
Mean blood lead 4 ug/dL,
patella bone lead 23 and
tibia bone lead 19 ug/g
bone mineral
Baseline mean MMSE score was 27 and mean change in MMSE
score over 3.5 years was 0.3. Change in MMSE associated with one
interquartile range increment for bone lead and blood lead found
relationship between patella lead and change in MMSE was unstable
when patella lead is >90 ug/g bone mineral. Examination of patella
lead below this level found a greater inverse association with MMSE
at lower lead concentrations ((3 = -0.25, 95% CI: -0.45, -0.05).
A similar but weaker association existed for tibia lead when values
>67 ug/g bone mineral were removed ((3 = -0.19, 95% CI: -0.39,
0.02). There was no association of MMSE change and blood lead
(P = -0.01, 95% CI: -0.13,0.11). There was no interaction of age
and bone lead. These are very high bone lead levels for
environmental exposure. The biological plausibility of change in the
MMSE over 3.5 years would have been reinforced if the change by
functional domain in the MMSE was provided.
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Europe
Nordberg et al. (2000)
Sweden
762 participants, mean age 88 years, in a
study of aging and dementia examined
MMSE. Used blood lead as dependent and
examined contribution of covariates and
MMSE.
Mean blood lead 3.7 ug/dL
Mean MMSE 25 found no relation of blood lead and MMSE. In this
population was fairly homogenous, all elderly Swedes, and the
likelihood of prior exposure to elevated lead levels was low.
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Table AX6-3.12. Symptoms Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Canada
Lindgren et al. (1999)
Holnessetal. (1988)
Smelter workers (n = 467) with a mean age
of 40 years completed the Profile of Mood
Scale. Factor structure of POMS validated in
this occupational population. Regression
analysis determined association with lead
exposure.
47 demolition workers with acute lead
intoxication - Phase 1-were followed with
blood lead and symptoms during engineering
modifications to control exposure -Phases
2-4. Workers stratified by blood lead and
symptom frequency was analyzed.
Mean blood lead 28
(8.5,4-62)ng/dL
Mean IBL 711
(415.5, 1-1537) ng-yr/dL.
Phase I- Mean blood lead
59 ug/dL SDN/A
Phase 2-Mean blood lead
30 ug/dL SDN/A
Phase 3-Mean blood lead
19 ug/dL SDN/A
Phase 4-Mean blood lead
17 ug/dL SDN/A
Factor analysis found one factor labeled "general distress" composed
of POMS subscales anger, confusion, depression, fatigue and tension
and a second factor labeled 'psychological adjustment'. IBL was
significantly associated with 'general distress' after adjustment for the
covariates (P = 0.28 [SE 1.51 x 10~4] p = 0.01) while there was no
relation with blood lead. The factor structure of POMS originally
validated in a clinical population had six mood subscales however the
factor structure in this occupational population was found to have
only two subscales.
Below blood lead <50 ug/dL percentage of workers reporting
symptoms was fatigue-25, headache-14 dizzy-9, sleep-8, abdominal
cramps-8, muscle ache-8, paresthesiae-8, appetite-7, constipation-6,
and weakness-6. All symptoms were significantly lower except for
paresthesiae when compared to group with blood lead >70 ug/dL.
Of interest, at beginning of Phase 4 when mean blood lead was
13 ug/dL, no symptoms were reported. At the end of Phase 4, mean
blood lead was 17 ug/dL and one worker complained of fatigue.
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Europe
Lucchini et al. (2000)
Italy
66 workers in lead manufacturing, mean age
40 (8.7) years and 86 controls mean age 43
(8.8) years were administered a questionnaire
with neuropsychological (14 items), sensory-
motor (3 items), memory (4 items) and
extrapyramidal (8 items), 10 Parkinson
symptoms and the Mood Scale. Group
comparisons and linear regression examined
relationship of symptoms and lead exposure.
Mean blood lead 27 (11.0,
6-61) ug/dL
Mean TWA 32 (14.1, 6-61)
ug/dL
Mean IBL 410 (360.8,
8-1315)ug-yr/dL.
Controls-mean blood lead 8
(4.5, 2-21) ug/dL
Lead exposed worker reported confusion, somnolence, abnormal
fatigue, irritability, and muscular pain more frequently (p < 0.04).
There were no group differences for the parkinsonism symptoms or
Mood Scale. Linear regression combing exposed and control group
found neurological symptoms significantly associated with blood lead
r = 0.22, p = 0.006). Neuropsychological symptoms were
significantly higher in the High-IBL compared to the Low-IBL group.
The estimated threshold for a significant increase (prevalence of 5%)
of a high score for neurological symptoms was at a blood lead of
12 ug/dL.
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Table AX6-3.12 (cont'd). Symptoms Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Latin America
Maizlish et al. (1995)
Venezuela
43 workers from a lead smelter, mean age 34
(9) years and 47 nonexposed workers, mean
age 3 5 (11) years completed the profile of
mood states (POMS) questionnaire and a
questionnaire of symptoms of the central and
peripheral nervous system, and
gastrointestinal. Prevalence ratios used to
examine symptoms and lead. ANCOVA and
linear regression adjusting for potential
confounders examined relationship of lead
exposure and POMS.
Mean blood lead 43 (12.1)
ug/dL
Mean peak blood lead 60
(20.3) ug/dL
Mean TWA 48 (12.1)
ug/dL
Controls
mean blood lead 15 (6)
ug/dL
mean peak blood lead 15
(6) ug/dL
mean TWA 15 (6) ug/dL
Significantly increased relative risks found for difficulty
concentrating (RR 1.8 [95% CI: 1.0-3.1]), often being angry or upset
without reason (RR 2.2 [95% CI: 1.2,4.1]), feeling abnormally tired
(RR 2.2 [95% CI: 0.9, 5.3]) and joint pain (RR 1.8, [95% CI: 1.0,
3.3]). The six subscales of the POMS were not significantly different
between the exposed and control groups. However dose-related
analysis found significantly poorer scores for tension-anxiety and
blood lead (p = 0.009), hostility and blood lead (p = 0.01) and TWA
(p = 0.04), and depression and blood lead (p =0.003) and peak lead
(p = 0.003) and TWA (p = 0.004).
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Asia
Schwartz etal. (2001)
Korea
803 lead-exposed Korean workers, mean age
40 years completed the Center for
Epidemiologic Studies Depression Scale.
Linear regression examined for association
of CES-D and lead biomarkers after
adjusting for the covariates.
Mean blood lead 32 (15.0)
ug/dL
Mean tibia lead 37 (40.3)
ug/g bone mineral
After adjustment for age, gender and education significant
associations found for CES-D and tibia lead ((3 = 0.0021 [SE 0.0008];
p < 0.01) but not with blood lead. This occupational lead-exposed
populations had higher past lead exposure compared to the current
mean blood lead of 32 ug/dL.
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Table AX6-3.12 (cont'd). Symptoms Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Asia (cont'd)
Lee et al. (2000)
Korea
Niu et al. (2000)
China
95 Korean lead exposed workers, mean age
43 years, completed questionnaire of lead-
related symptoms present over last three
months. Relationship between symptom
score and measures of lead exposure
assessed by linear regression. Logistic
regression use to model presence or absence
of symptoms for gastrointestinal,
neuromuscular, and general.
44 lead-exposed workers (17 men, 27
women) from lead printing houses, mean age
35 (4.9) and education 9.3 (no SD) years and
34 controls (19 men and 15 women), mean
age 33 (7.4) years and education 9.5 (no SD)
years completed the profile of mood state as
part of the NCTB. ANCOVA controlling for
age, sex and education examined group
differences and linear regression for dose-
response relationship.
DMSA-chelatable lead
Mean 289 (167.7) ug
ZPP 108 (60.6) ug/dL
MeanALAU3(2.8)mg/l
Mean blood lead 45 (9.3)
ug/dL
Mean blood lead 29 (26.5)
ug/dL
(8 workers blood lead
exceeded 50 ug/dL)
Controls
Mean blood lead 13 (9.9)
ug/dL
(1 control blood lead
exceeded 50 ug/dL)
Workers with DMSA -chelatable lead above the median of 261 ug
were 6.2 (95% CI: 2.4, 17.8) times more likely to have tingling or
numbness in their extremities, 3.3 (95% CI: 1.2, 10.5) times more
likely to experience muscle pain and 3.2 (95% CI: 1.3, 7.9) times
more likely to feel irritable. The workers with higher chelatable lead
were 7.8 (95% CI: 2.8,24.5) times more likely to experience
neuromuscular symptoms compared to workers with lower chelatable
lead. In this study ZPP predicted weakness of ankle and wrist (OR
2.9[95%CI: 1.1, 8.1]) and fatigue (OR 2.9 [95% CI: 1.1, 8.7]) while
ALAU predicted inability to sleep (OR 5.4 [95% CI: 1.2, 33.2]) and
blood lead was not significantly associated with any symptoms.
A measure of lead in bioavailable storage pools was the strongest
predictor of symptoms particularly neuromuscular.
POMS subscales for confusion (F = 3.02, p < 0.01), fatigue (F = 3.61,
p < 0.01), and tension (F = 2.82, p < 0.01) were significantly elevated
in the lead exposed group. Regression analyses found a dose response
(data not shown).
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Table AX6-3.13. Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States
Fiedler et al. (2003)
New Jersey
Balbus-Kornfeld et al.
(1995)
40 workers with lead exposure, mean age
48 (9.5) years completed a neurobehavioral
battery and was compared to 45
lead/solvent workers, mean age 47 (10.2),
39 solvent exposed workers, mean age 43
(9.4), and 33 controls, mean age 44 (10.2).
Group differences and dose-effect
relationships were assessed after adjusting
for potential confounding.
Reviewed 21 studies from 28 publications;
number of subjects ranged from 9-708.
Mean blood lead ug/dL
Mean bone lead ppm ug/g
(dw) Lead workers
14 (11.7)/2.7(0.7)
Lead/Solvent workers
12(11.6)72.8(0.6)
Solvent workers
5(4.1)7-1.8(1.8)
Controls
4(1.4)7-1.1(1.6)
Mean blood lead in most
exposed group 28-68
ug/dL. Only 5 studies used
a measure of cumulative
exposure or absorption of
Pb, 2 studies used duration
of exposure.
Of nineteen outcomes, significant differences found on the California
verbal learning test (CVLT) (p = 0.05) and positive symptom distress
index on the Symptom checklist-90-R. On the CVLT the controls
performed significantly better on trials 2 and 3 demonstrating
efficiency of verbal learning. Symbol digit substitution (SDS)
approached significance (p = 0.09) with lead and lead/solvent group
slower on latency of response but not accuracy. Bone lead was a
significant predictor of latency of response on SDS, total errors on
paced auditory serial addition task and simple reaction time non-
preferred hand. Bone lead and SRT, preferred hand approached
significance. This is a confusing study design as bone lead is used as
a predictor in workers both with and without occupational lead
exposure.
Dexterity (17/21 studies) and executive or psychomotor 11/21 studies
were the functional domains most commonly associated with lead.
Age not adequately controlled in most studies, usually matching
means or medians. Intellectual abilities prior to exposure usually
adjusted for with education however Vocabulary, a measure of overall
intellectual ability still different between the groups. The conclusion
reached that evidence of effects from cumulative exposure or
absorption of lead was inadequate.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Canada (cont'd)
Bleecker et al. (2005)
256 smelter workers currently employed and
took the test battery in English. Their mean
age was 41 (7.9) years, and education
10 (2.8) years. The purpose was to
determine whether components of verbal
memory as measured on the Rey Auditory
Verbal Learning Test (RAVLT) were
differentially affected by lead exposure.
Linear regression and ANCOVA assessed
the relationship of lead and components of
verbal learning and memory.
Mean blood lead 28 (8. 8)
Mean TWA 39 (12.3)
Mean IBL 725 (434)
Hg-yr/dL
Outcome variables RAVLT a word list test included measures of
immediate memory span and attention (Trial 1), best learning (Trial
V), incremental learning across the five trials (Total Score), and
storage (Recognition) and retrieval (Delayed Recall) of verbal
material. TWA significantly contributed to the explanation of
variance for Trial V (AR2 = 1.4%, p < 0.03) and Delayed Recall
(AR2 = 1.4%, p = 0.03) after adjusting for age and WRAT-R while
IBL did the same with Recognition (AR2 = 2.0%, p = <0.02) and
Delayed Recall (AR2 = 1.1%, p = 0.06). Workers stratified into
3 group by increasing clinical memory difficulties-Group 1 had normal
encoding, storage and retrieval; Group2 could encode and store verbal
information but had difficulty with retrieval and Group 3 had
abnormal encoding, storage and retrieval but was still able to leam
new verbal information. ANCOVA adjusting for age and WRAT-R
compared lead exposure across the memory groups. Blood lead
showed no difference but TWA and IBL were significantly higher in
Group 3 compared to Group 1 (p < 0.05 for both). Internal strategies
used on the RAVLT over the five trials found that Groups 1 and 2
remembered more words from the beginning of the list while group 3
remembered more from the end. At a time when blood lead was not
associated with performance, cumulative lead exposure resulted in
poorer storage and retrieval of previously learned material.
Alterations in the ability to organize materials in long term memory
interferes with retrieval efficiency.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period Study Description Lead Measurement Findings, Interpretation
Canada (cont'd)
Bleeckeretal. (1997a)
New Brunswick
1992-1993
Bleeckeretal. (1997b)
New Brunswick
1992-1993
The performance of the 467 current and
retired smelter workers as described in
Lindgren et al. (1996) administered a
screening neuropsychological battery by
testers blinded to the degree of lead exposure
of the worker had their performance
compared to age matched norms.
If performance on two or more tests in any
functional domain was below 1.5 standard
deviations the worker was invited for a
complete clinical evaluation. Eighty current
workers were identified by this criterion.
Mean years- age 44 (8.4), education 8 (2.8)
and duration employed 20 (5.3). Five
neuropsychological tests commonly
associated with lead exposure were
examined for a differential association with
blood lead, IBL,TWA and bone lead.
Of the 80 current smelter workers described
above 78 completed a simple visual reaction
time (SRT) and had mean years age 44 (8.2)
years, education 8 (7.2) and duration
employed20 (5.6).
Mean blood lead 26 (7.07)
Mean TWA 42 (8.4) ng/dL
Mean IBL 903 (305. 9)
Hg-yr/dL,
Mean tibial bone lead
41 ng/g bone mineral
Mean blood lead, 26 (7.2)
Mean blood lead from bone
7 (4.2) ng/dL
Mean blood lead from
environment 19 (7.0) ng/dL
Mean bone lead 40 (25.2)
Hg/g bone mineral
Relationship of 5 neuropsychological tests with 4 measures of lead
dose after adjusting for age age2 and education, education2 found
RAVLT trial V and Verbal Paired Associates were associated with
blood lead (AR2 = 6.2%, p = 0.02; AR2 = 5.5%, p = 0.07) and TWA
(AR2 = 3.2%, p = 0.09; AR2 = 13.9%; P = 0.00) while Digit Symbol
and Grooved Pegboard were associated with TWA (AR2 = 6.1%,
p = 0.00; AR2 = 5.5%, p = 0.02) and IBL (AR2 = 4.8%, p = 0.01;
AR2 = 5.7%, p = 0.02). Only grooved pegboard was associated with
bone lead (AR2 = 4.2%, p = 0.05). Block design was not associated
with any measures of lead dose. Age was an effect modifier with
grooved pegboard. There was enhanced slowing in older workers
when compared to younger workers with the identical IBL.
SRT consisted of 44 responses to a visual stimulus at interstimulus
intervals (ISI) varying between 1 through 10 seconds with a mean
SRT (median) of 262 (179 to 387) ms. Blood lead and median SRT
had a curvilinear relationship R2 = Pb+ Pb2,13.7%, p < 0.01) after
adjusting for age and education with slowing of SRT beginning at a
blood lead of approximately 30 ng/dL. No relationship existed
between bone lead and SRT. There was a stronger association
between Pb and Pb2 and SRT for the longer ISI = s, 6 to 10 seconds
(R = 13.9%, p < 0.01), as age was significantly related to the shorter
ISI = s but not the longer ones. In this population the contribution of
bone lead to blood lead had been previously where estimated where
for a bone lead level of 100 |ig Pb/g bone mineral, 17 ng Pb/dL of the
blood lead was derived from internal bone stores with the remainder
from the environment. Blood lead was fractionated to that from bone
(blood lead-bn) versus blood lead from the environment (blood lead-
en). Regression analysis to examine the relationship of blood lead-bn
and blood lead-en and SRT after adjusting for the covariates found
significant contribution to the variance of SRT only for blood lead-en
(R2 for blood lead-en + blood lead-en2 = 14.4%, p < 0.01). The
absence of a contribution by age and more stable responses with ISIs
of 6 to 10 sec supports using this component of SRT.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Canada (cont'd)
Lindgren et al. (2003)
New Brunswick
1992-1993
Braun and Daigneault
(1991)
Quebec
In an attempt to separate the effects of past
high lead exposure from a lower proximate
exposure, examination of the pattern of lead
levels of the 467 Canadian lead smelter
workers found 40 workers who had high past
exposure followed by years where 90% of
blood lead were above 40 ug/dL (High-
high = H-H) while another group of 40
workers had similar past high lead exposure
followed by years where 90% of blood lead
were below 40 ug/dL (High-low = H-L).
The groups did not differ on age, education,
years of employment or CES-D. Five
outcomes examined-Purdue Pegboard
assembly, Block Design, Digit Symbol, Rey
Auditory Verbal Learning Test-total score,
delayed Logical Memory.
41 workers from a secondary lead smelter,
mean age 35 (9.6) years and years of
education 10 (2.1) were compared to a
control group mean age 37 (10.1) years and
years of education 11 (1.3) on tests of
cognitive and motor function. MANCOVA
and dose-effect relationships after adjusting
for potential confounders were performed.
Mean IBL for past
exposure
H-H 633 (202.2) ug-yr/dL
H-L 557 (144.8) ug-yr/dL
Mean IBL for the
proximate exposure
H-H 647 (58.7) ug-yr/dL
H-L 409 (46.4) ug-yr/dL
Mean blood lead
H-H 37 (5.1) ug/dL
H-L 24 (5.2) ug/dL
Mean TWA 53 (7.5) ug/dL
Mean maximum blood lead
87 (22.4) ug/dL
Of the five neuropsychological measures examined only RAVLT
(total score) and Logical Memory (delayed) were significantly
different after adjusting for the covariates in the two pattern groups.
Use of regression analyses found pattern group contributed
significantly (R2 = 4%, p < 0.05) to the explanation of variance in
RAVLT after accounting for current blood lead (R2 = 3%, p < 0.10)
and IBL measures (R2 = 7%, p < 0.01). For past IBL, H-H pattern
correlated more strongly with RAVLT (r = -0.21) while H-L pattern
had no relationship with past exposure (r = 0.08). For proximate IBL
the difference was maintained between H-H (r = -0.11) and H-L
pattern (r = 0.00). The authors suggested that the absence of an
association between past high lead exposure and verbal memory in the
H-L pattern group may reflect reversibility of function when blood
lead is maintained below 40 ug/dL.
None of the measures of cognitive executive function showed group
differences. Partial correlation adjusting for age and education with
dose related variables found no statistical significance. On motor
function the exposed workers had significantly slower simple reaction
time (p = 0.05). However partial correlations with measures of dose
found dose-effect correlation in both negative and positive directions.
Group of exposed workers was mixed for lead exposure with 11
currently working and the remainder with no exposure up to 84
months. Also two of the exposed workers had been treated with
chelation.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Europe
Haiminenetal. (1998)
Finland
Lucchini et al. (2000)
Italy
Fifty-four lead battery workers were
stratified by those whose blood lead never
exceeded 50 ng/dL (n = 26) (group 1)
and those who had higher exposure in the
past (n = 28) (group 2) to examine the
neuropsychological effects of current low
level blood lead from higher blood lead in
the past. Mean age group Iwas 42 (9.3)
years, education 8 (1.7) years and years of
exposure 12 (6.7). Mean age group 2 was 47
(6.2) years, education 8(1.0) years and years
of exposure 21 (6.9). Analysis included
partial correlations within the groups and
ANCOVA within group 1 divided at the
median TWA3 of 29 ng/dL.
66 workers in lead manufacturing, mean age
40 (8.6) years, mean education 8 ( 2.4) years
and mean exposure time 11 (9) years and a
control group of 86 with mean age 43 (8.8)
years, mean years of education 9 (2.7) years.
Group differences examined and dose-effect
relationship with correlation and ANOVA.
Markers of lead exposure
for the group 1 were mean
IBL 330 ng-yr/dL,
Maximum blood lead
40 ng/dL, TWA 29 ng/dL
Tibial lead 20 ng/g
Calcaneal lead 79 ng/g
Past high exposure, group 2
Mean IBL 823 ng-yr/dL,
Maximum blood lead
69 (ig/dL, TWA 40 ng/dL,
Tibial lead 35 ng/g
Calcaneal lead 100 jig/g
IBL, TWA and maximum
blood lead were also
calculated for the previous
3 years with a median
TWA3 of 29 ng/dL
Mean blood lead 28 (11)
Control-mean blood lead 8
(4.5) ng/dL
Mean IBL 410 (360.8)
Hg-yr/dL,
Mean TWA 32 (14.1)
Mean years exposed
11(8.1)
Partial correlations controlling for age, sex and education in group 1
found block design, digit symbol, digit span, similarities, Santa Ana 1
and memory for design significantly associated with recent measures
of exposure and embedded figures with maximum blood lead. In
group 2 embedded figures, digit symbol, block design, and associative
learning were associated with IBL and /or maximum blood lead.
Calcaneal lead was weakly associated with digit symbol, digit symbol
retention, and synonyms. There was no association with tibial lead in
either group. Group 1 divided at the median TWA3 of 29 ng/dL
found the high group had lower scores for visuospatial and
visuoperceptive tasks (digit symbol, embedded figures and memory
for design). Overall past high exposure, blood lead >50 ng/dL, had
the greatest effect on tests requiring the encoding of complex visually
presented stimuli. The authors conclude that the effect of lead on
brain function is better reflected by history of blood lead than content
of lead in bone.
No association with neuropsychological tests (addition, digit span,
linger tapping symbol digit and motor test from Luria) and blood lead,
TWA or IBL were found. Blood lead and visual contrast sensitivities
at the high frequencies were significantly associated for the entire
group. Blood lead and serum prolactin in the whole group was
significantly associated. Increased prolactin secretion occurs with a
variety of neurotoxins and reflects impaired dopamine function in the
pituitary. The estimated threshold for a significant increase of high
prolactin levels was at a blood lead of 10 ng/dL.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Europe (cont'd)
Osterberg et al. (1997)
Sweden
38 workers, median age 42 (no range) years
at a secondary smelter stratified by finger
bone lead concentration and along with
19 controls matched triplets for age,
education and job level. Median years
employed 10 (2-35).
High bone lead
Median bone 32 (17-101)
Hg/g
Median blood lead 38
(19-50) ng/dL
Median peak blood lead 63
(46-90) ng/dL
Median IBL 408
(129-1659) ng-yr/dL
Low bone lead
Median bone 16 (-7-49)
Hg/g
Median blood lead 34 (17-
55) ng/dL
Median peak blood lead 57
(34-78) ng/dL
Median IBL 250 (47-835)
Hg-yr/dL
Controls
Median bone 4 (-19-1 8)
Median blood lead 4(1-7)
A cognitive test battery (36 tests) covering learning and memory,
visuomotor function, visuospatial function, concentration and
sustained attention found no impairment or dose-response
relationships with any of the markers of lead exposure. Deviating test
scores (belong to 10% lowest reference norms) were less in high bone
lead (1 vs. 4 vs. 4). None of the deviating parameters were
significantly correlated with any of the lead indices. Even when age
was taken into account the significant associations between outcome
and lead exposure metrics did not exceed chance in light of the
numerous analyses performed. These were the most heavily lead-
exposed workers in Sweden. It was unusual that the 2 visuomotor
tasks significantly different had better performance in the lead-
exposed workers compared to the controls.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Europe (cont'd)
Stolleiyetal. (1991)
England
StoUeiyetal. (1996)
England
Earth et al. (2002)
Austria
Seventy lead-exposed workers, mean age
41 (no SD) years, grouped by blood lead
(<20 |ig/dL, 21-40 ng/dL and 41-80 ng/dL)
examined on three occasions each separated
by four months. Tested on a computer for
syntactic reasoning, delayed five choice
reaction time, visual spatial memory, and
category search task.
Same as above except this was a further
analysis of the five choice reaction time.
47 lead storage-battery workers, mean age
40 (9.7) years and 53 nonexposed controls,
mean age 39 (8.4) years were matched for
age and verbal intelligence. Group
differences and dose-response relationship
were explored.
Low blood lead (no SD
provided)
Mean blood lead 14 ng/dL
MeanZPP13mg/dL
Mean urinary ALA 2 mg/L
Mean years exposed 7
Medium blood lead
Mean blood lead 31 ng/dL
MeanZPP33mg/dL
Mean urinary ALA 3 mg/L
Mean years exposed 10
High blood lead
Mean blood lead 52 ng/dL
Mean ZPP 77 mg/dL
Mean urinary ALA 6 mg/L
Mean years exposed 11
Same as above
Mean blood lead 31 (11.2)
IBL 384 (349.0) ng-yr/dL
Years employed 12 (9.0)
Controls
Mean blood lead 4 (2.0)
Lead exposure was stable over the 8 months of testing. The low lead
group drank significantly less alcohol and rated their work as less
demanding. Performance and exposure stable except in the high lead
group where decision time was slowed more than movement time
along with concentration difficulties that remained stable across
testing sessions. Movement and decision times were significantly
correlated for each duration of waiting. On the memory test of
recalled nouns, the memory deficit associated with lead (r = -0.35,
p = 0.003) was restricted to recall of nouns unrelated to task
(distracters) (p = 0.04) that did not improve with repetition suggestive
of difficulties with incidental learning. Workers with blood lead >40
Hg/dL had impairments that correlated best with average blood lead
over the preceding 8 months. Workers with blood lead between 21 to
40 ng/dL had essentially no impairment.
Movement and decision slowing was correlated with blood lead.
Slowed movement time was constant across response-stimulus
intervals in contrast to decision time that was increasingly affected by
lead especially at the shortest response-stimulus intervals.
This supported the finding that decision gaps, central in origin, as
opposed to movement gaps are selectively affected by lead exposure
in this population.
Significant differences were found for block design (p < 0.01), visual
recognition (p < 0.01) and Wisconsin card sorting (categories
p = 0.0005, total errors p = 0.0025, perseverations p = 0.001, loss of
sorting principle p = 0.003) but not SRT or digit symbol. In the
exposed group partial correlation adjusting for age found no
significant associations with IBL (n = 53). In the entire group the full
correlation was significant for blood lead and Wisconsin card sorting,
block design and visual recognition (n = 100). Visuospatial abilities
and executive function were better predicted by blood lead than
cumulative lead exposure. It is unusual that a frontal lobe task is
associated with blood lead when SRT and digit symbol sensitive to
the affects of lead are not.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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Latin America
Maizlish et al. (1995)
Venezuela
43 workers from a lead smelter, mean age 34
(9) years and 47 nonexposed workers, mean
age 35(11) years completed the WHO
neurobehavioral core test battery. ANCOVA
and linear regression adjusting for potential
confounders examined relationship of lead
exposure and NCTB.
Mean blood lead 43 (12.1)
Mean peak blood lead 60
(20.3) ng/dL
Mean TWA 48 (12.1)
Group comparison was significant for SRT (p = 0.06) but the lead
exposed workers performed faster. Linear regression found SRT
poorer performance with blood lead and TWA but not significant.
With peak blood lead SRT improved with increasing lead exposure.
In this study only symptoms were significantly different between
the groups. (See above).
Controls
Mean blood lead 15 (6)
Mean peak blood lead 1 5
(6) ng/dL
MeanTWA15(6)|ig/dL
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Asia
Schwartz etal. (2001)
South Korea
803 Korean lead exposed workers, 80% men
and 20% women, mean age 40 (10.1) years
from a variety of industries, and 135
controls, 92% men and 8% women, mean
age 35 (9.1) years. Educational levels lead-
exposed workers/controls
<6 years = 23% / 7%, 7-9 years 23% / 11%,
10-12 years = 46% / 70%, and >12 years
8% / 12%. Group differences on
neurobehavioral testing after controlling for
covariates and linear regression controlling
for covariates examined the presence of a
dose-effect relationship.
Lead-exposed workers
Mean blood lead 32 (15)
Tibia bone lead 37 (40.3)
DMSA-chelatable lead
level 186 (208.1) ng
Controls
Mean blood lead 5 (1.8)
Tibia bone lead 6 (7)
Nineteen outcomes examined. Compared to controls lead exposed
workers performed significantly worse on SRT, Digit Span, Benton
Visual Retention, Colored Progressive Matrices, Digit Symbol, and
Purdue Pegboard after controlling for age, gender and education. The
association of DMSA with test performance was lost by the addition
of blood lead. Bone lead was not associated with neurobehavioral
performance, blood lead was the best predictor for significant
decrements in neurobehavioral performance on trails B (P = -0.0025
[SE 0.0009], p < 0.01), Purdue Pegboard (dom p = -0.0159 [SE
0.0042], p < 0.01; non-dom p = 0.0169 [SE 0.0042], p < 0.01; both p
= -0.0142 [SE 0.0038], p < 0.01; assem p = -0.0493 [SE 0.0151],
p<0.01 ) and Pursuit Aiming (#corrp = -0.1629 [SE0.0473],
p < 0.01; #incorr p = -0.0046 [SE 0.0023], p < 0.05). The magnitude
of the effect for these eight tests significantly associated with blood
lead was an increase in blood lead of 5 ng/dL was equivalent to an
increase of 1.05 years in age. Use of Lowess lines for Purdue
Pegboard (assembly) and Trails B suggested a threshold at blood lead
18 ng/dL after which there is a decline of performance.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Asia (cont'd)
Schwartz etal. (2003)
South Korea
1997-2001
Longitudinal decline in neurobehavioral
performance examined in 576 of the above
group of lead exposed workers who
completed 3 visits at one year intervals.
Mean age at baseline was 41 (9.5) years and
job duration 9 (6.3) years and 76% were
men.
Compared to non-completers lead workers
who completed 3 visits were 3.3 years older,
baseline mean blood lead was 2.0ug/dL
lower, on the job 1.6 years longer, 24%
women vs. 10% of noncompleters, and
usually had less than high school education.
Models examined short-term versus long-
term effects. Final model had current blood
lead, tibia bone lead and longitudinal blood
lead and covariates.
Baseline mean blood lead
31(14.2)ug/dL
Tibia lead 38 (43) ug/g
Blood lead from baseline correlated with those from visit 2 and 3 and
baseline tibial lead correlated with that measured at visit 2. Cross-
sectional associations of blood lead or short-term change occurred
with Trails A (P = -0.0020 [95% CI: -0.0040, -0.0001]) and B
(P = -0.0037 [95% CI: -0.0057, -0.0017]), Digit Symbol
(P = -0.0697 [95% CI: -0.1375, -0.0019]), Purdue Pegboard
(dom P = -0.0131 [95% CI: -0.0231, -0.0031]; non-dom
(P = -0.0161 [95% CI: -0.0267, -0.0055]); both (P = -0.0163, [95%
CI: -0.0259, -0.0067]); assem (P = -0.0536 [95% CI: -0.0897,
-0.0175]), and Pursuit Aiming #corr (P = 0.1526, [95% CI: -0.2631,
-0.0421]) after covariates. However longitudinal blood lead was only
associated with poorer performance on Purdue Pegboard non-dom
(P = -0.0086 [95% CI: -0.0157, -0.0015](; both (P = -0.0063 [95%
CI: -0.0122, 0.0004]); assem (P = -0.0289 [95% CI: -0.0532,
-0.0046]). Historical tibial bone lead was associated with digit
symbol (P = -0.0067 [95% CI: -0.0120, 0.0014]) and Purdue
Pegboard dom (P = -0.0012, [95% CI: -0.0024, -0.0001]).
Magnitude of lead associations was expressed as the number of years
of increased age at baseline that was equivalent to an increase of lead
from the 25th to 75th percentile. At baseline, these lead associations
were equivalent to 3.8 years of age for cross-sectional blood lead, 0.9
years of age for historical tibial lead and 4.8 years of age for
longitudinal blood lead. Analyses showed decline in performance
over time related to tibia lead.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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Asia (cont'd)
Hwang et al. (2002)
South Korea
From the above cohort of 803 Korean lead
workers, 212 consecutively enrolled workers,
were examined for protein kinase C (PKC)
activity and the relations between blood lead
and neurobehavioral performance. PKC
activity assessed by measuring levels of
phosphorylation of three erythrocyte
membrane proteins. Seventy-four percent of
workers were men, mean age 36(0.8)years,
duration of exposure 9 (0.6) and education
93% had high school or less. For the female
workers, mean age 47 (0.9) years, duration of
exposure 6 (0.5), and education 95% had
high school or less.
Male workers
Mean blood lead 32 (13.0)
ug/dL
Mean tibia lead 38 (39.6)
ug/g
Mean ZPP 69(47.8) ng/dL
Female workers
Mean blood lead 20 (9.2)
ug/dL
Mean tibia lead 26 (14.7)
ug/g
Mean ZPP 72 (29.7) ng/dL
Blood lead was associated significantly with decrements in Trails B
(P = -0.003 [SE 0.002], p < 0.10), SRT (P = -0.0005 [SE 0.0003],
p < 0.10) and Purdue Pegboard (dom p = -0.21 [SE 0.010], p < 0.05);
non-dom (P = -0.021 [SE 0.010], p < 0.05); both (P = -0.021 [SE
0.009], p < 0.05). PKC activity as measured by back-phosphorylation
of erythrocyte membrane proteins was not associated with
neurobehavioral test scores. Addition of the interaction term of blood
lead by back-phosphorylation dichotomized at the median found
significant effect modification with the association of higher blood
lead and poorer neurobehavioral performance occurring only among
workers with lower back-phosphorylation levels that corresponds to
higher in vivo PKC activity. Association of blood lead and SRT for
the 52 kDa subunit with high in vivo PKC activity (adjusted
P = -0.001, p < 0.01) and for low in vivo PKC (adjusted p = -0.0001,
p = 0.92). The authors suggest that PKC activity may identify a
subpopulation at increase risk of neurobehavioral effects of lead.
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Chia et al. (2004) 120 workers from lead stabilizer factories,
Singapore mean age 40 (10.7) years, duration of
exposure 10.2 (7.9) were given a
neurobehavioral battery. Genotyping of
ALAD polymorphisms was performed.
ANCOVA used to test for differences in
neurobehavioral performance among ALAD
polymorphism types adjusting for age,
exposure duration and blood lead.
Mean blood lead 22 (9.4)
ug/dL
ALAD0.6 (0.25) urn of
porphobilinogen/h/ml of
RBC
ALAU0.9 (0.56) mg/g cr
Frequency of ALAD1 1, 87%, ALAD1 2, 12%, and ALAD2 2, 1%.
Mean blood lead adjusting for age and exposure duration was 20
Hg/dL for ALAD1 1 (n = 107) and 20.4 ug/dL for ALAD1 2and 2 2
(n = 13). However ALAU was significantly higher in ALAD1 1
(p = 0.023). After adjusting for the covariates significant differences
for grooved pegboard dominant hand (p = 0.01), non-dominant hand
(p = 0.04), and grooved pegboard mean time (p = 0.006) were found
between ALAD 1 1 and ALAD 1 2 & 2 2. Considering cognitive tests
were part of battery it is surprising education was ignored. As noted
by the authors the study only had 13 in the group with better
performance and the ALAD1 2 or 2 2 genotypes limiting the power.
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Table AX6-3.13 (cont'd). Neurobehavioral Effects Associated with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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Asia (cont'd)
Chiaetal. (1997)
Singapore
Niu et al. (2000)
China
Boeyetal. (1988)
Singapore
50 lead battery manufacturing workers, mean
age 36 (10.6) years, education 8.6 (2.1) years
duration of employment 9 (7.4) years and
97 controls, mean age 34 (3.7) years, and
education 12 (1.8) years were administered a
neurobehavioral battery. ANCOVA and
linear regression used to assess relationship
of lead dose and performance.
44 lead-exposed workers (17 men,
27 women) from lead printing houses, mean
age 35 (4.9) and education 9.3 (no SD) years
and 34 controls (19 men and 15 women),
mean age 33 (7.4) years and education
9.5 (no SD) years completed the NCTB.
ANCOVA controlling for age, sex and
education examined group differences and
linear regression for dose-response
relationship.
49 lead -exposed workers, mean age 26 (7.6)
years and 36 controls, mean age30 (6.4)
years completed SRT and 8 psychological
tests covering attention, vigilance, visual-
motor speed, short-term memory, visuomotor
tracking, visual scanning, and manual
dexterity. Control group was matched for
education level. Discriminate analysis of
neurobehavioral tests performed to determine
which best discriminate the groups.
Median blood lead of 38
(13.2- 64.6) ng/dL
Median IBL 264 (10.0-
1 146.2) ng-yr/dL
Controls
Median blood lead 6 (2.4 -
12.4) ng/dL
Mean blood lead 29 (26.5)
(8 workers blood lead
exceeded 50 |ig/dL)
Controls
Mean blood lead 13 (9. 9)
(1 control blood lead
exceeded 50 |ig/dL)
Mean blood lead 49 (15)
Controls
Mean blood lead 15 (3)
Significant group differences for Santa Ana, grooved pegboard, digit
symbol, pursuit aiming and Trails A and B after adjusting for age,
education, smoking, ethnic group and alcohol use. When the exposed
group was stratified by age, in the group >35 years the poorer
performance on digit symbol and Trails A was significantly
associated with cumulative lead and not blood lead after adjusting for
age and education.
SRT (F = 2.30, p < 0.05), digit symbol (F = 4.81, p < 0.01) pursuit
aiming # correct (F = 7.186, p < 0.01) and pursuit aiming total (F =
6.576, p < 0.01) had significantly poorer performance compared to
controls. No repression analyses provided.
Six tests were significantly different between the two groups-Digit
Symbol, Bourdon-Wiersma, Trails A, Santa Ana dominant, Flicker
Fusion and SRT. The group of tests that best differentiates lead-
exposed workers from nonexposed workers were Simple Reaction
Time, Digit Symbol (WAIS) and Trail Making Test (Part A) with
long latency in reaction time contributing three times more to the
derived function than Digit Symbol (WAIS) or Trails A.
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Table AX6-3.14. Meta-analyses of Neurobehavioral Effects with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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United States
Davis etal. (1990)
Meta-analysis of 32 studies of nerve
conduction studies and lead exposure.
Meyer-Baron et al.
(2000)
Goodman et al. (2002)
Meta-analysis of studies with blood lead <70
ug/dL found 12 studies with comparable test
procedure and sufficient documentation of
results. Thirteen tests from the 12 studies
examined.
Meta-analysis of 22 studies with median
blood lead <70 ug/dL, numbers of exposed
and unexposed workers given with scores
and dispersion on neurobehavioral tests.
Exposed group
Range of mean blood lead
31 to 49 ug/dL
Controls
Range of mean blood lead 6
to 18 ug/dL
Exposed group
Range blood lead 24 to
63 ug/dL
Unexposed group
Range blood lead 0 to
28 ug/dL
Presented 41 effect sizes with the overall effect size for all studies
D = -0.369 (p < 0.001). All median nerves combined was
D = -0.481 (p < 0.001) and for all ulnar nerves D = -0.211
(p < 0.001). The median motor was most sensitive with an effect
size of D = -0.553 (p < 0.001). Overall blood lead was a weak
measure of exposure for the peripheral nervous system. Paradoxical
association found effect size smaller with increasing blood lead but
increased with duration of exposure.
Block Design, Logical Memory, and Santa Ana had performance
deficits with small effect size. For Block Design the effect size was
comparable to changes observed with 20 years of aging. Aiming,
SRT, Trials A and B, Digit Span and Digit Symbol also had poorer
performance but the large variance for effect sizes suggest other
factors besides lead exposure influenced performance. The authors
conclude, "that the evidence of neurobehavioral deficits at a blood
lead of approximately 40 ug/dL is obvious."
Digit symbol and D-2 errors significant effect for fixed effects,
weighted random effects and unweighted random effects. Simple
reaction time, grooved pegboard, Trails A and B, picture completion
visual reproduction, eye-hand coordination and vocabulary had
significant effects for the fixed effects model only. The authors
conclude none of the individual studies were adequate or conclusive
of subclinical neurobehavioral effects of exposure to lead as the
biological effects of blood lead <70 ug/dL are inconsistent. (See
Schwartz et al. (2002) for comments).
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Table AX6-3.14 (cont'd). Meta-analyses of Neurobehavioral Effects with Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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United States (cont'd)
Schwartz et al. (2002)
Seeber et al. (2002)
Graves etal. (1991)
Letter to the Editor commenting on
shortcomings in the Goodman et al. (2002)
meta-analysis on studies of neurobehavioral
testing in workers occupationally exposed to
lead.
A comparison of the two meta-analyses
Meyer-Baron and Goodman) performed to
evaluate recommendations of a German BEI
of 40 ug/dL.
A meta-analysis on 11 case-control studies of
Alzheimer's disease for occupational
exposure to solvents and lead.
The six points regarding problems with the methodology included:
(1) no evaluation of quality of study design or statistical methods,
(2) data from poorly done and well done studies are combined,
(3) included 6 studies with no age adjustment and 3 with no
adjustment for education, (4) confounding of age and education
when addressed the variation across studies not discussed, (5) main
effect only examined exposed versus nonexposed comparisons that
are known to have the lowest power, cannot evaluated dose-effect
relationships and have a tendency for selection bias, and (6) few of
the 22 studies included contributed to effect size.
Effect size calculated for 12 tests in two meta-analyses and 10 tests
from one meta-analyses found subtle impairments associated with
blood lead between37 ug/dL and 52 ug/dL for Logical Memory,
Visual Reproduction, Simple Reaction Time, Attention Test 62,
Block Design, and Picture Completion, Santa Ana, Grooved
Pegboard and Eye-hand Coordination. Effect sizes related to age
norms between approximately 40 to 50 years. For example, -3 score
on Block Design = 10 to 15 years; -3.5 score on Digit Symbol =10
years; -21 score on Cancellation d2 = 10 years; and +5 to +6 on
Trails A = 10 to 20 years. This analyses concluded that both meta-
analyses supported recommendation for German BEI of 40 ug/dL.
Four studies had data for lead exposure with a pooled analysis of
relative risks for occupational lead of 0.71 (95% CI: 0.36, 1.41).
The exposure frequencies was 16/261 for the cases and 28/337 for
the controls.
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Table AX6-3.15. Neurophysiological Function and Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
oo
VO
Canada
Bleecker et al. (2005b)
New Brunswick
1992-=1993
74 current smelter workers, mean age
44 (8.4) years, education 8 (2.8) years and
employment duration 20 (5.3) year had
current perception threshold (CPT) measured
for large and small myelinated and
unmyelinated nerve fibers in the finger.
Linear regression modeled CPT on metrics
of lead dose after adjusting for covariates.
Interaction of lead dose and ergonomic
stressor on peripheral nerve function was
assessed.
Mean blood lead 26 (7.1)
ug/dL
Mean IBL 891 (298.8)
ug-yr/dL
Mean TWA 42 (8.4)ug/dL
Mean tibia bone 40 (23. 8)
5 metrics relating to IBL
cumulated only exposure
above increasing blood lead
ranging from 20 to
60 ug/dL
Blood lead and tibial bone lead were not associated with any of the
three nerve fiber populations. IBL and TWA accounted for a
significant percentage of the variance only for the large myelinated
nerve libers (AR2 = 3.9%, AR2 = 8.7% respectively). The relationship
of CPT and TWA was curvilinear with a minimum at a TWA of 28
ug/dL. Unique variance of CPT for large myelinated fibers explained
by different thresholds of IBL were IBL - 3.9%, p = 0.08; IBL20 -
5.8%, p < 0.03, IBL30 - 7.8%, p < 0.02; IBL40, p < 0.005; IBL50,
p < 0.005; and IBL60, p < 0.005. IBL60 also explained significant
variance of CPT for small myelinated nerve fibers demonstrating an
increased impairment in peripheral nerve function. This effect on
myelinated sensory nerve fibers was enhanced when a measure of
ergonomic stress was added to the model for IBL60.
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Europe
Kovalaetal. (1997)
Finland
60 workers in a lead battery factory with a
mean age of 43 (9) years and mean exposure
duration of 16 (8) years. Nerve conduction
studies, vibration thresholds, and quantitative
EEG were performed. Relationship of lead
exposure with peripheral nerve function and
quantitative EEG were examined by partial
correlation and regression analyses adjusting
for age.
Mean Tibial lead 26 (17)
mg/kg
Mean Calcaneal lead
88 (54) mg/kg
Mean IBL 546 (399)
ug-yr/dL
Mean TWA 34 (8.4) ug/dL,
Mean Max blood lead 53
(19) ug/dL,
Mean blood lead 27 (8.4)
ug/dL
The sensory amplitude of the median and sural nerves had a negative
correlation with IBL and duration of exposure that was not related to
age. Vibration threshold at the ankle related significantly to IBL and
duration of exposure after adjusting for age. Vibration threshold in
the finger was associated with blood lead and blood lead averages
over the past three years. The alpha and beta frequencies were more
present in workers with higher long term lead exposure such as tibial
and calcaneal, IBL and TWA. Overall historical blood lead measures
were more closely associated with peripheral nerve function than
bone lead concentrations. The study had no comparison group and
did not account for the effect of smoking and alcohol use or give their
usage in this population.
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Table AX6-3.15 (cont'd). Neurophysiological Function and Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Asia
Schwartz etal. (2001)
South Korea
1997-1999
Schwartz etal. (2003)
South Korea
1997-2001
804 workers from 26 different lead using
facilities and 135 controls with a mean age of
40 (10.1) and 35 (9.1) years respectively,
job duration of 8 (6.5) and 9 (5.3) years
respectively, and education level 42 % and
69% completed high school respectively had
comparable alcohol and smoking use. Linear
regression used to compare vibration
threshold in lead exposed and controls
controlling for potential confounders.
Longitudinal decline in neurobehavioral
performance examined in 576 of the above
group of lead exposed workers who
completed 3 visits at one year intervals.
Mean age at baseline was 41 (9.5) years and
job duration 9 (6.3) years and 76% were
men.
Compared to non-completers lead workers
who completed 3 visits were 3.3 years older,
baseline mean blood lead was 2.0ug/dL
lower, on the job 1.6 years longer, 24%
women vs. 10% of noncompleters, and
usually had less than high school education.
Models examined short-term versus long-
term effects. Final model had current blood
lead, tibia bone lead and longitudinal blood
lead and covariates.
Lead-exposed workers
Mean blood lead 32 (15)
ug/dL
Tibia bone lead 37 (40.3)
ug/g
DMSA-chelatable lead
level 186(208. l)ug
(4 hour collection)
Baseline mean blood lead
31 (14.2) ug/dL
Tibia lead 38 (43) ug/g
After adjustment for age, gender, education and height, tibia lead but
not blood lead was significantly associated with poorer vibration
threshold in the dominant great toe but not the finger (P = -0.0020
[SE 0.0007], p < 0.01). These results contrast with those for
neurobehavioral measures (see above) performed in the same study
where tibial lead was not a predictor of performance.
After adjustment for age, visit number, education, gender, height
(for vibration) and BMI (for grip strength and pinch) vibration
threshold in the dominant great toe and not the finger was associated
with tibia lead (P = -0.0006 [95% CI: -0.0010, -0.0002]) and
longitudinal blood lead (P = -0.0051 [95% CI: -0.0078, -0.0024])
in one Model and blood lead (P = -0.0019 [95% CI: -0.0039,
0.0001]) in another model.
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Table AX6-3.15 (cont'd). Neurophysiological Function and Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Asia (cont'd)
Chuang et al. (2000)
Taiwan
Chiaetal. (1996a)
Singapore
206 lead battery workers, mean age 41 years,
with annual blood lead for the previous five
years had vibration perception measured in
hand and foot. Relationship of lead exposure
term and vibration perception threshold
assessed with multiple regressions, hockey
stick regression analysis after adjusting for
potential confounders.
72 workers in a lead battery manufacturing
factory with a mean age of 30 years and
reference group of 82 workers had nerve
conduction studies and blood lead performed
every 6 months over the course of three
years. Only 28 lead battery workers
completed the program. At the end of the
first year of the 82 workers in the comparison
group only 26 remained and by year 3 this
had decreased to 4. Mean nerve conduction
values examined by ANCOVA between the
exposed and reference after adjustment for
age, ethnic group, smoking and drinking
habits. Analysis of serial nerve conduction
values and blood lead treated as a clustered
sample had the within-cluster regression
coefficient examined. The 28 exposed
workers were stratified by blood lead level
and the relationship between nerve
conduction values and blood tested within
the cluster.
Mean blood lead 28 ug/dL,
Mean blood lead over past
5 years 32 ug/dL
Mean maximum blood lead
39 ug/dL
Mean index of cumulative
exposure 425 ug-yr/dL,
Mean TWA 32 ug/dL
Mean working duration
13 years and life span in
work 31%.
The geometric mean blood
lead concentrations for the
6 testing periods were 37,
41, 42,40, 41, and
37 ug/dL.
The overall range for blood
lead was 16-73 ug/dL.
After adjustment for age, sex, body height, smoking, alcohol
consumption, and use of vibrating hand tools, significant association
between mean blood lead and mean TWA and vibration perception in
the foot were found. After adjustment for the covariates, a hockey
stick regression analysis of foot vibration threshold versus mean
blood lead concentration for 5 years found an inflection point around
30 ug/dL with a positive linear relation above this point suggesting
a potential threshold.
The relationship between blood lead levels and nerve conduction
values for the 28 exposed workers was significant for all outcomes
except median motor conduction velocity and ulnar sensory nerve
conduction velocity and ulnar sensory amplitude. The regression
correlation coefficients for blood lead >40 ug/dL was significant for
all parameters except the median sensory conduction velocity and
for blood lead <40 ug/dL there was no association with nerve
conduction values. Therefore the blood lead level associated with
no change in nerve conduction studies was <40 ug/dL.
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Table AX6-3.15 (cont'd). Neurophysiological Function and Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Asia (cont'd)
Chiaetal. (1996b)
Singapore
Chuang et al. (2004)
Taiwan
Yokoyama et al.
(1998)
Japan
Extension of above study - 72 workers in
lead battery manufacturing and 82 controls.
Mean duration of exposure 5.3 years.
181 lead battery manufacture workers were
stratified by milk drinkers, n = 158 and non-
or rare mild drinkers n = 23. Mean age in the
two groups was 40 and 36 years and working
duration 10/8 years respectively. Peripheral
nerve evaluation was with current perception
threshold at 3 frequencies 5Hz = C fibers,
250 Hz = A-delta fibers and 2000 Hz = A-
beta fibers. Linear regression estimated the
association of CPT and lead exposure
variable and adjustment of milk intake and
potential confounders.
17 gun-metal workers, mean age 48 years
and a 20 controls with a mean age of 45 years
had distribution of conduction velocities
(DCV) measured and the maximum median
sensory conduction velocity (SVC)
performed twice at a year interval. Group
differences controlling for confounders and
dose-effect relationships were examined.
Mean blood lead 37 ug/dL
Mean blood lead
cumulative
137 ug-yr/dL
Blood lead 25 ug/dL
milk drinkers
30 ug/dL non or rare milk
drinkers
TWA 28 ug/dL milk
drinkers
32 ug/dL non or rare milk
drinkers
IBL 316 ug-yr/dL milk
drinkers
245 ug-yr/dL non or rare
mild drinkers
Mean blood lead 40 ug/dL
Mean mobilized Pb
(CaEDTA) in urine
1 mg/24 h
ANCOVA found significant differences for all nerve conduction
parameters except three for the ulnar nerve, after adjusting for age,
ethnic groups, smoking and drinking habits. There was no
significant correlation between blood lead and blood leadCum with
nerve conduction values after linear regression with adjustment for
confounders. When blood leadCum was stratified- 12 workers
<40 ug-yr/dL, 28 workers 40-300 ug-yr/dL, 21 workers >300 ug-
yr/dL ANCOVA found significant differences for 5 nerve conduction
parameters. The strongest dose effect relationship was for sensory
nerve conduction velocity.
Age was significantly different but distributions of gender, smoking,
alcohol use, use of hand vibration tool, working history and height
were not different. Linear regressions found association of 5 Hz CPT
and 250 Hz CPT in hand and foot with blood lead and TWA but not
IBL. However the protective effects of drinking milk was present for
all fiber populations only in the hands. This paper presents an
unusual finding of subclinical lead neuropathy involving the
unmyelinated and small myelinated fibers. Toxic axonopathies
classically involve the large nerve libers. The main group difference
may be related to other nutritional deficiencies associated with the
malabsorption syndrome that lead to the non-milk drinking status.
ANCOVA controlling for age and alcohol found mobilized lead was
associated with significant slowing in the large nerve fibers while
blood lead was not. Workers with increased change in mobilized
lead over 1 year interval (mean 0.44 mg/24hr) had significant
reduction in large fiber (V95) conduction velocity while those
workers with less change in mobilized lead (0.08 mg/24hr) did not
have significant change in DCV or SVC. It appears that larger faster
conducting nerve fibers are susceptible to lead and a measure of body
burden (readily mobilized lead from soft tissue) is a stronger
predictor of this change than blood lead.
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Table AX6-3.15 (cont'd). Neurophysiological Function and Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Asia (cont'd)
Heetal. (1988)
China
Niu et al. (2000)
China
40 workers in a lead smelter with age range
20 to 45 years (no mean provided) and
duration of exposure 5.4 years. Fifty controls
age 20 to 55 years. Nerve conduction studies
examined 11 parameters. Student = s t-test
examined for differences between exposed
and controls.
44 lead-exposed workers (17 men,
27 women) from lead printing houses, mean
age 35 (4.9) and education 9.3 (no SD)years
and 34 controls (19 men and 15 women),
mean age 33 (7.4) years and education 9.5
(no SD) years had nerve conduction studies
for maximal motor nerve conduction
velocity. ANCOVA controlling for age, sex
and education examined group differences
and linear regression for dose-response
relationship.
Mean blood lead 40 ug/dL
Mean urinary lead 71 ug/dL
Mean ALAU5 ug/dL
Mean blood lead 29 (26.5)
ug/dL
(8 workers blood lead
exceeded 50 ug/dL)
Controls
Mean blood lead 13 (9.9)
ug/dL
(1 control blood lead
exceeded 50 ug/dL)
There were no symptoms or signs of peripheral nerve disorder.
Both motor and sensory conduction velocities were slowed in the
lead exposed groups. 10 nerve conduction parameters were
significant in the group with blood lead >40 ug/dL and 6 parameters
were significant in the group with blood lead <40 ug/dL. An unusual
finding in this study was the lack of age association with nerve
conduction values and therefore it was not controlled for in the
analyses.
Only 12 lead exposed workers and 24 controls examined for NCV.
Left ulnar nerve was significantly slower but the left median and
right ulnar were faster in the lead exposed and the right median was
slightly slower. This appears to be a finding of chance due to the
small n. For the lead exposed group mean left ulnar C V was
52 while the mean right ulnar CV was 59 while for the controls left
ulnar CV was 58 while the mean right ulnar CV was 55.
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Table AX6-3.16. Evoked Potentials and Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Canada
Bleecker et al. (2003)
New Brunswick
1992-1993
359 currently employed smelter workers,
mean age 41 years, had brainstem auditory
evoked potentials (BAEP) measured.
Relationship between absolute latencies and
interpeak latencies assessed using linear
regression after adjusting for potential
confounders. Exposure was assessed in cases
with clinical abnormalities in Wave I and I-V
interpeak latency compared to those workers
with normal BAEP using post-hoc analysis.
Mean blood lead 28 ug/dL
Mean TWA 39 ug/dL
MeanIBL719ug-yr/dL
Linear regression after the contribution of age found blood lead and
TWA were significantly associated with Wave I while IBL was
significantly associated with Wave III and I-III interpeak interval.
Four groups created with increasing abnormalities based upon
clinical cut-off scores for Wave I and I-V interpeak interval had
similar age. blood lead, TWA and IBL were all significantly higher
in the group with prolonged Wave I and I-V interpeak interval
compared to the group with normal BAEP = s. These findings
support involvement of the brainstem and auditory nerve with lead
exposure.
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Europe
Abbateetal. (1995)
Italy
Discalzi et al. (1992)
Italy
Discalzi etal. (1993)
Italy
300 lead exposed men ages 30 to 40 years in
good health with no other neurotoxic
exposure had P100 latency measured for
visual evoked potentials (VEP) for 15 and
30 minute of arc. Groups created based upon
blood lead had VEPS examined followed by
linear regression for each group.
49 lead exposed workers and 49 age and sex
matched controls had BAEPs measured.
Relationship of 6 BAEP outcome variables
and lead exposure examined with analysis of
variance and linear regression.
22 battery storage workers, mean age
35 years and 22 control group, age and sex
matched, with normal hearing had BAEPs
recorded. Latencies I and V and lead
exposure examined by ANOVA after
stratifying blood lead.
Blood lead 17 to 60 ug/dL
range
Mean blood lead for
4 groups
n = 39 23 ug/dL
n= 113 30 ug/dL
n = 89 47 ug/dL
n = 59 56 ug/dL
Mean blood lead 55 ug/dL
and TWA for previous 3
years 54 ug/dL
Mean blood lead 48ug/dL
ANOVA of the blood lead and PI 00 latencies were significantly
prolonged for 15 and 30 minutes of arc. Linear regression found the
association of blood lead and P100 were significant in each group but
the relationship was not proportional (angular coefficient). Effect of
blood lead on VEP began at 17-20 ug/dL. With age limited to one
decade, contribution from age was not a concern. Even though no
comparison group, careful screening ruled out other medical and eye
conditions and other potential exposures.
Latencies for waves I, III, V and interpeak latencies, I-V, I-III, and
III-V were all significantly prolonged in the lead-exposed workers
(p < 0.04). No significant association found with linear regression
between BAEP outcomes and exposure variables. In those workers
with TWA >50 ug/dL, I-V latency was significantly prolonged
compared to workers with TWA <50 ug/dL.
Interpeak latency I-V was significantly prolonged in lead exposed
workers (p = 0.001). No significant associations by linear regression
between I-V and lead exposure. Stratifying lead exposed workers by
blood lead 50 ug/dL found I-V interpeak latency significantly
prolonged (p = 0.03) in subgroup with higher blood lead.
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Table AX6-3.16 (cont'd). Evoked Potentials and Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Latin America
Counter et al. (2002)
Ecuador
30 lead-glazing workers, median age
35 years, had pure-tone thresholds and
BAEPs performed. Regression analyses
examined relations between auditory
outcomes and blood lead.
Mean blood lead 45 ug/dL
(range 11 to 80 ug/dL)
Sixty percent of the men and 20 percent of the women had abnormal
high-frequency thresholds, however there was no significant
relationship with blood lead and pure tone threshold at all
frequencies. Analysis of BAEPs found agreement between latencies
for Waves I, III and V and peripheral hearing status. Interpeak
latencies were within normal limits but no analysis provided with
lead exposure. Workers lived in a lead contaminated environment
from discarded lead-acid storage batteries. Therefore a measure of
chronic lead exposure may have been more appropriate.
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Asia
Holdstein et al. (1986)
Israel
20 adults and 8 children (mean age 27 years,
range 8-56 years) accidentally exposed to
lead through food until one year prior to
measurement of BAEP.
Hirataetal. (1993)
Japan
41 lead-exposed men from lead-glass-based
colors manufacturing (n = 20), production of
lead electrode plates (n = 8), casting of lead-
bronze (n = 4) and casting of lead pipes and
plates (n = 9) had mean age 41 years, mean
duration of exposure 13 years. A battery of
tests administered including radial nerve
conduction study, electroretinogram (ERG),
visual evoked potential (VEP), brainstem
auditory evoked potential (BAER), and short-
latency somatosensory evoked potential
(SSEP). Comparison group of 39 unexposed
used only for BAER analysis by Student's
t test. Correlation and linear regression
controlling for age examined the relationship
of lead and the other variables.
Adult mean blood lead
31 ug/dL
Children mean blood lead
22 ug/dL
In the adults 10 month
average blood lead in adults
43 ug/dL and in children
36 ug/dL
Mean blood lead 43 ug/dL
(13-70)
Mean TWA based upon
previous 5 years 43 ug/dL
(13-70)
Mean duration of exposure
13 (0.6-29) years.
In adults, latencies I, III and I-III and I-V interpeak intervals were
significantly longer than the control group (p < 0.05). When group
stratified by 10 month average blood lead I-III interpeak interval was
longer in the high group. Age and blood lead were not studied due to
few subjects. The I-III interpeak interval reflects transmission in the
lower brainstem and VHIth nerve.
Significant partial correlation after adjusting for age included TWA
and radial motor conduction velocity, blood lead and sensory
conduction velocity, exposure duration and VEP, blood lead and
SSEP-N20. Comparison of BAERs of 15 lead exposed and 39
controls found interpeak interval III-V was prolonged significantly.
It is not clear why comparison group only used for BAERs.
Considering the large number of variables examined with three
exposure terms some of the findings could be by chance alone.
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Table AX6-3.16 (cont'd). Evoked Potentials and Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
OD
Oi
Asia (cont'd)
Murataetal. (1993)
Japan
22 gunmetal foundry workers with age range
of 32 to 59 years and work duration of 1 to
19 years and control group matched for age,
no chronic disease and no lead exposure
participated. No significant difference
between groups for age, height, skin
temperature, alcohol consumption, and years
of schooling. The test battery consisted of
visual evoked potential (VEP), brainstem
auditory evoked potential (BAEP), short
latency somatosensory-evoked potential
(SSEP), event related potential (P300) and
EKG R-R interval variability. Paired-sample
t test examined for differences between the
matched groups. Dose-effect relationships
examined with partial correlation adjusting
for age and stepwise linear regression.
Blood lead 12 to 64 ug/dL
(no mean provided)
For VEPs, N75 and N145 were significantly prolonged in the lead
exposed workers. N9-N13 interpeak latency of the SSEP was
significantly prolonged. BAEP latencies showed no significant
differences. P300 believed to reflect cognitive function was
prolonged in the lead workers and correlated with blood lead, and
PbU. Autonomic nervous system effects were significantly
diminished for CVR.Rand for a measure of parasympathetic activity
C-CVRSA. Fifty percent of the outcome variables showed significant
group differences but there is limited dose effect for any outcome
within the exposed group. Small sample size limited conclusions
with 20 outcome variables and 8 biomarkers of lead exposure.
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O
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Table AX6-3.17. Postural Stability, Autonomic Testing, Electroencephalogram, Hearing Thresholds, and
Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Europe
Kovalaetal. (1997)
Finland
60 workers in a lead battery factory with a
mean age of 43 (9) years and mean exposure
duration of 16 (8) years. Quantitative EEG
were performed. Relationship of lead
exposure with quantitative EEG were
examined by partial correlation and
regression analyses adjusting for age.
Meantibiallead26(17)
mg/kg
Mean calcaneal lead
88 (54) mg/kg
Mean IBL 546 (399)
ug-yr/dL,
Mean TWA 34 (8.4) ug/dL,
Mean max blood lead 53
(19)ng/dL,
Mean blood lead 27 (8.4)
ug/dL
The alpha and/or beta frequencies were more present in workers with
higher long term lead exposure such as tibial (p < 0.05) and calcaneal
(p < 0.05), IBL (p < 0.01) and TWA (p < 0.05). Slow alpha in
workers was believed to correlate with increased episodes of
'microdrowsiness'. The study had no comparison group and did not
account for the effect of smoking and alcohol use or give their usage
in this population.
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o
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O
O
H
W
O
O
HH
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W
Asia
Yokoyama et al.
(1997)
Japan
Chiaetal. (1994)
Singapore
Chiaetal. (1997)
Singapore
49 chemical workers exposed to lead
stearate, mean age 48 (1.3) years and
23 controls, mean age 47 (2.5) had postural
sway evaluated. ANCOVA examined group
differences after adjusting for covariates.
60 lead storage workers, mean age 32 (7.7)
years and 60 controls, mean age 35 (7.4) had
postural sway parameters measured.
ANCOVA used to examine group differences
after adjusting for covariates. Linear
regression examined relationship between
lead exposure and postural sway.
The same 60 lead storage workers as above
and 60 control had postural sway data
examined for contribution of cumulative
blood lead fractionated over 10 years of
exposure.
Mean blood lead 18 (1.0)
ug/dL
Mean maximum blood lead
48 (3.8) ug/dL
TWA 24 (1.3) ug/dL
Cumulative blood lead 391
(48.2) ug-yr/dL
Mean blood lead 36 (11.7)
ug/dL
Controls
Mean blood lead 6 (2.4)
ug/dL
Mean blood lead 36 (11.7)
ug/dL
Controls
Mean blood lead 6 (2.4)
ug/dL
There were significant increases in sway in all directions at high and
low frequencies with eyes open and eyes closed (p < 0.05).
Regression analysis found blood lead associated with sway in the
anterior-posterior direction, .5-lHz (0.321, p = 0.03), l-2Hz (0.313,
p = 0.04) and TWA associated with right to left sway (0.326,
p = 0.02) after adjustment for the covariates age, height, weight and
alcohol consumption. The authors conclude that change in the
vestibule-cerebellum is affected by blood lead while in the anterior
cerebellar lobe is affected by past lead exposure.
Computerized postural sway measurements found lead workers
have poorer postural stability that increased with eyes closed
(p < 0.01). Regression analysis adjusting for age, height, and
weight found no significant association with blood lead.
The lead exposed group had significantly poorer performance on all
postural sway parameters with eyes closed compared to controls after
adjusting for height, weight, age and drinking habits (p < 0.01).
All postural sway parameters with eyes closed were significantly
associated with IBL for the 2 years prior to testing (n = 23, p < 0.05).
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Table AX6-3.17 (cont'd). Postural Stability, Autonomic Testing, Electroencephalogram, Hearing Thresholds, and
Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
oo
H
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o
o
H
O
O
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W
O
O
HH
H
W
Asia (cont'd)
Ratzon et al. (2000)
Israel
Teruyaetal. (1991)
Japan
Ishidaetal. (1996)
Japan
63 lead battery workers, mean age 39 (8.7)
years and 48 controls mean age 36 (11.8)
years, matched for age with similar sex and
education, had postural control measured.
Group differences examined with t test.
Dose-effect relations assessed with
Pearson = s correlation coefficients. Linear
regression done with exposure category as
major predictor.
172 lead exposed workers, mean age 34
(18.4-57.4)years had cardiac autonomic
nervous system evaluated by R-R intervals
variation with respiration measured.
128 workers in the ceramic painting industry,
58 men, mean age 55 (11.7) years and
70 women, mean age 52 (9.2) years had
measures of sympathetic function by
variations in R-R interval on EKG and
changes in finger blood flow with postural
changes using Doppler flowmetry.
Correlation analyses and linear regression
examined relationship of finger blood flow
and lead exposure after adjusting for
covariates.
Mean past blood lead
38 ug/dL, mean years
employed 11 and
cumulative lead determined
by average blood lead X
years employed
Mean blood lead 36 (5-76)
ug/dL
Men
Mean lead 17 (2.1) ug/dL
ALAD62 (28.3)5
Women
Mean blood lead 11 (1.7)
ug/dL
ALAD73 (20.8)%
Using a computerized sway measurement system the exposed
workers had significantly increased mean body oscillations with eyes
closed (p < 0.01) and head tilted forward (p < 0.001). Partial
correlation adjusting for education, coffee consumption, hours of
sleep and estimate of health was significant only for total lead
exposure and increased body oscillations with head tilted forward
(p= 2.25, p = 0.0089). In order to maintain balance lead exposed
workers required increased oscillations when visual and vestibular
inputs were altered.
Age adjustment controlled for by use of ratios of predicted to
observed values. A significant dose related decrease of R-R interval
variation during deep breathing was present in 132 workers with
stable blood lead over the past year (p < 0.01). This finding was
more prominent in younger workers with blood lead > 30 ug/dL but a
mild decrease present at blood lead >20 ug/dL. A decrease in R-R
interval variation indicates decreased cardiac parasympathetic
function.
22% had blood lead >20 ug/dL, and 43% had ALAD% <60%. The
46 workers in the lowest group with blood lead <10 ug/dL had
ALAD%>80% equivalent to nonoccupational exposure and therefore
served as the control group. Blood lead (P = 0.205, p = 0.02),
smoking (P = -0.464, p < 0.01), and BMI (P = 0.213, p = 0.01) were
significant predictors of change in finger blood flow with postural
change. Decrease in change of finger blood flow is compatible with
a peripheral sympathetic nerve impairment.
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Table AX6-3.17 (cont'd). Postural Stability, Autonomic Testing, Electroencephalogram, Hearing Thresholds, and
Occupational Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia (cont'd)
Niu et al. (2000)
China
44 lead-exposed workers (17 men, 27
women) from lead printing houses, mean age
35 (4.9) and education 9.3 (no SD) years and
34 controls (19 men and 15 women), mean
age 33 (7.4) years and education 9.5 (no SD)
years had autonomic nervous system
examined. ANCOVA controlling for age,
sex and education examined group
differences and linear regression for dose-
response relationship.
Mean blood lead 29 (26.5)
ug/dL
(8 workers blood lead
exceeded 50 ug/dL)
Controls
Mean blood lead 13 (9.9)
ug/dL
(1 control blood lead
exceeded 50 ug/dL)
Niu et al. (2000) examined autonomic nervous system in 44 lead
exposed workers, mean blood lead 29 ug/dL, and 34 controls, mean
blood lead, 13 ug/dL. Linear regression found association between
blood lead and decreased R-R interval with valsalva (F/T2.349,
p < 0.05) and duration of lead exposure and decreased R-R interval
with deep breathing (F/T 3.263, p < 0.01) after adjusting for age, sex,
education, smoking and drinking. In the same study, quantitative
EEG found significant abnormalities in the lead-exposed workers,
dominant low amplitude in 59%, dominant beta frequency in 42%
and abnormalities in 81%.
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O
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W
O
O
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Table AX6-3.18. Other Neurological Outcomes Associated with Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
O
O
H
6
o
o
H
O
O
H
W
O
United States
Louis et al. 2005
New York
63 cases of essential tremor (ET) and 101
controls, similar for age, 67 (16.6) and 65
(11.1) years, education, gender and ethnicity
were examined for interaction of blood lead
and ALAD gene polymorphisms and
increased odds of ET.
Louis et al. 2003
New York
100 cases of ET and 143 controls matched
for age, sex, and ethnicity.
The relationship between blood lead and ET
was examined.
ET
Mean blood lead 4 (2.2)
Controls
Mean blood lead 3 (1.5)
2 ET cases but no controls
had blood lead >10 ng/dL
ET
Mean blood lead 3 ng/dL
Controls
Mean blood lead 2 ng/dL
Of the 63 ET cases 18 (29%) vs. 17 (17%) of 101 controls had an
ALAD-2 allele (OR 1.98 [95% CI: 0.93, 4.21]; p = 0.077). When
log blood lead was examined by presence of ALAD2 allele in ET,
log blood lead was highest in ET cases with and ALAD2 allele,
intermediate in ET cases without an ALAD2 allele and lowest in
controls (test for trend, p = 0.10; p = 0.001). When ALAD2 allele
was present, blood lead was significantly associated with odds of ET
(OR 80.29 [95% CI: 3.08, 2.096]; p = 0.008). This increased odds
of ET with an ALAD-2 allele was 30 times greater than in an
individual with only an ALAD-1 alleles. In the highest log blood
lead tertile, ALAD2 allele was present in 22% of ET cases and 5% of
controls. It was proposed that increased blood lead along with the
ALAD2 allele could affect the cerebellum and thereby increase the
risk of tremor.
Ten cases and 7 controls had bone lead levels measured that were
significantly correlated with blood lead suggesting that higher blood
lead may have occurred in the past. Total tremor score was
correlated with blood lead (r = 0.14, p = 0.03). Logistic regression
adjusting for age and current cigarette smoking found the odds ratio
for ET was 1.19 (95% CI: 1.03,1.37) per unit increase in blood lead.
Blood lead was higher in those 39 ET cases with no family history.
Both current and lifetime prevalence of occupational lead exposure
was the same in ET cases and controls but those with history of
occupational exposure did have a higher blood lead than those
without this history (median, 3.1 ng/dL vs. 2.4 |ig/dL, p = 0.004).
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Table AX6-3.18 (cont'd). Other Neurological Outcomes Associated with Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
H
6
o
o
H
O
United States (cont'd)
Kamel et al. (2002)
Massachusetts
Kamel et al. (2003)
Massachusetts
Armonetal(1991)
Minnesota
109 cases of ALS and 256 controls matched
for age, sex and region of residence
examined the relation of lead and ALS.
As above, the same data was used to
determine the associations of ALS with
polymorphism in ALAD and the vitamin D
receptor (VDR) and the influence of
genotype.
A case-control design with 47 ALS patients,
mean age 61 with involvement of upper and
lower motor neurons and 201 controls, mean
age 62. For the lead exposure analysis
45 male matched pairs were examined.
Cases/controls
Mean blood lead
5(0.4)73(0.4) ug/dL
3 cases and no controls had
blood lead >10 ug/dL .
Patella lead 21(2.1)717
(2.0) ug/g
5 cases and 1 control had
patella lead levels >50 ug/g
Tibia lead 15(1.6)711(1.6)
ug/g
2 cases and no controls had
tibia lead >50 ug/g.
Same as above
Lifetime exposure to lead
of 200 hours or more (years
on job x hours spent per
week)
Increased risk of ALS was found for history of occupational lead
exposure (adjusted OR 1.9 [95% CI: 1.1, 3.3]) increased lifetime
days of exposure (adjusted OR 2.3 [95% CI: 1.1,4.9]). Association
of blood lead and ALS (adjusted OR 1.9 [95% CI: 1.4, 2.6]).
Elevation in both blood lead and patella and tibia bone lead was
found in ALS cases though the precision of these measurements was
questioned (Patella lead adjusted OR 3.6 [95% CI: 0.6, 20.6] and
tibia lead adjusted OR 2.3 [95% CI: 0.4, 14.5]). Therefore, this
study found lead exposure from historical questionnaire data and
biological markers associated with ALS.
The ALAD2 allele was associated with a 2-fold increase risk of ALS
after adjustment for the covariates, age, sex, region, education and
physical activity adjusted (OR 1.9 [95% CI: 0.60, 6.3]).
Additionally adjusting for blood lead strengthened the association of
ALAD2 and ALS risk adjusted (OR 3.6 [95% CI: 0.9,15]). This
was not found for bone lead or occupational history of lead exposure
(Patella adjusted OR 2.1 [95% CI: 0.61,6.9]; tibial adjusted (OR 2.2
[95% CI: 0.66, 7.3]; occup his adjusted (OR 2.4 [95% CI: 0.67,
8.7]). VDR was not associated with lead or ALS risk.
Of 13 discordant pairs for lead exposure, 11 were in ALS patient.
The relative risk was 5.5 (95%CI: 1.44,21.0). A dose-response was
weakened by 3 controls with highest lifetime exposure. Men with
ALS worked more often at blue collar jobs and significantly more
time welding (p < 0.01). These results expanded a prior pilot study
that found a higher incidence of heavy metal exposure in ALS cases.
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Table AX6-3.18 (cont'd). Other Neurological Outcomes Associated with Lead Exposure in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
O
to
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O
Europe
Chancellor et al.
(1993)
Scotland 1990-1991
Gunnarsson et al.
(1992) Sweden 1990
Guidetti et al. (1996)
Italy
Vincetietal. (1997)
Italy
A case-control design 103 ALS patients from
the Scottish Motor Neuron Disease Register
and matched community controls.
Differences in potential occupational
exposures were determined between cases
and controls.
A case-control study of 92 cases of MND
and 372 controls. MND included ALS,
progressive bulbar paresis (PBP), and
progressive muscular atrophy (PMA).
Relation of MND to risk factors including
occupational exposure examined.
A retrospective incidence, prevalence, and
mortality survey of ALS in northern Italy
was performed.
19 ALS cases, mean age 66 (14) years and
39 controls, mean age 64 (12.9) years.
Exposure to lead obtained
by lifetime employment
history from Office of
Population and Censuses
and Surveys. Physician's
record review and direct
interview questionnaire.
Exposure information
obtained by self-
administered questionnaire.
Mean air lead 3ug/m3 in
1975tolug/m3inl985;
blood lead in monitored
children decreased 18, 14,
and 11 ug/dL in same time
period.
Sporadic ALS
Mean blood lead of
13 (6.8) ug/dL
Controls
mean blood lead
11 (4.4) ug/dL
Odds ration for manual labor in ALS patients was 2.6 (95% CI: 1.1,
6.3). Occupational exposure to lead was more common in ALS
patients (OR 5.7 [95% CI: 1.6, 30]).
Exposure to heavy metals primarily from welding had an increased
Mantel-Haenszel odds ratio of 3.7 [95% CI: 1.1,13.0].
The area studied had documented lead pollution for years. Based
upon 79 cases incidence and prevalence rate were comparable to the
surrounding area.
There were no cases familial ALS. Blood lead between ALS cases
and controls was not significantly different. Blood lead was
associated with disability due to ALS but no support was found for
involvement of lead in the etiology of sporadic ALS.
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Table AX6-3.19. Occupational Exposure to Organolead and Inorganic Lead in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
O
oo
H
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o
o
H
O
United States
Schwartz etal. (1993)
Stewart etal. (1999)
Two hundred and twenty-two current
employees that manufactured tetraethyl lead
participated in a study to determine if there
was impairment on a neurobehavioral battery
associated with a measure of cumulative
exposure to organic and inorganic lead
derived from 12 years of air sampling.
Mean age was 44 (8.7) years, education
13 (1.7) years.
543 former organolead workers, mean years
since last exposurelS, examined for ongoing
neurobehavioral impairment related to past
lead exposure. Thirty-eight % were age 60
or older, predominantly white, 93% had at
least a high school degree. Linear regression
assessed the relationship between lead dose
and neurobehavioral function adjusting for
the covariates.
Cumulative lead exposure,
inorganic and organic
869 (769) ug-yr/m3
Mean years of exposure
13(9.5)
Meantibialleadl4(9.3)
Peak tibial bone lead
extrapolated back using a
clearance half-time of lead in
tibia of 27 years 24 (17.4)
DMSA chelatable lead level
19 (17.2) ug (urine collected
for 4 hours)
Exposure was divided into 4 groups with the lowest for years of
exposure and cumulative lead exposure serving as the reference
group. After adjustments for premorbid intellectual ability, age, race,
and alcohol consumption, cumulative lead exposure had differential
association poorer performance in many cognitive domains but most
often in manual dexterity and verbal memory/learning. Performance
on tests associated with exposure was 5 to 22% lower in the highest
groups when compared with the low exposure reference group.
Peak tibial lead was a significant predictor of poorer performance on
vocabulary (P = -0.063, p = 0.02), serial digit learning (P = -0.043,
p = 0.04), RAVLT trial 1 (P = -0.054, p = 0.03), RAVLT
recognition (P = -0.019, p = 0.03), Trails B (P = -0.002, p = 0.03),
finger tapping nondominant (P = -0.042, p = 0.02), Purdue pegboard
dominant (P = -0.043, p = 0.00); nondominant (P = -0.49, p = 0.00),
both (P = -0.038, p = 0.00) assembly ( p = -0.133, p = 0.00) and
Stroop (P = -0.014, p = 0.00). Current tibial lead had similar
associations Vocabulary (P = 0.103, p = 0.04), Digit Symbol (P =
-0.095, p = 0.05), finger tapping dominant( p = -0.87, p = 0.02 ),
Finger tapping nondominant (P = 00.102, p = 0.00 ), Purdue
Pegboard dominant (P = -0.065, p = 0.01), nondominant (P =
-0.091, p = 0.00), both (P = -0.068, p = 0.00), assembly (p =
-0.197, p = 0.03 ), Stroop (P = 0.017, p = 0.01). DMSA-chelatable
lead was only significantly associated with choice reaction time
(P =-0.001, p = 0.01).
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Table AX6-3.19 (cont'd). Occupational Exposure to Organolead and Inorganic Lead in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
H
6
o
o
H
O
United States (cont'd)
Stewart et al. (2002)
Balbusetal. (1997)
Balbusetal. (1998)
From the above group of former organolead
workers 535 were re-examined twice or four
times over a four year period. Also a
nonexposed control group of 118 had repeat
examinations. Mean age at first visit
exposed/controls 56 (7.4)759 (7.0),
percentage with at least a high school
education 66/71.2.
222 organolead manufacturing workers,
mean age 44 (8.7) years and 62 nonexposed
referents, mean age 43 (10) years performed
simple visual reaction time (SVRT). Linear
regression examined relationship between
lead exposure and mean RT, median RT and
standard deviation of RT after controlling for
covariates.
A second publication further examined the
above data for relationship of interstimulus
interval (ISI) and lead exposure.
First examination
Mean blood lead 5 (2.7) ug/dL
Mean tibia lead 14 (9.3) ug/g
Mean peak tibia lead 23 (16.5)
ug/g
Mean exposure duration 8
(9.7) years
Mean duration since last
exposure 16 (11.7) years
Mean blood lead 20 (9.5)
ug/dL
Mean peak urine lead level
143 (130)ug/L
Same as above
On 17 of 19 neurobehavioral tests, former organolead workers
demonstrated greater annual decline in adjusted test scores
compared to controls with significant differences for Rey complex
Figure copy, RAVLT Trial 1 and RAVLT recognition. Annual
declines in performance showed greater age-related change in lead
workers compared to controls for block design, digit symbol,
serial digit learning, finger tapping and Trails A. Blood lead did
not predict annual change scores but peak tibial lead did for
symbol digit, Rey Complex Figure delayed recall, RAVLT trial 1 ,
RAVLT delayed recall, Purdue pegboard (1 measure) and the
Stroop. For these 6 tests it was determined that an increase of
15.7 ug/g bone mineral of peak tibia lead was equivalent in its
effect on annual test decline to 5 more years of age at baseline.
Authors conclude that data supports ongoing cognitive decline
associated with past occupational exposure to lead.
Short ISIs,l-3 seconds, had no relationship with lead exposure
while ISIs of 4-6 seconds were significantly associated with blood
lead (P = 0.06 [SE 0.02], p = 0.02 along with ISIs of 7-10 seconds
(P = 0.05 [SE 0.02], p = 0.03). ISIs 7-10 seconds with peak urine
lead levels (P = 64.29 [SE 21.86], p < 0.01).
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Table AX6-3.19 (cont'd). Occupational Exposure to Organolead and Inorganic Lead in Adults
Reference, Study
Location, and Period Study Description
Lead Measurement
Findings, Interpretation
X
H
6
o
o
H
O
United States (cont'd)
Stewart et al. (2002)
Tassleretal. (2001)
Bollaetal. (1995)
Population as described in Stewart et al.
(1999) and Schwartz et al. (2000). Data on
20 neurobehavioral tests from 529 former
organolead workers were evaluated to
determine if the previously described
relationship with bone lead levels is
influenced by the apolipoprotein E
(ApoE) genotype.
490 former organolead workers, mean age
58 (7.5) years. The peripheral nervous
system was examined with sensory pressure
thresholds, and pinch and grip strength.
190 current workers in organolead
manufacturing (from the 222 described in
Schwartz et al. 1993) mean age 45 (8) years
compared to 52 referents, mean age 45 (8)
years and 144 solvent exposed workers,
mean age 42 (8) years.
Mean blood lead 5 (2.6) ng/dL
Mean DMSA-Chelatable lead
19 (16.3) ng,
Mean current tibia lead 15 (9.4)
Peak tibia lead 24 (17.6) ng/g
IH found organic lead was 65
to 70% of exposure in
production area.
Weighted average blood lead
24 (9.4) ng/dL
In 20 linear regression models, coefficients for the ApoE and tibia
lead interaction term were negative in 19 with significance
reached for digit symbol (P = -0.109 [SE 0.054], p < 0.05),
Purdue pegboard dominant (P = 0.068 [SE 0.028], p < 0.05) and
complex reaction time (P = -0.003 [SE 0.001], p<0.05) and
borderline significance existed for symbol digit (P = -0.046 [SE
0.026], p < 0.10), Trails A (P = -0.303, [SE 0.164] p < 0.10) and
Stroop (P = -0.013 [SE 0.008], p < 0.10). The slope of the
relation between tibia lead and neurobehavioral outcome was
more negative in those individuals with at least one s4 allele than
individuals without this allele. It is suggested that the presence of
one Apo-s-4 allele increases the risk of persistent central nervous
system effects of lead.
No strong association was found between lead biomarkers and
measures of sensory and motor function after adjusting for age.
The authors attributed the findings to decreased sensitivity of the
peripheral nerves in this dose range of inorganic lead or the
possibility of differential repair in the peripheral nervous system
compared to the central nervous system.
Lead and solvent exposure associated with adverse effects on tests
of manual dexterity. When compared to the solvent group lead
exposure had greater impairment on memory and learning and less
on executive/motor tests. An elevated neuropsychiatric score was
present in 43% of the lead group, 15% of the solvent and 7% of
the referent group.
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Table AX6-3.19 (cont'd). Occupational Exposure to Organolead and Inorganic Lead in Adults
Reference, Study
Location, and Period Study Description
Lead Measurement
Findings, Interpretation
to
o
o
United States (cont'd)
Mitchell etal. (1996)
58 organolead workers, self-selected for a
clinical evaluation. Mean age 45 (7.1)
years.
Mean blood lead 19 (6.5)
ug/dL
Mean lifetime blood lead 26
(9.1) ug/dL
Mean lifetime urine lead 51
(18.8) ng/L
The most common symptoms were memory loss 74%, joint pain
56%, trouble sleeping 54%, irritability 51%, paresthesias 49%,
fatigue 49%, nightmares 35%, moodiness 28%, headaches 21%
and depression 21%. Of the 31 workers receiving nerve
conduction studies, 29% were normal, carpal tunnel syndrome
36%, cubital tunnel syndrome 3%, median neuropathy 3%, ulnar
neuropathy 23%, mononeuropathy in lower extremity 5%, tarsal
tunnel syndrome 7% and sensorimotor polyneuropathy 36%. 39
workers had neurobehavioral evaluation with 64% had abnormal
tests of which 46% were considered to be consistent with a toxic
exposure.
O
o
2
o
H
O
o
HH
H
W
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CHAPTER 6 ANNEX
ANNEX TABLES AX6-4
December 2005 AX6-107 DRAFT-DO NOT QUOTE OR CITE
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Table AX6-4.1. Renal Effects of Lead - General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
O
OO
United States
Kim et al. (1996)
Boston, MA
1979 - 1994
459 men in the Normative Aging Study; periodic exams
every 3-5 years
Mean serum creatinine at baseline
1.2 mg/dL
Random effects modeling, adjusting for baseline age, time
since initial visit, body mass index, smoking status, alcohol
ingestion, education level, hypertension (defined as blood
pressure >160 or 95 mmHg or anti-hypertensive medication
use), and, in longitudinal analysis, baseline serum creatinine
and time between visits.
Mean (SDt blood lead at baseline
9.9(6.1)ug/dL
Blood lead levels from stored red
blood cells were adjusted for
hematocrit; the assay and
adjustment procedure were
validated against freshly collected
samples. Storage tubes were
shown to be lead free.
Cross-sectional
Positive association between log transformed blood lead and
concurrent serum creatinine. 10-fold higher blood lead level
associated with 0.08 mg/dL higher serum creatinine (95% CI:
0.02, 0.13 mg/dL).
Association stronger in participants with lower peak blood lead
levels. P coefficient (95% CI) in the 141 participants whose peak
blood lead < 10 jig/dL:
0.06 (0.023, 0.097)
Longitudinal
Positive association between log transformed blood lead and
change in serum creatinine over subsequent follow-up period in
participants whose peak blood lead was <25 ug/dL
P coefficient (95% CI: 0.027 [0.0, 0.054])
Slope of age-related increase in serum creatinine steeper in group
with highest quartile of time weighted average lead exposure
compared to the lowest quartile
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Table AX6-4.1 (cont'd). Renal Effects of Lead - General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
O
VO
United States (cont'd)
Muntner et al. (2003)
U.S.
1988-1994
Blood lead levels measured in 15,211 adult subjects enrolled
in the NHANES III study.
Study cohort representative of U.S. population; non-Hispanic
African Americans, Mexican Americans, the elderly and
children over-sampled to allow stable estimates in these
groups.
Hypertension defined as blood pressure > 140 and/or 90
mmHg and/or current antihypertensive medication use.
Based on evidence of interaction between blood lead and
hypertension, the population was stratified by hypertension
for further analysis.
4,813 hypertensives; 10,398 normotensives.
Elevated serum creatinine (%)
defined as > 99th percentile of each race-gender specific
distribution for healthy young adults [age 20-39 without
hypertension or diabetes]
11.5 % (hypertensives)
1.8 % (normotensives)
Chronic kidney disease (%)
chronic kidney disease defined as GFR <60 mL/min/1.73
m2; estimated by MDRD equation (Levey et al. [1999])
10 % (hypertensives)
1.1% (normotensives)
Multiple logistic regression
Age, race, gender, diabetes, systolic blood pressure, smoking
status, history of cardiovascular disease, body mass index,
alcohol consumption, household income, marital status, and
health insurance
Mean blood lead
4.21 (0.14) ug/dL (hypertensives)
3.30 (0.10) ug/dL (normotensives)
Higher odds ratios of both increased serum creatinine and chronic
kidney disease by quartile of blood lead in hypertensives but not
in normotensives
Hypertensives
Odds ratios for elevated serum creatinine after full adjustment:
Blood lead (range, Ug/dL) %
Quartile 1
Quartile 2
Quartile 3
Quartile 4
(0.7 to 2.4)
(2.5 to 3. 8)
(3.9 to 5.9)
(6.0 to 56.0)
7.2
12.1
12.4
16.3
Odds ratio (95% CD
1.00
1.47(1
1.80(1
2.41 (1
.03,
.34,
.46,
2.10)
2.42)
3.97)
p < 0.001 for chi-squared test for trend
Odds ratios for chronic kidney disease after full adjustment:
Blood lead % Odds ratio (95% CD
Quartile 1 6.1 1.00
Quartile 2 10.4 1.44(1.00,2.09)
Quartile 3 10.8 1.85(1.32,2.59)
Quartile 4 14.1 2.60(1.52,4.45)
p < 0.001 for chi-squared test for trend
Associations were similar when lead was entered as a log
transformed continuous variable.
In non-hypertensives, higher blood lead was associated with a
higher prevalence of chronic kidney disease, but not elevated
serum creatinine, in diabetics.
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Table AX6-4.1 (cont'd). Renal Effects of Lead - General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
United States (cont'd)
Paytonetal. (1994)
Boston, MA
1988- 1991
Shadick et al. (2000)
Boston, MA
1991-1996
Blood lead levels measured in 744 men enrolled in the
Normative Aging Study
Serum creatinine
1.3 mg/dL
Measured creatinine clearance
88.2 mL/min
Calculated creatinine clearance
71 mL/min
Multiple linear regression adjusting for age, body mass
index, analgesic and diuretic use, alcohol consumption,
smoking status, systolic/ diastolic blood pressure
777 participants in all male Normative Aging Study
Mean blood lead
8.1 ug/dL
Blood lead levels below the limit
of detection of 5 ug/dL were
receded as 4 ug/dL (n not stated).
Mean blood lead
5.9 ug/dL
Mean Tibia Lead
20.8 ug/g bone mineral
Mean Patella Lead
30.2 ug/g bone mineral
In blood lead negatively associated with In measured creatinine
clearance
B coefficient (95% CD
-0.04 (-0.079, -0.001)
10 ug/dL higher blood lead associated with a 10.4 mL/min lower
creatinine clearance
Borderline significant associations (p < 0.1) between blood lead
and both serum creatinine (P = 0.027; neither SE nor CI provided)
and estimated creatinine clearance (P = -0.022; neither SE nor
CI provided)
A significant association between patella lead and uric acid (P
[95% CI: 0.007 [0.001, 0.013]); p = 0.02) was found, after
adjustment for age, BMI, diastolic blood pressure, alcohol
ingestion, and serum creatinine. Borderline significant
associations between tibia (p = 0.06) and blood lead (p = 0.1) and
uric acid were also observed. Notably these associations were
significant even after adjustment for blood pressure and renal
function, providing further evidence that low level lead increases
uric acid. Fifty-two participants had gout; lead dose was not
associated with risk for gout.
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Table AX6-4.1 (cont'd). Renal Effects of Lead - General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
H
6
o
o
H
O
United States (cont'd)
Tsaih et al. (2004)
Boston, MA
1991—2001
448 men enrolled in the Normative Aging Study
Baseline Serum Creatinine
1.3 mg/dL
Longitudinal analysis of data from 2 evaluations a mean of 6
years apart
Annual change in serum creatinine = (follow-up serum
creatinine - baseline serum creatinine) / years of follow up
Covariates assessed = age, age squared, body mass index,
hypertension (defined as blood pressure > 160 or 95 mmHg
or physician diagnosis with use of antihypertensive
medication), diabetes (defined as use of oral hypoglycemic
drugs or insulin or reported physician diagnosis), smoking
status, alcohol consumption, analgesic use, and, in
longitudinal models, baseline serum creatinine and its square
Six percent and 26% of subjects had diabetes and
hypertension, at baseline, respectively.
Baseline blood lead
6.5 (4.2) ug/dL
Baseline tibia lead
21.5 (13.5) ug/g bone mineral
Baseline patella lead
32.4 (20.5) ug/g
Mean blood lead levels and serum creatinine decreased
significantly over the follow-up period in the group. Lead dose
not associated with change in creatinine overall
Significant interaction of blood and tibia lead with diabetes in
predicting annual change in serum creatinine
Beta coefficient (95% CI) for natural In baseline blood lead 0.076
(0.031, 0.121) compared to 0.006 (-0.004, 0.016) for non-
diabetics
Beta coefficient (95% CI) for natural In baseline tibia lead 0.082
(0.029, 0.135) compared to 0.005 (-0.005, 0.015 for non-
diabetics
Significant interaction of tibia lead with hypertensive status in
predicting annual change in serum creatinine
Beta coefficient (95% CI) for natural In baseline tibia lead 0.023
(0.003, 0.019) compared to 0.0004 (-0.001,0.002 for non-
hypertensives
Follow-up serum creatinine was also modeled separately in
longitudinal analyses; diabetes modified the association between
baseline tibia lead and follow-up serum creatinine.
O
V
O
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to
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O
Table AX6-4.1 (cont'd). Renal Effects of Lead - General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
United States (cont'd)
Wu et al. (2003)
Boston, MA
1991-1995
709 men enrolled in the Normative Aging Study
Serum creatinine
1.2mg/dL
Calculated creatinine clearance
71.3 mL/min
Serum uric acid
6.5 mg/dL
Multiple linear regression, adjusting for age, body mass
index, blood pressure or HTN (depending on model), and
alcohol ingestion. Uric acid models also adjusted for serum
creatinine, other outcome models adjusted for smoking
status and analgesic medication use.
Blood lead
6.2 (4.2) ug/dL
Tibia lead
22 (13.4) ug/g bone mineral
Patella lead
32.1 (19.5) ug/g bone mineral
Significant inverse association between patella lead and
creatinine clearance
Beta coefficient = -0.069, SE not provided
Borderline significant (p = 0.08) inverse association between tibia
lead and creatinine clearance. Borderline significant (p = 0.08)
positive associations between tibia and patella lead and uric acid.
No lead measure significantly associated with serum creatinine.
ALAD gene polymorphism also assessed. 114 participants had
the ALAD2 variant allele (7 were homozygous). None of the
three renal outcomes differed by genotype. Effect modification
by genotype on the association between tibia lead and serum
creatinine was observed; the beta coefficient (and slope) was
greater in the with group with the variant allele (P = 0.002; p =
0.03 [SE not provided]).
Effect modification of borderline significance (p < 0.1) on
relations between of patella and tibia lead with uric acid was
observed; this was significant in participants whose patella lead
levels were above 15 ug/g bone mineral (P = 0.016; p = 0.04 [SE
not provided]). Similar to the serum creatinine model, patella
lead was associated with higher uric acid in those with the variant
allele. Genotype did not modify lead associations in models of
estimated creatinine clearance.
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Table AX6-4.1 (cont'd). Renal Effects of Lead - General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Europe
De Burbure et al. (2003)
France
Study date not provided
600 adults (399 exposed, 201 age and gender matched controls)
400 children (200 exposed, 200 age and gender matched controls).
Age ranged from 8.5 to 12.3 years.
Exposure from residence near smelters
Exclusion criteria for children included obesity, diabetes and puberty;
for adults included pregnancy, cancer, diabetes and kidney disease.
Serum creatinine
1.43 mg/dL (adult male controls)
1.38 mg/dL (exposed adult males)
1.33 mg/dL (adult female controls)
1.26 mg/dL (exposed adult females)
Urinary P^-microglobulin
68.16 ug/g cr (adult male controls)
76.29 ug/g cr (exposed adult males)
63.79 ug/g cr (adult female controls)
71.98 ug/g cr (exposed adult females)
87.8 ug/g cr (boy controls)
97.3 ug/g cr (exposed boys)
88.2 ug/g cr (girl controls)
94.8 ug/g cr (exposed girls)
Urinary NAG
1.12 lU/g cr (adult male controls)
1.24 lU/g cr (exposed adult males)
0.98 lU/g cr (adult female controls)
1.28 lU/g cr (exposed adult females)
2.29 lU/g cr (boy controls)
1.70 lU/g cr (exposed boys)
2.21 lU/g cr (girl controls)
1.07 lU/g cr (exposed girls)
Urinary RBP
82.8 ug/g cr (adult male controls)
85.8 ug/g cr (exposed adult males)
83.42 ug/g cr (adult female controls)
95.81 ug/g cr (exposed adult females)
94 ug/g cr (boy controls) 99 ug/g cr (exposed boys)
110 ug/g cr (girl controls) 109 ug/g cr (exposed girls)
Renal outcome measures also included urinary total protein, albumin,
transferrin, and brush border antigens
Multiple linear regression adjusting for age, sex, body mass index, area
of residence, smoking, alcohol ingestion, mercury, cadmium and
urinary creatinine level
Geometric mean blood lead
7.13 ug/dL (adult male controls)
6.78 ug/dL (exposed adult
males)
4.17 ug/dL
(adult female controls)
5.25 ug/dL
(exposed adult females)
3.42 ug/dL (boy controls)
4.22 ug/dL (exposed boys)
2.74 ug/dL (girl controls)
3.69 ug/dL (exposed girls)
Adults
Mean blood lead level higher in exposed women but not
men. None of the renal outcomes analyzed showed any
significant difference between exposed and unexposed
groups. After adjustment for covariates, blood lead was
not associated with any renal outcomes.
Children
Mean blood lead levels higher in exposed. The highest
geometric mean blood cadmium was 0.52 ug/L. None of
the renal outcomes were significantly higher in exposed.
After adjustment for covariates, blood lead was not
associated with any renal outcomes, however, blood
cadmium was positively associated with NAG. This
association was present in both control and exposed areas.
Participants with extremes of urinary creatinine excluded
from data analyses. As a result, number of subjects in
data tables substantially less than in study.
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(^
Table AX6-4.1 (cont'd). Renal Effects of Lead - General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Europe (cont'd)
Factor-Litvak et al.
(1993)
Kosovo, Yugoslavia
1985-1986
Staessen et al. (1990)
London, England
Study date not provided
1447 Yugoslavian women in prospective study of
environmental lead exposure and pregnancy
Exposure from Kosovska Mitrovica with a lead smelter,
refinery and battery plant. Controls from Pristina, 25 miles
away
Renal outcome = Proteinuria assessed with a dipstick
Exclusionary criteria included HTN (n = 37 excluded,
similar blood lead levels to remaining participants)
Multiple logistic regression adjusting for age (linear and
quadratic), height (linear and quadratic), cigarette smoking,
gestational age (linear and quadratic), daily milk
consumption, no. of previous live births, average weekly
meat consumption, hemoglobin level and ethnic group.
531 London civil servants
(398 male, 133 female)
Exclusionary criteria = occupational exposure to heavy
metals
Blood Lead
17.1 ug/dL (582 exposed)
5.1 ug/dL (865 controls)
Mean blood lead
12.4 |ig/dL (men)
10.2 ug/dL (women)
Proteinuria (negative, trace, or > 1+)
Exposed = 16.2% negative, 74.1% trace and 9.7% with > 1+
proteinuria. Controls = 32.4% negative, 60.6% trace and 7.1%
with > 1+ proteinuria. Authors attributed overall high proportion
of proteinuria to pregnancy.
Higher blood lead associated with increased odds ratio for trace
and > 1+ proteinuria.
Comparing women in upper 10th percentile of exposure to lower
10th percentile of exposure, adjusted odds ratios (95% CI) for
trace and >1+proteinuria was 2.3 (1.3, 4.1) and 4.5 (1.5, 13.6),
respectively.
Limitations = limited renal outcomes assessed.
After removal of 2 outliers, the study found no significant
correlation between serum creatinine and log blood lead in men.
No correlation between serum creatinine and log blood lead in
women
O
o
o
H
O
Serum creatinine
1.10 mg/dL (men)
0.88 mg/dL (women)
Limitations = lack of adjustment in data analysis, limited lead
dose and renal outcome assessment, loss of power by analyzing
gender in separate models
o
V
o
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O
to
O
O
Table AX6-4.1 (cont'd). Renal Effects of Lead - General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
H
6
o
o
H
O
Europe (cont'd)
Staessen et al. (1992)
Belgium
1985-1989
Blood lead levels were measured in 1981 adult subjects (965
males, 1016 females) enrolled in the Cadmibel study of
general Belgian population in four cadmium polluted and
unpolluted areas.
Inclusion criteria included age > 20 years and residence in
one of four study areas for >8 years. Participants were
randomly selected from the study areas; participation rates
were 78% in the two rural areas but only 39% in the urban
areas (one area from each category was known to be
cadmium polluted).
Measured creatinine clearance
99 mL/min (males)
80 mL/min (females)
Calculated creatinine clearance
80 mL/min (males)
69 mL/min (females)
Multiple linear regression
Covariates assessed included age, age squared, gender (by
stratifying), body mass index, blood pressure, ferritin level,
smoking status, alcohol ingestion, rural vs. urban residence,
analgesic and diuretic use, blood and urinary cadmium,
diabetes, occupational exposure to heavy metals, and gamma
glutamyl transpeptidase
Blood lead 11.4 ug/dL (males)
7.5 ug/dL (females)
Zinc protoporphyrin also assessed
After adjustment, log transformed blood lead negatively
associated with measured creatinine clearance
B coefficient (95% CD
-9.5 (-0.9, -18.1) males
-12.6 (-5.0, -20.3) females
A 10 fold increase in blood lead associated with a decrease in
creatinine clearance of 10 and 13 mL/min in men and women
respectively
Log transformed blood lead also negatively associated with
calculated creatinine clearance
B coefficient (95% CD
-13.1 (-5.3, -20.9) males
-30.1 (-23.4, -36.8) females
Log transformed zinc protoporphyrin negatively associated with
measured and calculated creatinine clearances and positively
associated with serum (32- microglobulin in both sexes and with
serum creatinine in men
Blood lead positively associated with serum p2-microglobulin in
men
O
V
O
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to
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O
Table AX6-4.1 (cont'd). Renal Effects of Lead - General Population
X
Oi
H
6
o
o
H
O
Reference, Study
Location, and Period
Asia
Lin et al., Am J
Nephrol. (1993)
Taiwan
Study date not provided
Study Description
123 adults living near a lead battery factory for more than 10
years
Divided into 3 groups by proximity to the factory
Group 1 <500 m (n = 49)
Group 2 1000-1500 m (n = 47)
Group 3 farther away (n = 27)
Lead Measurement
Blood lead
16.6 ug/dL (Group 1)
13.5 ug/dL (Group 2)
7.9 ug/dL (Group 3)
EDTA diagnostic chelation
(done in Group 1)
Findings, Interpretation
Significantly higher prevalence of abnormal urinary NAG found
in the exposed group 1 compared to the control group 3 (55.6%
compared to 11.1%; p < 0.001). However, mean NAG not
significantly higher in Group 1 .
In all 45 participants in whom both measures were obtained,
EDTA chelatable lead was not correlated with urinary NAG
126.1 ug/24hrs
Satarugetal.,EHP
(2004)
Bangkok, Thailand
Study date not provided
Exclusionary criteria included history of exposure to
nephrotoxicants and nephrotoxicant medications, such as
NSAIDs.
24 hour urinary NAG excretion
3.3 U/day (Group 1)
2.4 U/day (Group 3)
Multiple linear regression with adjustment for age
118 Thai adults (53 men, 65 women)
Renal outcome measures noted below, also include BUN and
total urinary protein.
Serum creatinine
0.94 mg/dL (males)
0.66 mg/dL (females)
Urinary NAG
4.4 U/g cr (males)
4.6 U/g cr (females)
Urinary P^-microglobulin
51 ug/g cr (males)
29 ug/g cr (females)
Mean "serum" lead
0.42 ug/dL (males) 0.3 ug/dL
(females)
Note - cannot determine from
article if actually serum lead
(much less commonly used) or
blood lead
Mean urinary lead
1.3 ug/g cr (males) 2.4 ug/g cr
(females)
Urinary cadmium (CdU) also
assessed
excretion. However, a significant correlation between EDTA
chelatable lead <200 ug/24 hrs and urinary NAG excretion was
observed in the 39 participants in this group. Further evaluation
with multiple linear regression, adjusting for age, revealed a
Pcoefficient (95% CI: 0.034 [0.009, 0.059]); p = 0.01.
No correlation noted between blood lead level and urinary NAG.
Limitations = small sample size, plots indicate potential for
influential outliers.
In men, urinary lead excretion correlated only with urinary
protein at borderline significance (r = 0.22, p < 0.06),
In women, urinary lead excretion correlated with urinary NAG (r
= 0.5, p < 0.001), protein (r = 0.31, p = 0.01) and
P2.microglobulin (r = 0.36, p = 0.002) excretion.
After adjustment for CdU, only association between urinary lead
and NAG remained significant.
Three urinary renal biomarkers correlated with CdU, although
only at borderline significance (p = 0.06) for p2-microglobulin.
Limitations = small sample size, lead dose assessment since only
urine lead used in renal analyses, limited data analysis
O
^
O
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to
O
O
Table AX6-4.1 (cont'd). Renal Effects of Lead - General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia (cont'd)
Satarug et al.,
Toxicology (2004)
Bangkok, Thailand
Study date not provided
96 Thai men
Subjects subdivided into nonsmokers (n = 53), current
smokers (n = 27),
and ex-smokers (n = 16).
Renal outcome measures noted below, also include BUN and
total urinary protein.
Serum creatinine
0.94 mg/dL (nonsmokers)
0.93 mg/dL (smokers)
0.96 mg/dL (ex-smokers)
Urinary NAG
4.4 U/g cr (nonsmokers)
4.2 U/g cr (smokers)
3.8 U/g cr (ex-smokers)
Urinary P^-microglobulin
51 ug/g cr (nonsmokers)
95 ug/g cr (smokers)
98 ug/g cr (ex-smokers)
Mean "serum" lead
0.42 ug/dL (nonsmokers)
0.9 ug/dL (smokers)
0.61 ug/dL (ex-smokers)
Mean urinary lead
1.3 ug/g cr (nonsmokers)
1.4 ug/g cr (smokers)
1.4 ug/g cr (ex-smokers)
Urinary cadmium (CdU)
also assessed
Urinary lead correlated with urinary protein (r = 0.49, p < 0.01) in
smokers and at borderline significance (r = 0.22; p = 0.06) in
never smokers. Also correlated with p2-microglobulin in ex-
smokers at borderline significance (r = 0.39; p = 0.06)
CdU correlated with urinary NAG in current and never smokers
and at borderline significance (p = 0.07) in ex-smokers. Also
correlated with urinary protein and p2-microglobulin in current
smokers and, at borderline significance, in never smokers.
Limitations = small sample size, lead dose assessment since only
urine lead used in renal analyses, limited data analysis
Middle East
Mortada et al. (2004)
Egypt
Study date not provided
68 Egyptian men (35 smokers, 33)
Renal outcomes included serum creatinine, BUN, and P2-
microglobulin and urinary albumin, NAG, p2-microglobulin,
alkaline phosphatase, and y-glutamyl transferase.
Blood lead
14.4 ug/dL (smokers)
10.2 ug/dL (nonsmokers)
Lead also measured in urine, hair,
and nails
Also measured cadmium, and
mercury
Blood and hair lead levels significantly higher in smokers as
compared to nonsmokers.
No significant differences in renal outcome measures by smoking
status. No correlation between exposure indices and renal
outcome measures.
Limitations: small sample size, data analysis -no adjustment.
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Table AX6-4.2. Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
United States
Smith etal. (1995)
U.S.
Study date not provided
691 construction workers
96 participants with the ALAD2 allele
Mean blood lead
7.8 ug/dL (ALAD11)
7.7 ug/dL (ALAD12 or 22)
Higher mean BUN (p = 0.03) in participants with the ALAD2
allele compared to those with the ALAD11 genotype.
However, after adjustment for age, alcohol ingestion and
blood lead, the association was no longer significant. Effect
modification was not evaluated.
X
oo
H
6
o
o
H
O
O
V
O
Europe
Bergdahl et al. (1997)
Sweden
Study date not provided
Cardenas et al. (1993)
Belgium
Study date not provided
89 lead workers; 7 had the ALAD2 allele
34 controls; 10 had the ALAD2 allele
N = 41 lead smelter workers, 41 controls (all males)
Study started with 50 lead smelter workers and 50 controls.
Blood lead level >35 |lg/dL and exposure >1 year were required
in exposed workers. Participants with renal disease, renal risk
factors, such as diabetes or regular analgesic medication use, or
urinary cadmium >2 |lg/g creatinine, were excluded.
Multiple linear regression; adjusted for urinary creatinine and, in
some cases, BMI
Serum creatinine
1.02 mg/dL (workers)
1.03 mg/dL (controls)
Battery of more than 20 renal biomarkers obtained including:
RBP
68 ug/L (workers)
64 ug/L (controls)
NAG
1.56 U/L (workers)
1.21U/L (controls)
Median blood lead
31.1 ug/dL in lead workers with
ALAD11
28.8 ug/dL in lead workers with
ALAD12or22
3.7 ug/dL in control workers with
ALAD11
3.7 ug/dL in control workers with
ALAD12or22
Mean Blood lead
48.0 ug/dL (workers)
16.7 ug/dL (controls)
Mean duration of lead
exposure = 14 years
Urinary cadmium also measured
as potential confounder
Higher crude mean serum creatinine (p = 0.11) in participants
with the ALAD2 allele compared to those with the ALAD11
genotype. Adjusted data not presented.
Serum creatinine was not increased in lead workers compared
to controls; associations between lead dose and serum
creatinine, if assessed, were not specifically reported.
In all 82, blood lead:
-associated with thromboxane B2(P = 0.36, p < 0.01)
-negatively associated with 6-keto-prostaglandin FI aipha (P =
-0.179, p< 0.01)
-neither SE P nor CI provided
Zinc protoporphyrin positively associated with sialic acid
excretion
NAG increased in lead workers but associated with CdU
Limitations = sample size, potential for healthy worker bias,
limited statistical analysis
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Europe (cont'd)
Coratelli et al. (1988)
Study location and date
not provided; authors
from Italy
Pels etal. (1994)
Study location and date
not provided
Garcon et al. (2004)
France
Study date not provided
20 lead battery factory workers
20 controls
12 month longitudinal study
Renal outcomes = urinary alanine aminopeptidase, NAG and
lysozyme
81 male lead workers; 45 age matched controls
Extensive exclusionary criteria
Renal outcomes
Serum creatinine
Glomerular markers = 6-keto-prostaglandin FI aipha, thromboxane
B2, and fibronectin
Proximal tubular markers = brush border antigens (BBA, BB50,
HF5) and intestinal alkaline phosphatase
Distal nephron markers = prostaglandin E2, prostaglandin F2 alpha
Thirty-five male nonferrous metal smelter workers
Renal outcomes = di-microprotein, (32-microglobulin, retinol
binding protein, a and ji glutathione S transferases (GST)
Oxidative stress markers also measured.
All variables log transformed
Initial mean blood lead
47.9 ug/dL (workers)
23.6 ug/dL (controls)
Median blood lead
42.1 ug/dL (workers)
7.0 ug/dL (controls)
Mean blood lead = 39.6 ug/dL
Mean blood cadmium = 5.8 ug/L
Mean urine cadmium = 4.7 ug/g
creatinine
NAG and lysozyme higher in exposed compared to controls
throughout study. A statistically significant decline in urinary
NAG was noted in association with a one month period of
decreased occupational exposure in the lead workers. NAG
correlated with time of exposure (nonlinear) but not blood
lead. Clinical renal function measures were not studied.
Serum creatinine similar in exposed compared to controls.
Medians of several markers statistically greater in workers
compared to controls. After adjustment for age and
erythrocyte protoporphyrin, several renal marker outcomes
showed "some relation" to blood lead. The table of these data
shows r and r2 but not beta coefficients making the actual
statistical method used unclear.
Study limitations include lack of adjustment in statistical
analysis, potential for healthy worker bias.
Correlations between urine lead and cadmium and the renal
outcomes assessed (not blood lead or cadmium).
Significant positive correlations included:
urine lead and a GST (p < 0.01)
urine cadmium and RBP (p < 0.05)
Also, urine cadmium and 8-OhdG negatively correlated
Limitations = use of urine lead, lack of adjustment for other
covariates, sample size
Significant correlations between blood lead and two markers
of oxidative stress were observed along with a correlation
between blood cadmium and one marker of oxidative stress
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
O
Europe (cont'd)
Gennartetal. (1992)
Study location and dates
not provided; authors
from Belgium
Gerhardsson et al.
(1992)
Sweden
Study date not provided
98 lead workers and 85 controls from initial group of 221
Renal outcomes = urinary retinol-binding protein, p-2
microglobulin, albumin, NAG, and serum creatinine and p-2
microglobulin and estimated creatinine clearance
Exclusionary criteria included lack of exposure to other metals or
solvents, urinary cadmium < 2 ug/g creatinine, neurologic or renal
disease, certain medications, blood lead level >40 ug/dL
(workers) and < 40 ug/dL for controls.
70 current lead smelter workers
30 retired lead smelter workers
31 active and 10 retired truck assembly workers (controls)
Renal outcomes = serum creatinine, urinary p-2 microglobulin,
NAG, and albumin, clearances of creatinine, albumin, relative
albumin, p-2 microglobulin and relative p-2 microglobulin
Blood lead measured annually since 1950; time integrated blood
lead index = summation of annual blood lead measurements
Mean Blood lead
51 ug/dL (workers)
20.9 ug/dL (controls)
Mean duration of employment
10.6 years
Median Values
Blood lead
31.9 ug/dL (current lead
workers)
9.9 ug/dL (retired lead workers)
4.1 ug/dL (current control
workers)
3.5 ug/dL (retired control
workers)
Time integrated blood lead index
369.9 ug/dL (current lead
workers)
1496.1 ug/dL (retired lead
workers)
Calcaneus lead
48.6 ug/g bone mineral (current
lead workers)
100.2 ug/g bone mineral (retired
lead workers)
Tibia lead
13.0 ug/g bone mineral (current
lead workers)
39.3 ug/g bone mineral (retired
lead workers)
3.4 ug/g bone mineral (current
control workers)
12.0 ug/g bone mineral (retired
control workers)
Mean renal outcomes were not different in workers compared
to controls. Prevalence of abnormal values was not greater in
workers compared to controls. An analysis of variance, in all
participants, by categorical blood lead, duration of
employment, ZPP, and delta-aminolevulinic acid showed no
relations with any of the outcomes (data were not shown).
Limitations include high lead levels in controls, adjustment
only for age in statistical analysis, potential healthy
worker bias
Creatinine clearance was higher in lead workers; p-values not
reported for this or other median values between lead workers
and controls.
In current lead workers, blood lead was positively correlated
with urinary p-2 microglobulin and time integrated blood lead
index was correlated with NAG (data not shown).
Strengths include assessment of cumulative lead, inclusion of
former workers
Limitations = statistical analysis, lack of power by stratifying
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
Europe (cont'd)
Pergande et al. (1994)
Study location and date
not provided; research
team is German
Roels et al. (1994)
Belgium
Study date not provided
82 male lead workers
44 age-matched healthy male volunteers without known exposure
to lead and living "in areas distant from the exposed people"
Renal outcomes = serum creatinine and P2 microglobulin, urinary
albumin and 14 other early biological effect markers
Exclusion criteria included prescription medication use and many
diseases; 11 workers and 3 controls excluded.
76 lead smelter workers (including 21 participants from Cardenas
etal. [1993] [Dr. Roels, email communication])
68 controls
All males
Matched for age, sex, socioeconomic status, residence, and
workshift characteristics.
Extensive exclusionary criteria included renal disease, analgesic
abuse, chronic medication for gout, diabetes, occupational
exposure to other nephrotoxicants, and prior EDTA chelation.
Renal outcomes included serum creatinine and urea nitrogen,
measured creatinine clearance, NAG, RBP, serum and urinary P2-
microglobulin, as well as other renal early biological effect
markers.
Measured creatinine clearance
121.3 mL/min/1.73 m (workers)
115.5 mL/min/1.73 m2 (controls)
Multiple linear regression, adjusted for age, urinary cadmium,
hypertension, serum gamma-glutamyl transpeptidase, smoking,
exposure status (exposed vs. control), and interaction between
exposure variables and hypertension
Mean blood lead
42.1 ug/dL (workers)
7.0 ug/dL (controls)
Erythrocyte protoporphyrin also
measured
Blood lead
43.0 ug/dL (workers)
14.1 ug/dL (controls)
Tibia Lead
66 ug/g bone mineral (workers)
21 ug/g bone mineral (controls)
CdU also measured
Serum creatinine and P2 microglobulin not increased in
exposed compared to control participants; correlations with
these outcomes not reported. Blood lead and/or erythrocyte
protoporphyrin correlated with 9 of the urinary renal
outcomes.
Study limitations include lack of adjustment in statistical
analysis, potential for healthy worker bias, potential for
differences between exposed and control groups.
Creatinine clearance measured before and after an oral protein
load to determine if eicosanoid changes in Cardenas et al.
(1993) had clinical implications (Acute protein ingestion
causes increased renal perfusion and transient hyperfiltration
thought to be mediated by changes in vasodilator prostanoids.
Therefore, it was hypothesized that, if the changes noted in
Cardenas et al. (1993) were clinically significant, the
hyperfiltration response would be diminished in the lead
workers.)
All participants had normal baseline creatinine clearances
(>80 mL/min/1.73 m2). Both control and lead-exposed
workers showed a similar increment in creatinine clearance
after protein load.
However, mean creatinine clearance was statistically higher in
lead workers compared to controls. Log tibia lead was
positively correlated with log measured creatinine clearance
in the combined group (P = 0.0319, SE not provided).
This was unexpected as the change in eicosanoids found in the
initial study would not seem to result in vasodilatation with
increased GFR. Unfortunately, it was not possible to measure
eicosanoid levels in the follow-up study. No other significant
associations between lead measures and renal outcomes were
observed. CdU associated with NAG.
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
to
Europe (cont'd)
Verschoor et al. (1987)
Study location and date
not provided; authors
from The Netherlands
155 lead workers (lead battery and plastic stabilizer)
126 control industrial workers
Workers with renal disease, HTN, prescription medications
excluded
Renal outcomes = BUN, serum creatinine, uric acid, P2-
microglobulin, and RBP, and urinary RBP, NAG, albumin, uric
acid, p2-microglobulin, IgG, and total protein. Urine protein
electrophoresis performed on subset (n =
25)
Cadmium in blood and, in a subset of exposed workers, in urine
was also assessed due to this exposure in one plant each from
which lead exposed and control workers were drawn
Blood lead
47.5 ug/dL (workers)
8.3 ug/dL (controls)
Zinc protoporphyrin also used as
lead dose measure
Mean renal outcomes in all participants shown by categorical
lead levels. NAG and RBP higher at blood lead levels >21
ug/dL compared to those below this level (statistical
significance not reported). Serum p2-microglobulin and
urinary total protein lower at blood lead levels >21 ug/dL
compared to those below this level (again, statistical
significance not reported).
In simple linear regression models of log transformed urinary
total protein, urinary RBP, NAG and serum p2-microglobulin,
higher log transformed blood lead was significantly associated
with lower serum p2-microglobulin and higher RBP and
NAG.
A matched pair analysis of 55 pairs matched for age within 5
years, smoking, socioeconomic status, and duration of
employment found no differences in renal outcomes between
exposed and controls.
Limitations = lack of adjustment, potential for healthy worker
bias, occupational cadmium exposure (including in controls)
not adequately adjusted for
Latin and South America
Cardozo dos Santos
etal. (1994)
Study location and date
not provided; authors
from Brazil
166 lead battery workers
60 control workers
Renal outcomes = serum creatinine, NAG, urine albumin, and
total urinary protein, y-glutamyl-transpeptidase, alanine-
aminopeptidase
Median blood lead
36.8 ug/dL (workers)
11.6 ug/dL (controls)
Significant results
Median NAG higher in exposed group (p < 0.001). Blood
lead level and duration of exposure correlated with NAG in
combined group (Spearman's correlation coefficients = 0.32
and 0.22, respectively, p < 0.001 for both).
No results mentioned for serum creatinine.
Limitations = statistical analysis (no regression for renal
outcomes)
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Latin and South America (cont'd)
Pinto de Almeida et al. 52 primary lead smelter workers (had to have worked > 5 years on Mean blood lead
(1987) production line) 64.1 ug/dL (workers)
Northeast Brazil 25.5 ug/dL (controls)
Study date not provided 44 control paper mill workers in same city
Also measured zinc
All males protoporphyrin and delta-
aminolevulinic acid
Renal outcomes = BUN, serum creatinine, uric acid, proteinuria,
creatinine clearance
Only 2 participants excluded for medical reasons
Mean serum creatinine and uric acid higher in exposed than
controls (1.23 vs. 1.1 mg/dL; p < 0.05 and 6.6 vs. 4.7 mg/dL;
p < 0.001, respectively)
Serum creatinine > 1.5 mg/dL present in 32.7% lead workers
compared to only 2.3% controls.
Serum creatinine correlated with duration of employment.
Limitations = data analysis including lack of adjustment,
several outcomes not analyzed.
X
to
oo
Australia
Pollock and Ibels (1988) Thirty-eight bridge workers
Harbor Bridge workers Twenty-four hour urine lead excretion following 1 g of EDTA
in Sydney, Australia Renal outcomes = serum creatinine, creatinine clearance, and 24
Study date not provided hour urine protein excretion
Blood lead mean & range
34.8; 21.8 to 56.2 ug/dL (lead
intoxication)
19.9; 9.5 to 26.1 ug/dL
(nontoxic)
EDTA chelatable lead range
443 to 2366 ug/24 hrs (lead
intoxication)
131 to 402 ug/24 hrs (nontoxic)
No significant differences in renal outcomes by lead exposure
group. Two workers in high exposure group had evidence of
lead nephropathy.
O
O
*
O
H
O
c
O
s
O
V
O
HH
s
Asia
Chiaetal., OEM (1994)
Study location not
provided; authors from
Singapore
1982-1992 (blood lead
measurements obtained
every 6 months over
this time)
128 lead workers
152 control workers without lead or cadmium exposure
Renal outcomes = total NAG, NAG-B isoenzyme (released with
lysosomal breakdown assoc with cell membranes, thought to
indicate proximal tubular cell toxicity), NAG-A (released by
exocytosis).
Cross-sectional outcomes but longitudinal exposure data.
Median blood lead
33.8 ug/dL (workers)
8.7 ug/dL (controls)
Median cumulative blood lead
(mean of 3.6 blood lead levels
per worker)
208.3 ug-yr/dL
Change in blood lead
(in 6 months preceding NAG
measurement)
Mean = 5.8%
NAG not different in exposed compared to control workers.
After adjustment for race, recent change in blood lead was
significantly associated with all NAG outcomes (standardized
partial regression coefficients ranged from 0.31 for NAG-A to
0.64 for total NAG; neither SE nor CI provided).
In contrast, current blood lead was inversely associated with
NAG-A and NAG-B separately but, oddly, not with total
NAG. Authors do not comment on these inconsistencies.
NAG not associated with cumulative lead dose.
Strengths = longitudinal exposure data
Limitations = data analysis clarity and adjustment
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
Asia (cont'd)
Chia et al., Ann Acad
Med Singapore (1994)
Study location not
provided; authors from
Singapore
1982-1992 (blood lead
measurements obtained
every 6 months over this
time)
Chia et al., Toxicol
Letters (1995)
Study location not
provided; authors from
Singapore
1982-1993 (blood lead
measurements obtained
every 6 months over this
time)
63 lead workers of >6 months work duration (median = 3 years)
91 lead workers of <6 months work duration were considered
controls
Renal outcomes = urinary BB-50 (brush border antigen in
proximal tubule), total NAG, NAG-B isoenzyme, RBP, a-1-
microgobulin, albumin and urine and serum p2-microglobulin.
Cross-sectional outcomes but longitudinal exposure data.
137 lead stabilizer workers
Control group of 153 postal workers (older than lead workers)
Renal outcomes = serum creatinine, four hour creatinine
clearance, serum (3-2 microglobulin, serum a-1 microglobulin,
urine albumin
Longitudinal blood lead data (mean of 4.5 measurements per lead
worker)
Lead Dose Measures
(means or medians not stated)
Most recent blood lead, time
integrated blood lead index,
relative % change in blood lead,
absolute change in blood lead,
# of times blood lead level >40,
50, and 60 ug/dL.
Lead Dose Measures
(means or medians not stated)
Most recent blood lead, time
integrated blood lead index,
relative % change in recent blood
lead, absolute change in recent
blood lead, # of times blood lead
level >40, 50, and 60 ug/dL.
Urinary BB-50 higher in exposed compared to recent hire
"control" workers. Time integrated blood lead, # times blood
lead >40 ug/dL, and relative change in recent blood lead were
associated with urinary BB-50.
Strengths = longitudinal exposure data
Limitations = data analysis content (lead dose means not
reported), clarity and adjustment.
In analysis of covariance modeling, adjusted for age and race,
mean serum a-1 microglobulin and urine albumin were
significantly higher in control compared to lead workers.
Serum p-2 microglobulin was significantly higher in lead
workers > 30 years of age.
After adjustment for age, race, and smoking, prevalence rates
for abnormal values of serum creatinine and (3-2
microglobulin were higher in the highest category of time
integrated blood lead index in workers > 30 years of age (PRR
[95% CI: 3.8 [1.1, 13.3] and 10.3 [3.9, 26.9], respectively).
Strengths = longitudinal exposure data
Limitations = data analysis content (lead dose means not
reported), clarity and adjustment
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
Asia (cont'd)
Chiaetal., AJIM (1995)
Study location not
provided; authors from
Singapore
1982-1993 (blood lead
measurements obtained
every 6 months over this
time)
Endo et al. (1990)
Study location not
provided; authors from
Japan
1987
Endo et al. (1993)
Study location and date
not provided; authors
from Japan
128 lead stabilizer factory workers
93 unexposed control subjects (evaluated at pre-employment
examination; all quit within 1 month of hire)
Blood and urinary cadmium also measured on random subset (40
controls and 31 lead workers)
Renal outcomes = serum (3-2 microglobulin and urinary a-1
microglobulin, (3-2 microglobulin, albumin, RBP
39 male workers
7 female workers (none directly exposed to lead)
secondary lead refinery, mean job duration = 10.5 years
Renal outcomes = BUN, serum creatinine and uric acid, urinary
NAG, and tubular reabsorption of phosphate
99 male lead workers
Renal outcomes = serum creatinine and serum and urine alpha-1-
microglobulin
Mean recent blood lead
32.6 ug/dL (workers)
9.0 ug/dL (controls)
Mean time integrated blood lead
index
119.9 (ug/dL) x yr (workers)
0.05 (ug/dL) x yr (controls)
Mean relative change in recent
blood lead
28.2 % (workers)
Mean absolute change in recent
blood lead
6.4 (ug/dL)/year (workers)
# of times blood lead level >40,
50 and 60 ug/dL
Mean blood lead
Ranged from 24.1 to 67.6 ug/dL
(males)
19.6 ug/dL (females)
Other lead measures included
urinary lead, delta-
aminolevulinic acid, and
coproporphyrin.
Median blood lead
Ranged from 7.9 ug/dL in
category I consisting of 16 office
workers who did not work
directly with lead to 76.2 ug/dL
in 16 workers in the highest
exposure group (category V).
Only urinary a-1 microglobulin was significantly higher in
lead workers compared to controls.
In multiple linear regression analysis, adjusted only for
ethnicity and smoking, at least one lead measure was
significantly associated with each of the five renal outcomes.
Outcome
Ua-lMG
Ua-lMG
U P-2 MG
URBP
S P-2MG
UAlb
Lead measure
cum. blood lead
# blood lead >50
cum. blood lead
# blood lead >50
# blood lead >60
# blood lead >60
P (95% CD
0.10(0.06,0.14)
0.43 (0.04, 0.82)
0.05 (0.01, 0.09)
0.35(0.12,0.59)
0.47(0.29,0.65)
0.66(0.13, 1.19)
Cadmium dose measures reportedly not significant in these
models (although power would have been reduced as
cadmium measured only in a subset).
Strengths = longitudinal exposure data
Limitations = data analysis clarity and adjustment. Overlap in
populations between this study and earlier ones possible
Significant correlations of blood lead and delta-amino-
levulinic acid with BUN and NAG were observed. The
correlation between blood lead and NAG was dependent on a
small number of workers whose blood lead levels were above
80 ug/dL.
Limitations include absence of adjustment in statistical
analysis, small sample size.
Median urinary alpha-1-microglobulin significantly higher in
categories III - V compared to the low exposure group of
office workers. This was also the only renal outcome to be
significantly correlated with blood lead (Spearman rank
correlation).
After alpha-1-microglobulin adjusted for age and blood lead
(by stratifying); few significant differences noted. However,
analysis approach resulted in substantial loss of power.
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
to
Oi
Asia (cont'd)
Hsiao et al. (2001)
Taiwan, PR China
1991-1998
Huang et al. (1988)
Beijing, China
Study date not provided
N = 30 lead battery workers
Mean serum creatinine at baseline
— 1.0 mg/dL (based on figure; exact values not provided)
Longitudinal Analysis, 8 annual evaluations.
Generalized estimating equations used to adjust for
autocorrelation in multiple datapoints from each participant.
Adjusted for age, gender, and, in models of change in serum
creatinine, creatinine at beginning of interval.
Mean blood lead at baseline
—35 ug/dL (based on figure;
exact values not provided)
Mean duration of exposure
at baseline
13.1 years
40 lead workers (4 women)
Control group not described
Renal outcomes = serum beta-2-microglobulin and urinary beta-2-
microglobulin, total protein, IgG
Geometric mean blood lead
Cross-sectional
higher blood lead associated with lower concurrent
serum creatinine.
Longitudinal
Change in blood lead negatively associated with concurrent
change in serum creatinine (p = 0.07).
Blood lead at the beginning of the interval not associated with
change in serum creatinine in the following year.
Associations may represent lead-related hyperfiltration.
However, as noted by the authors, cumulative lead dose may
also be a factor. Mean blood lead declined greatly just before
renal data collection started. Therefore, the inverse
longitudinal associations could be due to persistently elevated
cumulative dose (which was unmeasured but, as evidenced by
the long half-life of bone lead, likely did not decline as much
as blood lead). However, authors did not model cumulative
blood lead or analyze effect modification by time period, age,
or exposure duration to determine if these associations
changed in a pattern consistent with hyperfiltration. The
small sample size also limits conclusions that may be drawn
from these results since a small number of individuals may be
overly influential.
Strengths = longitudinal data
Limitations = data analysis content (lead dose means not
reported), clarity and adjustment
Increased urinary (32 microglobulin in workers compared to
controls
Multiple limitations including lack of information on control
group, data analysis
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
H
6
o
o
H
O
Asia (cont'd)
Jung et al. (1998)
Korea
Study date not provided
Konishi, et al. (1994)
Study location
not provided; research
team from Japan
1991
Kumar and
Krishnaswamy (1995)
India
Study date not provided
75 randomly selected male lead workers
64 male office workers (controls)
Renal outcomes = BUN, serum creatinine, uric acid and urinary
NAG, albumin, tti microglobulin and |32 microglobulin
99 male lead workers, including 16 office workers to serve at
controls
renal outcomes = fractional clearances of tti microglobulin and |32
microglobulin (utilizing serum and urinary levels of both
biomarkers), BUN, serum creatinine, uric acid and urinary NAG
22 auto mechanics volunteers
27 male control workers (from Institute performing study)
Renal outcomes = serum creatinine, 4 hour creatinine clearance
and urinary NAG and (3-2 microglobulin
Renal disease, diabetes, HTN and occupational exposures
excluded in controls, possibly excluded in workers
Mean Blood lead
Means ranged from 24.3 to
74.6 ug/dL (workers)
7.9 ug/dL (controls)
Other lead measures included
zinc protoporphyrin,
8-aminolevulinic acid activity
and urinary lead, coproporphyrin,
and
8-aminolevulinic acid
Median blood lead
Range from 7.9 ug/dL in controls
to 76.2 ug/dL in Category V
Blood lead range
24.3 - 62.4 ug/dL (exposed)
19.4 - 30.6 ug/dL (controls)
Blood lead, zinc protoporphyrin, and urinary 8-aminolevulinic
acid significantly correlated with BUN, NAG, and tti
microglobulin (appears to be combined group analysis)
Limitation = statistical analysis - lack of adjustment
Urinary NAG, tti microglobulin and fractional clearance of tti
microglobulin increased with higher blood lead category.
Spearman rank correlation between fractional clearance of tti
microglobulin and blood lead was significant. This relation
also assessed by multiple linear regression with adjustment for
age; both independent variables were significantly associated
with the fractional clearance of tti microglobulin.
Limitation = statistical analysis - lack of adjustment
Urinary NAG and p2 microglobulin levels were significantly
higher in exposed compared to controls. However, only NAG
was significantly correlated with blood lead (r = 0.58, p <
0.01).
Limitations = study size and lack of adjustment in analysis,
values for 4 hour creatinine clearance in abnormal low range
in both exposed and controls
O
V
O
-------
o
O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
oo
H
6
o
o
H
O
O
V
O
Asia (cont'd)
Limetal. (2001)
Singapore
1999
Blood lead levels every
6 months from 1982 to
1999
Ongetal. (1987)
Singapore and Japan
Study date not provided
Wang et al. (2002)
Taiwan
Study date not provided
55 male lead workers
workers followed since 1982, many of same workers as in Chia
etal., AJIM(1995)
Renal outcomes = 4 hour creatinine clearance and urinary
albumin, RBP, oil microglobulin, (32 microglobulin, NAG, NAG-
A, and NAG-B
Exclusionary criteria included diabetes, HTN, recent ingestion of
analgesics, antipyretics, or antibiotics, and thalassemia;
24 participants of the original 80 were excluded as a result.
One female also excluded.
209 lead workers (51 females)
30 control workers from research staff
Renal outcomes = BUN, serum creatinine, calculated creatinine
clearance, and urinary NAG
229 lead battery workers, including 109 females
Renal outcomes = BUN, serum creatinine, serum uric acid
Multiple linear & logistic regression
Adjustment for age, gender, smoking, alcohol ingestion, milk
ingestion.
Mean current blood lead
24.1 ug/dL
Cumulative blood index
880.6 ug x yrs/dL (geometric
mean)
Number of times blood lead
exceeded 40 ug/dL 1.9
(geometric mean)
Mean blood lead
42.1 jig/dL (males) 31.9 ug/dL
(females)
Urine lead also measured
Mean blood lead
67.7 ug/dL (males)
48.6 ug/dL (females)
In separate models, after adjustment for age and smoking,
higher categorical cumulative blood index and number of
times blood lead exceeded 40 ug/dL were associated with
lower creatinine clearance (P < 0.001).
After adjustment, higher number of times blood lead exceeded
40 ug/dL was associated with higher urinary albumin, tti
microglobulin, RBP, NAG, and NAG-B. Similarly,
cumulative blood index was associated with higher urinary
albumin, tti microglobulin, RBP, and p2 microglobulin.
No associations between recent blood lead and any of the
renal outcomes was observed.
Analysis of covariance was used to adjust for smoking and
age
Limitation = statistical analysis - lack of adjustment, small
sample size, potential for healthy worker bias
Blood lead correlated with BUN(r = 0.16; p < 0.01), serum
creatinine (r = 0.26; p < 0.001) and creatinine clearance (r = -
0.16; p < 0.01). Blood lead associated with NAG after
adjustment for age (method not specified).
Higher NAG in exposed compared to controls when stratified
by categorical age.
Strengths = sample size
Limitations = statistical analysis - lack of adjustment, urinary
NAG not adjusted for urine dilution
P coefficient (95% CI) for blood lead in model of BUN, after
adjustment for lead job duration/age = 0.062 (0.042, 0.082).
P coefficient (95% CI) for blood lead in model of uric acid,
after adjustment for gender and weight = 0.009 (0.001, 0.016).
Blood lead not associated serum creatinine
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O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
VO
Asia (cont'd)
Weaver et al. (2003a)
South Korea
1997-1999
N = 803 lead workers including 164 females and 94 former lead
workers
Serum Creatinine:
0.90 mg/dL
Calculated creatinine clearance
94.7mL/min
4-hr measured creat. clearance
114.7mL/min
RBP
63.6 ug/g creatinine
NAG
215.3 |lmol/h/g creatinine
Multiple linear regression, adjusting for age, gender, BMI, work
status (current vs. former worker), HTN or blood pressure
(depending on model), and, for the EBE markers, alcohol
ingestion and diabetes.
42 associations modeled (7 lead measures with 6 renal outcomes)
Interaction models that assessed effect modification by age in
tertiles in 24 associations (4 lead exposure/dose measures with
6 renal outcomes).
Blood lead
32.0 ug/dL
Tibia Lead
37.2 |lg/g bone mineral
DMSA-chelatable lead
767.8 |lg/g creatinine
Lead exposure also assessed with
job duration and three
hematologic measures as
surrogates for lead dose
(aminolevulinic acid in plasma,
zinc protoporphyrin,
and hemoglobin).
Mean CdU measured in
n= 191 subset
1.1 ug/g creatinine
After adjustment, higher lead measures associated with worse
renal function in 9 of 42 models.
Associations in the opposite direction (higher lead measures
associated with lower serum creatinine and higher creatinine
clearances) in five models.
Opposite direction (inverse) associations observed only in
models of the clinical outcomes whereas the associations
between higher lead dose and worse renal function were
predominantly among the biomarker models.
In three of 16 clinical renal interaction models, positive
associations between higher lead measures and worse renal
function in participants in the oldest age tertile were
significantly different from associations in those in the
youngest age tertile which were in the opposite direction
- this pattern was observed at borderline significance (p < 0.1)
in 3 other models
- pattern was not observed in the EBE marker models
CdU associated with NAG.
Authors concluded that occupational lead exposure in the
moderate dose range has an adverse effect on renal function.
Inverse associations may represent hyperfiltration.
Environmental cadmium may have an adverse impact, at least
on NAG.
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O
to
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O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia (cont'd)
Weaver et al. (2003b)
Korea lead workers
1997-1999
798 lead workers with genotype information in same population
as in Weaver et al. (2003a)
79 (9.9%) participants were heterozygous for the ALAD2 allele
(none was homozygous).
89 (11.2%) had VDR genotype Bb or BB
Blood lead
31.7 ug/dL(ALADI 1)
34.2ug/dL(ALAD12)
31.6ug/dL(VDRbb)
34.8 ug/dL (VDR Bb or BB)
Tibia Lead
37.5 |lg/g(ALADI 1)
31.4ug/g(ALAD12)
37.1 ug/g(VDRbb)
38.1 ug/g (VDR Bb or BB)
Data were analyzed to determine whether polymorphisms in
the genes encoding 8-aminolevulinic acid dehydratase
(ALAD), endothelial nitric oxide synthase (eNOS), and the
vitamin D receptor (VDR) were associated with renal
outcomes or modified relations of lead exposure and dose
measures with renal outcomes.
After adjustment, participants with the ALAD2 allele had
lower mean serum creatinine and higher calculated creatinine
clearance. Effect modification by ALAD on associations
between blood lead and/or DMSA-chelatable lead and three of
six renal outcomes was observed. Among those with the
ALAD 12 genotype, higher lead measures were associated
with lower BUN and serum creatinine and higher calculated
creatinine clearance.
No significant differences were seen in renal outcomes by
VDR genotype nor was consistent effect modification
observed.
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O
to
O
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia (cont'd)
Weaver et al. (2005a)
Korea
1997-1999
N = 803 current and former lead workers; 164 females
Serum Uric acid
4.8 mg/dL
Other renal outcomes as listed in Weaver et al. 2003a
Multiple linear regression
Interaction models that assessed effect modification by age in
tertiles
Blood lead
32.0 ug/dL
Tibia Lead
37.2 (40.4) ug/g bone mineral
DMSA-chelatable lead
767.8 ug/g creatinine
Work to address whether one mechanism for lead-related
nephrotoxicity, even at current lower levels of lead exposure, is via
increasing serum uric acid. Assessed 1) whether lead dose was
associated with uric acid and 2) whether previously reported
associations between lead dose and renal outcomes (Weaver et al.,
2003) were altered after adjustment for uric acid.
After adjustment for age, gender, body mass index, and alcohol use,
lead biomarkers not associated with uric acid in all participants.
However, in interaction models, both blood and tibia lead were
significantly associated in participants in the oldest age tertile (P
coefficient and 95% CI: 0.0111 (0.003, 0.019) and 0.0036 (0.0001,
0.007) for blood and tibia lead, respectively). These models were
further adjusted for blood pressure and renal function.
Hypertension and renal dysfunction are known to increase uric acid.
However, they are also risks associated with lead exposure.
Therefore, adjustment for these variables in models of associations
between lead dose and uric acid likely results in over-control. On
the other hand, since non-lead related factors contribute to both
renal dysfunction and elevated blood pressure, lack of adjustment
likely results in residual confounding. Therefore, as expected,
associations between lead dose and uric acid decreased after
adjustment for systolic blood pressure and serum creatinine,
although blood lead remained borderline significantly associated (P
(95% CI) = 0.0071 (-0.001, 0.015). However, when the population
was restricted to the oldest tertile of workers with serum creatinine
greater than the median (0.86 mg/dL), likely the highest risk
segment of the population, blood lead remained significantly
associated with uric acid even after adjustment for systolic blood
pressure and serum creatinine (P = 0.0156)
Next, in models of renal function in all workers, uric acid was
significantly (p < 0.05) associated with all renal outcomes except
NAG.
In models in the oldest tertile of workers (266 workers, median age
51.1 years, range 46.0 to 64.8 years), after adjustment for uric acid,
associations between lead dose and NAG were unchanged, but
fewer of the previously significant (p < 0.05) associations noted
between lead dose and the clinical renal outcomes in Weaver et al.
(2003a) remained significant.
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to
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O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
Asia (cont'd)
Weaver et al. (2005b)
South Korea
1999-2001
N = 652 lead workers including 149 females and 200 former
workers
Patella lead measured in the third evaluation of the same study
reported in Weaver et al. (2003a). Data collection performed a
mean of 2.2 years after collection of the data presented in Weaver
et al. (2003a).
Same renal outcomes as Weaver et al. (2003a)
Serum Creatinine:
0.87mg/dL
Calculated creatinine clearance
97.0 mL/min
Multiple linear regression, adjusting for age, gender, BMI, work
status (current vs. former worker), HTN or blood pressure
(depending on model), diabetes, smoking status, and, for the
clinical measures, use of analgesics
Interaction models assessed effect modification by age,
dichotomized at the 67th percentile
Mean blood lead
30.9 ug/dL
Mean Tibia Lead
33.6 ug/g bone mineral
Mean Patella Lead
75.1 ug/g bone mineral
Mean DMSA-chelatable lead
0.63 |lg Pb/mg creatinine
All 4 lead measures were correlated (Spearman's r = 0.51 - 0.76).
Patella, blood and DMSA-chelatable lead levels positively
associated with NAG
Higher DMSA-chelatable lead associated with lower serum
creatinine and higher calculated creatinine clearance
Interaction models
All four lead measures associated with higher NAG among
participants in oldest age tertile
Higher blood, tibia, and patella lead associated with higher serum
creatinine among older participants
-beta coefficients less in the lead workers whose ages were in the
younger two-thirds of the age range; difference between slopes in
the two age groups was statistically significant only for association
of blood lead and serum creatinine
Inverse DMSA associations (higher DMSA-chelatable lead
associated with lower serum creatinine and higher calculated
creatinine clearance) significant in younger workers
Patella lead associations were consistent with those of blood and
tibia lead; DMSA-chelatable lead associations unique.
Authors hypothesized that similarities between patella, blood, and
tibia lead associations could be due, in part, to high correlations
among the lead biomarkers in this population. Despite similar high
correlations, DMSA-chelatable lead associations with serum
creatinine and calculated creatinine clearance were unique. This
biomarker is dependent on renal function and the collection time
was only 4 h. Therefore, the amount of lead that is excreted in this
relatively short time period after chelation may be influenced not
only by bioavailable lead burden, but also by high-normal as well
as actual supranormal glomerular filtration which are more
common in the younger workers.
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to
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O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia (cont'd)
Weaver et al. (2005c)
Korea
1997-1999
798 current and former lead workers.
same population as in Weaver et al. (2003a,b)
Ye et al. (2003)
Chinese lead workers
Study date not provided
216 lead workers
Renal outcomes = urinary NAG and albumin
Geometric mean blood lead
37.8 (ig/dL (n = 14 workers with
the ALAD12 genotype)
32.4 |lg/dL (n = 212 workers with
the ALAD 11 genotype)
31.9 ug/dL (VDR bb)
41.7 ug/dL (in 20 participants
with VDR Bb or BB)
Data were analyzed to determine whether polymorphisms in
the genes encoding 8-aminolevulinic acid dehydratase
(ALAD), endothelial nitric oxide synthase (eNOS), and the
vitamin D receptor (VDR) were associated with uric acid or
modified relations of lead exposure and dose measures with
uric acid.
Uric acid not different by ALAD or VDR genotype. Among
older workers (age > median of 40.6 years), ALAD genotype
modified associations between lead dose and uric acid levels.
Higher lead dose was significantly associated with higher uric
acid in workers with the ALAD11 genotype; associations
were in the opposite direction in participants with the variant
ALAD12 genotype.
After adjustment for age, NAG was borderline higher in those
with the ALAD variant allele whose blood lead levels were
>40 |lg/dL (p = 0.06). In all lead workers, after adjustment
for age, gender, smoking and alcohol ingestion, a statistically
significant positive association between blood lead and
creatinine adjusted NAG was observed in the workers with
the ALAD 12 genotype but not in lead workers with the
ALAD 11 genotype (the groups were analyzed separately
rather than in an interaction model).
No effect modification by VDR genotype on associations
between blood lead and urinary albumin and NAG observed
(separate analysis reduced power).
Middle East
Al-Neamy et al. (2001)
United Arab Emirates
Feb-June, 1999
100 "industrial" workers exposed in a range of industries
100 working controls
matched for age, sex, and nationality
Renal Outcomes = BUN, serum creatinine
Blood lead
77.5 ug/dL (workers)
19.8 jig/dL (controls)
Mean BUN and serum creatinine not statistically different
between exposed workers and controls
Limitations = data analysis
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to
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O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Middle East (cont'd)
Ehrlich et al. (1998)
South Africa
Study date not provided
El-Safty et al. (2004)
Egypt
Study date not provided
382 lead battery factory workers
Mean age = 41.2 years
All males
Multiple linear regression adjusted for age, weight, and height
(Covariates assessed for inclusion also included smoking, alcohol
ingestion, and diabetes)
Clinical renal outcomes included serum creatinine, uric acid,
and BUN.
Mean serum creatinine
1.13mg/dL
Renal early biological effect markers (NAG, RBP, intestinal
alkaline phosphatase, tissue nonspecific alkaline phosphatase,
Tamm-Horsfall glycoprotein, epidermal growth factor, and
microalbuminuria) were measured in 199 participants randomly
selected by tertiles of current blood lead.
45 lead workers with lead job duration <20 years
36 lead workers with lead job duration >20 years
75 control workers
Renal outcomes = urinary oCi-microglobulin, NAG, and
glutathione S-transferase
Mean blood lead
53.5 ug/dL
Mean exposure duration 11.6 years
Mean cumulative blood lead
(defined as sum of the average
blood lead in each year over all
years of employment; done in
subset of 246 with past blood lead
data)
579.0 (ug x yr)/dL
Mean historical blood lead (defined
as cumulative blood lead divided
by years of exposure)
57.3 ug/dL
Mean tibia lead
69.7 |lg/g bone mineral (measured
2 years after initial study on
random sample of 40)
Median urine lead
Ranged from 15.4 ug/g creatinine
in nonsmoking control workers to
250.4 ug/g creatinine in smoking
lead workers with > 20 years lead
job duration
After adjustment for age, weight, and height, categorical
current and historical blood lead and zinc protoporphyrin
were associated with serum creatinine and uric acid, in
separate models. Associations between cumulative blood
lead or exposure duration and the renal outcomes were not
observed.
Among the EBE markers, only current blood lead was
borderline associated with NAG (p = 0.09).
Associations with renal dysfunction were observed at blood
lead levels <40 |lg/dL. Not explained by an effect on blood
pressure since lead measures not associated with blood
pressure. Blood cadmium measured in 56 participants
2 years after the initial study. All low (< 1.2 |lg/L)
suggesting that occupational level cadmium exposure was
not a contributing factor. The authors did implicate lead
body burden which was substantial based on mean tibia lead.
However, cumulative blood lead was not associated in this
study and mean tibia lead in Roels et al. (1994) was similar
(in that study a positive association with creatinine clearance
was observed).
Medians of all 3 renal outcomes significantly higher in lead
workers irregardless of smoking status (analysis stratified by
smoking status).
Urine lead significantly correlated with urinary tti-
microglobulin and glutathione S-transferase in nonsmoking
lead workers and with NAG as well in smoking lead
workers.
Limitations include using urine lead as sole lead dose
measure and data analysis.
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X
H
6
o
o
H
O
Table AX6-4.2 (cont'd). Renal Effects of Lead - Occupational Population
December 2005
Reference, Study
Location, and Period
Middle East (cont'd)
Mortadaetal. (2001)
Egypt
Study date not provided
Study Description
43 traffic policemen
52 matched control office workers (similar in terms of age,
gender, smoking, and "social life").
Lead Measurement
Blood lead
32.1 ug/dL (exposed)
12.4 ug/dL (controls)
Lead also measured in hair, urine
Findings, Interpretation
NAG and albumin significantly higher in policemen
compared to controls. NAG positively correlated
(Pearson's) with job duration and blood and nail lead.
Urinary albumin positively correlated with job duration and
blood and hair lead.
Renal outcomes = serum creatinine, beta-2 microglobulin, BUN
and urinary (3-2- microglobulin, NAG, alkaline phosphatase,
y-glutamyl transferase, and albumin.
Exclusionary criteria included diabetes, HTN, hepatic, renal or
urologic diseases.
and nails
Limitations: data analysis - no adjustment, use of parametric
correlation techniques with data likely to be nonparametric;
study size
o
V
o
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o
O
to
O
O
Table AX6-4.3. Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
Oi
United States
Osterloh et al. (1989)
Northern CA
Study date not provided
Steenland et al. (1990)
Michigan
Diagnosis from
1976-1984
40 male subjects with hypertensive nephropathy (hypertension
preceded renal insufficiency; serum creatinine 1.8-4 mg/dL)
24 controls with renal dysfunction from other causes
Patients recruited from the Kaiser Permanente Regional
Laboratory database (large health maintenance organization) in
northern California
325 men with ESRD (diabetes, congenital and obstructive
nephropathies excluded)
controls by random digit dialing, matched by age, race, and place
of residence.
Mean blood lead
7.3 ug/dL (in both hypertensive
nephropathy and controls CRI
from other causes)
Mean EDTA chelatable lead levels
153.3 ug/72 hours (hypertensive
nephropathy)
126.4 jig/72 hours (control CRI)
No significant difference in EDTA chelatable lead levels;
highest chelatable lead level was 609.2 |lg/72 hours.
Lead dose and serum creatinine were not correlated.
Blood and chelatable lead levels much lower than those
reported by Wedeen et al. (1983) and Sanchez-Fructuoso
et al. (1996).
Only 17% of their study participants had a history of
possible lead exposure based on questionnaire, again much
lower than the two other studies.
Risk of ESRD significantly related to moonshine alcohol
consumption (OR = 2.43), as well as analgesic consumption,
family history of renal disease, and occupational exposure to
silica or solvents.
Europe
Behringer et al. (1986)
Germany
Study date not provided
Colleoni and D'Amico
(1986)
Italy
(-1982-1985)
16 patients with CRI (median serum creatinine = 2.2 mg/dL) and
gout
19 patients with CRI (median serum creatinine = 5.1 mg/dL)
without gout
21 healthy controls
Lead excretion in the 96 hours after administration of 1 g EDTA
iv
12 consecutive patients with CRI (mean serum creatinine = 3.3
mg/dL) and gout, renal diagnosis consistent with chronic
interstitial nephritis in all; 7 had history of occupational lead
exposure
12 controls with chronic glomerulonephritis and no history of
lead exposure or gout
Lead excretion in the 48 hours after administration of 1.5 g
EDTA im
Median blood lead
7.2 ug/dL (controls)
11.5 ug/dL (CRI, no gout)
15.3 ug/dL (CRI & gout)
Median EDTA chelatable lead
(ug/4 days/1.73m2)
63.4 (controls)
175.9 (CRI, no gout)
261.3 (CRI & gout)
Mean EDTA chelatable lead
(ug/48 hrs)
180 (CRI, no gout)
505 (CRI & gout)
EDTA chelatable lead higher in gout patients who developed
gout after CRI than those in which gout preceded CRI
(statistical test results not mentioned or shown). Authors
conclude a role for lead in patients with gout occurring in
setting of CRI and that lead may contributes to renal function
decline in established renal disease from other causes.
Limitations = small groups, limited data analysis
Significantly higher EDTA chelatable lead in the group with
CRI and gout compared to CRI alone. EDTA chelatable
lead significantly correlated with serum creatinine in patients
with CRI and gout but not CRI alone. Authors conclude that
lead is cause of CRI with gout but renal insufficiency alone
not responsible for increased lead body burden (absence of
evidence for reverse causation).
Limitations = small sample size, limited data analysis
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
December 2005
Reference, Study
Location, and Period
Europe (cont'd)
Colleoni et al. (1993)
Italy
Study date not provided
Study Description
All 115 patients on hemodialysis at the time of the study; 41
women
Blood lead data from prior study of 383 healthy controls in same
geographical area served as comparison
Lead Measurement
Mean blood lead
(corrected for hemoglobin)
19.9 ug/dL (patients)
14.7 ug/dL (controls)
Findings, Interpretation
Significantly higher mean blood lead in hemodialysis
patients compared to healthy controls. 13% had blood lead
levels >30 ug/dL. Blood lead level was not associated with
duration of hemodialysis. Mean lead levels higher in
X
Creswell et al. (1987)
Germany and Australia
Study date not provided
Fontanel's et al. (2002)
Spain
Study date not provided
Jones et al. (1990)
Study location and date
not provided; authors
from UK
Koster et al.
Study location and date
not provided; authors
from Germany
See discussion below under Australia
ALAD/restored ALAD as a possible index of lead poisoning in
chronic renal failure patients.
27 dialysis patients
59 healthy controls
91 patients with CRI ( median serum creatinine = 2.5 mg/dL)
46 age-matched normal controls.
Lead excretion in the 4 days after
1 g EDTA iv
Mean blood lead
8.1 ug/dL (patients)
10.0 ug/dL (controls)
Mean Blood lead
(corrected for hemoglobin)
11.2 ug/dL (patients)
7.6 ug/dL (controls)
EDTA chelatable lead
164.7 ug/4 days /1.73 m2 (patients)
63.6 ug/4 days /1.73 m2 (controls)
smokers and in relation to alcohol ingestion. Lead not
detectable in dialysis fluids.
Limited data analysis
Restored ALAD was measured after the addition of zinc
and dithiothreitol (DTT) to the incubation media.
The ALAD/restored ALAD ratio was found to correlate
with the results of the EDTA lead mobilization test.
Patients excreting 1,115 to 3860 ug lead per 72 hours had a
ratio of 0.19 while chronic renal failure patients excreting
an average of 322 ug lead (range 195 to 393) had a ratio of
0.47. In comparison, normal controls had a ratio of 0.5.
Tibia lead levels not correlated with blood lead but were
correlated with lead in bone biopsy measurements
(r = 0.42).
Limitations = data analysis
CRI patients had significantly higher blood and EDTA
chelatable lead levels than controls. In 13% of the CRI
patients, EDTA chelatable lead exceeded the highest value
in controls (328.8 ug). EDTA chelatable lead levels were
correlated with serum creatinine in patients (r = 0.37;
p < 0.007).
Limitations = data analysis
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O
to
O
O
Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
oo
Europe (cont'd)
Miranda-Carus et al.
(1997)
Spain
1990-1994
27 patients with gout and CRI
50 patients with gout only
26 controls with normal renal function and no gout
Multiple purine metabolism measures including serum urate,
hypoxanthine, and xanthine, as well as their excretion, clearance
and fractional excretion measures
Mean blood lead
17.8 ug/dL (gout & CRI)
14.9 |ig/dL (gout only)
12.4 |ig/dL (controls)
EDTA chelatable lead
845 ug/120 hrs (gout & CRI)
342 jig/120 hrs (gout only)
215 jig/120 hrs (controls)
Lead dose measures significantly higher in patients with gout
and CRI compared to the other two groups. EDTA
chelatable lead inversely correlated with creatinine
clearance. Each of the 2 patient groups were dichotomized
by EDTA-chelatable lead level of 600 Jig/120 hours,
resulting in 3 small groups (n ranging from 6 to 14) and one
group of 44 participants with gout and EDTA chelatable lead
below the cut-off. No significant differences in mean purine
metabolism measures were observed. It is not clear whether
correlations between EDTA-chelatable lead and the purine
measures were assessed and if so whether the small groups
were combined for this analysis. Thus lack of power may be
one reason for the inconsistency with Lin's work. Different
lead body burdens may be a factor as well.
Uric acid parameters were unchanged following chelation in
6 participants with EDTA-chelatable above 600 jig/120
hours. Again higher lead body burdens may be a factor but
the small number and limited details on the group make firm
conclusions difficult.
Nuytsetal. (1995)
Belgium
Study date not provided
Case-control study
272 cases with chronic renal failure (all types) matched to 272
controls by age, sex and residence
Exposure assessed by 3 industrial hygienists blinded to case or
control status
Significantly increased odds ratio for chronic renal failure
with lead exposure (odds ratio = 2.11 [95% CI: 1.23, 4.36])
as well as several other metals. Increased risk with diabetic
nephropathy.
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O
Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
vo
Europe (cont'd)
Sanchez-Fructuoso et al.
(1996)
Spain
Study date not provided
296 patients:
Group I = 30 normal control subjects
Group II = 104 patients with essential HTN & normal renal
function
Group III-A = 68 patients with HTN and CRI of uncertain
etiology but presumed nephroangiosclerosis
Group III-B = 64 patients with HTN, CRI, and gout
Group IV =30 patients with CRI of known etiology
Mean blood and EDTA-chelatable
lead levels:
Group I
16.7 ug/dL
324 ug/72 hrs
Group II
16.8 ug/dL
487 ug/72 hrs
Group III-A
18.5 ug/dL
678 ug/72 hrs
Group III-B
21.1 ug/dL
1290 ug/72 hrs
Group IV
16.5 ug/dL
321 ug/72 hrs
EDTA chelatable lead >600 ug/72 hrs in 16 patients in group
II, 30 patients in group III-A, 44 patients in group III-B, but
no patients in either group I and IV.
Mean blood and EDTA chelatable lead levels in the patients
with CRI of known cause were not statistically different
from controls with normal renal function. However, baseline
urinary lead excretion was lower in group IV. This provides
conflicting evidence regarding the "reverse causality"
hypothesis of increased lead burden due to decreased
excretion in CRI
Significant correlations noted between bone lead levels
(assessed by biopsy) and EDTA chelatable lead level in
12 patients whose chelatable lead levels were >600 ug/72
hours; provides support for validity of chelatable lead levels
in CRI.
A positive correlation was observed between serum
creatinine levels and EDTA-chelatable lead levels
>600 ug/72 hrs but not below this level.
In group III, mean measured creatinine clearance was
significantly lower in those with EDTA chelatable lead
levels >600 |lg/72 hrs compared to participants with
chelatable lead < 600 |lg/72 hrs.
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Europe (cont'd)
Van de Vyver et al.
(1988)
Belgium, France
and Germany
Study date not provided
Winterberg et al. (1991)
Study location and date
not provided; authors
from Germany
Transiliac bone biopsies obtained from:
11 cadavers without known lead exposure and with normal renal
function
13 patients with CRI, gout and/or HTN 22 lead workers
153 dialysis patients
Iliac crest bone lead measured by biopsy in:
8 controls
8 patients with CRI
14 dialysis patients
Mean transiliac lead levels
5.5 ug/g (153 dialysis pts)
20.6 ug/g (in highest 5% dialysis
pts)
3.7 ug/g (in 10 pts on dialysis due
to analgesic nephropathy)
6.3 ug/g (11 cadavers)
30.1 ug/g (22 lead workers)
Mean iliac crest bone lead levels
1.63 ug/g (8 controls)
2.18 ug/g (8 patients with CRI)
3.59 ug/g (in 14 dialysis pts)
In 5% of the hemodialysis patients studied, bone lead
concentrations approximated the levels found in active lead
workers, suggesting lead as a primary cause of their renal
failure. Levels in the 10 patients with analgesic nephropathy
were the lowest (all <7 ug/g), evidence against reverse
causality.
In the combined group of 13 patients with CRI, gout and/or
HTN and 22 lead workers, EDTA chelatable lead correlated
with lead in bone biopsies (r = 0.87).
Noted that the bone lead levels in patients with analgesic
nephropathy and cadaver controls in Van de Vyver et al.
(1988) were much higher than in control groups of other
researchers. They reiterated the concern that lead did
accumulate due to decreased renal excretion.
Latin and South America
Navarro et al. (1992)
Venezuela
Study date not provided
1 8 dialysis patients
14 controls
Bone (biopsy) and blood levels of lead and several other metals
Mean blood lead
5.2 ug/dL (patients)
11.5 ug/dL (controls)
Mean lead in bone
9.7 ug/g (patients)
7.0 ug/g (controls)
Blood but not bone lead significantly higher in patients
compared to controls. Authors concluded that bone
accumulation of aluminum, iron and vanadium, but not lead,
occurred in dialysis patients.
Limitations = sample size, data analysis including lack of
adjustment
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
£
Australia
Craswell et al. (1987)
Germany and Australia
Study date not provided
Price etal. (1992)
Queensland, Australia
1981-1986
German participants from industrialized area where chronic lead
nephropathy not previously observed
Gp 1 = 8 healthy controls (from hospital staff)
Gp 2a = 12 CRI patients, no gout or lead exposure
Gp 2b = 7 CRI patients, no gout but + lead exposure
Gp 3a = 7 CRI patients with gout but no lead exposure
Gp 3b = 6 CRI patients with gout and lead exposure
Australian participants from Queensland site of known chronic
lead nephropathy
Gp 1=9 healthy controls (from hospital staff)
Gp 2a = 14 CRI patients, no gout or lead exposure
Gp 2b =11 CRI patients, no gout but + lead exposure
Gp 3a = 25 CRI patients with gout but no lead exposure
Gp 3b = 11 CRI patients with gout and lead exposure
CRI defined as serum creatinine > 1.5 mg/dL
"excess" EDTA chelatable lead defined as lead excreted over 4
days after EDTA minus twice baseline lead excreted pre-EDTA
8 renal patients compared with age-matched controls
X-ray fluorescence of finger bone lead conducted twice 5 years
apart
Median blood lead (hemoglobin
corrected)
Gp 1
German = 6.8 ug/dL
Australian =11.0 ug/dL
Gp2a
German = 6.2 ug/dL
Australian = 9.1 ug/dL
Gp2b
German = 8.5 ug/dL
Australian =16.2 ug/dL
German =10.6 ug/dL
Australian =12.8 ug/dL
Gp3b
German =12.0 ug/dL
Australian = 27.1 ug/dL
Median "excess" EDTA chelatable
lead
Gp 1
German = 68.4 jig
Australian =82.9 jig
German = 126.4 jig
Australian = 393.7 ug
Gp2b
German = 489.0 ug
Australian = 1181.1 jig
German = 227.9 ug
Australian = 808.1 ug
Gp3b
German = 422.7 jig
Australian = 1077.5 ug
Using nonparametric statistical techniques due to skewed
data, German participants excreted statistically less lead than
their Australian counterparts. Mean EDTA chelatable lead
levels were significantly higher in German patients with gout
than in those without gout; the observed increase in the
Australian patients was of borderline significance (p < 0.1).
Limitations = small groups, limited data analysis
Authors conclude that lead in bone half-life is similar in
renal patients compared to age-matched controls. Study
limitations substantial, however.
Limitations = small numbers (although bone lead measured
in more patients, many were below the limit of detection,
inclusion of outliers without formal statistical analysis.
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
Asia
Lin et al. (1992)
Chinese population
(likely in Taiwan)
Study date not provided
Lin and Huang (1994)
Taiwan
Study date not provided
Lin and Lim (1994)
Taiwan
Study date not provided
10 healthy controls
10 patients with CRI but no gout
8 patients with gout and subsequent CRI
6 patients with CRI and subsequent gout
Exclusionary criteria included + history of occupational or
environmental lead exposure
Group 1 = 10 patients with normal renal function and no gout;
Group 2 = 10 patients with CRI (serum creatinine >1.4 mg/dL)
and subsequent gout; Group 3 = 20 patients with CRI but no gout
All males
Lead body burden assessed with 1 g EDTA iv followed by 72 hr
urine collection
Gp 1 = 12 healthy controls
Gp 2 = 10 patients with HTN
Gp 3 = 12 patients with HTN, then CRI (hypertensive
nephropathy)
Gp 4 = 12 patients with CRI only
Gp 5 = 12 patients with CRI not due to HTN, but subsequent
HTN
Mean EDTA chelatable lead in
ug/72hrs/ 1.73m2
90.2 (controls)
98 (CRI, no gout)
171.6 (gout, then CRI)
359.8 (CRI, then gout)
Mean EDTA chelatable lead
Gp 1=60.55 ug/72 hrs
Gp 2 = 252.24 ug/ 72 hrs
Gp3 = 84.86 ug/72hrs
Mean EDTA chelatable lead
Gp 1 = 76.6 ug/ 72 hrs
Gp2 = 67.96 ug/72hrs
Gp3 = 182.9ug/72hrs
Gp3 = 84.46 ug/72hrs
Gp3 = 92.86 ug/72hrs
Lead body burden higher in patients with CRI and gout,
especially when CRI precedes gout.
Limitations = small sample sizes, statistical analysis
Mean EDTA chelatable lead and serum urate significantly
higher in the patients with gout. After adjustment for
creatinine clearance, log transformed EDTA chelatable lead
was significantly associated with serum urate levels
(P [95% CI: 0.757 [0.142, 1.372]; p < 0.05), daily urate
excretion (P [95% CI: -60.15 [-118.1, -2.16]); p < 0.05),
urate clearance (P [95% CI: -0.811 [-1.34, -0.282];
p < 0.05), and fractional urate excretion (P [95% CI: -1.535
[-2.723, -0.347]; p < 0.05). EDTA chelatable lead not
associated with creatinine clearance.
Limitations = small sample sizes, limited adjustment in
regression analyses.
Higher mean EDTA chelatable lead level in Gp 3;
5 of 12 had history of gout developing after CRI
Limitations = small sample sizes, limited analyses
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia (cont'd)
Lin et al. (1999)
Taiwan
Study date not provided
32 patients selected from 102 patients with serum creatinine from
1.5 -4.0 mg/dL who were followed in the Institution's outpatient
clinics
Eligibility criteria included serum creatinine from 1.5 — 4.0
mg/dL, stable renal function over 6 months before study entry;
controlled blood pressure and cholesterol; daily protein intake <1
g/kg body wt; no known history of exposure to lead or other
heavy metals and EDTA chelatable lead >150 but <600 |lg/72
hour.
Exclusionary criteria included potentially reversible or unstable
renal disease (i.e., due to systemic diseases such as lupus and
diabetes), and nephrotoxicant medications.
Patients divided into 16 patients receiving 1 g EDTA i.v. weekly
for two months and a control group of 16 patients who received
no therapy
Mean EDTA chelatable lead levels
pre-chelation
254.9 |lg/ 72 hrs in group
receiving subsequent chelation
279.7 |lg/ 72 hrs in control group
Blood lead levels not mentioned
Rates of progression of renal insufficiency were followed by
reciprocal of serum creatinine during the 12 months prior to
therapy and for 12 months following therapy. Rates of
progression of renal insufficiency were similar in the
treatment group and the control group during the baseline
observation. However, improvement in renal function was
observed during EDTA chelation. Following chelation,
renal function stabilized in the treated group but continued to
decline in the control group. At 12 months after treatment,
the mean difference in the change in the reciprocal of serum
creatinine between the two groups was 0.000042 L/|lmol per
month (95% CI: 0.00001,0.00007). Results using a
sensitivity analysis for patients lost to follow-up (only one in
each group) gave similar results.
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia (cont'd)
Lin et al., Arch Intern
Med. (2001)
Taiwan
Study date not provided
24 month prospective observational study
110 patients with CRI dichotomized by EDTA chelatable lead
level of 80 ug / 72 hrs into two groups of 55 each
Eligibility criteria included serum creatinine from 1.5 — 4.0
mg/dL, stable renal function (decrease in GFR <5 mL/min over 6
months); blood pressure <140/90 mmHg; cholesterol level <240
mg/dL; daily protein intake <1 g/kg body wt; no known history of
exposure to lead or other heavy metals and EDTA chelatable lead
<600 Hg/72 hour.
Exclusionary criteria included potentially reversible or unstable
renal disease (i.e., due to systemic diseases such as lupus and
diabetes), nephrotoxicant medications, and drug allergies.
196 patients initially screened for study; details on reasons for
non-eligibility not provided.
Primary outcome = 1.5 times increase in the initial creatinine
level or need for dialysis; secondary outcome = change in
creatinine clearance
Cox proportional-hazards model analysis for primary outcome.
Mean differences in creatinine clearance compared at sequential
time points with t or Mann-Whitney U tests.
Adjustment for age, gender, baseline BMI, smoking, proteinuria,
hypertension, hyperlipidemia, daily protein intake, and underlying
renal disease
Intention-to-Treat and sensitivity analyses compared creatinine
clearance a by time period in high and low lead groups.
3 month clinical trial of chelation with 1 year follow-up
At 24 months, 36 patients whose EDTA chelatable lead levels
were 80 - 600 |lg/72 hours and serum creatinine levels of <4.2
mg/dL were randomized; 24 to a 3-month treatment period
consisting of weekly chelation with 1 g EDTA iv until their
excreted lead levels fell below 80 |lg/72 hours and 12 to placebo
infusion.
Intention-to-Treat and sensitivity analyses compared creatinine
clearance by time period in treated and control groups.
Mean blood lead levels
6.6 ug/dL in high normal lead
body burden group (n = 55)
3.9 ug/dL in low normal lead body
burden group (n = 55)
Mean EDTA chelatable lead levels
pre-chelation
182.9 ug/ 72 hrs in high normal
lead body burden group (n = 55)
37.9 jig/ 72 hrs in low normal lead
body burden group
(n = 55)
24 month prospective observational study
Lead dose measures were only significant differences
between high and low normal lead body burden groups. Of
the 96 participants who completed the observation study, 14
patients in the high normal body lead burden group reached
the primary endpoint compared to 1 patient in the low body
lead burden group (p < 0.001 by log-rank test).
From month 12 to month 24, creatinine clearance in high
normal body lead burden patients was at least borderline
statistically lower than in low body lead burden patients;
from 18-24 months, 95% CI excluded 0. 95% CI for the
difference at 24 months was (-15.0, -3.8); difference in
creatinine clearance between groups was 0.15 mL/s at that
point.
In a Cox multivariate regression analysis, chelatable lead
was significantly associated with overall risk for the primary
endpoint (relative risk = 41.5 [95% CI: 3.9, 440.8]; p =
0.002]). In this model, age, basal BMI, and basal daily
proteinuria were also associated with increased risk.
3 month clinical trial of chelation with 1 year follow-up
The two groups were similar in baseline renal risk factors
(although numbers small so beta error possible).
Mean EDTA dose during the 3 month period was 5 ug.
After three months of lead chelation therapy, the body lead
burden of the patients in the chelation group decreased from
198 to 39.2 ug. After 3 months of chelation and 3 months of
follow-up, creatinine clearance increased by 0.08 mL/s in the
treated group but declined by 0.04 mL/s in the controls.
At the end of the study period, mean creatinine clearance
was 0.68 mL/s in the chelated group compared to 0.48 mL/s
in the control group (p < 0.05; 95% CI for the difference
between groups = -25.0 to -0.2).
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia (cont'd)
Lin et al., Kidney
International (2001)
Study location and date
not provided; authors
from Taiwan
Lin et al. (2002)
Study location and date
not provided; authors
from Taiwan
101 patients with CRI (defined as serum creatinine between 1.5
and 3.0 mg/dL)
67 with CRI and gout
34 with CRI only
Eligibility criteria included no known history of lead exposure,
certain diagnoses and medications. CRI must have preceded gout
Randomized chelation trial
30 participants with CRI, gout, and EDTA-chelatable lead levels
between 80.2 and 361 |lg/72 hours randomized to either a
treatment group receiving 1 gram EDTA iv per week for 4 weeks
(N = 20) or to a control group who received glucose in normal
saline iv.
84 healthy participants
27 participants with gout
All with normal renal function (defined as serum creatinine
<1.4 mg/dL)
Participants with a history of occupational heavy metal exposure,
EDTA-chelatable lead levels >600 |lg/72 hours, or systemic
diseases were excluded.
Randomized chelation trial
24 participants with EDTA-chelatable lead levels between 75 and
600 Hg/72 hours randomized to either a treatment group receiving
1 gram EDTA iv per week for 4 weeks (N = 12) or to a control
group who received glucose in normal saline i.v.
Multiple linear regression, adjustment for age, sex, BMI,
daily protein intake, and creatinine clearance.
Mean blood lead
5.4 ug/dL (CRI and gout)
4.4 ug/dL (CRI only)
Mean EDTA-chelatable lead
138.1 ug/ 72 hrs (CRI and gout)
64.2 ug/ 72 hrs (CRI only)
(p<0.01)
Mean blood lead
3.9 ug/dL (controls)
4.2 ug/dL (gout)
Mean EDTA-chelatable lead
45 ug/ 72 hrs (controls)
84 jig/ 72 hrs (gout) (p < 0.0001)
In 101, EDTA-chelatable lead higher in patients with CRI
and gout compared to those with CRI only.
EDTA-chelatable lead, but not blood lead, was associated
positively with serum urate and negatively with daily urate
excretion, urate clearance, and fractional urate excretion.
Randomized chelation trial
The two groups had similar uric acid, renal function, and
lead measures pre-chelation. In the treated group, mean
EDTA-chelatable lead declined from 159.2 to 41 |lg/72
hours; mean serum urate decreased from 10.2 to 8.6 mg/dL
(% change compared to the control group = -22.4; [95% CI:
-46.0, -1.5]; p = 0.02), and mean urate clearance increased
from 2.7 to 4.2 mL/min ((% change compared to the control
group = 67.9; [95% CI: 12.2, 121.2]; p < 0.01). Daily and
fractional urate excretion were also significantly different
between the two groups. Mean measured creatinine
clearance increased from 50.8 to 54.2 mL/min (% change
compared to the control group = 8.0; [95% CI: -0.4,20.1];
p = 0.06).
Significantly higher mean EDTA-chelatable lead and lower
urate clearance were present in patients with gout compared
to those without (3.7 versus 6.0 mL/min/1.73 m2; p < 0.001
for urate clearance)
After adjustment, EDTA-chelatable lead associated with all
four uric acid measures (serum urate, daily urate excretion,
urate clearance, and fractional urate excretion). Blood lead
associated with serum urate. All associations in same
direction as in Lin et al. (2001).
Randomized chelation trial.
The two groups had similar urate, renal function, and lead
measures pre-chelation. In the treated group, mean blood
and EDTA-chelatable lead levels declined (from 5.0 to 3.7
|lg/dL and 110 to 46 Hg/72 hours, respectively). Statistically
significant improvement observed in all four urate measures
in the treated group compared to the control group.
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
Oi
Asia (cont'd)
Lin et al. (2003)
Study location and date
not provided; authors
from Taiwan
24 month prospective observational study
202 patients with CRI
Eligibility criteria included serum creatinine from 1.5 - 3.9
mg/dL, stable renal function (decrease in GFR <5 mL/min over 6
months); blood pressure <140/90 mmHg; cholesterol level <240
mg/dL; daily protein intake <1 g/kg body wt; no known history of
exposure to lead or other heavy metals and EDTA chelatable lead
<600 ng/72 hour.
Exclusionary criteria included potentially reversible or unstable
renal disease (i.e., due to systemic diseases such as lupus and
diabetes), nephrotoxicant medications, and drug allergies.
250 patients initially observed, loss due to noncompliance or
unstable renal function, baseline data on the 48 who left or were
removed from the study not provided.
Cox proportional-hazards model analysis for primary outcome.
Generalized estimating equations (GEE) for associations between
baseline chelatable lead or blood lead level and longitudinal
change in GFR (estimated by an MDRD equation [Levey et al.,
1999]) and by measurement of creatinine clearance.
Adjustment for age, gender, baseline BMI, smoking, baseline
serum creatinine, proteinuria, hypertension, hyperlipidemia, daily
protein intake, and underlying renal diseases.
Mean blood lead levels
5.3 ug/dL in total group
(n = 202)
6.1 ug/dL pre-chelation in
chelated group (n = 32)
5.9 ug/dL pre-chelation in control
group
Mean EDTA chelatable lead levels
pre-chelation
104.5 ug/72 hrs in total group (n =
202)
150.9 ug/72 hrs pre-chelation in
chelated group
144.5 ug/72 hrs pre-chelation in
control group
24 month prospective observational study
Primary endpoint = increase in serum creatinine to 1.5 times
baseline or need for hemodialysis; occurred in 24
participants. Secondary endpoint = change in estimated
glomerular filtration rate (GFR)
In a Cox multivariate regression analysis, chelatable lead
was significantly associated with overall risk for the primary
endpoint (hazard ratio for each 1 |lg chelatable lead was 1.00
[95% CI: 1.00, 1.01]; p = 0.03). In this model, baseline
serum creatinine was also associated (hazard ratio for each
1 mg/dL was 2.75 [95% CI: 1.46, 5.18]; p = 0.002) and, at
borderline significance (p < 0.1), baseline daily protein
excretion and smoking were as well.
The association between baseline chelatable lead and change
in GFR was modeled using GEE. Estimate = -0.003
(p = <0.001) (neither SE nor CI provided). In this model,
gender and daily protein intake were associated with
increased GFR; baseline serum creatinine level, daily urinary
protein excretion, and the presence of polycystic kidney
disease were significant predictors of a progressive decline
in glomerular filtration rate.
Based on this model, a 10 |lg higher baseline chelatable lead
level was associated with a GFR decrease of 0.03 mL per
minute per 1.73 m2 of body-surface area during the 2 year
observation period. Although statistically significant, this
effect is clinically small. Furthermore, it is 40 fold lower
than that reported in Yu et al. (2004) over a follow-up period
that is only two-fold shorter.
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Asia (cont'd)
Lin et al. (2003) (cont'd)
Study location and date
not provided; authors
from Taiwan
27 month clinical trial of chelation
At 24 months, 64 patients whose EDTA chelatable lead levels
were 80 - 600 |lg/72 hours and serum creatinine levels of <4.2
mg/dL were randomized; half to a 3-month treatment period
consisting of weekly chelation with 1 g EDTA iv until their
excreted lead levels fell below 60 |lg/72 hours and half to five
weeks of placebo infusion.
Intention-to-Treat analysis compared creatinine clearance and
GFR by time period in treated and control groups
27 month clinical trial of chelation
The two groups were similar in baseline renal risk factors
(although numbers small so beta error possible).
After three months of lead chelation therapy, the body lead
burden of the patients in the chelation group decreased from
150.9 to 43.2 ug and their mean blood lead levels decreased
from 6.1 to 3.9 ug/dL. GFR increased by 3.4 mL/min/1.73
m2 in the treated group; in contrast, it decreased by 1.1
mL/min/1.73 m2 in the control group. Mean EDTA dose
during the 3 month period was 5.2 ug.
In the subsequent 24 months, chelation in 19 (59%)
participants was repeated due to increases in serum
creatinine in association with rebound increases in EDTA
chelatable lead levels. Each received one additional
chelation series (mean = 4.1 g EDTA) a mean of 13.7
months after the first chelation period. Control patients
receiving placebo weekly for five weeks every six months.
At the end of the study period, mean estimated glomerular
filtration rate increased by 2.1 mL/min/1.73 m ofbody-
surface area in the chelated group compared to a decline of
6.0 in the controls (p < 0.01; 95% CI for the difference
between groups = -11.0 to -5.1).
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Table AX6-4.3 (cont'd). Renal Effects of Lead - Patient Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
oo
Asia (cont'd)
Yu et al. (2004)
Study location and date
not provided; authors
from Taiwan
121 patients followed over a four year observational period
Eligibility criteria included serum creatinine from 1.5 -3.9
mg/dL, stable renal function (decrease in GFR <5 mL/min
over 6 months); blood pressure <140/90 mmHg; cholesterol
level <240 mg/dL; daily protein intake <1 g/kg body wt; no
known history of exposure to lead or other heavy metals and
EDTA chelatable lead <600 |lg/72 hour.
Exclusionary criteria included potentially reversible or
unstable renal disease (i.e., due to systemic diseases such as
lupus and diabetes), medical noncompliance (patients were
followed for 6 months to assess compliance before
enrollment in the study), nephrotoxicant medications, and
drug allergies.
Cox proportional hazards model analysis for primary
outcomes and generalized estimating equations (GEE) for
associations between baseline chelatable lead or blood lead
level and longitudinal change in GFR (estimated by an
MDRD equation [Levey et al., 1999])
Adjustment for age, gender, baseline BMI, smoking, baseline
serum creatinine, proteinuria, hypertension, hyperlipidemia,
daily protein intake, use of ACE inhibitor or angiotensin-
receptor antagonists (since not all patients were on these),
and chronic glomerulonephritis (other underlying renal
diseases included in GEE as well)
Mean (SD) blood lead at baseline
3.4 (1.3) |lg/dL in 58 patients with
"low-normal" EDTA chelatable lead
levels (<80 |lg lead/72 hours)
4.9 (2.6) ng/dL in 63 patients with
"high-normal" EDTA chelatable lead
levels (>80 but <600 |lg/72 hours)
The two groups (dichotomized by diagnostic EDTA chelatable
lead of 80 |lg lead/72 hours ) were similar in most baseline risk
factors other than lead body burden. Borderline statistically
significant (p < 0.1) differences included mean older age in the
high chelatable lead group and certain renal diagnoses (chronic
glomerulosclerosis, chronic interstitial nephritis, hypertensive
nephropathy; surprisingly both of the latter two diagnoses were
less common in the lower lead body burden group).
Fifteen patients in the "high-normal" chelatable lead group
reached the primary endpoint (doubling of serum creatinine
over the 4 year study period or need for hemodialysis)
compared to only two in the "low-normal" group (p = 0.001 by
Kaplan-Meier analysis).
In a Cox multivariate regression analysis, chelatable lead was
significantly associated with overall risk for the primary
endpoint (hazard ratio for each 1 |lg chelatable lead was 1.01
[95% CI: 1.00-1.01; p = 0.002]). In this model, the only other
variable reaching at least borderline significance (p < 0.1) was
baseline serum creatinine.
The associations between baseline chelatable lead or blood lead
level and change in GFR were modeled separately using GEE.
Estimates =
-0.1295 (p = 0.002) for lead body burden (neither SE nor CI
provided)
-4.0123 (p = 0.02) for blood lead (neither SE nor CI provided)
Based on these models, a 10 |lg higher baseline chelatable lead
level or l|lg/dL higher blood lead level predicted 1.3 and 4.0
mL/min declines in GFR, respectively, during the four year
study period. Similar to the primary outcome analysis, of the
many traditional renal risk factors adjusted for in these models,
only diagnosis of chronic interstitial nephritis was significantly
associated, in this case with an increase in GFR. Of note,
chronic interstitial nephritis was also a more frequent diagnosis
in the group with the low-normal chelatable lead levels (p =
0.09).
The authors stated that these patients were not included in
earlier publications (which are described below in Section
6.4.4.3.3 Therapeutic EDTA Chelation in Patients).
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Table AX6-4.4. Renal Effects of Lead - Mortality
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
VO
United States
Cooper (1988);
Cooper, Wong and
Kheifets (1985)
16 U.S. plants
Employment between
1946 and 1970; mortality
from 1947 to 1980
Steenland et al. (1992)
Idaho
Employed between 1940
and 1965; mortality up to
1988
4519 male battery plant workers
2300 male lead production workers
Employed for at least one year between 1946 and 1970
Cause of death per death certificate (extrapolated when missing)
Standardized mortality ratios (SMRs) compared with national
age-specific rates. PMR also assessed
Analyzed separately by battery and lead production, by hire date
before and after 1/1/1946, and by cumulative years of
employment
(1-9, 10-19, 20+)
1990 male lead smelter workers
employed in a lead-exposed department for at least one year
between 1940 and 1965
Vital status was determined using records from the Social
Security Administration and the National Death Index.
Mean blood lead
63 ug/dL in n = 1326 battery
workers
80 ug/dL in n = 537 production
workers
Past lead exposures poorly
documented prior to 1960
Mean blood lead
56.3 ug/dL (n = 173, measured in
1976)
High lead exposure defined as
workers from departments with an
average >0.2 mg/m3 airborne lead
or >50% of jobs had average
levels more than twice that level
(1975 survey), n = 1,436 in this
category.
Follow-up >90% in both groups; 2339 deaths observed
"chronic or unspecified nephritis" SMR
222 (95% CI: 135, 343) in battery workers
265 (95% CI: 114, 522) in lead production workers
"other hypertensive disease" SMR ("includes HTN and
related renal disease without mention of heart disease)"
320 (95% CI: 197, 489) in battery workers
475 (95% CI: 218, 902) in lead production workers
Race adjusted proportionate mortality ratios analyses similar.
Nephritis deaths observed primarily in workers hired before
1946.
Limitations = due to mortality analysis (inaccuracies of death
certificates, exposure assessment generally limited)
Compared to the U.S. white male population, the
standardized mortality ratio (SMR) for chronic kidney
disease, based on only 8 deaths, was 1.26 (95th CI = 0.54,
2.49). SMR = 1.55 in high lead exposure group, also not
significant. The SMR for chronic kidney disease increased
with duration of exposure from 0.79 in workers exposed 1-5
years to 2.79 in workers exposed >20 years; however SMR
was not significant.
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Table AX6-4.4 (cont'd). Renal Effects of Lead - Mortality
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Europe
Bernard et al. (1995)
Czech Republic
Study date not provided
Fanning (1988)
UK
Deaths from 1926-1985
144 children living close to a lead smelter (exposed groups 1 and
2)
51 controls living in a rural area presumed to be relatively
unpolluted with lead.
Mean age = 13.5 years.
Renal outcome measures included urinary albumin, RBP, NAG,
Clara cell protein and p2-microglobulin.
Retinol binding protein
73.8 ug/g cr (controls)
109.4 ug/g cr (exposed group 1)
117.8 ug/g cr (exposed group 2)
P2-micro globulin
60.3 ug/g cr (controls)
89.1 ug/g cr (exposed group 1)
66.4 ug/g cr (exposed group 2)
NAG
1.56 lU/g cr (controls)
2.32 lU/g cr (exposed group 1)
1.46 lU/g cr (exposed group 2)
Multiple linear adjusting for age and gender.
Deceased males identified through pension records of lead battery
and other factory workers
867 deaths of mean with high lead exposure compared to 1206
men with low or no lead exposure
Blood lead
8.7 ug/dL (control boys)
8.39 ug/dL (control girls)
10.9 ug/dL (exposed boys 1)
9.4 ug/dL (exposed girls 1)
14.9 |ig/dL (exposed boys 2)
12.9 ug/dL (exposed girls 2)
Range of blood lead
40-80 ug/dL since -1968 in high
lead exposure group; thought not
to have had clinical lead poisoning
due to medical surveillance
<40 ug/dL since -1968 in little or
no exposure group
Mean blood lead levels significantly higher in both exposed
groups compared to the control group. In contrast, blood
cadmium levels were similar among all groups. After
adjustment for age, sex, blood cadmium, and zinc
protoporphyrin, log transformed blood lead was associated
with log transformed RBP (P coefficient = 0.302, p = 0.005
[SE nor CI provided]).
Odds ratio for renal disease = 0.62, not significant, based on
only 11 deaths. Similar for diagnosis of nephritis. Possible
decreasing odds ratio over time of deaths with mention of
nephritis on death certificate but not significant and numbers
still quite small.
Limitations = standard mortality study issues although
deaths compared with other workers and not general
population which is a strength in this type of study.
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Table AX6-4.5. Renal Effects of Lead - Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
United States
Hu(1991)
U.S.
Study date not provided
Loghman-Adham (1998)
Chicago, IL
Study date not provided
McDonald and Potter
(1996)
Boston, MA
1991
Moel and Sachs (1992)
Chicago, IL
1974-1989
21 of 192 adults who were hospitalized at Boston Children's
Hospital between 1932 to 1942 for childhood lead poisoning
were traced to a Boston area address. Matched on age, sex, race,
and neighborhood to 21controls.
Mean (SD) blood lead 6.0 ug/dL
(lead poisoned)
7.5 ug/dL (controls)
134 children and young adults, 8 to 13 years after chelation
therapy for severe lead poisoning
Mean age at poisoning = 2.3 years
Mean age at follow-up = 13.4 years
Mean peak blood lead level
121 ug/dL
Mean blood lead level at time
of study
18.6 ug/dL
454 pediatric hospital patients who were diagnosed with lead
poisoning between 1923 and 1966 were traced through 1991
Mortality study, comparison with U.S. population
62 participants with blood lead >100 ug/dL, diagnosed and
chelated between 1966 and 1972, together with 19 age-matched
control siblings with initial blood leads less than 40 ug/dL. Mean
age at follow-up = 22 years.
Renal outcomes = serum creatinine, uric acid, and (32-
microglobulin, fractional excretion of p2-microglobulin, urinary
protein:creatinine ratio, and tubular reabsorption of phosphate.
Mean initial blood lead
150.3 ug/dL (highly poisoned as
children)
Data for siblings not available as
levels <40 ug/dL not quantified.
No significant differences in blood lead level, serum
creatinine, or BUN. Mean measured creatinine clearance
higher in the previously lead poisoned group compared to
controls (112.8 vs. 88.8 mL/min/1.73 m2 [p < 0.01]). Mean
in the lead exposed group was also higher than the predicted
value of 94.2 mL/min/1.73 m2 from the nomogram of Rowe
et al. (1976). Suggests lead-related hyperfiltration. As noted
in section 6.4, one survivor, identified but not included in the
study, had disease consistent with lead nephropathy.
Limitations = small study size and concern for survivor bias
in the study group.
Mean serum creatinine was normal (0.8 mg/dL). Calculated
creatinine clearance normal in all but 3 children. No
correlation between either initial or current blood lead and
serum creatinine or calculated creatinine clearance.
Urinary a-amino nitrogen concentrations were significantly
increased compared with 19 healthy age matched controls
and were correlated with current blood lead levels. Thirty-
two children (24%) had glycosuria. Fractional excretion of
phosphate, however, was normal in all children. The author
concluded that a partial Fanconi syndrome could persist for
up to 13 years after childhood lead poisoning. The author
notes that the prognostic significance of this is unknown at
present.
Chronic nephritis was not a significant cause of death.
Mortality from all cardiovascular disease was elevated
(observed/expected = 2.1 [95% CI: 1.3, 3.2]) and cerebral
vascular deaths were particularly common among women
(observed/expected = 5.5 [95% CI: 1.1, 15.9]).
There were no statistical differences in either renal function
or blood pressure between study subjects and control
siblings. Initial blood lead level was not associated with
serum creatinine, after adjustment for age, gender and body
mass index. A modest increase in serum creatinine values
was observed over a nine-year period in four of the 62 study
subjects (up to 1.6 mg/dL).
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Table AX6-4.5 (cont'd). Renal Effects of Lead - Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
Europe
Factor-Litvak et al.
(1999)
Kosovo, Yugoslavia
1985-1993
Pels etal. (1998)
Poland
1995
577 children followed at 6 month intervals through 7.5 years of
age.
Divided into a high exposure and a low exposure group, based
on residence in Kosovska Mitrovica with a lead smelter, refinery
and battery plant or in Pristina, 25 miles away.
Renal outcome = Proteinuria assessed with a dipstick.
Multiple logistic regression modeling of proteinuria
dichotomized as either any or none, adjusting for socioeconomic
status, maternal education/ intelligence, and quality of
childrearing environment.
112 children (50 controls, 62 exposed)
Mean age = 9.9 years and 10.6 years in controls and exposed
group, respectively.
Numerous (29) renal outcome measures were examined
including serum creatinine and p2-microglobulin, and urinary
NAG, RBP, Clara cell protein, p2-microglobulin, 6-keto-
prostaglandin FIO
(6-keto-PGFi0), prostaglandin E2 (PGE2) and thromboxane B2
(TXB2).
Urinary RBP
46 ug/g cr (exposed)
42 ug/g cr (controls)
Urinary [^-microglobulin
89 ug/g cr (exposed)
37 ug/g cr (controls)
Serum creatinine
0.63 mg/dL (exposed)
0.63 mg/dL (controls)
Mead blood lead from graph
peaked at —38 ug/dL between ages
3-5 in Kosovska Mitrovica and at
—10 ug/dL in controls. Blood lead
level (not means) range = 1-70
ug/dL
Blood lead
13.3 ug/dL (exposed)
3.9 ug/dL (controls)
In higher exposed group, adjusted OR for proteinuria was
3.5 (CI = 1.7 — 7.2); adjusted odds of proteinuria increased
by 1.15 (CI = 1.1 — 1.2) per unit increase in blood lead in the
higher exposed group. Proteinuria unrelated to blood lead in
lower exposed control group.
Limitations = limited renal outcomes assessed, high dropout
rate in the study.
Significantly higher mean serum p2-microglobulin, and
urinary transferrin, 6-keto-PGFi0, thromboxane B2,
epidermal growth factor, (32-microglobulin, PGE2, and Clara
cell protein in the exposed children. In contrast, NAG-B
was lower in the exposed group. Categorical blood lead
associated with prevalence of values above the upper
reference limits for several biomarkers. Urinary 6-keto-
PGFio, TXB2, p2-microglobulin, Clara cell protein,
epidermal growth factor and PGE2 positively correlated with
blood lead (r = 0.441, 0.225, 0.203, 0.261, 0.356, and 0.23,
respectively; all with significant p-values)
Limitations = data analysis, limited adjustment
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Table AX6-4.5 (cont'd). Renal Effects of Lead - Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Europe (cont'd)
Price etal. (1999)
Belgium, Poland,
Germany and Italy
Study date not provided
Schareretal. (1991)
Germany
1988-1989
Sonmez et al. (2002)
Turkey
Study date not provided
Urinary lead measured in 481 European children (236 controls,
245 exposed) aged 6-14 years.
Several renal outcome measures assessed including urinary
NAG and p2-microglobulin; values not reported
22 children, age 5-14 years, with CRI
20 siblings or neighbors as lower exposed group
16 control children without known lead exposure
39 adolescent auto repair workers (mean age 16.2 years)
13 adult battery workers as positive controls (mean age 32 years)
29 rural adolescents as negative controls (mean age 14.8 years)
Serum creatinine
0.99 mg/dL (exposed group)
0.99 mg/dL (positive/ adult controls)
0.89 mg/dL (negative/ adolescent controls)
Urinary NAG
4.7 lU/g cr (exposed group)
7.4 lU/g cr (positive/ adult controls)
3.1 lU/g cr (negative/ adolescent controls)
Mean urinary lead
Range from 3.9 to 7.2 ug/g cr
(controls)
Range from 5.2 to 24.6 ug/g cr
(exposed)
Mean blood lead
2.9 ug/dL in children with CRI,
not tested in other groups
Mean dental lead content
2.8 ug/g in children with CRI
1.7 ug/g in sibs/neighbors
1.4 ug/g in controls
Blood lead
8.13 ug/dL (exposed group)
25.3 ug/dL
(positive/adult controls)
3.49 ug/dL
(negative/ adolescent controls)
Urinary lead generally higher in exposed children as
compared to controls. Authors unexpectedly found
substantial differences in renal biomarkers by study site.
Authors note several renal biomarkers differed between
exposed and control groups. Also questioned the use of
"control" groups in ubiquitous exposures.
Lead levels in teeth significantly higher in both the patient
and sibling/neighbor control groups compared to the
unexposed control group.
All participants had normal blood urea, creatinine, and uric
acid levels as well as normal routine urinalysis
Blood lead level and urinary NAG significantly higher in
adolescent auto repair workers compared to the negative
control group
Limitations = data analysis, lack of adjustment
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Table AX6-4.5 (cont'd). Renal Effects of Lead - Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Europe (cont'd)
Staessen et al. (2001)
Belgium
1999
Verberketal. (1996)
Romania
1991-1992
100 exposed and 100 control children
Mean age = 17 years
Two exposed groups were recruited from industrialized suburbs
while the control group was recruited from a rural area.
P^-microglobulin
5.22 ug/mmol cr (controls)
5.3 ug/mmol cr (exposed group 1)
9.09 ug/mmol cr (exposed group 2)
0.65 mg/L (controls)
0.63 mg/L (exposed group 1)
0.71 mg/L (exposed group 2)
Multiple linear regression adjusting for sex and smoking status
151 children who resided at different distances from a lead
smelter
Mean age = 4.6 years.
Renal outcomes = urinary RBP, NAG, di-microglobulin,
albumin and alanine aminopeptidase.
Geometric means
Urinary RBP
49.4 ug/g cr
Urinary NAG
6.9 U/g cr
Urinary q^-microglobulin
2.4 mg/g cr
Urinary alanine aminopeptidase
19.8U/gcr
Multiple regression analysis adjusting for age and gender
Blood lead 1.5 ug/dL (controls)
1.8 ug/dL (exposed group 1)
2.7 ug/dL (exposed group 2)
Blood lead
34.2 (22.4) ug/dL
Blood lead, p2-microglobulin, and Cystatin-C levels higher
in exposed group 2 as compared to controls and exposed
group 1
After adjustment for sex and smoking status, blood lead was
associated with both pVmicroglobulin and cystatin-C.
A two-fold increase in blood lead was associated with a
3.6 % increase in Cystatin-C ([95% CI: 1.5, 5.7]; p <
0.0001) and a 16% increase in p2-microglobulin ([95% CI:
2.7, 31]; p = 0.02). Blood cadmium was not associated with
either outcome.
After adjustment for age and gender, a 10 ug/dL increase in
blood lead was associated with a 13.5% increase in NAG
excretion (90% CI = 10.2-17%). No threshold was
observed. No other significant associations noted.
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Table AX6-4.5 (cont'd). Renal Effects of Lead - Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Africa
Dioufetal. (2003)
Senegal
1998
38 Senegalese children
(19 exposed, 19 controls)
Age range = 8-12 years old.
Renal function assessed by measuring urinary alpha-glutathione
S-transferase (aGST)
Mean (SD) blood lead
10.7 (1.7) ug/dL (exposed)
6.1 (1.8) jig/dL (controls)
Blood lead significantly higher in exposed group (urban
dwellers) as compared to controls (rural dwellers).
Unclear as to whether aGST was higher or lower in controls
as compared to exposed group (stated to be higher in
controls in the results section BUT stated to be higher in the
exposed group in the discussion). Regardless, the difference
was not statistically significant.
Limitations = small sample size, data analysis
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CHAPTER 6 ANNEX
ANNEX TABLES AX6-5
December 2005 AX6-156 DRAFT-DO NOT QUOTE OR CITE
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Table AX6-5.1. Cardiovascular Effects of Lead
Reference, Study
Location, and
Period
Study Description
Lead Measurement
Findings, Interpretation
United States
X
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Cheng etal. (1998)
US-Boston, Normative
Aging Study (VA)
1991-1995
775 males (97% white), mean age (SD)
[range] 67.8 years (7.3) [48-93].
Multiple linear regression models of
heart rate-corrected QT and QRS
electrocardiogram intervals were
adjusted by stepwise entry of covariates,
retaining only those that remained
significant at p < 0.10. Linear blood
lead, tibia, and patella bone lead were
apparently (not described in text) entered
separately. Logistic regression models
for Minnesota ECG Coding Center
diagnoses of intraventricular conduction
deficit (IVCD), atrioventricular
conduction deficit (AVCD), and
arrhythmia were adjusted by covariates
the same way. Only analyses stratified
by age (<65 years, n = 277; >65 years, n
= 498) were presented
Arithmetic mean (SD) blood
lead: 5.8 ug/dL (3.4)
Mean (SD) tibia lead: 22.2 ug/g
(13.4)
Mean (SD) patella lead:
30.8 ug/g (19.2)
Multiple regression models of QT intervals, adjusted for age, alcohol intake, BMI, and
diastolic blood pressure, found that only tibia and patella lead were significantly
related to outcome in the under 65 group. Every 10 ug/g increase of tibia and patella
lead was associated with a 5.0 ms (95% CI: 0.8, 9.2) and 3.0 ms (95% CI: 0.2, 5.8)
increase in QT interval, respectively. Multiple regression models of QRS intervals,
adjusted for age, fasting glucose level, and diastolic blood pressure, also found that
only tibia and patella lead were significantly related to outcome in the under 65 group.
Every 10 ug/g increase of tibia and patella lead was associated with a 4.8 ms (95% CI:
1.8, 7.8) and 2.2 ms (95% CI: 0.1, 4.4) increase in QRS interval, respectively. There
were no significant effects of lead in the 65 and over group.
Logistic regression models of IVCD, adjusted for age and serum HDL level, found that
only tibia lead was significantly related to outcome in the under 65 group. Every 10
ug/g increase of tibia lead was associated with increased odds of IVCD, OR 2.23 (95%
CI: 1.28, 3.90). There were no significant lead effects in the 65 and over group for
IVCD. Logistic regression models of AVCD, adjusted for age and serum HDL level,
found that both tibia and patella lead were significantly related to outcome in the 65
and over group. Every 10 ug/g increase of tibia lead and patella lead was associated
with increased odds of AVCD, OR 1.22 (95% CI: 1.02, 1.47) and OR 1.14 (95% CI:
1.00, 1.29), respectively. Lead was not significantly related to AVCD in the under 65
group.
There were no significant effects of lead on arrhythmia in either age group.
Stepwise models may capitalize on chance associations. Linear blood lead
specification may not be appropriate in some or all of these models. Not clear if three
models were constructed for each stratified analysis for each outcome, each based on a
different lead index. No statistical comparisons across strata. No model diagnostics
were presented.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and
Period Study Description
Lead Measurement
Findings, Interpretation
United States (cont'd)
X
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Cheng etal. (2001)
US-Boston, Normative
Aging Study (VA)
1991-1997
833 males (—97% white), average age
(SD):
65-68 years, depending on hypertension
group
(6.8-7.8) for blood pressure study.
474 males with no history of
hypertension at first measurement,
returning up to 6 years later for
hypertension study.
Linear multiple regression models of
blood pressure and Cox proportional
hazard models of new cases of
hypertension after up to 7 years, with
one group of covariates forced into
models based on biological plausibility
and another group forced based on
significant univariate or bivariate results
or >20% effect modification of lead
variable coefficient in multiple models.
Linear blood lead, tibia lead, and patella
lead forced in separate models.
Arithmetic mean (SD) blood
lead: 5.9-6.4 ug/dL (3.7-4.2),
depending on hypertension group
(only data shown).
Multiple regression models of blood pressure always included age, age-squared, BMI,
family history of hypertension, daily alcohol consumption, and daily calcium
consumption. Increasing tibia lead concentration was associated with increased
systolic blood pressure (diastolic not addressed) in baseline measurements in subjects
(n = 519) free from definite hypertension (systolic > 160 mmHg, diastolic > 95 mmHg,
or taking daily antihypertensive medication). Each increase of 10 ug/g tibia lead
concentration was associated with an increase in systolic blood pressure of 1.0 mmHg
(95% CI: 0.01, 1.99). Patella and linear blood lead were not significant.
Cox proportional hazard models always included age, age-squared, BMI, and family
history of hypertension. In follow up (n = 474), only increasing patella lead predicted
increasing risk of definite hypertension in those classified as normotensive at baseline.
For every 10 ug/g increase in patella lead risk ratio increased 1.14 (95% CI: 1.02,
1.28). Combining borderline hypertension (systolic 141-160 mmHg or diastolic 91-95
mmHg) with definite hypertension (n = 306), the relative risk ratio of becoming a
combined hypertensive associated with a 10 ug/g increase in patella lead was 1.23
(95% CI: 1.03, 1.48). Linear blood lead and tibia lead were not significant.
Linear blood lead is not indicated for blood pressure models due to strong likelihood of
significant residual heteroscedasticity and non-normality. Relatively small sample size
may have prevented tibia blood lead significance in the Cox proportional hazard
models.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and
Period Study Description
Lead Measurement
Findings, Interpretation
United States (cont'd)
X
Den Hond et al. (2002)
US-NHANES III
1988-1994
4,685 white males, 5,138 white females,
1,761 black males, 2,197 black females,
from 20 years up. Log-transformed
blood lead, systolic and diastolic blood
pressure measured at survey time and
analyzed with forward, stepwise multiple
regression with covariates.
Geometric Mean
(25th-75th percentile)
blood lead:
White Male Mean 3.6 ug/dL
(2.3-5.3)
White Female Mean 2.1 ug/dL
(1.3-3.4)
Black Male Mean 4.2 ug/dL
(2.7-6.5)
Black Female Mean 2.3 ug/dL
(1.4-3.9)
After adjusting for age, age-squared, BMI, hematocrit, smoking, alcohol, and an
indicator variable for use of antihypertensive medications, each model was further
modified by a unique mix of other covariates, including: coffee consumption, dietary
calcium, dietary sodium/calcium ration, total serum protein, total serum calcium,
diabetes, and poverty index. Log lead was forced in last.
In stratified analyses, only blacks had significant positive blood pressure associations
with log blood lead. Each doubling of blood lead was associated with increase of black
male systolic blood pressure of 0.9 mmHg (95% CI: 0.04, 1.8), black female systolic
blood pressure of 1.2 mmHg (95% CI: 0.4, 2.0), and female diastolic blood pressure of
0.5 mmHg (95% CI: 0.01, 1.1). In white males only, each doubling of blood lead was
significantly associated with a decrease in diastolic blood pressure of -0.6 mmHg
(95% CI: -0.9, -0.3).
Stepwise models can relay on chance associations due to multiple testing and usually
lead to a different pattern of covariate adjustment in different models. Inclusion of
likely confounding variables such as serum calcium could have affected estimated lead
effects. No justification given for age and race stratification. No testing for significant
lead coefficient differences between each stratum. No model diagnostic tests reported.
No explanation offered for inverse relationship between lead and diastolic blood
pressure in white males. No adjustment for survey design.
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Gerr et al. (2002)
US-Spokane WA and
area around Silver
Valley ID
1994
502 young people, age 19-29 years, 53%
female, nearly evenly divided into the
Spokane group (no unusual childhood
exposure) and the Silver Valley group,
where a lead smelter operated during
their childhood. Multiple regression
models of systolic blood pressure and
diastolic blood pressure. All covariates
forced into model as block with both
linear blood lead and tibia bone lead in
each model.
Mean (SD) blood lead only given
stratified on tibia lead category:
(Tibia < 1 ug/g) blood lead mean
1.9 ug/dL (1.6)
(Tibia 1-5 ug/g) blood lead mean
2.3 ug/dL (2.1)
(Tibia 6-10 ug/g) blood lead
mean 2.4 ug/dL (2.4)
(Tibia <10 ug/g) blood lead mean
3.2 ug/dL (2.3)
No other descriptive tibia lead
data given.
Adjusting for sex, age, height, BMI, education, income, current smoker, current
alcohol use, childhood residence (the two recruitment areas), current birth control pills,
hemoglobin, and serum albumin, only tibia lead, and not linear blood lead, was
significantly related to systolic and diastolic blood pressure. Compared to the < 1 ug/g
tibia lead category, subjects in the >10 ug/g category had 4.3 mmHg (95% CI: 1.4,
6.7) higher systolic blood pressure and 2.8 mmHg (95% CI: 0.4, 5.2) higher diastolic
blood pressure.
Linear blood lead is not indicated for blood lead-blood pressure models. No diagnostic
testing reported. Insufficient descriptive data given for tibia lead.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and
Period Study Description
Lead Measurement
Findings, Interpretation
United States (cont'd)
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Glenn et al. (2003) 496 males, mean (SD) (range) age 55.8
US-New Jersey (7.4, (40-71) years, working or formerly
1994-1998 working at a plant producing tetraethyl
or tetramethyl lead until 1991, were
followed from 10 months to 3.5 years
during which blood pressure was
repeatedly tested. Blood lead was tested
only at baseline. Tibia lead was tested in
1991 (at the end of organic lead
production at the plant) and called "peak
tibia lead" and again during 1997 (year
3). Generalized estimating equations
with an exchangeable correlation
structure for repeated measurements
were used for systolic and diastolic
blood pressure. One group of covariates
was forced into the model as a block
(age at baseline, race, BMI, indicator
variable for technician, lead variable
(linear blood lead, peak tibia lead, and
tibia lead each tested separately),
duration of follow up, and the interaction
between the lead variable and the
duration term. Potential confounding
variables were entered stepwise and
retained in the model if significant.
Alternate models not using linear time
were constructed, using quartile of
follow up time to avoid assuming a
linear relationship of change in blood
pressure with time.
Arithmetic mean (SD, range)
blood lead at baseline:
(4.6, 2.6-1-20) ug/dL.
Tibia lead at year 3:
14.7(9.4,-1.6-52) ng/g
Peak tibia lead: 24.3 (18.1,-2.2-
118.8)
Controlling for baseline age, BMI, antihypertensive medication use, smoking,
education, technician and number of years to each blood pressure measurement, each 1
ug/dL increase in linear baseline blood lead was associated with average systolic blood
pressure increase of 0.25 mmHg/year (95% CI: 0.05, 0.44), each 10 ug/g increase in
year 3 tibia lead with an average increase of 0.78 mmHg/year (95% CI: 0.24, 1.31),
and each increase of 10 ug/g of peak tibia lead with an average increase of 0.34
mmHg/year (95% CI: 0.05, 0.62). Similar results were obtained using the follow up
time quartile designation for systolic blood pressure with all subjects and with subjects
not taking antihypertensive medications.
This was one of the few studies using a prospective design and that used a statistical
technique accounting for repeated measures. No justification given for using an
exchangeable correlation structure instead of an alternate one. Only examined cortical
bone lead (tibia) and not trabecular bone lead (patella or calcaneus). Linear blood lead
may not be indicated for use in blood lead-blood pressure models. Stepwise modeling
involves multiple testing of the same data set with no control for altered probabilities.
No model diagnostics presented.
O
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and
Period Study Description
Lead Measurement
Findings, Interpretation
United States (cont'd)
X
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O
V
O
Glenn et al. (2001) 213 males (92% white), mean (SD) age
US-New Jersey 58.0 (7.4) years, working or formerly
1996-1997 working at a plant producing tetraethyl
or tetramethyl lead until 1991, were
genotyped for ATP1A2(5') and
ATP1A2(3') polymorphism. ATPase is
thought to play a role in regulating blood
pressure and lead inhibits its activity.
Blood pressure, blood lead, and tibia
lead were measured. Multiple linear
regression models were used for systolic
and diastolic blood pressure. Logistic
regression model was reported for
hypertension (systolic > 160 mmHg,
diastolic > 96 mmHg, or taking
antihypertensive medications).
Covariate entry methods not specified,
but were likely stepwise. Covariates for
the blood pressure model were age, use
of antihypertensive medications, alcohol,
smoking, season of year, linear blood
lead, tibia lead (the two lead measures
apparently tested separately),
ATP1A2(5') and ATP1A2(3')
polymorphism (each tested separately),
and an interaction term between
polymorphism and lead. Covariates for
the hypertension models were age, BMI,
lifetime alcoholic drinks, linear blood
lead and tibia lead, and polymorphism,
each lead measure and polymorphism
tested separately.
Arithmetic mean (SD, range)
blood lead:
5.2ug/dL(3.1, 1-20).
Mean (SD) tibia lead: 16.3 ug/g
(9.3)
None of the relationships between the ATP1A2(5') polymorphism and either blood or
bone lead or blood pressure were significant.
The ATP1A2(3') polymorphism was homogenous for the 10.5 kilobase allele
(10.5/10.5) in 11 subjects, heterogeneous for the 10.5 and 4.3 kilobase allele (10.5/4.3)
in 82 subjects, and heterogeneous (10.5/4.3) in 116 subjects. Prevalence of the 10.5
allele was significantly higher in blacks than in whites.
Regression coefficients of 4.3/4.3 and 10.5/4.3 genotypes were not significantly
different and all subsequent analyses compared the 10.5/10.5 genotype with the
combined 4.3/4.3-10.5/4.3) genotype. The significant interaction between linear blood
lead and the 10.5/10.5 genotype showed that for every 1 ug/dL of blood lead systolic
blood pressure increased 5.6 mmHg (95% CI: 1.2, 9.9) more than the blood pressure
of the combined genotype group. Blood lead range of the combined genotype group
was twice that of the 10.5/10.5 group. When data were truncated to make blood lead of
both groups cover the same range, coefficients of the genotype-linear blood lead
interaction term did not change appreciably. Authors state that tibia lead interacted
with genotype on blood pressure but showed no data to estimate either type or size of
effect. Diastolic blood pressure was not related to genotype, to lead or to the
interaction between lead and genotype.
Prevalence of hypertension (30% in total sample) was significantly higher among the
10.5/10.5 group (63.4 %) than among the combined group (28.3 %). Adjusting for age,
BMI, and lifetime alcohol, the odds of hypertension in the 10.5/10.5 group were OR
7.7 (95% CI: 1.9, 31.4) compared to the 4.3/4.3 group. The heterogeneous group was
not significantly different from the 4.3/4.3 group.
Linear blood lead specification not indicated for blood lead-blood pressure modeling.
Examination of partial residual plot for systolic blood pressure and linear blood lead
shows typical heterogeneity of residuals as a function of predicted values. Thus,
presented coefficients may be inefficient and biased. Only 9 subjects were
homogenous for 10.5/10.5 in the multiple regression model. Only cortical bone lead
was tested, not trabecular bone lead. Cortical bone lead models not shown or
quantitatively described. Blood lead rounded to nearest unit ug/dL. Mixed organic-
inorganic lead exposure. Relatively small sample size may have prevented detection of
other significant effects. No model diagnostics described.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
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to
United States (cont'd)
Huetal. (1996)
US-Boston-Normative
Aging Study-VA
1991-1994
590 males (over 98% white), mean age
around 67 years, divided into 146
hypertensives (systolic > 160 mmHg,
diastolic >95 mmHg, or daily
antihypertensive medication) and 444
non-hypertensives. Linear blood lead,
tibia and patella bone lead added
separately to logistic regression model
containing forced covariates of age,
race, BMI, family history of
hypertension, pack-years smoking,
alcohol ingestion dietary sodium and
calcium. Then, a backward
elimination procedure starting with all
covariates, including all lead variables,
resulted in a model in which only
significant covariates were retained.
Hypertensives:
Arithmetic mean (SD) blood
lead:6.9 ug/dL (4.3)
Mean tibia lead:
23.7 ug/g (14.0)
Mean patella lead:
35.1 ug/g (19.5)
Non-hypertensives:
Arithmetic mean (SD)
blood lead:
6.1 ug/dL(4.0)
Mean tibia lead:
20.9 ug/g (11.4)
Mean patella lead:
31.1 ug/g (18.3)
Logistic regression model with all forced covariates revealed no significant lead effects
when the three lead variables were forced into the model separately. After backward
elimination, the only significant covariates left were BMI and family history of
hypertension. Of all the lead variables, only tibia lead remained in the model. With
each increase of 10 ug/g of tibia lead, odds of being classified hypertensive rose (OR
1.21;95%CI: 1.04, 1.43).
Stepwise regression, backward or forward, involves multiple testing with the same data
set, capitalizes on chance occurrence in the data set, and gives over-optimistic
probability values. No model diagnostic testing.
H
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V
O
Korricketal. (1999)
US-Boston-Nurse Health
Study
1993-1995
284 women, from 47-74 years, mean
age (SD) 58.7 (7.2), were divided into
97 cases (systolic > 140 mmHg,
diastolic > 90 mmHg, or physician-
diagnosed hypertension) and
195 controls. Controls were further
classified as low normal (<121/75
mmHg) and high normal >121/75
mmHg). Three ordinal regression
models were constructed, each
containing either blood lead, tibia lead
or patella lead with forced entry of all
other covariates. A final backwards
elimination ordinal regression model
started with all covariates, including
all lead variables, excluding each until
only significant variables were left.
Interactions were tested in the final
model between patella lead and
alcohol use, age, and menopausal
status.
Mean blood lead (SD, range): 3.1
ug/dL (2.3 ,
<1-14)
Mean tibia lead (SD): 13.3 ug/g
(9.0, -5-69)
Mean patella lead (SD):
17.3 ug/g (11.1,-5-87)
Only patella lead was significantly related to increased odds of hypertension in the
preliminary models, adjusted for age, BMI, alcohol, dietary calcium and sodium, ever
smoke, and family hypertension. Each 10 ug/g increase in patella lead was associated
with increased odds of hypertension OR 1.28 (95% CI: 1.03, 1.60). In the backward
elimination model adjusted for age, BMI dietary sodium and family hypertension, only
natural log transformed patella lead remained in the model. One natural log increase in
patella lead was associated with increased odds of hypertension OR 1.03 (95% CI:
1.00, 1.05). None of the interaction tests were significant.
Small study size may have limited power to detect significant interactions. The
proportional odds assumption of the ordinal regression model was verified. Note that
the odds ratios above are for movement from one of the two lower categories, low
normal and high normal, to the next higher category as patella lead increased. No
other model diagnostic tests reported. It was not clear why the original models
appeared to use all linear lead terms and the final model appeared to use natural log
transformed lead terms, at least for the bone lead.
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Table AX6-5.1(cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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O
United States (cont'd)
Lustberg and Silbergeld
(2002)
US-NHANES II
1976-1980, follow up
to 1992
4190 persons, 30 to 74 years, 929 of whom died
during follow up, had baseline blood lead
measurements during the NHANES II period.
Proportional hazard models for circulatory
disease-related death (ICD-9 codes 390-459) were
based on the complex survey design, but not
weighted. Presented models were unadjusted,
adjusted for age and sex, and adjusted for age, sex,
location, education, race, income, smoking, BMI,
and exercise. Blood lead was entered as an ordinal
three-category variable.
Blood lead <10 ug/dL,
n = 818
Blood lead 10-19 ug/dL,
n = 2735
Blood lead 20-29 ug/dL,
n = 637
Blood lead > 30 ug/dL,
n = 102, excluded from
analysis
Crude, sex and age adjusted, and multivariate adjusted circulatory disease
mortality were all significantly increased in the 20-29 ug/dL group compared
to the <10 ug/dL reference group. Risk ratio for the highest lead group for
crude circulatory mortality was 1.74 (95% CI: 1.25, 2.40), for age and sex
adjusted circulatory mortality was 1.48 (95% CI: 1.10, 2.01), and for
multivariate circulatory mortality was 1.39 (95% CI: 1.01, 1.91).
Stratified analyses were performed by race, sex, age, smoking, education,
etc., but only for all-cause mortality. No model diagnostics reported.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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ON
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O
United States (cont'd)
Nash et al. (2003)
US-NHANES III
1988-1994
1084 premenopausal and 633 postmenopausal
women, from 40 to 59 years. Multiple linear
regression models with covariates, including linear
blood lead, entered as a block for systolic and
diastolic blood pressure. Logistic regression
models with same covariates and lead quartile
added last for hypertension.
Mean (range) blood lead by
lead quartile:
1st quartile mean 1.0 ug/dL
Range: 0.5, 1.6
2ntl quartile mean 2.1 ug/dL
Range 1.7,2.5
3ri quartile mean 3.2 ug/dL
Range 2.6, 3.9
4th quartile mean 6.4
Range 4.0, 31.1
Linear blood lead was entered last after forcing in age, race/ethnicity, alcohol
use, cigarette smoking, BMI, and kidney function (serum creatinine) in
multiple regression models for all women and women stratified by
menopause status for systolic and diastolic blood pressure. Lead quartile was
added to logistic regression models of hypertension (systolic > 140 mmHg,
diastolic > 90 mmHg or taking antihypertensive medication with the same
covariates as the blood pressure models, in all women and stratified by
menopausal status. Tested additional models in which women treated for
hypertension were excluded from models. All models were adjusted for
sample design and weighting.
Each increase of 1 ug/dL of blood lead was significantly associated with a
0.32 mmHg (95% CI: 0.01, 0.63) increase of systolic blood pressure and a
0.25 mmHg (95% CI: 0.07, 0.43) increase of diastolic blood pressure in all
women without respect to menopausal status. In analyses stratified by
menopausal status, only postmenopausal women showed a significant blood
lead effect. For each 1 ug/dL increase of blood lead was associated with
significantly increased diastolic blood pressure of 0.14 (95% CI: -0.11, 0.39
sic.) only in postmenopausal women.
Referenced to the first blood lead quartile, no other quartile showed
significantly increased odds for hypertension in all subjects or in subjects
stratified by menopausal status. With further analyses stratified by systolic
and diastolic hypertension without women taking antihypertensive
medications, in the combined group of pre and postmenopausal women the
odds of diastolic hypertension were significant when the 4th lead quartile was
compared to the 1* quartile (OR 3.4 [95% CI: 1.3,8.7]). In a model of only
postmenopausal women untreated for hypertension, odds of diastolic
hypertension were significantly increased in the higher three quartiles of
blood lead (OR 4.6 [95% CI: 1.1, 19.2]); OR 5.9 [95% CI: 1.5,23.1]);
OR 8.1 [95% CI: 2.6, 24.7]), respectively) and odds of systolic hypertension
were significant only for the two middle lead quartiles (OR 3.0 [95% CI: 1.3,
6.9]; OR 2.7 [95% CI: 1.2, 6.2]), respectively.
Linear blood lead is suspect in linear regression models of blood pressure as
it is usually associated with biased and inefficient estimation of lead
coefficients due to probable heteroscedasticity and non-normal distribution of
residuals. No model diagnostics were reported. No statistical testing for
differences in lead coefficients according to strata. Nine stratified models
overall. Not all stated significance levels and standard errors in the blood
pressure model table corresponded for certain variables.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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ON
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H
O
United States (cont'd)
Nawrot et al. (2002)
31 US and European
studies, community and
occupational!}7 exposed,
published between 1981
and 2001.
48 different groups, 32 of which were only of men,
15 of which were only of women, and one
studying both sexes. Total meta-analysis
N > 58,490. Age ranged from 15 to 93 years,
depending on the study. Two methods of meta-
analysis were used, subject-weighted and non-
weighted, using study-reported effect sizes and
standard errors, transformed from the original
study specification of blood lead (linear,
logarithmic, or blood lead group) to a single effect
size for doubling of blood lead. Also did analyses
stratified by race and sex.
Mean blood lead concentration
across studies ranged from
2.3 to 63.8 ug/dL. Total range
of blood lead across studies
was 0 to 97.9 ug/dL.
Each doubling of blood lead was associated with a significant 1.0 mmHg
(95% CI: 0.5, 1.4) increase in systolic blood pressure and a significant 0.6
mmHg (95% CI: 0.4, 0.8) increase in diastolic blood pressure. Stated that
differences in lead effect were not statistically different between sexes, but
did not describe test nor give statistics other than p-values. Presented black
and white differences as a trend for blacks to be "more susceptible than
whites," but presented no tests.
Statistically examined assumptions of homogeneity of effect and found no
significant heterogeneity. Tested for publication bias (statistically significant
results tend to be published more than non-significant results) and found no
evidence. Found no significant effects of removing one study at a time in
sensitivity analysis. It appears that the presented results of effect sizes and
confidence intervals were calculated by the subject-weighted method, but this
was not made explicit. Included some studies that presented no lead
coefficients or standard errors, assuming effect size of zero, though the
reported effect sizes without these studies did not appear to be different from
overall effect sizes. For studies using a linear lead measure, effect sizes were
calculated by doubling the arithmetic mean blood lead. If the concentration-
response curve for the lead-blood pressure relationship was really better
characterized by a log-linear function, the authors' use of studies with a linear
blood lead term with high average blood lead led to over-estimation of the
slope of the relationship and those studies with low blood lead averages
produced an under-estimation of the slope of the relationship.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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ON
ON
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O
United States (cont'd)
Procter etal. (1996)
US-Boston-Normative
Aging Study (VA)
1992-1993
798 men from 17 to 44 years. Multiple linear
regression models of natural log blood lead on
systolic and diastolic blood pressure. All
covariates forced into model.
Arithmetic mean (SD, Range)
blood lead:
6.5 ug/dL (4.0, 0.5-35)
Natural log blood lead, age, age-squared, BMI, adjusted dietary calcium,
exercise, indicator variables for current and former smoker, daily alcohol
consumption, sitting heart rate, and hematocrit were entered into multiple
regression models without regard for significance.
Increased diastolic, but not systolic, blood pressure was significantly
associated with increased blood lead. Each natural log increase in blood lead
was associated with a 1.2 mmHg (95% CI: 0.1, 2.2) increase in diastolic
blood pressure.
Interactions between dietary calcium and blood lead on blood pressure were
not significant. Further analyses stratified on use of antihypertensive
medication and those older than or equal to 74 years still revealed significant
blood lead-diastolic blood pressure relationships.
Blood lead in over half the study group (n = 410) was determined by
analyzing previously frozen erythrocytes collected several years prior to the
blood pressure measurements used in the study and corrected by using
hematocrit values also measured when blood was originally collected.
Combining both groups means that nearly half the group was tested for the
effects of blood lead on blood pressure measured at the same time, the other
half measured several years apart. There was no correction in models for this
potential effect. The effect of taking antihypertensive medication could have
been assessed in a single model by using an indicator variable. No statistical
testing for the effects of stratification on the blood lead-blood pressure
relationship. No model diagnostics.
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O
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
ON
H
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O
O
V
O
United States (cont'd)
Rothenbergetal. (1999)
U.S.-Los Angeles
1995-1998
Rothenberg et al. (2002)
U.S.-Los Angeles
1995-2001
1188 immigrants and 439 immigrants, from 15 to
43 years, all women in third trimester of
pregnancy. Multiple regression models of natural
log blood lead on systolic and diastolic blood
pressure with all covariates forced into models.
Covariates selected from larger set based on
significant univariate or bivariate tests.
668 women, 15 to 44 years, studied in third
trimester pregnancy and again a mean of 10 weeks
postpartum. Exclusion criteria were diabetes,
renal or cardiovascular disease, extreme postnatal
obesity (BMI > 40), and subjects using stimulant
drugs. Multiple linear regression models of
natural log blood lead, tibia and calcaneus lead on
systolic and diastolic blood pressure with all
covariates and all lead variables forced into model.
Separate models for third trimester and
postpartum, excluding all women with
hypertension (see below) during each specific
period. Logistic regression for hypertension
(systolic > 140 mmHg or diastolic >90), specific to
third trimester and postpartum periods with the
same covariates and lead variables.
Geometric Mean (SD) blood
lead:
Immigrants: 2.3 ug/dL(1.4,
1.5)
Non-immigrants: 1.9 ug/dL
(1.2,1.4)
Geometric mean blood lead
(SD):
3rd trimester: 1.9 ug/dL
(3.6, 1.0)
postpartum: 2.3 ug/dL
(4.3, 1.2)
Tibia mean lead (SD):
8.0 ug/g (11.4)
Calcaneus mean lead (SD):
10.7 ug/g (11.9)
Natural log blood lead, age, BMI, coffee drinking, iron supplementation,
and job stress were entered as a block without regard to significance in linear
multiple regression models of systolic and diastolic blood pressure stratified
by immigration status.
Increased blood lead was significantly associated with increased blood
pressure only in immigrants. Each natural log unit increase in blood lead was
associated with a 1.7 mmHg (95% CI: 0.7, 2.8) increase in systolic blood
pressure and a 1.5 mmHg (95% CI: 0.5, 1.9) increase in diastolic blood
pressure in immigrants.
Used and reported model diagnostic tests, as evidenced by the use of standard
error calculations robust to residual heteroscedasticity. Stated reasons for
stratification on immigrant status were significant differences between the
two groups in blood lead, blood pressure, age, BMI, and education. Did not
statistically test difference in lead coefficients between the immigration
strata. Did not correct for potential non-linearity in age effects on blood
pressure.
Multiple linear regression models for normotensives adjusted for postnatal
hypertension (3ri trimester model only), BMI, age, parity, smoking, alcohol,
immigrant status, and educational level plus all three lead indices. Only
calcaneus lead was associated with blood pressure in 3ri trimester models.
Every 10 ug/g increase in calcaneus lead was associated with 0.70 mmHg
(95% CI: 0.04, 1.36) increase in systolic blood pressure and a 0.54 mmHg
(95% CI: 0.01, 1.08) increase in diastolic blood pressure. In postpartum
models, natural log blood lead was the only variable statistically associated
with blood pressure. Every natural log unit increase in blood lead was
associated with -1.52 mmHg (95% CI: -2.83, -0.20) decrease in systolic
blood pressure and a -1.67 mmHg (95% CI: -2.85, -0.50) decrease in
diastolic blood pressure.
In logistic models, only calcaneus lead was significantly associated with
increased odds for hypertension. Each 10 ug/g increase in calcaneus lead
was associated with an OR 1.86 (95% CI: 1.04, 3.32) of 3rd trimester
hypertension. None of the lead variables was associated with postpartum
hypertension.
Models did not use age-squared covariate. Models did not use repeated
measures statistics. No statistical comparisons between 3ri trimester and
postpartum models. Model diagnostic tests reported.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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oo
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O
United States (cont'd)
Schwartz et al. (2000)
US-Eastern
1996-1997
543 mostly former organolead workers,
predominantly white (92.8%), at a
tetraethyl/tetramethyl plant, mean (SD) [range]
age 7.6 (7.6) [41.7-73.7] years had blood lead,
DMSA-chelatable lead (4-hr, urinary lead
excretion after a single 10 mg/kg dose of DMSA)
measured for modeling systolic and diastolic blood
pressure and hypertension (systolic >160 mmHg or
diastolic > 96 mmHg or taking antihypertensive
medications. Tibia lead ~2 years later was also
used as a lead index. For blood pressure, linear
multiple regression with backward elimination of
non-significant covariates or covariates that "had
important influence on the coefficients for the
lead-dose terms." Each lead variable was tested in
a separate model. Potential covariates for these
models were age, BMI, current tobacco use, and
current use of antihypertensive medications. Other
models were constructed taking out those subjects
using antihypertensive medications. Both linear
and linear + quadratic blood and tibia lead terms
were tested. Logistic regression analyses were
used to test the effect of the lead variables on
hypertension, controlling for age, diabetes, lifetime
alcohol consumption, and BMI. Logistic models
also tested each lead measure in interaction with
age.
Blood lead arithmetic mean
(SD, range) 4.6 ug/dL
(2.6, 1-20)
DMSA-chelatable lead mean
(SD, range) 19.0 ug
(16.6, 1.2-136)
Tibia lead mean (SD, range)
14.4(9.3, -1.6-52)
Adjusting for age, BMI, current smoking, and current use of antihypertensive
medications, each 1 ug/dL increase in blood lead-squared was significantly
associated with 0.189 mmHg (95% CI: 0.087, 0.330) increase in systolic
blood pressure with three outliers removed. With the same covariates, each
1 |ig/dL increase in linear blood lead was significantly associated with
0.310 mmHg (95% CI: 0.028, 0.592) in diastolic blood pressure taken over a
2-year period (n = 525). No other lead variables were significant.
For the hypertension models, only the interaction of linear blood lead by age
was significant, with subjects showing significant decrease in odds ratio of
hypertension with every joint increase of 1 ug/dL blood lead and 1 year
increase in age (linear blood lead x age OR 0.98; [95% CI: 0.97, 0.99]). The
interaction suggested a concentration-response relationship between linear
blood lead and hypertension only up to —58 years of age.
Authors note that blood pressure findings "were not affected by exclusion or
inclusion of subjects using antihypertensive medications," but do not present
either the data or the statistical tests to evaluate that conclusion. No other
model diagnostics were reported. Although blood lead was also modeled as a
quadratic lead term for systolic blood pressure, no analysis was shown for
non-linear blood lead terms for diastolic blood pressure.
Trabecular bone lead was not tested, though other studies indicate that it is a
better lead index than cortical lead for cross-sectional blood pressure and
hypertension study.
Although the backward procedures described could have resulted in less than
the full set of considered covariates entering the models, all model
presentations were limited to showing the lead coefficients and all models
indicated in a footnote that the lead coefficients were adjusted for each
possible covariate for that model. While this is possible with the short list of
covariates, given the 14 models presented one might expect to see at least one
model where one of the covariates did not remain.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
ON
H
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H
O
O
^
O
United States (cont'd)
Schwartz (1991)
NHANES II
US
1976-1980
Schwartz (1995)
15 prior US and European
studies published between
1985 and 1993
Under 10,000 subjects (exact number not
reported), males and females, aged 25 to 74 years
for left ventricular hypertrophy results with
logistic regression. Linear blood lead used for
LVH. For blood pressure results, multiple linear
regressions stratified by sex, with one block of
variables forced, another block of variables entered
with stepwise regression, aged 6 months to 74
years, exact number not given. Natural log blood
lead used for linear regression. Both logistic and
linear regressions adjusted for survey design.
Total subjects not specified, men and women ages
18 to 74 years. Random effects meta-analysis with
inverse variance weighting of lead-blood pressure
coefficients from each study. Sensitivity analysis
performed by dropping study with largest or
smallest effect.
No blood lead descriptive data
given.
Blood lead levels not stated.
Used logistic regression to study lead effect on left ventricular hypertrophy
(LVH) determined by a combination of electrocardiogram parameters and
body habitus, controlling for age, race, and sex. Every 10 ug/dL blood lead
increase was associated with increased odds of LVH of 1.33 (95% CI: 1.20,
1.47). Interaction terms for race by blood lead and sex by blood lead were
not significant.
Blood pressure models stratified by sex always included BMI, age and age-
squared, race, and natural log blood lead. Male blood pressure model also
included family history of hypertension, cholesterol, height, cigarette use,
serum zinc, and tricep skin fold. Female model also included serum zinc,
family history of hypertension, tricep skin fold, and cholesterol. Every 1
natural log unit of blood lead increase was associated with an increase in
diastolic blood pressure of 2.93 mmHg (95% CI: 0.93, 4.98) in males and
1.64 mmHg (95% CI: 0.27, 3.01). Used interaction terms for race-blood
lead and sex-blood lead in a non-stratified model and found no significant
effect of race or sex on the blood lead-blood pressure coefficient.
Incomplete reporting of subject size for models and for descriptive statistics
for all variables in models. Tested both linear and log transformed lead in
preliminary testing. Found log lead had lower probability values than linear
lead for blood pressure, and linear lead had lower probability values than log
lead for LVH. No testing of significant difference between the two blood
lead specifications. No model diagnostics reported. Only reported diastolic
blood pressure results.
Each doubling of natural log blood lead level was associated with an increase
of 1.25 mmHg (95% CI: 0.87, 1.63) systolic blood pressure. Sensitivity
analysis showed negligible change in meta-analysis coefficient. Concluded
that adding newer studies would not change calculated coefficient. Noted
lead-blood pressure slope was larger at lower lead levels than at higher lead
levels.
The study only analyzed systolic, not diastolic, blood pressure. Superseded
by Nawrot et al. (2002).
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
H
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United States (cont'd)
Vupputuri et al. (2003)
US-NHANES III
1988-1994
5188 white women, 2300 black women, 5360
white men, and 2104 black men, aged 18 years and
older. Survey adjusted multiple linear and logistic
regression were used to assess linear blood lead
effect on systolic and diastolic blood pressure and
hypertension in race and sex stratified models.
Arithmetic mean (SD) blood
lead:
White women 3.0 ug/dL (7-2)
Black women 3.4 ug/dL (4.8)
White men 4.4 ug/dL (7.3)
Black men 5.4 ug/dL (9.3)
Multiple linear regression models were all adjusted for age, education, BMI,
alcohol consumption, leisure time physical activity, dietary sodium and
potassium, and total calories. Only black women and men showed significant
linear lead effects. Every 1 ug/dL increase in blood lead was associated with
an increase of 0.47 mmHg (95% CI: 0.14, 0.80) in systolic and 0.32 mmHg
(95% CI: 0.11, 0.54) diastolic blood pressure in black women, and 0.25
mmHg (95% CI: 0.06, 0.44) systolic and 0.19 mmHg (95% CI: 0.02,0.36)
diastolic blood pressure in black men.
Odds of hypertension (systolic > 140 mmHg, diastolic >90 mmHg, or taking
antihypertensive medication) significantly increased for every SD
(3.3 Ug/dL) of blood lead level in black women (OR 1.39 [95% CI: 1.21,
1.61]), in white women (OR 1.32 [95% CI: 1.14, 1.52]), in black men (OR
1.26 [95% CI: 0.99, 1.19]), but not in white men.
Linear blood lead terms are usually not appropriate in multiple linear
regression models of blood pressure. Furthermore, they reported their results
in terms of change in 1 SD unit of lead. Linear SD of lead is incorrect for
log-normal distributions of blood lead. No model diagnostic tests reported.
Discrepancy between Methods report of race-lead and sex-lead interactions in
simple, not multiple, analyses, but Results reports significant interactions for
race-lead and sex-lead in multiple regression models for both linear
regression and logistic regression models, without showing the results of the
interaction analyses. The probability of the stated interactions (p < 0.001)
appears extremely low, given the degree of 95% CI overlap in lead
coefficients among the stratified models. No model diagnostics reported.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
United States (cont'd)
X
Michaels et al. (1991)
US-New York City
1961-1984
1261 males, average age (range) at the beginning
of study 49.6 years (19-83), representing 24,473
person-years were followed. 498 died in the
interval. Subjects belonged to the International
Typographical Union and worked at two large city
newspapers. Hot lead linotyping was discontinued
at the newspapers during 1974-1978, providing the
primary source of occupational exposure. Last
exposure for all subjects still employed was at the
end of 1976.
Standardized mortality ratios (SMR) were
calculated using the LTAS program developed by
NIOSH, calculating the expected number of deaths
of the cohort referenced to a comparison
population, in this case disease-specific mortality
rates from New York City. Cohort was stratified
based on years of employment. Causes of death
were based on ICD-8 codes.
Exposure was estimated based
on years of linotype
employment before the end of
1976. Authors note that, based
on measurements at other print
shops using hot lead linotype,
air lead levels probably did not
exceed 20 ug/m3.
Standardized mortality ratio was significant (SMR = 1.68 [95% CI: 1.18,
2.31]) only for cerebrovascular disease in those working, and thus exposed,
for 30 years or more. Neither arteriosclerotic heart disease (ICD-8 410-414)
nor vascular lesions of the central nervous system (ICD-8 430-438) had
significant SMR in the total cohort not stratified by years of exposure.
No direct measurement of lead exposure. Many groupings of ICD codes
were explored in stratified and unstratified analyses, with the only
significantly elevated SMR found for cerebrovascular disease. No a priori
hypotheses. General weakness of all studies relying on a comparison
population is that the cohort belongs to the comparison population and can
influence the comparison mortality rates in direct proportion to the ratio
between cohort and comparison population size.
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O
V
O
Morris etal. (1990)
US-sampled from general
population around
Portland, OR responding
to ads to participate in
clinical trials of non-
pharmacological
management of blood
pressure.
1984-1989?
145 males and 106 females, 73% with arterial
pressures > 105 mmHg, provided blood pressure
measurements once a week over four consecutive
weeks. Blood for lead analysis was collected
during this period. Stepwise multiple regression
was used to construct separate models of systolic
and diastolic blood pressure stratified by sex.
Covariates available to be entered were age, BMI,
dietary calcium and "other nutrient intakes,"
ionized serum calcium, erythrocyte protoporphyrin
and natural log transformed blood lead
Arithmetic mean (SD) blood
lead:
Males: 8.0 ug/dL (4.4)
Females: 6.9 ug/dL (3.6)
Natural log blood lead was only a significant predictor of blood pressure in
males. Adjusting for age and ionized serum calcium, every one natural unit
increase in blood lead was significantly associated with a 4.58 mmHg
(neither SE nor CI stated) in systolic blood pressure and, adjusting for
hemoglobin, age, and current smoking, a 1.90 mmHg (neither SE nor CI
stated) in diastolic blood pressure.
The usual precautions regarding multiple testing and different covariate
patterns in stratified models constructed with stepwise regression apply.
Reporting of effects not complete. Small sample size limits conclusions
about non-significant effects. High prevalence of hypertensives in sample
due to study recruitment design. Blood lead technique, as represented by
presented graph, had a detection limit of 5 ug/dL. No model diagnostics.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
United States (cont'd)
Navas-Acien (2004)
US-NHANES IV-Phase 1
1999-2000
2125 subjects (1070 males, 1055 females),
age 40-> 70 years were tested for peripheral
arterial disease (PAD; n = 139) by taking the ratio
of the ankle mean systolic blood pressure to the
arm mean systolic blood pressure. Any subject
with the ratio <0.90 was classified as PAD.
Logistic regression analysis was weighted and
adjusted by sample design. Covariates forced into
the models were age, sex, race, education, and lead
quartile (Model 1); Model 1 covariates plus BMI,
alcohol intake, hypertension, diabetes,
hypercholesterolemia, glomerular filtration rate,
and C-reactive protein (Model 2); Model 2
covariates plus self-reported smoking status and
serum cotinine (Model 3); and Model 3 covariates
plus cadmium quartile (Model 4). Tested
interactions between lead and cadmium on PAD,
and between lead and sex, race, smoking status,
renal function, and c-reactive protein on PAD.
Tested for trend of OR as a function of lead
quartile.
Geometric mean blood lead
(25%-75% percentile):
2.1 ng/dL(1.4, 2.9)
Lead quartile 1: <1.4 ug/dL
Lead quartile 2: 1.4-2.1 ug/dL
Lead quartile 3: 2.1-2.9 ug/dL
Lead quartile 4: >2.9 ug/dL
Odds for PAD significantly increased with lead quartile (1st quartile used as
comparison) for all four models. Only models 1 and 2, however, showed a
significant increase in odds of PAD for the 4th lead quartile compared to the
1st lead quartile, OR 3.78 (95% CI: 1.08, 13.19) and OR 4.07 (95% CI: 1.21,
13.73). None of the tested interactions with blood lead quartile were
significant.
Well-designed study with sound statistical analysis. Including two variables
for smoking in Models 3 and 4 (smoking status and cotinine) may have over-
controlled for smoking). There was a trend toward increased blood lead level
with increased smoking status and with increased cotinine levels, though no
statistical tests of trend were reported. Thus the two smoking variables and
lead may have been confounded with PAD. No model diagnostic tests
reported.
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Sokas et al. (1997) 264 active or retired construction workers, over
US-Maryland 99% men, who were not involved in lead work at
1989-1990 time of testing, mean age (range) 43 years (18-79).
Multiple regression modeling of systolic and
diastolic blood pressure adjusted for covariates of
BMI, age, hematocrit, erythrocyte protoporphyrin,
race, linear blood lead and a race-linear blood lead
interaction. Method of covariate entry not made
explicit, though it appeared to be forced.
Mean blood lead (range):
8.0 ug/dL (1-30).
Linear blood lead was not significantly related to either systolic or diastolic
blood pressure, though the race by linear blood lead interaction was
marginally significant (p = 0.09). Each 1 ug/dL increase in blood lead
increased black systolic blood pressure 0.86 mmHg (no SE or 95% CI
reported) more than white systolic blood pressure.
Linear blood lead term may not be appropriate. Small sample compromises
interpretation of non-significant results. By using erythrocyte protoporphyrin
and blood lead in the same model, these two measures of lead exposure may
have been confounded. Incomplete reporting of procedures and results. No
model diagnostic tests reported.
O
V
O
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
United States (cont'd)
Soreletal. (1991)
US-NHANES II
1976-1980
2056 females, 2044 males, 473 blacks and 3627
whites, from 1 8-74 years, were used in survey
design and weight adjusted multiple linear
regressions stratified by sex, with separate models
for systolic and diastolic blood pressure.
Covariates included age, BMI, race, and poverty
income ratio and linear blood lead. Method of
covariate entry not specified but may have been
forced. Different covariate groups were used for
different models. Primary test for the effect of
race on the lead-blood pressure relationship was to
note the change in the race coefficient in models
with and without the linear blood lead variable.
Age-adjusted arithmetic mean
blood lead:
Black female: 13.2ug/dL(no
variance information for any
blood lead)
White female: 12.1 ug/dL
Black male: 20.1 ug/dL
White male: 16.8 ug/dL
Linear blood lead was significantly related only to diastolic blood pressure in
males, adjusting for age and BMI. For every 1 ug/dL blood lead increase
diastolic blood pressure increased 0. 13 mmHg (95% CI: 0.04, 0.21). Adding
race to the model with and without linear blood lead terms did not appear to
change the race coefficient. Adding poverty index to the models with and
without blood lead produced the same small change in poverty index
coefficient.
Linear blood lead may not be appropriate. Only confidence intervals were
used to assess the significance of changes in race and poverty index
coefficients across models with and without lead, instead of using interaction
terms of these two variables with lead. Incomplete reporting of procedures
and results. No model diagnostic tests reported.
Sharp etal. (1990)
US-San Francisco, CA
1986
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O
After exclusion of subjects under treatment for
hypertension, 249 male bus drivers, 132 of whom
were black, age from 31 to 65 years, were used in
race stratified multiple regression models of
systolic and diastolic blood pressure with covariate
forced entry of age, age-squared, BMI, caffeine
use, tobacco use, and natural log blood lead.
Alcohol use was added in other models. Other
models stratified by caffeine use.
Geometric mean (range) blood
lead:
Black males: 6.5 ug/dL (3-21)
Non-black males: 6.2 ug/dL
(2-15)
Significant log blood lead effects were noted in blacks. In models excluding
alcohol use, for every one natural log unit increase of blood lead, systolic
blood pressure rose 7.53 mmHg (95% CI: 0.86, 14.2) and diastolic blood
pressure rose 4.72 mmHg (95% CI: 0.15,9.29). Stratified by
infrequent/frequent caffeine users, only black infrequent caffeine users
showed a significant response to blood lead. For every one natural log unit
increase of blood lead, systolic blood pressure rose 16.69 mmHg (95% CI:
3.83, 29.5) and diastolic blood pressure rose 10.43 mmHg (95% CI: 1.26,
19.6). Non-black blood pressure was decreased with increasing natural log
lead but was marginally significant. In all non-black subjects, for every unit
increase in natural log blood lead, systolic blood pressure decreased -5.71
mmHg (95% CI: -12.0,0.6). Addition of alcohol to the models decreased
all coefficients a small amount. Progressive addition of age, BMI, caffeine,
and tobacco, in that order, progressively increased the coefficient of natural
log blood lead in models of systolic and diastolic blood pressure in blacks.
Removal of two black outliers did not materially change the results for
blacks.
No statistical tests for comparing stratified models, models with and without
caffeine use, effect of progressive addition of covariates, or addition of
alcohol. Influence diagnostics reported for detecting the two outlying
subjects. No other diagnostic tests reported. Small differences in text and
table reports of the same coefficients. Small sample size limits interpretation
of non-significant results.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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O
Europe
Menditto et al. (1994)
Europe-Rome-New Risk
Factors Survey
1989-1990
1319 males, mean (range) age 63 (55-75) years,
not treated for hypertension, were used in forward
stepwise multiple linear regression models of
systolic and diastolic blood pressure with available
covariates of age, BMI, heart rate, serum high
density lipoprotein, non-high density lipoprotein,
triglycerides, glucose, cigarette use, alcohol use,
sum of five skinfold thicknesses (triceps, biceps,
subscapular, suprascapular, and suprailiac), and
natural log transformed blood lead.
Median (2.5th-97.5th
percentiles, range) blood lead
11.3 ug/dL (6.2-24.7, 4-44.2)
Only BMI, heart rate, and serum glucose were not simultaneously and
significantly correlated with both natural log blood lead and blood pressure.
In a systolic blood pressure model adjusted for BMI, age, heart rate, high and
non-high density lipoprotein, triglycerides, glucose, and cigarettes, each unit
increase in natural log blood lead was significantly associated with a 5.6
mmHg (95% CI: neither SE nor CI stated) increase in blood pressure. In a
diastolic blood pressure model adjusted for BMI, heart rate, age, cigarettes,
triglycerides, and high density lipoprotein, each unit increase in natural log
blood lead was significantly associated with a 1.7 mmHg (95% CI: neither
SE nor CI stated) increase in blood pressure. In stratified models for alcohol
drinkers (n = 1068) and non-drinkers (n = 251) only alcohol drinkers showed
significant natural log blood lead associated blood pressure increase, with
lead coefficients similar to those of the entire group.
Authors observed change in natural log blood lead coefficient produced by
successive addition of covariates to models. In no case did the coefficients
change by more than 30% after addition of a covariate. Authors noted that
wine was the predominant drink in alcohol users and that the correlation
between alcohol consumption and natural log blood lead level was the
highest among all correlations reported (p < 0.001; correlation coefficient
not stated).
No statistical tests were made to determine if the change in lead coefficients
with addition of covariates was significant, nor were statistical tests made to
determine if the lead coefficients in the alcohol use stratified models were
significantly different. Small size of the non-alcohol drinking group in
stratified analysis precludes interpretation of non-significant effects.
Incomplete reporting of results. Paper published in a supplement issue
reporting meeting papers may indicate that it received less that the normal
peer-review scrutiny for published research articles. No model diagnostic
tests were reported.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
H
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O
O
V
O
Europe (cont'd)
M011eretal. (1992)
Europe-Denmark-
Copenhagen County-
Glostrup Population
Studies
1976-1990
A cohort born in 1936 was followed at age 40
(women n = 546, men n = 504), age 45 (women
n = 430, men n = 463) and again at age 51 (men
only n = 439). Reported no difference in results if
subjects taking antihypertensive medications were
excluded. Reported results included these
subjects. Linear multiple regression models of
systolic and diastolic blood pressure of follow up,
stratified by sex and by year, used a sequence of
forced entry of covariates: natural log blood lead
was tested alone (unadjusted), then adjusted for
tobacco, cholesterol, physical activity, and sex
(Model 1), then adjusted for the above covariates
plus systolic blood pressure (Model 2), and then
adjusted for the above covariates plus alcohol
(Model 3). Another group of linear multiple
regression models of change of systolic and
diastolic blood pressure from age 40 to 51 years in
men only, following the same covariate entry
scheme as above, but used change in covariates
instead of the original covariates. All subjects
were followed until 54 years of age (from 1976 to
1990) to assess lead association with total
mortality and with coronary heart disease (CHD;
ICD-8 410-414) and cardiovascular disease (CVD;
ICD-8 430-435) combined morbidity and mortality
using Cox proportional hazards models (n = 1050).
Cox models were adjusted as above.
Arithmetic mean (SD, range)
blood lead by age and sex:
Women 40 years: 9.6 ug/dL
(3.8) [4-39]
Women 45 years: 6.8 ug/dL
(3.5)[2-41]
Men 40 years: 13.6 ug/dL
(5.7) [5-60]
Men 45 years: 9.6 ug/dL (4.3)
[3-39]
Men 51 years: 8.3 ug/dL(4.1)
[2-62]
In women, each one unit increase in natural log blood lead was associated
with a significant increase in systolic blood pressure of 4.93 mmHg
(p = 0.002; neither SE nor CI stated) at age 40 and an increase of 2.64 mmHg
(p = 0.06; neither SE nor CI stated) at age 45, in models adjusted for tobacco,
BMI, and physical activity (Model 1). When alcohol (Model 2) or alcohol
plus hemoglobin (Model 3) were added to the models lead-blood pressure
relationships were not significant at either age. With each one unit change in
natural log blood lead, diastolic pressure increased 4.26 mmHg (p = 0.002;
neither SE nor CI stated) at 40 years and 3.26 mmHg (p = 0.002; neither SE
nor CI stated) at 45 years in Model 1. In Model 2, the increase in diastolic
blood pressure was 3.21 mmHg (p = 0.02; neither SE nor CI stated) at 40
years and 2.86 mmHg (p = 0.01; neither SE nor CI stated) at 45 years.
In Model 3, the increase in diastolic blood pressure was 2.65 mmHg
(p = 0.07; neither SE nor CI stated) at 40 years and 2.78 mmHg (p = 0.01;
neither SE nor CI stated) at 45 years.
In men, the only significant association between natural log blood lead and
blood pressure was at 45 years. For every increase of one unit of natural log
blood lead the increase in systolic blood pressure was 2.73 mmHg (p = 0.05;
neither SE nor CI stated).
The change in blood lead between 40 and 51 years was not significantly
associated with change in systolic or diastolic blood over the same period in
any of the models.
None of the relative hazard ratios for CHD and DVD combined morbidity
and mortality between 40 and 54 years were significantly related to blood
lead concentration. Total mortality, however, was significantly increased
with increased blood lead. In Model 1, every increase of one natural log unit
of blood lead was associated with an increased relative hazard of mortality of
1.96 (p = 0.009; neither SE nor CI stated). For Model 2, every increase of
one natural log unit of blood lead was associated with an increased relative
hazard of mortality of 1.82 (p = 0.03; neither SE nor CI stated). There were
40 cases of CHD recorded, of which 13 were fatal. There were 54 cases of
CVD recorded, of which 19 were fatal. Of the total of 46 subjects who died
during the period, 32 (70%) died of cardiovascular problems. It was not clear
if blood lead at a particular age or a mean blood lead across ages was used in
the Cox proportional hazards models.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
Oi
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O
Europe (cont'd)
M011eretal. (1992)
(cont'd)
Though this study was one of the few to use a longitudinal design, it did not
take advantage of that design feature in blood pressure modeling. Cross-
sectional multiple regression modeling at each age loses valuable information
available in repeated measures modeling. Power to detect significant effects
is much higher in repeated measurement modeling than in cross-sectional
modeling. Analyzing only change in blood pressure loses information
regarding starting and ending blood pressure. Including change in blood lead
is problematical due to the unknown history of lead exposure prior to the start
of the study, the resultant bone lead load as a result of past exposure, the
unknown lead contribution of bone to blood, and the unknown relative
contributions of past exposure and present exposure to alteration in blood
pressure. Modeling other covariates as change is also questionable. BMI, to
pick a covariate with known and strong effects on blood pressure, may be
high and relatively constant over the study period or low and relatively
constant over the study. In both cases, the change in BMI will be small, but
the high BMI will be associated with higher blood pressure than will the low
BMI. Thus, both cases modeled as change in BMI should have the same
effect on blood pressure when the high BMI subject has expected higher
blood pressure than the low BMI subject. Using difference scores for the
dependent and the exposure variables also risks confounding secular trends in
either or both of these variables, for whatever reasons, with independent
difference variable effect on dependent difference variable effect.
The Cox proportional hazards model, however, is longitudinal in nature.
Failure to detect significant associations between lead and cardiovascular
morbidity/mortality could have been due to the small sample size used for
this type of analysis. The blood pressure part of the study did not take
mortality into account during the study, which could have produced a
progressively increasing "healthy subject" effect. Since subjects taking
antihypertensive medications were included in analyses, an indicator variable
should have been used to account for them, whether or not their exclusion in
preliminary testing produced no apparent change in results. This paper
contained a good discussion of confounding variables. Incomplete reporting
of results and procedures. No model diagnostic tests were reported.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period Study Description
Lead Measurement
Findings, Interpretation
X
H
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^
O
Europe (cont'd)
Staessen et al. (1996)
Europe-Belgium-PheeCad
study.
1985-1995
359 men and 369 women participated at baseline
(between 1985 and 1989) and again about 5 years
later (median 5.2 years) at follow up (between
1991 and 1995), mean age (range) at baseline 46
years (20-82), about half of whom were recruited
from towns surrounding a non-ferrous smelter
(targeted to produce high cadmium exposure) and
half from towns without heavy metal production.
Over half the men had occupational exposure
(59.0% from the near smelter towns, 17.4% from
the other towns).
Four different outcomes were explored: time-
integrated conventional blood pressure (average of
10 baseline and 5 follow up blood pressure
measurements), 24-hour ambulatory blood
pressure only during the follow up period (average
of readings every 20 minutes from 8 AM to 10 PM
and every 45 minutes from 10 PM to 8 AM,
weighted by interval between measurements),
difference in conventional blood pressure over the
five year follow up period, and incidence of
developing hypertension during follow up.
Geometric mean (5%-95%
percentile) by sex and time
period:
Baseline women: 6.6 ug/dL
(3.3-14.5)
Follow up women: 4.8 ug/dL
(1.7-11.8)
Baseline men: 11.4 ug/dL
(5.6-28.8)
Follow up men: 7.7 ug/dL
(3.7-20.1)
The study was one of the few prospective longitudinal studies reported and
was innovative in its use of 24-hour ambulatory blood pressure as one of its
outcome variables.
Time-integrated conventional blood pressure models:
In 187 peri- and post-menopausal women, after adjusting for age, BMI,
gamma-glutamyltransferase activity, and hematocrit, each increase of one
unit of natural log blood lead was associated with an increase in diastolic
blood pressure of 7.49 mmHg (95% CI: 1.48,13.50). Noothertime-
integrated conventional blood pressure measurements were significantly
associated with time-integrated natural log blood lead in either men or
women, nor in stratified groups within sex.
Ambulatory 24-hour blood pressure models:
In all 345 women, after adjusting for age, hematocrit, gamma-
glutamyltransferase activity, and oral contraceptive use, each one unit
increase in natural log blood lead was associated with an increase of diastolic
blood pressure of 3.49 mmHg (95% CI: 0.02, 6.96). When the group was
limited to the 174 premenopausal women each unit increase in natural log
blood lead was associated with an increase of diastolic blood pressure of
5.48 mmHg (95% CI: 0.56, 10.40).
Difference in blood pressure between baseline and follow up:
After adjustment for change in BMI, beginning use of antihypertensive
medication and contraceptive medication during the follow up period, and
starting smoking there was no significant relationship between difference in
either systolic or diastolic blood pressure and blood lead in women. After
adjustment for change in BMI, change in exposure at work, change in
smoking, beginning use of antihypertensive medication in men there was no
significant relationship between difference in either systolic or diastolic blood
pressure and blood lead in men.
Incidence of hypertension:
At baseline 107 (14.7%) and 120 (16.5%) subjects had borderline and
definite hypertension, respectively. At follow up 98 (13.5%) and 186
(25.5%) had borderline and definite hypertension, respectively. 51 of 501
initially normotensive subjects became borderline hypertensive and 47 of the
501 became border line hypertensive during the follow up period. After
adjusting for sex, age, and BMI, natural log baseline blood lead was not
related to significant risk ratios of becoming hypertensive (not stated, but
presumably combined definite and borderline hypertension) or becoming a
definite hypertensive.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
oo
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O
Europe (cont'd)
Staessen et al. (1996)
(cont'd)
Multiple regression models were used to test the
association between natural log transformed blood
lead (mean of baseline and follow up lead) and
blood pressure (systolic and diastolic), stratified by
sex, then further stratified by use of
antihypertensive medications in men and
menopausal status in women. Age and age-
squared (calculated in quintiles) were forced into
the models, then remaining covariates were
stepwise added to the model. Though not
explicitly stated, natural log blood lead (mean of
baseline and follow up) was likely forced in last.
Other candidate covariates were BMI, hemoglobin
or hematocrit, serum gamma-glutamyltransferase
activity (an index of alcohol use) and serum
calcium, 24 hour urinary sodium and potassium
excretion, energy expenditure, exposure to heavy
metals (at the workplace), social class, smoking
and drinking habits, menstrual status in women,
and use of antihypertensive medications, oral
contraceptives, and hormone replacement therapy.
In ambulatory blood pressure models, differences
between baseline and follow up blood pressure
models were constructed in the same way. For the
difference models "concurrent variations in blood
lead concentrations" were used, presumably
difference in baseline and blood lead. For the
hypertension incidence model two definitions of
hypertension were used: definite hypertension
(systolic >160 mmHg, diastolic >95 mmHg or
taking antihypertensive medications) and
borderline hypertension (systolic between 141 to
159 mmHg and diastolic between 91 to 94
mmHg). Method of covariate entry into
hypertension incidence models not stated.
Baseline natural log blood lead was used as the
exposure index.
The study does not use the full power of repeated measurements in the
analyses. For problems encountered when collapsing repeated measurements
to difference measures, see M011er (1992) above. Stepwise regressions are
prone to capitalizing on chance results due to multiple testing of the same
data and almost always produce a different mix of covariates when they are
stratified. Thus, it was puzzling to find that where information on the effects
of stepwise covariate addition to models was available in this article, that the
same covariates were listed for both models based on the stratification
variable. There is excessive reliance on fractionation of the data set due to
multiple stratification, sometimes reducing the number of subjects in a model
to as few as 171. Even the models using the most subjects had only
359 subjects. Low power to detect significant effects cautions against any
interpretation of non-significant results. The time-integrated model used
10 baseline blood pressure measurements and 5 follow up blood pressure
measurements, thus weighting the average toward baseline blood pressure.
The entry of the biochemical correlate of alcohol use in most of the models
suggests that lead effects and lead-containing alcohol effects on blood
pressure were confused, especially given the European setting and the time
period during which the study was conducted. Control for use of
hypertensive medication rarely entered models and partial control for this
variable was achieved only by stratified analyses, further reducing power to
detect significant effects in the remaining subgroup. No justification was
given for stratified analyses. Incomplete information in statistical methods
and results complicates interpretation. It was uncertain if stepwise regression
was used for logistic models. No comparisons were performed to assess
possible bias due to subject attrition over the course of the study. The over
six decades of age represented in the sample was modeled by linear and
quadratic terms based on age quintiles rather than continuous age, making it
likely that adequate control for age effects on blood pressure was not
achieved and that the "healthy subject" effect seen in older groups was not
controlled. If stepwise addition of significant covariates was used in the
blood pressure difference models, were covariates in those models that were
marked in the coefficient column as non-significant not included in the
models, and if that were so, it is unclear from where the probability values
that substitute for the coefficients of those variables were derived. There
were no model diagnostic tests reported.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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Europe (cont'd)
Staessen et al. (1993)
Belgium-Cadmibel Study
1985-1989
827 males and 821 females recruited from two
areas in Belgium, one of them surrounding a non-
ferrous smelter, mean age (SD) 46 (15) and 44
(15) years, in men and women respectively.
Subjects taking antihypertensive medication were
excluded from the analyses. Stepwise multiple
regression models of systolic and diastolic blood
pressure were stratified by sex. Covariates
available for entry were age and age-squared,
BMI, pulse rate, log protoporphyrin, log gamma-
glutamyltranspeptidase, serum calcium, log serum
ferritin, log serum creatinine, log serum zinc,
urinary calcium, urinary sodium, and urinary
potassium. Natural log blood lead was the only
variable forced into the models. Additional
models tested the interaction of serum calcium and
blood lead on blood pressure.
Geometric mean blood lead
(range), stratified by sex:
Male blood lead 10.4 ug/dL
(2.7, 84.9)
Female blood lead 6.2 ug/dL
(1.3,42.4)
In men, adjusting for age and age-squared, BMI, pulse rate, log gamma-
glutamyltranspeptidase, serum calcium, and log serum creatinine, every unit
natural log blood lead increase was significantly associated with a -5.2
mmHg (95% CI: -0.5, -9.9) decrease in systolic blood pressure. Natural log
blood lead was not significant in the model for diastolic blood pressure for
men nor the systolic or diastolic blood pressure for women.
Adjusting for age and age-squared, BMI, pulse rate, and log gamma-
glutamyltranspeptidase, the interaction term between natural log blood lead
and serum calcium was only significant for systolic blood pressure in women.
Every doubling of blood lead was associated with a 1.0 mmHg decrease in
systolic blood pressure at serum calcium concentration of 2.31 mmol/L (25th
percentile) and an increase in systolic blood pressure of 1.5 mmHg at serum
calcium concentration of 2.42 mmol/L (75th percentile).
Stepwise multiple regression analyses run risks of accepting chance
associations due to multiple analyses of the same data set. The role of
alcohol use or alcohol use markers in confounding lead effect on blood
pressure in this setting has already been noted. The unexplained interaction
between serum calcium and blood lead highlights the potential confounding
role of serum calcium with lead in blood pressure studies. The study shows
graphs indicating distinct differences in the age-serum calcium and age-blood
lead relationships for men and women. From 50-70 years of age serum
calcium is higher than from < 29-49 years in women and exceeds serum
calcium of men at those older ages. The steepest rise in women's blood lead
with age occurs between the 40-49 and 50-59 year decades. The timing of
these changes in women suggests that menopause may be a factor, which was
accounted for only in the model for diastolic blood pressure. It also suggests
that serum calcium level and age were also confounded in the blood pressure
models. As serum creatinine clearance and blood lead are inversely related,
and serum creatinine is a significant covariate in the systolic blood pressure
model for men with a significant negative blood lead coefficient, it is possible
that serum creatinine and blood lead are confounded with blood pressure in
the men's systolic blood pressure model. There were no assessments of
subject selection bias due to exclusions. The authors note examining quintile
blood pressure relationships with all covariates to determine the acceptability
of the linear relationship implied by the linear modeling technique. No other
model diagnostic tests were reported.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement Findings, Interpretation
X
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Europe (cont'd)
Bost et al. (1999)
Europe-England-Health
Survey for England
1995
Fewtrell et al. (2004)
Global
1988-2002
2763 women and 2563 men from a multi-stage
stratified probability survey representative of the
English population living in private residences, mean
(SE) age for men 47.5 years (0.34) and for women
47.7 years (0.33) (all subjects 16 years and older)
were used in an analysis of blood lead association
with systolic and diastolic blood pressure. Stepwise
multiple regression analysis were used testing natural
log blood lead against common log systolic blood
pressure and non-transformed diastolic blood
pressure, with the following potential covariates: age,
BMI, smoking status, region of residence, social class,
and alcohol consumption. Models were stratified by
sex, with and without adjustment for alcohol,
including or excluding those taking antihypertensive
medications.
Using available global figures on categorized blood
lead ranges by age group, authors calculated relative
risk ratios relating increased blood pressure to
ischemic heart disease, cerebrovascular disease,
hypertensive disease, and other cardiac diseases.
They used a calculation of "impact fraction," based on
the proportion of the population within the particular
lead exposure category and the relative risk at that
exposure category compared to the risk at the
reference level. They used the meta-analysis of
Schwartz (1995) to derive an accumulating 1.25
mmHg increase in blood pressure in men for 5-10, 10-
15, and 15-20 ug/dL, and an increase of 3.75 mmHg
for blood lead levels above 20 ug/dL. Comparable
blood pressure increases in women for each lead
category was 0.8 mmHg for each of the first three
categories and 2.4 mmHg for blood lead >20 ug/dl.
Geometric mean blood lead:
Men: 3.7 ug/dL (no stated
measure of variance)
Women: 2.6 ug/dL (no
stated measure of variance
See left for blood lead
categories used.
Model tables presented only standardized variable coefficients. The most
consistent results were reported on common log lead association with men's
diastolic blood pressure. Every doubling of blood lead was significantly
associated with an increase of 0.78 mmHg (95% CI: 0.01, 1.55) diastolic
blood pressure, adjusted for age, log BMI, and alcohol, but excluding men on
antihypertensive medication. Every doubling of blood lead was significantly
associated with an increase of 0.88 mmHg (95% CI: 0.13, 1.63) in the same
model with men on antihypertensive medication. Every doubling of blood
lead was significantly associated with an increase of 0.96 mmHg (95% CI:
0.23, 1.70) in the same model excluding men on antihypertensive medication
and not adjusting for alcohol. Every doubling of blood lead was significantly
associated with an increase of 1.07 mmHg (95% CI: 0.37, 1.78) including
men taking antihypertensive medication and not accounting for alcohol.
None of the multiple regression models had significant lead terms for
women.
This report was not sufficiently detailed. Stepwise regression modeling is
prone to the usual pitfalls. Survey design adjusted analysis not used. Lead
was not entered in models in which criterion probability was exceeded
(p > 0.05). No rationale given for stratifying. No testing of differences
among lead coefficients for the different models was made, which would
have been especially valuable to compare models adjusted and not adjusted
for alcohol use. No explanation for using log systolic blood pressure as
dependent variable. No model diagnostics reported.
The largest risk ratios were for hypertensive disease populations at ages 15-
44, calculated at 1.12, 1.41, 1.78, and 2.00 for each of the four lead categories
for men, and 1.08, 1.25, 1.45, and 1.56 for women. Risk ratios for all disease
categories increased with increasing lead category and decreased for
populations older than 44 years.
The authors assumed a linear relationship between blood pressure and blood
lead, whereas available evidence suggests it may be non-linear. If blood
lead-blood pressure concentration-response function is log-linear, as
implicitly accepted by over half the reviewed studies, the calculated global
risk ratios for all cardiovascular disease will be overestimated at higher blood
lead levels and underestimated at lower blood lead levels.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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Europe (cont'd)
Gerhardsson et al. (1995)
Europe-southern Sweden
1969-1989
664 male workers at a secondary lead smelter had
blood lead tested every 2-3 months since 1969.
The past blood lead level of 201 workers who had
been working at the plant from before 1969 was
estimated from their 1969 results. Median (10th
percentile, 90th percentile) year of birth was 1943
(1918, 1960). Median (10th percentile, 90th
percentile) duration of employment was 2.8 years
(0.3, 25.7) and median (10th percentile, 90th
percentile) duration of follow up was 13.8 years
(2.8, 20.9). A total of 8706 person-years were
represented in the study. Standardized mortality
ratios based on county mortality tables by calendar
year, cause, sex and five-year age group were
calculated. Cardiovascular diseases were coded by
ICD-8 from death certificates.
Arithmetic mean blood lead
levels dropped from
approximately 62 ug/dL in
1969 to approximately 33
ug/dL in 1985. 95%
confidence intervals were
difficult to extract from the
presented graph, but appeared
to be no more than 5-6 ug/dL
about the mean.
All cardiovascular disease mortality (ICD-8 390-458) was significantly
elevated above that expected from the county mortality tables (SMR =1.46
[95% CI: 1.05, 2.02]), with 39 of the 85 deaths observed in the cohort. For
just ischemic heart disease (ICD-8 410-414), SMR = 1.72 (95% CI: 1.20,
2.42) in the plant workers with 34 of the 85 deaths observed in the cohort.
There were no deaths recorded for cerebrovascular diseases (ICD-9 430-438).
There was no apparent concentration-response relationship, using peak blood
lead and time-integrated blood lead.
Problems inherent in using standardized mortality ratios in such mortality
studies have been discussed above. The sample size was too small (85 all
cause deaths among 664 workers) to interpret non-significant results.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Europe (cont'd)
Henseetal. (1994)
Denmark- Augsburg-
MONICA study
1987-1988
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1703 men and 1661 women, age 28-67 years, used
multiple regression models stratified by sex, and in
men, stratified by rural/urban residence to examine
the effect of recent alcohol consumption (over last
weekend) on the relationship of linear blood lead
on systolic and diastolic blood pressure. Alcohol
consumption was stratified into 0 g/day, <40
g/day, and >40 g/day groups. Women's results
were adjusted by age, hematocrit, BMI, place of
residence, and smoking. Covariates of men's
blood pressure not stated.
Total range of blood lead for
women (mean and variance not
given): 3-14ug/dL
Total range of blood lead for
men (mean and variance not
given): 5-14.5 ug/dL
Women's blood lead stratified
by alcohol:
0 g/day: 3-8 ug/dL
<40 g/day: 4-10 ug/dL
> 40 g/day: 5-14ug/dL
Rural men's blood lead
stratified by alcohol:
0 g/day: 5-11 ug/dL
<40 g/day: 6-12 ug/dL
>40 g/day: 7-14.5 ug/dL
Urban men's blood lead range
not shown.
Blood lead ranges read from
graphs and are only
approximate.
The effect of linear blood lead on systolic and diastolic blood pressure varied
directly by alcohol consumption. In women, every 1 ug/dL increase in blood
lead was significantly associated with an increase of 1.30 mmHg (95% CI:
0.45, 2.15) systolic blood pressure only for women drinking >40 g/day of
alcohol (n = 83). Every 1 ug/dL increase in blood lead was significantly
associated with an increase of 0.27 mmHg (95% CI: 0.02, 0.52) and
0.86 mmHg (95% CI: 0.33, 1.39) diastolic blood pressure in those drinking
<40 g/day (n = 877) and >40 g/day, respectively.
In urban men, there were no significant effects of linear blood lead on blood
pressure. In rural men drinkers consuming <40 g/day (n = 463) and
>40 g/day (n = 356) each 1 ug/dL increase in blood lead was significantly
associated with an increase of systolic blood pressure of 0.65 mmHg (95%
CI: 0.21, 1.09) and 0.45 mmHg (95% CI: 0.05, 0.99), respectively. In these
same two groups of men, each 1 ug/dL increase in blood lead was associated
with an increase of 0.39 mmHg (95% CI: 0.09, 0.69) and 0.30 mmHg (95%
CI: 0.03, 0.57), respectively.
The report lacked important details. Method of covariate entry not
mentioned. Men's covariates not mentioned. Complete blood lead
description not given. No comparison of selected group with non-selected
group (10.4% of total sample not used due to missing data). Uncontrolled
confounding between range of blood lead and alcohol consumption was
especially notable in women (blood lead range and mid-points increased with
increasing alcohol consumption. Linear blood lead may not be the
appropriate metric to use for blood pressure studies. Age-square covariate
should also have been used, given the range of ages. No rationale given for
stratification. Authors could not explain why rural men and not urban men
showed the direct association between alcohol consumption and strength of
lead effect. No statistical comparison of lead coefficients within and across
strata. No model diagnostic tests presented.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Europe (cont'd)
Maheswaran, et al. (1993)
Europe-England-
Birmingham
1981
809 out of 870 workers, mean (SD) age 43.3 (10.4)
years, at an lead acid battery plant were used in the
study. Women and workers taking
antihypertensive medications were excluded.
Used multiple linear regression analyses of
systolic and diastolic blood pressure, forcing age,
BMI, alcohol use, linear blood lead, zinc
protoporphyrin, years of work exposure, cigarette
smoking as covariates.
Geometric mean (SD) blood
lead was:
31.6 ug/dL (5.5 sic.)
Linear blood lead was not significant for either systolic or diastolic blood
pressure.
Authors used two indices of lead exposure in the same models. Over much
of the studied blood lead range, zinc protoporphyrin was likely collinear with
blood lead. Linear blood lead may not be the appropriate metric to use in
blood pressure models. Did not use age-squared to adjust for non-linear
relationship of blood pressure with age. Did not report model diagnostics.
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Telisman et al. (2004)
Europe-Croatia-Zagreb
Date of data collection not
given.
100 workers from factories producing lead-based
products, mean (range) age 30 (20-43) years.
Exclusion criteria were absence of psychological
stress (e.g., death in family) over last 4 months,
absence of verified diabetes, coronary heart
disease, cerebrovascular and peripheral vascular
disease, renal disease, hyperthyroidism,
androgenital syndrome, primary aldosteronism,
and "other diseases that could influence blood
pressure or metal metabolism." Linear or natural
log blood lead were considered for stepwise entry
in models of systolic and diastolic blood pressure,
forcing in all other covariates: blood cadmium,
BMI, age, serum zinc, serum copper, hematocrit,
smoking, and alcohol.
Arithmetic mean (range) blood
lead:
36.7 ug/dL (9.9-65.9)
Neither linear nor natural log blood lead entered as significant in multiple
regression models of systolic and diastolic blood pressure.
Very small sample size limited power to detect significant effects; non-
significant effects should not be interpreted as lack of effect. Too many
covariates for a small study. Almost no subjects below 10 ug/dL. Taking
hypertensive medications not controlled, likely a problem with top systolic
and diastolic blood pressure in the group 170 mmHg and 110 mmHg,
respectively. No model diagnostic testing reported.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Asia
Lee etal. (2001)
Korea-Chonan
1997-1999
798 workers from various lead-using or producing
factories, mean (SD, range) age 40.5 years (10.1)
[17.8-64.8], 79.4% male, were classified as to
Vitamin D receptor genotype (VDR: bb or
Bb/BB) and delta-aminolevulinic acid dehydratase
(ALAD: 1-1 or 1-2) genotype, as VDR
polymorphism has been implicated in
modifications of lead absorption and lead uptake
and release from bone as well as risk for elevated
blood pressure and hypertension, and ALAD
polymorphism affects lead binding to it in the
erythrocyte, the major storage depot of lead in
blood. The hypothesis was that polymorphism
type could influence the effect of lead on blood
pressure and hypertension.
Multiple linear regression models of linear blood
lead, DMSA-chelatable lead, and tibia lead effect
on systolic and diastolic blood pressure with
potential covariates of age and age-squared, sex,
creatinine clearance, hemoglobin, weight, height,
BMI, job duration, tobacco and alcohol
consumption, pack-years of tobacco, and
cumulative life time alcoholic drinks. Stepwise
procedure allowed retention of covariates only if
they were significant or "there were substantive
changes in the coefficients of predictor variables
after" their inclusion. In the models shown,
Appearance of multiple lead variables and the
interaction between lead variables and genotype
for each gene depended upon the specific model.
Both ALAD and VDR receptor polymorphism
were sometimes tested simultaneously in each
model containing polymorphism terms and
sometimes VDR appeared without ALAD.
Arithmetic mean (SD, range)
blood lead 32.0 ug/dL
(15.0,4-86)
Mean (SD, range) DMSA-
chelatable lead 186 ug
(208.4, 4.8-2103)
Mean (SD, range) tibia lead
37.2 ug/g (40.4, -7 to 338)
With simple t-tests, subjects with VDR Bb/BB allele were significantly older,
had more DMSA-chelatable lead, and had higher systolic and diastolic blood
pressure than subjects with VDR bb allele.
In multiple regression models of systolic blood pressure, controlling for age
and age-squared, sex, BMI, antihypertensive medication use, and cumulative
life-time alcoholic drinks, adding tibia lead, VDR type, and ALAD type, each
increase of 10 ug/g of tibia lead was associated with an increase of 0.24
mmHg (95% CI: -0.01, 0.49) and VDR BB/Bb type was associated with an
increase of 3.24 mmHg (95% CI: 0.18, 6.30) blood pressure compared to the
VDR bb type. ALAD genotype was not significant. In the same model, but
substituting linear blood lead for tibia lead, each increase in 1 ug/dL of linear
blood lead was associated with an increase of 0.07 mmHg (95% CI: 0.00,
0.14) and VDR BB/Bb type was associated with an increase of 2.86 mmHg
(95% CI: -0.22, 5.94) blood pressure compared to the VDR bb type. ALAD
genotype had no significant effects on blood pressure.
When both tibia and linear blood lead were entered simultaneously along
with VDR genotype, adjusting for the same covariates, only VDR Bb/BB
was significant; compared to VDR bb, blood pressure was 3.51 mmHg (95%
CI: 2.41, 8.61) higher. ALAD genotype had no significant effects on blood
pressure.
In a model without any lead terms, VDR genotype was interacted with the
age and the age-squared terms. The VDR Bb/BB genotype interaction with
the linear age term was significant for systolic blood pressure. Compared
with the bb genotype the VDR Bb/BB genotypes' blood pressure increased
0.36 mmHg (95% CI: 0.06, 0.66) per year faster with increasing age.
There were no significant effects of any lead variable with diastolic blood
pressure, though the VDR Bb/BB genotype had significantly higher blood
pressure (1.9 mmHg; not enough information given to calculate CI) than the
bb genotypes.
There were no significant interactions of the lead measures with the
genotypes for either ALAD or VDR.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Asia (cont'd)
Lee etal. (2001)
(cont'd)
Lustberg et al. (2004)
Korea-Chonan
1997-1999 (period of
enrollment; no statement
on dates of data collection)
Logistic regression analysis was used to test the
effect of the lead indices on hypertension (systolic
>160 mmHg or diastolic >96 mmHg or taking
antihypertensive medications) using the same
group of potential covariates, testing the lead terms
and the lead-genotype interaction terms separately.
The hypertension models tested both gene
polymorphisms separately.
793 (number given for genotype analysis; numbers
in models not given) current and former lead
workers, mean (SD) age 40 (10) years and 80%
male, were genotyped for the three polymorphisms
of endothelial nitric oxide synthase (eNOS) (GG,
GT, TT), an enzyme that is a modulator of
vascular resistance. The effect of genotype and the
interaction of genotype with blood lead and tibia
lead on systolic and diastolic blood pressure were
evaluated by multiple linear regression analyses,
forcing covariates of age (modeled as a 2 degree of
freedom spline with knot at 45 years), sex, natural
log BMI, smoking and alcohol consumption, high
school education, and job duration. Both blood
lead and tibia lead were entered as percentiles and
entered together. Logistic models of hypertension
(systolic > 140 mmHg or diastolic >90 mmHg or
reported use of antihypertensive medication) used
the same covariates. Interaction terms between
each of the lead measures (plus a lead-squared
term) and genotype was used to determine
differential effect of lead according to genotype.
Lead according to genotype:
Arithmetic mean (SD) blood
lead, GG: 32(15)ug/dL
Arithmetic mean (SD) blood
lead, TG/TT: 32(15)ug/dL
Mean (SD) tibia lead, GG: 37
(42) Hg/g
Mean (SD) tibia lead, TC/TT:
36 (34) ug/g
Subjects with the Bb/BB genotypes had a significantly higher odds
hypertension prevalence (OR 2.1 [95% CI: 1.0, 4.4]) than subjects with the
bb genotype, adjusting for age, sex, BMI, tibia lead, and current alcohol use.
There were no significant effects of any lead variable nor of ALAD on
hypertension status.
Linear blood lead may not give efficient and unbiased estimates of blood lead
effect on blood pressure. The descriptive data shows highly skewed
distributions for blood lead, DMSA-chelatable lead, and tibia lead in this
group, suggesting that coefficients of all lead effect on blood pressure may
not have been efficient and unbiased. Stepwise models usually produce
different covariate patterns for different models, though the tables indicate
that the covariates used for all the models discussed above were the same.
No model diagnostic tests were reported.
85% (673/793) of the group were typed GG, 14% (114/793) were TG, and
1% (6/793) were TT. TG and TT groups were combined for analysis
(TG/TT).
Mean systolic and diastolic blood pressures, adjusted for all covariates, were
not significantly different between GG and TG/TT groups.
In multiple regression models for systolic and diastolic blood pressure,
neither percentile blood lead nor percentile tibia lead, entered together, were
significant predictors. Interaction terms between the lead variables and
genotype were not significant.
In the logistic regression model for hypertension, neither percentile blood
lead nor percentile tibia lead, entered together, were significant predictors.
Reporting was incomplete: number of subjects entering the models were not
stated; no comparisons between recruited subjects and subjects not used in
models. Despite reporting non-significant interactions, the paper showed
both loess plots and tables of analyses stratified by genotype, reporting
significant associations between both tibia and blood lead in the GG
genotype, insignificant in the other. Inspection of the loess plots revealed
striking non-linearity for both adjusted blood lead-systolic blood pressure and
adjusted tibia lead-systolic blood pressure relationships. Small group size of
the TG/TT genotypes and highly unbalanced terms of the interaction may
have contributed to the non-significant interactions. Although the interaction
lead term was also probed as a quadratic function, the tibia lead interaction
was not, suggesting that poor concentration-response specification in the
model may also have contributed to the lack of significant main effects and
interactions.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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Asia (cont'd)
Nomiyama et al. (2002)
China, Beijing
No statement on dates of
data collection
123 female lead-exposed leaded crystal toy
workers, mean age (range) 27.3 (17-44) years, and
70 female sewing workers (reference group), mean
age (range) 24.2 (16-58) years were tested.
Forward stepwise multiple regression models of
systolic and diastolic blood pressure of the
combined groups were used with linear blood lead
and a set of covariates. Variables with p < 0.2
were allowed to enter. The covariate set was
selected from a larger set of potential covariates by
factor analysis, and a representative variable from
each factor was selected for possible entry in the
regressions.
Alternate models were constructed using four
ordered categories of blood lead, instead of the
linear continuous blood lead variable. Logistic
regressions were used to determine the odds of
elevated systolic (> 125 mmHg) and elevated
diastolic (> 80 mmHg) blood pressure as a function
of blood lead category.
Blood lead mean (SD, range)
in lead workers: 55.4
(13.5, 22.5-99.4 ug/dL
Blood lead mean (SD, range)
in non-lead workers:
6.4(1.6, 3.8-11.4) ug/dL
Adjusted for age, urine protein, and plasma triglyceride, each 1 ug/dL
increase in linear blood lead significantly associated with a 0.13 mmHg
increase in systolic blood pressure (no SE or CI given; p = 0.0003). Adjusted
for plasma triglyceride, age, urine protein, plasma low density lipoprotein,
and hypertension heredity, each 1 ug/dL increase in linear blood lead was
associated with a 0.10 mmHg increase in diastolic blood pressure (no SE or
CI given; p = 0.0001).
Using the ordered categories of blood lead and the same covariates for
systolic and diastolic blood pressure, the 40-60 ug/dL group had 4.2 mmHg
(95% CI: 0.0, 8.5) higher systolic blood pressure and 4.1 mmHg (95% CI:
1.3, 6.8) higher diastolic blood pressure than the reference group (blood lead
(<11.4 ug/dL). The group with >60 ug/dL blood lead had 7.5 mmHg (95%
CI: 3.0, 12.0) systolic blood pressure and 6.3 mmHg (95% CI: 3.4, 9.1)
diastolic blood pressure higher than the reference group.
Logistic regression models for "elevated" blood pressure, modeled using the
same covariates were similar. In the 40-60 ug/dL group odds of systolic
blood pressure > 125 mmHg and diastolic blood pressure > 80 mmHg were
4.26 (95% CI: 1.07, 17.04) and 2.43 (95% CI: 0.97, 6.04), respectively,
higher than the reference group. The odds of "elevated" systolic and diastolic
blood pressure in the group with blood lead >60 ug/dl were 7.48 (95% CI:
1.86, 30.12) and 3.31 (95% CI: 1.29, 8.50), respectively.
Incomplete reporting in paper: no model N, no SEs for linear blood lead
regressions, no description of type of factor analysis used or dates of data
collection. Innovative use of factor analysis to select covariates that,
depending on how the factor analysis was run, could have produced a set of
orthogonal variables for model entry. However, BMI was not included in the
original set of covariates or in the models. Small sample size limits
conclusions based on nonsignificant results. Stepwise regression produced a
different covariate pattern for each component of blood pressure. The linear
blood lead variable may be inappropriate given the marked skewness of
blood lead in descriptive analysis. The 11 ug/dL gap in blood lead between
lead workers and non-lead workers could have introduced problems in
analyses with continuous blood lead. Larger age spread in non-exposed
group than in exposed group could have caused misspecification of age
variable. No control for antihypertensive medication use. No model
diagnostics reported.
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Table AX6-5.1 (cont'd). Cardiovascular Effects of Lead
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
oo
Asia (cont'd)
Wu et al. (1996)
Central Taiwan
No statement on dates of
data collection
222 workers in two lead battery plants, 112 men,
mean (range) age 36.2 (18-67) years, and 110
women, mean (range) age 36.2 (18-71) years were
tested for blood lead relationships with systolic
and diastolic blood pressure in multiple regression
models, using a fixed, forced set of covariates:
age, sex, BMI, working history, years of work,
noise exposure, natural log ambient air lead
concentration, and ordered categorical blood lead
concentration.
Arithmetic mean (SD, range)
blood lead:
Women: 44.6(18.4)
[8.3-103.1] ug/dL
Men: 60.2(26.8)
|[17.0-150.4] ug/dL
Using four ordered blood lead categories (<25ug/dL [n = 16/222; 6.8%],
25-40 ug/dL [58/222; 26.1%], 41-60 ug/dL [63/222; 27.9%], and >60 ug/dL
[85/222; 38.3%]) adjusted systolic and diastolic blood pressure were not
significantly related to the top three blood lead categories compared to the
lowest, natural log ambient lead. Years in work environment was a
significant predictor of both systolic and diastolic blood pressure, but age was
only marginally significant for systolic blood pressure and not significant for
diastolic blood pressure.
Small study size limits any conclusions drawn from non-significant results.
Three measures, all related to lead exposure, were simultaneously tested in
the models. While blood lead may only be weakly correlated with years of
work, ambient air lead would be expected to be much better correlated with
blood lead. There is a clear possibility of collinearity among those three
variables, which would inflate standard errors and reduce coefficients.
Authors selected ordered categories of lead to "avoid unnecessary assumption
of linearity." The use of natural log air lead concentration suggests that some
diagnostics were run, but no model diagnostic tests were reported. No
control for antihypertensive medication use.
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CHAPTER 6 ANNEX
ANNEX TABLES AX6-7
December 2005 AX6-188 DRAFT-DO NOT QUOTE OR CITE
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Table AX6-7.1. Recent Studies of Lead Exposure and Genotoxicity
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
oo
VO
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V
O
Europe
Fracasso et al. (2002)
Italy
Paulus et al. (2003)
Poland
Case-control design.
37 workers employed at a battery plant.
29 student and office worker volunteers with
no known occupational exposure to
genotoxins.
Peripheral lymphocytes isolated from whole
blood.
Reactive Oxygen Species (ROS) production,
cellular GSH level, PKC isoforms, and DNA
breaks (via comet) assayed.
ANOVA and logistic regression used to
compare workers vs. healthy volunteers.
Adjusted for age, alcohol use, and smoking.
Cross-sectional design.
Battery plant workers: 34 acid battery,
22 alkaline battery, and 52 plant personnel
from departments with no known exposure to
Pb or Cd.
Lymphocytes isolated from whole blood.
SCE, MN, DNA damage (via comet) assayed.
Means compared via ANOVA.
Battery plant workers. Blood lead
categories used for some comparisons,
with <25, 25-35, and >35 ug/lOOmL as
cutpoints.
Mean blood Pb 39.6 ug/lOOmL for
workers, 4.4 ug/100mL for volunteers.
Workers considered Pb-exposed if
from acid battery department,
Cd-exposed if from alkaline, unexposed if
from other department.
Mean blood Pb 504 ug/L for
Pb-exposed workers, 57 ug/L for
Cd-exposed, and 56 ug/L for other
workers.
OR (95% CI)
Workers vs. Volunteers:
ROS: 1.43 (0.79-2.60)
DNA Breaks (Tail Moment): 1.07 (1.02-1.12)
GSH: 0.64(0.49-0.82)
PKC a reduced in workers, atypical PKC unchanged vs. volunteers
(no statistics provided).
Means (SE) via blood lead category for ROS and GSH:
<25 ug/ug/100 mL 4.9 (0.4) and 12.8 (0.8)
25-35 ug/100 mL 5.4 (0.7) and 7.7 (1.7)
>35ug/100mL 5.4 (0.5) and 9.2 (1.2)
Major analyses controlled for age, smoking, and alcohol intake.
Analyses by blood lead category not controlled for age, smoking, or
alcohol intake but these factors said not to influence endpoint and/or
results "significantly." No control for potential coexposures.
Mean (SD)
Pb exposed workers (all combined):
SCEs 7.48(0.88)
MN 18.63 (5.01)
NDI 1.89 (no SD given)
Cd exposed workers (all combined):
SCEs 6.95 (0.79)
MN 15.86(4.92)
NDI 1.96 (no SD given)
Other workers (all combined):
SCEs 6.28(1.04)
MN 6.55 (3.88)
NDI 1.86 (no SD given)
Elevation of SCEs and MN vs. controls at p < 0.05 and p < 0.01,
respectively.
Both SCEs and MN elevated among Pb exposed workers as well as
Cd-exposed workers compared to controls. Differences greatest for Pb-
exposed workers.
Higher SCE and MN also occurred among Pb-exposed workers after
stratification by smoking status.
No direct control for potential coexposures, but mean blood Cd no higher
in Pb-exposed than in other worker group.
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Table AX6-7.1 (cont'd). Recent Studies of Lead Exposure and Genotoxicity
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
Europe (cont'd)
Van Larebeke et al.
(2004)
Belgium
Cross-sectional design.
99 female nonsmokers, ages 50-65,
drawn from rural and industrial areas.
Peripheral lymphocytes isolated from
blood. HPRT variant frequency
determined.
Lead concentration measured in
blood (serum).
Women also classified as above vs.
below median for blood Pb
HPRT variant frequency
Above median serum Pb: 9.45 x 10'6
Below median serum Pb: 5.21 x 10'6
P-value for difference =0.08 adjusted for age, education,
smoking, BMI, and serum Se. (Significant inverse association
noted between variant frequency and serum Se.)
Uncontrolled for potential exposure to other genotoxins.
X
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Latin America
Minozzo et al. (2004)
Brazil
Cross-sectional design.
26 workers employed at a battery
recyclery for 0.5 to 30 years.
29 healthy volunteers of similar age
range and SES.
Peripheral lymphocytes isolated from
whole blood.
Fixed blood slides stained with Giemsa
visually evaluated to determine
micronuclear frequency (MN) and
cellualr proliferation as nuclear
division index (NDI).
ANOVA and logistic regression used
to compare workers vs. healthy
volunteers. Adjusted for age, alcohol
use, and smoking.
Battery recyclery workers were
considered exposed.
Blood lead also determined.
Mean blood Pb 35.4 ng/dL for
workers, 2.0 |ig/dL for volunteers.
Mean (S.D.)
Means (SD) for -workers and volunteers
MN 3.85 (2.36) and 1.45 (1.43)
NDI 1.77 (0.22) and 1.89 (0.18)
Kendal correlation coefficient
All -workers {assuming recyclery workers only, not total
population, but no population number given in Table.}
Blood Pb x MN: 0.061 (p = 0.33)
Blood Pbx NDI: 0.385 (p = 0.003)
Not controlled for age or SES, although worker and volunteer
populations said to be of similar age and SES. Uncontrolled for
potential coexposures. Correlations appear uncontrolled for
smoking, age, or other factors. Differences in MN and NDI
minor for smokers vs. nonsmoker, however. Diet "type"
"similar" for workers and controls, although no definition of
similarity provided.
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Table AX6-7.2. Key Occupational Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
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United States
Steenlandetal. (1992)
(follow-up of Selevan
etal. (1985)
U.S.
1940-1988
Wong and Harris
(2000)
(follow-up of Cooper
etal. (1985)
U.S.
1947-1995
Cohort design.
1,990 male workers employed for
at least 1 year in a lead-exposed
department at a U.S. lead smelter
in Idaho during 1940-1965.
Mortality traced through 1988 to
determine cause of death.
SMR computed for workers vs.
national rates for age-comparable
counterparts.
Cohort design.
Lead battery plant (4,518) and smelter
(2,300) workers.
Worker mortality was followed up
through 1995.
Cause of death was identified from
death certificates.
Mortality was compared with U.S.
national age-, calendar-year-, and
gender-specific rates to compute the
SMR.
(See additional entry for nested study
of stomach cancer.)
Exposure categorizations based on
airborne lead measurements from
1975 survey. High-lead-exposure
subgroup consisted of 1,436 workers
from departments with an average of
least 0.2 mg/m3 airborne lead or
>50% of jobs showing 0.40 mg/m3
or greater. Mean blood lead 56 ug/dL
in 1976.
Workers were evaluated as a whole,
and also as separate battery plant and
smelter worker populations.
Job histories were also used to
stratify workers by cumulative years
of employment (1-9,10-19, 20+),
date of hire (pre-1946 vs. 1946 on),
and lag between exposure and cancer
(<20, 20-34, >34 years). Mean blood
lead 80 ug/dL during 1947-72 among
smelter workers, 63 ug/dL among
battery workers.
SMR (95% CI); no. of deaths
Total cohort:
Nonsignificantly elevated RRs: kidney, bladder, stomach, and
lung cancer.
High-lead-exposure subgroup:
Kidney 2.39 (1.03,4.71); 8
Bladder 1.33 (0.48, 2.90); 6
Stomach 1.28 (0.61,2.34); 10
Lung 1.11 (0.82, 1.47); 49.
No control for smoking or exposure to other metals.
SMR (95% CI)
Battery plant -workers:
All cancer 1.05(0.97,1.13)
All respiratory 1.13 (0.98, 1.29)
Stomach 1.53 (1.12, 2.05), significant
Lung, trachea, bronchus
1.14 ( 0.99, 1.30), marginal significance
Thyroid, Hodgkin's: nonsignificant
Bladder 0.49 (0.23, 0.90), significant depression
Smelter -workers:
Digestive, respiratory, thyroid: nonsignificant
Lung 1.22(1.00, 1.47), nonsignificant
Battery plant and smelter -workers combined:
All cancer 1.04(0.97,1.11)
All respiratory 1.15 (1.03, 1.28), significant
Stomach 1.47 (1.13, 1.90), significant
Lung, trachea, bronchus
1.16(1.04, 1.30), significant
Thyroid/endocrine 3.08 (1.33, 6.07), significant
Lung and stomach risks lower for pre-1946 hires; higher for
workers employed 10-19 years than <10, but lower for
>19 years; SMRs peaked with 20- to 34-year latency for lung,
but <20 years for stomach.
No control for smoking or exposure to other agents.
No assessment of employment history after 1981.
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Table AX6-7.2 (cont'd). Key Occupational Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
to
United States (cont'd)
Wong and Harris
(2000)
U.S.
1947-1995.
(Nested in Wong and
Harris 200 cohort.)
Case-control design.
Cases: the 30 stomach cancer cases
occurring in a Philadelphia lead
battery plant.
Controls'. 120 age-matched cohort
members.
Mean exposure was compared for
cases vs. controls. Odds of exposure
were also computed for increasing
quartiles of cumulative exposure.
Job titles were used to classify lead
exposure as low, intermediate, or
high; total months of any exposure,
of intermediate or high exposure
only, and of cumulative exposure,
with months weighted by 1, 2, or 3 if
spent in low-, intermediate-, or high-
exposure job.
Mean months of employment, of intermediate or high exposure, or
of weighted exposure to lead were all nonsignificantly lower
among cases.
OR for cumulative weighted exposure in the 10 years prior to
death:
First quartile 1.00
Second quartile 0.62
Third quartile 0.82
Fourth quartile 0.61
P for trend = 0.47; ORs showed no positive association with
any index of exposure.
Analyses appear uncontrolled for smoking, other occupational
exposures, or other risk factors.
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Europe
Fanning (1988)
(Cases overlap those
occurring in
Dingwall-Fordyce and
Lane, 1963; and
Malcolm and Barnett,
1982).
U.K.
1926-1985
Proportional mortality/cohort design.
Subjects: 2,073 deceased males
identified through pension records of
lead battery and other factory workers
in the U.K.
Workers dying from a specific cancer
were compared with workers dying
from all other causes
Workers were classified as High or
moderate lead exposure vs. little or
no exposure based on job titles.
OR (95% CI) [Number of deaths]
Lung cancer: 0.93 (0.8, 1.1) [76 deaths]
Stomach cancer 1.34 [31 deaths]
No associations for other cancer types; elevations in stomach and
total digestive cancers limited to the period before 1966.
O
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Table AX6-7.2 (cont'd). Key Occupational Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
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O
Europe (cont'd)
Anttilaetal. (1995)
Finland
1973-1988
Cohort plus case-referent design.
20,700 workers with at least one blood
lead measurement between 1973 and
1983.
Workers were linked to the Finnish
Cancer Registry for follow-up through
1988. Fro deceased workers, cause of
death was identified from death
certificate.
Mortality and incidence were compared
with gender-, 5-year age, and 4-year
calendar-year matched national rates.
Blood lead concentration.
Exposure was categorized according
to the highest peak blood level
measured:
Low: 0-0.9 nmol/L
[Otol8.6ng/dL]
Moderate: 1-1.9 |imol/L
[20.7 to 39.4 ng/dL]
High: 2-7.8 (imol/L
[41.4 to 161.6 ng/dL]
Mean blood lead 26 |ig/dL.
Total cohort:
No elevation in total or site-specific cancer mortality
Moderately exposed:
Total respiratory and lung cancer:
SIR =1.4 (95% CI: 1.0, 1.9) for both
Total digestive, stomach, bladder, and nervous system:
nonsignificant elevations
Highly exposed:
No increase in risks
All cancer:
RR=1.4(95%CI: 1.1,1.8)
Lung or tracheal:
RR = 2.0(95%CI: 1.2,3.2)
No increase in high-exposure group
No RRs reported for other cancers
Case-referent substudies:
Lung cancer ORs increased with increasing cumulative
exposure to lead
Highly exposed: squamous-cell lung cancer OR = 4.1
(95% CI: 1.1, 15) after adjustment for smoking.
Short follow-up period limits statistical power, offset to a
large degree by the substantial sample size. No control for
exposure to other potential carcinogens.
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Table AX6-7.2 (cont'd). Key Occupational Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
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O
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V
O
Europe (cont'd)
Anttilaetal. (1996)
Finland
1973-1988
(Nested analysis based
onAntillaetal. 1995
cohort)
Gerhardsson et al.
(1995a)
Sweden
1969-1989
Case-control design.
(See Anttila et al. 1995 for basic
information on the source population.)
Cases'. 26 Finnish men with CNS
cancer.
Controls: 200 Finnish men without
CNS cancer.
Nested case-control analysis.
Cohort design.
684 male Swedish secondary lead
smelter workers with lead exposure.
Cancer incidence among workers was
traced through 1989.
Incidence was compared with county
rates.
Peak blood lead levels used to
categorize exposure as 0.1-0.7,
0.8-1.3, and 1.4-4.3 ng/L.
Cumulative exposure estimated by
using mean annual blood lead level to
categorize exposure as 0, 1-6, 7-14,
or 15-49 ng/L.
Interviews were used to obtain
occupational history and other risk-
factor data from patients or next
of kin.
Blood lead level: any worker with a
detectable blood lead level was
classified as exposed.
OR (no. of cases or deaths)
CNS cancer incidence (26 cases):
Rose with increasing peak lifetime blood lead measurements;
not significant
Glioma mortality (16 deaths):
Rose consistently and significantly with peak and mean blood
lead level, duration of exposure, and cumulative exposure.
Mortality by cumulative exposure, controlled for cadmium,
gasoline, and year monitoring began:
Low (13 subjects) 2.0(2)
Medium (14 subjects) 6.2 (2)
High (16 subjects) 12.0(5)
1 death among 26 subjects with no exposure: test for trend
significant at/> = 0.02.
Controlled for smoking as well as exposure to cadmium and
gasoline. Complete follow-up with minimal disease
misclassification.
SIR (95% CI); no. of cases
All malignancies:
1.27(0.91, 1.74); 40
Respiratory:
1.32 (0.49, 2.88); 6
All gastrointestinal:
cohort 1.84(0.92,3.29; 11
highest quartile 2.34 (1.07, 4.45); 9
Stomach:
1.88(0.39, 5.50); 3
Colon:
1.46 (0.30, 4.28); 3
SIRs for all other sites except brain were nonsignificantly
elevated; too few cases.
No control for smoking. Small numbers, so meaningful dose-
response analyses not possible for most cancer sites.
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Table AX6-7.2 (cont'd). Key Occupational Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
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O
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V
O
Europe (cont'd)
Lundstrom et al.
(1997)
(follow-up of
Gerhardsson et al.
(1986)
(see also subcohort
analyses of Englyst
etal.,2001).
Sweden
1928-1987
Englyst etal. (2001)
(follow-up and sub-
analysis of Lundstrom
etal., 1997).
Sweden
1928-1987
Cohort design.
3,979 copper and lead smelter workers.
Standardized mortality and incidence
ratios were computed for workers
compared with age-, year-, gender-, and
county-specific rates for the general
population.
Nested cohort analysis.
Limited to 1,093 workers in the
smelter's lead department, followed
through 1997.
Incidence was compared with county
rates; age-specific SIRs with 15-year
lag.
Fro some analyses, the entire cohort
was treated as exposed. For others,
job histories were used to single out
1,992 workers belonging to
departments thought to be exposed to
"lead only." Mean blood lead
monitoring test results across time
were used to single out a "highly
exposed" group of 1,026 workers
with blood lead levels >10 jimol/L
[>207|ig/dL].
Mean blood lead 60 ng/dL in 1959.
Workers were divided into
Subcohorts I and II for ever and
never worked in areas generally
associated with exposure to arsenic
or other known carcinogens (701 and
383 workers, respectively).
Detailed individual assessment of
arsenic exposure was made for all
lung-cancer cases.
SMR (95% CI); no. of deaths
Lung:
Total cohort 2.8 (2.0, 3.8); 39
Highly exposed 2.8 (1.8, 4.5); 19
SIR (95% CI); no. of cases
Lung -with 15-year lag:
Total cohort 2.9 (2.1,4.0); 42
Highly exposed 3.4 (2.2, 5.2); 23
Lead-only 3.1 (1.7, 5.2); 14
Lead-only highly exposed 5.1 (2.0, 10.5); 7
Other highly exposed (total cohort),
•with 15-year lag:
Brain 1.6 (0.4,4.2); 4
Renal pelvis, ureter, bladder 1.8 (0.8, 3.4); 9
Kidney 0.9 (0.2, 2.5); 3
All cancer 1.1 (0.9, 1.4); 83.
No control for smoking.
SIR (95% CI); no. of cases
Subcohort I (coexposed):
Lung 2.4 (1.2, 4.5); 10
Subcohort II (not coexposed):
Lung 3.6(1.2, 8.3); 5
Subjects with lung cancer found to have history of "considerable"
exposure to arsenic: 9/10 among Subcohort I, 4/5 among
Subcohort II.
No control for smoking.
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Table AX6-7.2 (cont'd). Key Occupational Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
Oi
Oi
Europe (cont'd)
Carta et al. (2003)
Sardinia
1972-2001
Cohort design.
918 lead smelter workers.
Mortality traced from 1972 through
2001.
Standardized mortality ratios
computed.
Smelter workers considered exposed.
Job histories also used to categorize
degree of exposure based on
environmental and blood lead
measurements for specific
departments and tasks during
1985-2001.
SMR; number of cases
Smelter workers as a whole
All cancer 1.01 ; 108
Gastric cancer 1.22 ; 4
Lymphoma/leukemia 1.82 ; 6
Lung cancer 1.21 ; 18
Highly exposed workers
Lung cancer 1.96 (95% C.I. 1.02, 3.68) for highest exposure
group, with statistically significant upward trend.
Analyses for worker population as a whole supported by
presence of dose-response pattern for lung cancer based on
estimated exposure. Modest population size, inability to assess
dose-response for cancers of interest other than lung. No control
for smoking or other occupational exposures.
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Table AX6-7.3. Key Studies of Lead Exposure and Cancer in the General Population
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
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O
O
V
O
United States
Jemal et al. (2002)
(same cohort as in
Lustberg and Silbergeld,
2002 except for inclusion
criteria)
U.S.
1976-1992.
Lustberg and Silbergeld
(2002) (same cohort as
Jemal et al., 2002 except
for inclusion criteria)
U.S.
1976-1992.
Cohort design.
3,592 white participants from the 1976-
1980 NHANES II survey who had blood
lead measured at entry.
Mortality was followed through 1992 via
NDI and SSADMF.
RRs were calculated for the various
exposure groups compared to survey
participants with the lowest exposure,
adjusted for age and smoking.
Cohort design.
4,190 U.S. participants from the 1976-1980
NHANES II health and nutrition survey
who had blood lead measured at entry and
whose levels fell below 30 ug/dL.
Mortality was followed through 1992 via
NDI and SSADMF.
RRs were calculated for the various
exposure groups compared to survey
participants with the lowest exposure,
adjusted for age, smoking and other factors.
Blood lead (ug/dL) was measured by
atomic absorption and used to classify
subjects into exposure quartiles or
groups above vs. below median
exposure.
Median blood lead 12 ug/dL.
Blood lead (ug/dL) measured by
atomic absorption was used to classify
subjects into exposure groups:
Low: <10
Medium: 10-19
High: 20-19
Mean blood lead 14 ug/dL.
RR (95% CI); no. of deaths
Lung (above vs. below median):
Total cohort 1.5 (0.7, 2.9); 71
M 1.2(0.6, 2.5); 52
F 2.5 (0.7, 8.4); 19
Stomach (above vs. below median):
Total cohort 2.4 (0.3, 19.1); 5
M 3.1(0.3, 37.4); 4
F no deaths in referent group
All cancer: total cohort by quartile (age-adjusted) 1.0, 1.2, 1.3, 1.5 (P for
trend 0.16).
Smoking was controlled for. Lead levels occurring in the general population
were examined, not just those in workers with high occupational exposure
potential. Exposure to other carcinogens were not examined. Potential for
residual confounding by degree and duration of smoking exists (only
controlled for never, former, current <1, current 1+ pack/day). Limited case
numbers yield low statistical power for stomach or other cancers.
RR (95% CI)
All cancer, vs. low exposure:
Medium 1.5 (0.9, 2.5)
High 1.7(1.0,2.8)
Lung, vs. low exposure:
Medium 1.7(0.6,4.8)
High 2.2(0.8,6.1)
Non-lung, vs. low exposure:
Medium 1.5 (0.8, 2.8)
High 1.5 (0.8, 2.8).
Significant upward trends noted for all-cause and for cardiovascular mortality
with increasing lead category.
Smoking was controlled for. Lead levels occurring in the general population
were examined , with individuals showing levels consistent with intense
occupational exposure excluded, thus allowing exploration of potential effects
outside of groups experiencing intense occupational exposure. Exposure to
other carcinogens were not examined. Potential for residual confounding by
degree and duration of smoking exists (only controlled for never, former,
current < 1, current 1+ pack/day). Limited case numbers yield low statistical
power for stomach or other cancers.
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Table AX6-7.4. Other Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
oo
H
6
o
o
H
O
O
V
O
United States
Mallinetal. (1989)
Illinois
1979-1984
Coccoetal. (1998a)
U.S.
1984-1992
Coccoetal. (1998b)
U.S.
1984-1992
Case-control design.
Cases: random sample of 10,013 deaths
from 7 specific cancers, identified from
death certificates for Illinois males
between 1979 and 1984.
Controls: 3,198 randomly selected deaths
from other causes.
Odds of exposure computed for glass
workers vs. other occupations.
Case-control design.
Cases: all 27,060 brain cancer deaths
occurring among persons aged 35 or older
during 1984-1992, from U.S.
24-state death certificate registry.
Controls: 4 gender-, race-, age-, and
region-matched controls per case selected
from deaths due to nonmalignant causes.
Subjects were subdivided into 4 groups by
gender and race (white or African-
American) for all analyses.
Case-control design.
Cases: all 28,416 CNS cancer deaths
occurring among persons aged 35 or older
during 1984-1992, from U.S.
4-state death certificate registry.
Controls: 4 gender-, race-, age-, and
region-matched controls per case selected
from deaths due to nonmalignant causes.
Subjects were subdivided into 4 groups by
gender and race (white or African-
American) for all analyses.
Exposure was based on
occupations abstracted from death
certificates.
No specific measure of lead
exposure; glass workers can be
considered potentially exposed.
A job-exposure matrix was
applied to death certificate-listed
occupations to categorize persons
as having low, medium, or high
probability and intensity of
exposure.
Death certificate listed industry
and occupation was used to
categorize decedents. No
estimates of lead exposure
specifically.
Brain cancer, white male glass workers:
OR = 3.0, P < 0.05 (significant)
No significant associations for other cancer sites.
No control for smoking or other risk factors. Poor specificity for lead
exposure.
Risk of brain cancer mortality increased consistently with intensity of
exposure among African-American males, but not other race-gender
groups.
Probability of exposure alone was not consistently associated with risk.
In the high-probability group, risk increased with exposure intensity for
all groups except African-American women (only 1 death in the high-
probability group).
Exposure estimate was based solely on occupation listed on death
certificate, hence there was substantial opportunity for misclassification.
OR (95% CI)
All occupations or industries with ORs above 1.0 and P-value <0.05 in at
least one race-gender group were reported
Newspaper printing and publishing industry:
white M 1.4(1.1-1.8)
black M 3.1(0.9-10.9)
Typesetting and compositing:
white M 2.0(1.1-3.8)
white F 1.3(0.4-3.8)
black F 4.2 (0.6-30.7)
No deaths among black males.
Only two lead exposure associated occupations or industries showed a
statistically significant elevation of mortality. No specific measures of
lead exposure. Occupation based solely on death certificate, hence there
was substantial opportunity for misclassification.
-------
o
O
to
O
O
Table AX6-7.4 (cont'd). Other Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
H
6
o
o
H
O
O
V
O
United States (cont'd)
Coccoetal. (1999)
U.S.
1984-1996
Case-control design.
Cases: all 41,957 stomach cancer deaths
occurring among persons aged 35 or
older during 1984-1996, from U.S. 24-
state death certificate registry.
Controls: 2 gender-, race-, age-, and
region-matched controls per case
selected from deaths due to
nonmalignant causes.
Subjects were subdivided into 4 groups
by gender and race (white or African-
American) for all analyses.
A job-exposure matrix was
applied to death certificate-
listed occupations to categorize
persons as having low, medium,
or high probability and intensity
of exposure.
OR (95% CI)
Adjusted for age, ethnicity, marital status, urban residence, and
socioeconomic status.
Elevated ORs:
white F, high prob. 1.53(1.10-2.12)
blackM, high prob. 1.15 (1.01-1.32)
black F, high prob. 1.76(0.74-4.16)
Highly exposed group included 1,503 white and 453 black men and
65 white and 10 black women; no pattern of increase across exposure
levels.
Intensity of exposure showed no association with stomach cancer
except for black women:
Low 1.82 (1.04-3.18) (significant)
Moderate 1.39
High 1.25.
No control for other occupational exposures. Exposure estimate
based on occupation listed on death certificate and hence subject to
misclassification due to missing longest-held job.
Canada
Rischetal. (1988)
Canada
1979-1982
Case-control design.
Cases: 826 Canadian men with
histologically confirmed bladder cancer
during 1979-1982.
Controls: 792 controls from Canadian
population, matched on age, gender, and
area.
Odds of exposure to lead for cases vs.
controls were computed, adjusted for
smoking and other risk factors.
Subjects were interviewed
regarding length of
occupational exposure to lead
compounds, as well as 17 other
substances.
OR (95% CI)
61 men ever exposed to lead (smoking-adjusted):
2.0(1.2-3.5)
Trend per 10 years' duration of exposure:
1.45 (1.09-2.02) (significant).
No other substances showed significant associations with bladder
cancer.
Controlled for smoking, marital status, socioeconomic status,
education, ethnicity, and urban vs. rural residence.
No control for other occupational exposures. Low control interview
rate (53%), which could result in biased control sample.
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o
O
to
O
O
Table AX6-7.4 (cont'd). Other Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
to
O
O
Canada (cont'd)
Siemiatycki et al.
(1991)
Canada
Case-control design.
Cases: 3,730 various histologically
confirmed cancers.
Controls: specific cancer types were
compared with other cancers as a control
group, excluding lung cancer.
Separate subgroup analysis was
restricted to French Canadians.
Occupational exposure to
293 substances, including lead,
was estimated from interviews.
Exposure was classified as
"any"; a subgroup with
"substantial" exposure also was
identified.
OR (90% CI); no. of cases
Any exposure to lead:
Lung 1.1 (0.9-1.4); 326
(French Canadians only)
Stomach 1.2 (1.0-1.6); 126
Bladder 1.3 (1.0-1.6); 155
(French Canadians only)
Kidney 1.2 (1.0-1.6); 88
ORs rose in the "substantial" exposure subgroup for stomach and
lung, but not for bladder or kidney cancer.
Controlled for smoking but not for other occupational exposures.
H
6
o
o
H
O
O
V
O
Europe
Sankilaetal. (1990)
Finland
1941-1977
Cohort design.
1,803 male and 1,946 female glass
workers employed for at least 3 months
at one of 2 Finnish glass factories in
1953-1971 or 1941-1977.
Cancer incidence was compared with
age-, gender-, and calendar-year-specific
national rates.
Stomach, lung, and skin cancer rates also
were compared separately for 201 male
and 34 female glassblowers and non-
glassblowers.
No specific lead exposure
indices were computed.
Analyses did examine glass
workers as a whole and then
glassblowers specifically,
which comprised the group at
highest risk for lead exposure.
SIR (95% CI); no. of cases
Lung cancer, all glass workers:
male 1.3 (1.0-1.7); 62
female 1.1 (0.5-2.3); 7
Lung cancer risk showed no specificity for glassblowers.
Skin cancer, M&Fcombined:
All workers 1.5 (0.8-2.7); 11
little difference between genders
Glassblowers 6.2 (1.3-18.3); 3
Stomach cancer, M&F combined:
Glassblowers 2.3 (0.9-5.0); 6
No increase in other glass workers
No increase in cancers of other sites. No control for smoking
or occupational coexposures.
-------
o
O
to
O
O
Table AX6-7.4 (cont'd). Other Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
to
O
H
6
o
o
H
O
O
V
O
Europe (cont'd)
Kauppinen et al.
(1992)
Finland
1976-1981
Wesseling et al. (2002)
Finland
1971-1995
Case-control design.
Cases: 344 primary liver cancer deaths
reported to the Finnish Cancer Registry
in 1976-1978 or 1981.
Controls: registry-reported stomach
cancer (476) or myocardial infarction
(385) deaths in the same hospitals,
frequency matched by age and gender.
Cohort design, but at ecologic level.
413,877 Finnish women with occupation
reported in 1970 linked to Finnish
Cancer Registry to identify new cases of
brain or nervous system cancer arising
form 1971 to 1995.
Poisson regression was used to calculate
SIRs for exposed vs. unexposed groups.
Questionnaires regarding job
history and personal habits were
sent to the closest available
relative.
U.K. based job-exposure matrix
was used to rate potential
exposure to 50 substances,
including lead compounds
Industrial hygienists also
inspected histories to identify
those with highly probable
exposure and rate it as high,
low, or moderate (< 10 years
high or 10+ years low
exposure)
Reported occupation in 1970
was used to classify women
into job titles. Potential
exposure for each job title was
estimated using a job matrix
after excluding women in the
highest social classes or in
farming. Lead and 23 other
workplace agents examined.
Rates for each job title were
calculated, and SIRs for low
and medium/high exposure
calculated (average estimated
blood lead of 0.3 umol/L served
as cutpoint between low and
medium/high exposure).
OR (95% CI)
52 workers with potential lead exposure'.
0.91(0.65-1.29)
11 women with potential lead exposure'.
1.84(0.83-4.06)
5 men with probable moderate exposure:
2.28 (0.68-7.67)
None had high exposure and only 1 had low exposure, whereas
4 controls had high exposure.
Female controls appeared to underreport their job history.
Most controls had stomach cancer, which if caused by lead
would bias results toward the null. Few subjects were rated as having
a high probability of exposure.
SIR (95% CI), unadjusted for other metals
Low exposure: 1.25(0.68-1.81)
Medium/High exposure: 1.33 (0.90-1.96)
SIR (95% CI), adjusted for Cd and Ni exposure
Low exposure: 1.18(0.88-1.59)
Medium/High exposure: 1.24 (0.77-1.98)
All results were adjusted for birth cohort, period of diagnosis, and job
turnover rate.
Incidence, exposure to lead, and potential confounding factors were
calculated at the level of job title rather than at the individual level.
Exposure and other estimates were based on data for all workers
pooled, not for women specifically. Job classification was based on a
single year, not lifetime job history.
-------
o
O
to
O
O
Table AX6-7.4 (cont'd). Other Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
to
O
to
H
6
o
o
H
O
Europe (cont'd)
Pesch et al. (2000)
Germany
1991-1995
Kandiloris et al. (1997)
Greece
Cordioli et al. (1987)
Italy
1953-1967
Case-control design.
Cases: 935 renal-cell cancer patients
in live German areas.
Controls: 4,298 region, age, and
gender-matched controls from the
surrounding population.
ORs were adjusted for age, center,
and smoking.
Case-control design.
Cases: 26 patients with histologically
confirmed laryngeal carcinoma and no
history of lead exposure or toxicity.
Controls: 53 patients with similar
demographic profiles and no history of
cancer from the same hospital.
Cohort design.
468 Italian glass workers employed for
at least one year between 1953 and 1967.
Mortality among workers was tracked
and cause of death was determined for
deceased workers. Standardized
mortality ratios were computed for
workers vs. national population
counterparts.
Job histories were used to
categorize exposure to
cadmium, lead, and other
potential as low vs. medium,
high, or substantial. Separate
exposure estimates were
obtained from British and from
German-derived job-exposure
matrices.
Blood lead levels and ALAD
activity were measured.
Workers producing low-quality
glass containers were classified
as lead-exposed.
OR (95% CI); no. of cases
Substantial lead exposure based on British matrix:
M 1.5 (1.0-2.3); 29
F 2.6 (1.2-5.5; 11
Substantial lead exposure based on British matrix:
M 1.3 (0.9-2.0); 30
F not reported.
Analyses controlled for smoking. No control for exposure to other
occupational agents.
Blood lead levels were similar, but ALAD activity was significantly
lower in cases than controls (Mean 50.79 U/L vs. 59.76 U/L, p <
0.01). No control for other risk factors. Potential distortion by
effects of disease on Pb and/or ALAD parameters.)
SMR (95% CI); no. of deaths
All cancer 1.3 (0.8-1.8); 28
Lung 2.1 (1.1-3.6); 13
Laryngeal 4.5 (1.2-11.4); 4
O
V
O
-------
o
O
to
O
O
Table AX6-7.4 (cont'd). Other Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
to
O
oo
H
6
o
o
H
O
O
V
O
Europe (cont'd)
Coccoetal. (1994a)
(expansion of Carta
etal. 1994).
Sardinia
1931-1992
Coccoetal. (1994b)
Sardinia
1951-1988
Coccoetal. (1996)
Sardinia
1973-1992
Cohort design.
1,741 male Sardinian lead and zinc
miners from two mines employed at
least one year between 1931 and 1971.
Mortality traced through 1992 to
determine cause of death.
Mortality among miners was compared
with age- and calendar-year-specific
regional rates to compute an SMR.
All miners were considered to
be exposed to lead.
Cohort design.
526 female Sardinian lead and zinc
miners from the same mines as in Cocco
etal. (1994a).
Mortality traced through 1992 to
determine cause of death.
Mortality among miners was compared
with age- and calendar-year-specific
regional rates to compute an SMR.
Cohort design.
1,222 male Sardinian lead and zinc
smelter workers whose G6PD
phenotypes had been determined,
employed any time from 1973-1990.
Mortality traced through 1992 to
determine cause of death.
Mortality was compared with regional
rates.
All miners were considered to
be exposed to lead.
All workers were considered to
be exposed to lead.
Workers were subdivided into
6PD-normal and -deficient
groups.
SMR (95% CI); no. of deaths
All cancer 0.94 (0.83-1.05); 293
1.21; 16
1.15; 17
1.28; 7
1.17; 8
0.61; 8
0.91; 21
0.83; 86
3.67 (1.35-7.98); 6
Prostate
Bladder
Kidney
Nervous system
Oral
Lymphohemopoietic
Digestive
Peritoneum
(significant)
No other P-values <0.05.
No control for smoking or exposure to silica, radon, or
other exposures.
SMR (95% CI)
Liver 5.02 (1.62-11.70) (significant)
Lung 2.32 (0.85-5.05) (nonsignificant)
Other cancers showed nonsignificantly reduced rates.
No control for smoking or exposure to silica, radon, or other
exposures. Low statistical power due to small population and paucity
of cancers during follow-up.
SMR (no. of deaths)
All cancer and lung cancer: lower than expected.
Stomach cancer: higher (2 observed vs. 0.6 expected).
G6PD-normal 0.26 (10)
G6PD-deficient 0.18(2)
G6PD deficiency had little apparent effect on mortality: cancer and
all-cause mortality was slightly lower among G6PD-deficient
workers than among G6PD-normal workers.
No control for smoking or exposure to other agents in the smelter.
Healthy worker bias-evident (all-cause mortality 31 observed vs. 44
expected), brief follow-up, low proportion of older ages (mean age at
entry 30, average follow-up less than 11 years), no cumulative
exposure data.
-------
o
O
to
O
O
Table AX6-7.4 (cont'd). Other Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
to
O
H
6
o
o
H
O
O
V
O
Europe (cont'd)
Coccoetal. (1997)
Sardinia
1931-1992
Wingren and Axelson
(1987,1993)
(update of Wingren
and Axelson, 1985,
same basic cohort as in
Wingren and
Englander(1990)
Sweden
1950-1982
Cohort design.
1,388 male production and maintenance
workers employed for at least 1 year at a
Sardinian lead and zinc smelter between
June of 1932 and July of 1971.
Mortality was followed up through 1992.
Mortality was compared with age- and
calendar-year-specific regional rates.
Since regional rates were only available
for 1965 and later, analyses were limited
to this period.
Case-control design.
Source population: 5,498 men aged
45 or older in 11 Swedish parishes,
including 887 glass workers.
Cancer-specific nested case-control
analysis:
Cases: deaths due to stomach, colon,
and lung cancer from 1950-1982
Controls: deaths due to causes other
than cancer or cardiovascular disease
All workers were considered to
be exposed to lead.
Glass workers were considered
exposed.
Glassblowers also singled out
as workers with higher
exposure potential.
Job history applied to job
matrix to categorize
occupations as low, moderate,
or high lead exposure.
SMRs vs. regional rates (95% CI); no. of deaths
Lung 0.82 (95% CI 0.56-1.16); 31
Stomach 0.97 (0.53-1.62); 14
All cancers 0.93 (0.78-1.10); 132
Kidney 1.75 (0.48-4.49); 4
Bladder 1.45 (0.75-2.53); 12
Brain 2.17 (0.57-5.57); 4
Kidney cancer showed a significant trend toward increasing risk with
increasing duration of exposure
No significant trends were noted for lung or other cancers
Brain cancer excess was limited to workers employed for 10 years or
less.
No control for smoking or exposure to arsenic or other smelter-
related exposures. No data on intensity of exposure.
Strong association of smelter work with pneumoconiosis and other
respiratory disease (SMR = 4.47, 95% CI = 3.37 to 5.80); since this
outcome includes silicosis, which is thought to predispose individuals
to lung cancer, some lung cancer deaths may have been missed due to
misclassification of cause of death based on death certificates.
OR (90% CI); no. of deaths
All glass workers:
Lung 1.7 (1.1-2.5); 86
Stomach 1.5 (1.1-2.0); 206
Colon 1.6 (1.0-2.5); 79
Glassblowers:
Lung 2.3
Stomach 2.6
Colon 3.1
Glassblowers singled out from glass workers as a whole thus showed
higher estimated risk. ORs for high or moderate vs. low exposure
showed no consistent increase for lung or stomach cancer, however,
although they did show mild upward trend for colon cancer. No
control for smoking or other occupational exposures.
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o
O
to
O
O
Table AX6-7.4 (cont'd). Other Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings and Interpretation
X
to
O
H
6
o
o
H
O
O
V
O
Europe (cont'd)
Wingren and
Englander(1990)
Sweden
1964-1985
(same population as in
case-control analyses
of Wingren and
Axelson 1985,1987,
1993)
Dingwall-Fordyce
and Lane (1963)
U.K.
1925-1962
Malcolm and Barnett
(1982) (follow-up of
Dingwall-Fordyce and
Lane, 1963)
U.K.
1925-1976
Cohort design.
625 Swedish glass workers employed for
at least 1 month between 1964 and 1985.
Mortality was compared with national
rates.
Cohort design.
425 male employees drawing pensions
from U.K. battery plants.
Standardized mortality for employees vs.
national population counterparts.
Cohort design.
1,898 lead-acid battery workers.
Mortality was traced for the lead-acid
battery workers to determine cause of
death. The proportion of deaths due to
cancer (all types and major
subcategories) among the worker
population was compared to that seen in
corresponding members of the general
population, yielding a PMR.
Workers from areas with
airborne lead levels up to 0.110
mg Pb/m3 were classified as
exposed.
Battery plant workers were
assumed to be exposed, and
their mortality compared to that
of like age and gender in the
U.K. population as a whole.
Urinary lead excretion was also
used to categorize workers by
estimated exposure (none, light,
or heavy): 80 lightly and 187
heavily (at least 100 ng/L)
exposed.
Job histories were reviewed to
classify workers' lead exposure
as high, medium, or none.
SMR (95% CI)
Pharyngeal:
9.9 (1.2-36.1) (significant)
Lung:
1.4 (0.5-3.1) (nonsignificant)
Colon', (nonsignificant)
SMR (95% CI); no. observed deaths
All cancer:
1.2 (0.8-1.7); 267
No consistent increase in SMRs across categories of increasing lead
exposure.
Limitations: No cancer site-specific analyses. No control for
potential confounders including smoking and exposure to arsenic or
other metals.
Proportionate mortality ratio (PMR)
All cancers:
1.15 (136 deaths),^ > 0.05
By exposure:
None
Medium
High
1.02
1.06
1.30
No significant excesses for individual cancer sites except for
digestive cancer PMR of 1.67, p < 0.01, among nonexposed workers.
The difference in exposure for the high and medium exposure groups
narrowed greatly over the follow-up, thus complicating interpretation
of dose-response patterns. No control for smoking or occupational
exposure to other carcinogens.
-------
o
O
to
O
O
Table AX6-7.4 (cont'd). Other Studies of Lead Exposure and Cancer
Reference, Study
Location, and Period
Study Description
Lead Measurement Findings and Interpretation
X
Oi
to
O
Oi
Europe (cont'd)
Ades and Kazantzis
(1988)
U.K.
1943-1982
Cohort design.
4,393 male zinc, lead, and cadmium
smelter workers.
(Workers bom after 1939 or who had
worked less than one year at the facility
were excluded.)
Workers followed up for mortality.
Nested case-control analysis also
conducted to quantitatively assessed
cadmium and, secondarily, arsenic, lead,
and other metal exposures among 174
cases.
Job histories were used to
quantify cadmium exposure and
assign ordinal ranks for
exposure to lead and other
metals.
Standardized lung cancer
mortality ratio computed for
workers vs. national rates.
SMR (95% CI); no. of deaths
Cohort:
Lung 1.25 (1.07-1.44) (174)
Increased significantly with duration of employment.
Nested case-control analyses did not implicate any department or
process, nor did cadmium, zinc, sulfur dioxide, or dust exposure
account for the observed increase.
Cumulative exposure to lead and to arsenic both showed positive
associations with lung cancer, but the relative importance of these
two exposures could not be determined.
Cadmium exposure did not account for the elevated SMR, but
analyses could not control for exposure, and were not adjusted for
smoking.
H
6
o
o
H
O
O
V
O
Asia
Huetal. (1998)
China
1989-1996
Huetal. (1999)
China
1989-1996
Case-control design.
Cases: 218 patients with histologically-
confirmed primary gliomas occurring
during 1989-1996 at 6 Chinese hospitals.
Controls: 436 patients with non-
neurological, nonmalignant disease,
matched by age, gender, and residence
from the same hospitals (excluding one
cancer-only center).
Case-control design.
Cases: 383 patients with histologically
confirmed primary meningiomas
occurring during 1989-1996 at 6 Chinese
hospitals.
Controls: 366 patients with non-
neurological, nonmalignant disease
matched by age, gender, and residence
from the same hospitals (excluding one
cancer-only center).
Patients were interviewed, and
those with factory or farm
occupations were further
interviewed to identify
exposure to lead (or other
potentially toxic substances).
Occupational exposure to lead
Not reported for any glioma patients, but was reported for 4 controls.
No control for exposure to other occupational or environmental
agents.
Patients were interviewed, and OR (95% CI); no. of cases
those with factory or farm
occupations were further
interviewed to identify
exposure to lead (or other
potentially toxic substances).
Occupational exposure to lead:
M 7.20 (1.00-51.72); 6
F 5.69 (1.39-23.39); 10
Results were adjusted for income, education, and fruit and vegetable
intake, plus cigarette pack-years for the women. No control for
exposure to additional metals or other occupational exposures.
-------
% Table AX6-7.4 (cont'd). Other Studies of Lead Exposure and Cancer
o
CD
3 Reference, Study
0, Location, and Period Study Description Lead Measurement Findings and Interpretation
"I
Q Asia (cont'd)
o
'~f> Shuklaet al. (1998) Case-control design. Heavy metal content was Bile lead content: mean (SE) (mg/L):
India Cases: 38 patients with newly measured in bile drawn from Gall bladder cancer: 58.38(1.76)
1995-1996 diagnosed, histologically confirmed gall the gall bladder at time of Gallstones: 3.99(0.43)
bladder cancer cases assembled from a surgery.
surgical unit. Cadmium and chromium levels also were elevated in cancer patients,
Controls: 58 patients with gall stones but less than lead. No control for smoking or any other risk factors.
diagnosed at the same surgical unit,
matched on geographic area.
Mean bile lead content was compared
r* between cases and controls.
H
6
o
o
H
O
o
V
o
-------
CHAPTER 6 ANNEX
ANNEX TABLES AX6-8
December 2005 AX6-208 DRAFT-DO NOT QUOTE OR CITE
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o
O
to
O
O
Table AX6-8.1. Effects of Lead on Immune Function in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
O
VO
United States
Sarasua et al. (2000)
ATSDR Multi-site
Study: Granite City,
IL, Galena, KA; Joplin,
MO; Palmerton, PA
1991
Rabinbowtiz et al.
(1990)
Boston, MA
1979-1987
Design: cross-sectional
Subjects: children and adults (n = 2036)
Outcome measures: total lymphocyte count,
lymphocyte phenotype abundance, serum
IgA, IgG, and IgM.
Analysis: multivariate linear regression
Design: cross-sectional
Subjects: infants/children (n= 1768)
Outcome measures: incidence of illness in
children was solicited from parents by
questionnaire
Analysis: relative risk of illness estimated
from incidence ratios, highest: combined
lower blood lead deciles, without adjustment
for covariates or confounders.
Blood lead (ug/dL) mean
(SD, 5^-95^ %tile):
6-35 mo: 7.0(16,1.1-
16.1)
36-71 mo: 6.0(4.3,1.6-
14.1)
6-15 yr: 4.0(2.8,1.1-9.2)
16-75 yr: 4.3(2.9,1.0-
9.9)
Cord blood lead (ug/dL)
~90fh%ti\e: 10
Shed tooth lead (ug/g)
-gO^/otile: 5
Significant association (p < 0.05) between increasing blood lead and
increasing serum IgA, IgG, IgM, and B-cell abundance (%, no.), and
decreasing T-cell abundance (%) in 6-35 mo age category; adjusted
for age, sex, and study site. Comparison of outcome means across
blood lead quartiles (1st quartile as reference, [+], higher, [-] lower):
[+] lymphocyte count (4* quartile, p = 0.02), T-cell count (4th
quartile, p = 0.09), B-cell count (4th quartile, p < 0.01), B-cell % (4th
quartile, p = 0.09).
Relative risk (unadjusted) was elevated for the following illness
categories: severe incidence of ear infection, 1.2 (95% CI: 1.0-1.4),
other respiratory illness, 1.5 (96% CI: 1.0-2.3), school absence for
illness other than cold or flu, 1.3 (95% CI: 1.0-1.5)
H
6
o
2
o
H
O
Lutzetal. (1999)
Springfield-Green Co,
MO
NR
Design: cross-sectional
Subjects: children (n = 279; age range: 9
mo-6 yr)
Outcome measures: differential blood cell
counts; lymphocyte phenotype abundance
(%); and serum IL-4, soluble CD25, CD27,
IgE and IgG (Rubella).
Analysis: nonparametric comparison of
outcome measures (adjusted for age) for
blood lead categories, correlation
Blood lead (ug/dL) range:
Blood lead categories: <10
ug/dL, 10-14 ug/dL,
15-1 9 ug/dL, 20^15 ug/dL
Significant association (p <0.05) between increasing blood lead
(categorical) and increasing serum IgE levels, after adjusting for age.
o
HH
H
W
-------
o
O
to
O
O
Table AX6-8.1 (cont'd). Effects of Lead on Immune Function in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
I
to
o
H
6
o
2
o
H
O
Europe
Annesi-Maesano et al.
(2003)
France
1985,1992
Karmaus et al. (2005)
Germany
1994-1997
Reigart and Graber
(1976)
NR
NR
Design: cross-sectional
Subjects: mother/newborn pairs (n = 374),
mean age 30 yr
Outcome measures: maternal venous and
newborn cord serum IgE levels
Analysis: multivariate linear regression,
ANOVA
Design: cross-sectional
Subjects: children (n = 331, 57% male), age
7-8 yrs (96%), 9-10 yrs (4%)
Outcome measures: differential blood cell
count; lymphocyte phenotype abundance;
and serum IgA, IgE, IgG, IgM
Analysis: multivariate linear regression
Design: clinical
Subjects: children (n = 19), ages 4-6 years
Outcome measures: serum IgA, IgG, IgM,
total complement and C-3, before and after
immunization with tetanus toxoid
Analysis: none; presentation of prevalence
of clinically low, normal, and high values of
outcome measures
Blood lead (ug/dL) mean
(SD)
infant cord: 67.3(47.8)
maternal: 96.4(57.7)
Hair lead (ppm) mean
(SD):
infant: 1.38(1.26)
maternal: 5.16(6.08)
Blood lead (ug/dL) mean
(95% CI):
males: 2.5(1.1^.4)
females (2.8 (1.5^1.8)
Blood lead quartile ranges:
<2.2 (n = 82)
2.2-2.8 (n= 81)
2.8-3.4 (n= 86)
>3.4(n=82)
Blood lead (ug/dL) mean
(range):
high: >40(n= 12): 45.3
(41-51)
low: <30(n=7): 22.6
(14-30)
Significant (p < 0.0001) association between increasing infant hair
lead and infant cord serum IgE levels.
Although medical histories were taken to identify potential IgE risk
factors (asthma, allergies) and "confounders" (e.g., smoking), these
do not appear to have been quantitatively integrated into the
regression models. Allergy status and blood levels were reportedly
unrelated to load biomarkers or serum IgE (basis for conclusion not
reported).
Significant association between blood lead (p < 0.05) and serum IgE
(not monotonic with quartile range). Comparison of adjusted mean
outcomes (p<0.05) across blood lead quartiles (1st quartile as
reference, [+], higher, [-] lower): [-] CD3+ T-cells (2nd quartile), [-]
C3+CD8+ T-cells (2nd quartile), [+] C3+CD5+CD19+B-cells (2nd
quartile).
Covariates retained: age, sex, environmental exposure to tobacco
smoke, infections (in last 12 mo), serum cholesterol, and
triglycerides.
No apparent difference in prevalence of abnormal values for serum
immunoglobulin or complement (no statistical analysis applied).
o
HH
H
W
-------
o
O
to
O
O
Table AX6-8.1 (cont'd). Effects of Lead on Immune Function in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
Europe (cont'd)
Wager-nova etal. (1986)
Czech
NR
Design: longitudinal cohort (repeated
measures for 2-years)
Subjects: children (n = 92, 38 females) ages
11-13 yrs residing near a smelter; reference
group (n = 67, 36 females), ages 11-13 years
Outcome measures: serum IgA, IgE, IgG,
IgM
Analysis: comparison of outcome measures
and between exposed and reference groups,
stratified sex and season of sampling
Blood lead (jig/dL) mean:
lead: -23^2
reference: —5-22
Significant (p NR, statistic NR) lower serum IgE and IgM levels in
exposed group compared to reference group.
Latin America
H
6
o
2
o
H
O
Pineda-Zavaleta et al.
(2004)
Mexico
NR
Design: cross-sectional
Subjects: children (n = 30 female, 35 male)
ages 6-11 years, residing near smelter
Outcome measures: mitogen- (PHA) and
cytokine- (IFN-y) induced nitric oxide and
superoxide production in lymphocytes
Analysis: multivariate linear regression
Blood lead (|ig/dL) mean
(range) for 3 schools:
l(n = 21): 7.0(3.5-25.3)
2(n = 21): 20.6
(10.8^9.2)
3(n = 23): 30.4
(10.3^7.5)
Significant (p = 0.036) association between increasing blood lead
concentration and covariate adjusted decreasing nitric oxide
production in PHA-activated lymphocytes (P = -0.00089, 95% CI:
-0.0017 to-0.00005).
Significant (p = 0.034) association between increasing blood lead
concentration and covariate adjusted increasing super oxide
production in IFN-y-activated lymphocytes (P = -0.00389, 95% CI:
0.00031 to 0.00748). Covariates considered included age, sex,
allergies, and blood arsenic (age, sex, and blood arsenic were
retained).
Significant effect of sex on associations, significant blood lead-
arsenic interaction.
Covariates considered included age, sex, allergies, urinary arsenic
(age, sex, and urinary arsenic were retained).
o
HH
H
W
-------
o
O
to
O
O
Table AX6-8.1 (cont'd). Effects of Lead on Immune Function in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
to
Asia
Sunetal. (2003); Zhao
et al. (2004)
China
NR
Design: cross-sectional
Subjects: children (n = 73) age 3-6 yrs
Outcome measures: serum IgE, IgG, IgM;
lymphocyte phenotype abundance
Analysis: Nonparametric comparisons of
outcome measures stratified by blood lead
Blood lead (ng/dL) mean
(SD, range) (n = 217):
9.5(5.6,2.6^3.7)
Females: significantly higher (p < 0.05) IgE levels in high blood
lead category (> 10 ng/dL, n = 16) compared to low category (<10
Hg/dL, n = 17), and significantly lower IgG and IgM levels. A
multivariate analysis of association between blood lead and IgE was
noted but not described in sufficient detail to evaluate.
All children: significantly lower (p < 0.05) CD3+CD4+ (%),
CD3+CD8+ (%), CD4+CD8+ (%) in high blood lead (> 10 ng/dL,
n = 38) compared to low blood lead (10 |ig/dL, n = 35) group.
ANOVA, analysis of variance; CI, confidence interval; Ig, immunoglobulin; IFn-y interferon- y; IgG, immunoglobulin G; IgM, immunoglobulin M; IL-4, interleukin-4; NR, not
reported; PHA, phytohemagglutinin; SD, standard deviation
H
6
o
2
o
H
O
o
HH
H
W
-------
o
O
to
O
O
Table AX6-8.2. Effects of Lead on Immune Function in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
I
to
OJ
United States
Pinkertonetal. (1998)
U.S.
NR
Design: cross-sectional cohort
Subjects: adult male smelter workers
(n = 145, mean age 32.9±8.6); reference
group, male hardware workers (n = 84, mean
age30.1±9.3)
Outcome measures: differential blood cell
counts; lymphocyte phenotype abundance;
serum IgA, IgG, IgM; salivary IgA;
lymphocyte proliferation (tetanus toxoid)
Analysis: multivariate logistic regression
with comparison of adjusted outcome
measures between exposed and nonexposed
groups
Blood lead (ug/dL) median
(range)
lead: 39(15-55)
reference: <2 (<2-12)
Covariate-adjusted outcomes in lead workers that were significantly
(p < 0.05) different from nonexposed ([+], higher, [-] lower): [-] %
monocytes, [-] % CD4+CD8+ cells, [-] % CD8+CD56+cells.
Significant (p < 0.05) adjusted regression coefficients in exposed
group for independent variable:
blood lead: [+] CD19+ B-cells (%, no)
time-integrated blood lead: [-] serum IgG, [+] CD4+CD45RA+ cells
(%, no.)
Covariates considered in the analysis included age, race, smoking
habits, alcohol consumption, marijuana use, work shift, and various
factors that might stimulate or suppress the immune system (e.g.,
exposure to direct sunlight, sleep hours, allergy, flu or cold
symptoms). Covariates retained in the final model were age, age,
race, work shift, smoking habits.
H
6
o
2
o
H
O
Sarasua et al. (2000)
ATSDR Multi-site
Study: Granite City,
IL, Galena, KA; Joplin,
MO; Palmerton, PA
1991
Design: cross-sectional cohort
Subjects: children and adults (n = 2036)
Outcome measures: total lymphocyte count,
lymphocyte phenotype abundance, serum
IgA, IgG, and IgM
Analysis: multivariate linear regression
Blood lead (ug/dL) mean
(SD, 5^-95^ %tile):
6-35 mo: 7.0(16,1.1-
16.1)
36-71mo: 6.0(4.3,1.6-
14.1)
6-15 yr: 4.0(2.8,1.1-9.2)
16-75 yr: 4.3(2.9,1.0-
9.9)
No significant association (<0.05) between blood lead and outcomes
in adults (age > 16 yr).
Covariates retained: age, sex, cigarette smoking, and study site.
o
HH
H
W
-------
o
O
to
O
O
Table AX6-8.2 (cont'd). Effects of Lead on Immune Function in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
I
to
£
United States (cont'd)
Fischbein et al. (1993)
New York
NR
Design: cross-sectional cohort
Subjects: adult firearms instructors (n = 51),
mean age 48 yr; age-matched reference
subjects (n = 36).
Outcome measures: lymphocyte phenotype
abundance, lymphocyte proliferation (PHA,
PMW, Staph. aureus)
Analysis: comparison of outcome measures
between reference and blood lead categories;
multivariate linear regression
Blood lead (ng/dL) mean
(SD)
lead high (>25): 31.4(4.3)
lead low (<25): 14.6(4.6)
reference: <10
Outcomes in lead workers that were significantly (p < 0.05) different
from reference group ([+], higher, [-] lower):
[-] CD+3 cells (%, no.), [-] CD4+ cells (%, no.), [-] CD4+CD8+ cells
(no.), [-] HLA-DR cells (no.), [+] CD20+ cells (%, no.), [-] mitogen
(PHA)-induced lymphocyte proliferation, [-] mitogen (PWM)-
induced lymphocyte proliferation; [-] lymphocyte response in
mixed-lymphocyte culture. No effect on antigen (Staph. aureus)-
induced lymphocyte proliferation.
Significant (p < 0.05) association between increasing blood lead and
decreasing abundance of CD4+ phenotypes (%), and decreasing
lymphocyte proliferative response in mixed lymphocyte cultures.
Covariates retained: age, sex, smoking habits, and duration of
exposure.
H
6
o
2
o
H
O
Europe
Bergeret et al. (1990)
France
NR
Design: cross-sectional cohort
Subjects: adult battery smelting workers
(n = 34), mean age 40 yr; reference subjects
(n = 34), matched for age, sex, ethnic origin,
smoking and alcohol consumption habits,
intake of antibiotics, andNSAIDs
Outcome measures: PMN chemotaxis
(FMLP); PMN phagocytosis (opsonized
zymosan)
Analysis: comparison of outcome measures
between worker and reference groups
Blood lead (|ig/dL) mean
(SD):
lead: 70.6(18.)
reference: 9.0(4.3)
Significantly (p < 0.05) lower PMN chemotactic response (index)
and phagocytic response in lead workers.
o
HH
H
W
-------
o
O
to
O
O
Table AX6-8.2 (cont'd). Effects of Lead on Immune Function in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
I
to
l^ft
H
6
O
2
O
H
O
O
HH
H
W
Europe (cont'd)
Ewers etal. (1982)
Germany
NR
Cosciaetal. (1987)
Italy
NR
Governaetal. (1987)
Italy
NR
Design: cross-sectional cohort
Subjects: adult male battery manufacture or
smelter workers (n = 72), mean age 36.4 yr
(16-58); reference workers (n = 53), mean
age 34.8 yr (21-54)
Outcome measures: serum IgA, IgG, IgM,
C3; saliva IgA
Analysis: parametric and nonparametric
comparison of outcome measures between
lead workers and reference subjects; linear
regression
Design: cross-sectional cohort
Subjects: adult lead workers (n = 32, 2
female), mean age 42.8 yr (SD 11.5);
reference subjects (n = 25), mean age 38.6 yr
(SD 13.3)
Outcome measures: serum IgA, IgG, IgM,
C3-C4; lymphocyte phenotype abundance
Analysis: parametric comparison of
outcome measures between worker and
reference groups
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 9), mean age 38.4 yr (SD 13.7);
age-matched reference subjects (n = 18)
Outcome measures: PMN chemotaxis
(zymosan-activated serum)
Analysis: parametric comparison of
outcome measures between worker and
reference groups, correlation
Blood lead (|ig/dL) mean
(range):
lead: 55.4.0(18.6-85.2)
reference: 12.0 (6.6-20.8)
Significantly (p < 0.05) lower serum IgM, lower salivary IgA in lead
workers compared to reference group.
Blood lead (ng/dL) mean
(SD):
lead: 62.3(21.6)
reference: NR
Outcomes in lead workers that were significantly (p < 0.05) different
from reference group ([+], higher, [-] lower): [-] serum IgM, [+]
serum C4, [+] lymphocyte abundance (%), [-] T-cell abundance (%,
no., E-rosette forming cells), [+] B-cell abundance (%,no.,
immunoglobulin-bearing cells), [+] CD8+ cell abundance (no.).
Blood lead (|ig/dL) mean
(SD):
lead: 63.2(8.2)
reference: 19.2(6.4)
Significantly (p < 0.05) lower PMN chemotactic response to
zymosan activated serum. Effect magnitude was not correlated with
blood lead.
-------
o
O
to
O
O
Table AX6-8.2 (cont'd). Effects of Lead on Immune Function in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
to
Oi
H
6
o
2
o
H
O
Europe (cont'd)
Valentino etal. (1991)
Italy
NR
Kimberetal. (1986)
UK
NR
Design: cross-sectional cohort
Subjects: adult male lead scrap refining
workers (n = 10), mean age 41.1 yr (SD 7.3,
range: 28-54); age-matched reference
subjects (n= 10)
Outcome measures: PMN chemotaxis (C5 or
FMLP) and phagocytosis (FMLP)
Analysis: comparison of outcome measures
between worker and reference groups,
correlation
Design: cross-sectional cohort
Subjects: adult male TEL manufacture
workers (n = 39) mean age: 45.1 yr; and
age-matched reference subjects (n = 21);
mean age 32.2 yr
Outcome measures: serum IgA, IgG, IgM;
mitogen (PHA)-induced
lymphoblastogenesis; and NK cell
cytotoxicity
Analysis: comparison of outcome measures
for exposed and reference groups
Blood lead (ug/dL) mean
(SD, range):
lead: 33.2(5.6,25^12)
reference: 12.6 (2.5, 8.9-
18)
Significantly (p < 0.002) lower PMN chemotactic response to C5 or
FMLP and higher stimulated production of LT (leukotriene)B4 in
lead workers compared to reference group. Effect magnitude
correlated with blood lead. No effect on phagocytic activity.
Blood lead (ug/dL) mean
(SD, range):
lead: 38.4(5.6,25-53)
reference: 11.8(2.2,8-17)
No significant (p < 0.05) differences in outcomes between exposed
and reference groups.
o
HH
H
W
Latin America
Queiroz etal. (1993)
Brazil
NR
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 39), mean age 33.9 yr (SD 12.1,
range: 18-56); reference subjects (n = 39)
matched by age and race
Outcome measures: PMN chemotaxis
(endotoxin LPS); phagocytic (endotoxin
LPS) respiratory burst activity (NBT
reduction)
Analysis: nonparametric comparison of
outcome measures between worker and
reference groups
Blood lead (ug/dL) range:
lead: 14.8-91.4 (>30,
n=52)
reference: <10
Significantly (p < 0.001) lower chemotactic activity of PMNs, and
lower phagocytic respiratory burst, in lead workers relative to
reference group.
-------
o
O
to
O
O
Table AX6-8.2 (cont'd). Effects of Lead on Immune Function in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
H
6
O
2
O
H
O
Latin America (cont'd)
Queirozetal. (1994a)
Brazil
NR
Queirozetal. (1994b)
Brazil
NR
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 60), mean age 33.9 yr (range:
18-56); reference subjects (n = 49) matched
by age and race
Outcome measures: PMN phagocytic/lytic
activity (opsonized yeast)
Analysis: nonparametric comparison of
outcome measures between worker and
reference groups
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 33), mean age 32.4 yr (range:
18-56); reference subjects (n = 20) matched
by age and race
Outcome measures: serum IgA, IgG, IgM;
mitogen (PHA)-induced lymphocyte
proliferation
Analysis: parametric comparison of
outcome measures between worker and
reference groups
Blood lead (ug/dL) range:
lead: 14.8-91.4 (>30,
n = 27)
reference: <10
Significantly (p < 0.001) lower lytic activity of PMNs in lead
workers relative to reference group.
Blood lead (ug/dL) range:
lead: 12.0-80.0 (>30,
n = 27)
reference: <10
No significant difference in outcomes (p < NR; SD of lead worker
and reference groups overlap) between lead workers and reference
group.
O
HH
H
W
Asia
Kuoetal. (2001)
China
NR
Design: cross-sectional cohort
Subjects: adult battery manufacture workers
(n = 64, 21 female), ages: <40 yr 14, >50yr,
14); nonexposed reference subjects (n = 34,
17 female).
Outcome measures: differential blood cell
counts, lymphocyte phenotype abundance
Analysis: comparison of outcome measures
in exposed and reference groups,
multivariate linear regression
Blood lead (ug/dL) mean:
lead workers: 30
Significantly (p < 0.05) adjusted mean higher monocytes (%, no.),
lower B cells (%), lower lymphocytes (no.), and lower granulocytes
(no.) in lead workers compared to controls.
Covariates retained: age, gender, and disease status (definition not
reported).
-------
o
O
to
O
O
Table AX6-8.2 (cont'd). Effects of Lead on Immune Function in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
oo
H
6
O
2
O
H
O
O
HH
H
W
Asia (cont'd)
Mishra et al. (2003)
India
NR
Alomran and
Shleamoon(1988)
Iraq
NR
Cohen etal. (1989)
Israel
NR
Design: cross-sectional cohort
Subjects: adult males occupationally
exposed to lead (n = 84), mean age 30 yr;
reference subjects (n = 30), mean age 29 yr
Outcome measures: serum IFN-y level,
mitogen (PHA)-induced lymphocyte
proliferation, NK cell cytotoxicity
Analysis: comparison of outcome measures
between lead-exposed and reference groups,
correlation
Design: cross-sectional cohort
Subjects: adult lead (oxide) workers
(n = 39), mean age 35.6 yr (9,2, SD); age-
matched reference subjects (n = 19)
Outcome measures: serum IgA, IgG;
mitogen (PHA, Con-A)-induced lymphocyte
proliferation
Analysis: comparison of outcome measures
between lead workers and reference group
Design: cross-sectional cohort
Subjects: adult male occupationally lead
exposed (n = 10), age range 22-70; age-
matched reference subjects (n = 10)
Outcome measures: mitogen (Con A, PHA)-
induced-lymphocyte proliferation and T-
suppressor cell proliferation; lymphocyte
phenotype abundance
Analysis: parametric comparison of
outcome means between lead-exposed and
reference groups
Blood lead (ng/dL) mean
(SD, range):
3-wheel drivers (n = 30):
6.5(4.7,0.0-17.5)
battery workers (n = 34):
128.1 (13.2^100.8)
jewelry makers: 17.8
(18.5,3.1-76.8)
reference: 4.5 (NR, 1.6-
9.8)
Blood lead (jig/dL) mean:
lead: 54-64
reference: NR
Blood lead (ng/dL) range:
exposed: 40-51
reference: <19
Significantly (p < 0.001) lower lymphocyte proliferative response to
PHA in lead-exposed groups compared to reference groups, higher
IFN-y production by blood monocytes.
Significantly (p < 0.05) lower lymphocyte proliferative response to
PHA or Con A in lead workers, compared to reference group.
Significantly (p < 0.02) higher mitogen (Con-A)-induced suppressor
cell activity. No significant (p not reported) effects on abundance of
T-cells (E-rosette-forming cells), OKT+4, OKT+8, or OKT4+/T8+
ratio; mitogen (Con A or PHA)-induced lymphocyte proliferation.
-------
o
O
to
O
O
Table AX6-8.2 (cont'd). Effects of Lead on Immune Function in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
VO
H
6
O
2
O
H
O
Asia (cont'd)
Sataetal. (1998)
Japan
NR
Sataetal. (1997)
Japan
NR
Heo et al. (2004)
Korea
NR
Design: cross-sectional cohort
Subjects: adult male lead stearate
manufacture workers (n = 71), mean age 48
yr (range: 24-74); reference subjects
(n = 28), mean age 55 yr (range: 33-67).
Outcome measures: lymphocyte phenotype
abundance
Analysis: comparison of outcome measures
in exposed and reference groups
(ANCOVA), multivariate linear regression
Design: clinical
Subjects: adult male lead smelter workers
(n = 2) who underwent CaEDTA therapy
Outcome measures: serum IgA, IgG, IgD,
IgM; lymphocyte phenotype abundance
Analysis: Parametric comparison of
outcome measures before and after
treatment, correlation of outcome means with
blood lead
Design: cross-sectional cohort
Subjects: adults, battery manufacture
workers (n = 606; 52 females); ages: <30 yr,
n=184;>40yr,n=123.
Outcome measures: serum IgE, IL-4, IFNy
Analysis: comparison of outcomes measures
(ANOVA), stratified by age and blood lead
Blood lead (ug/dL) mean
(range):
lead: 19(7-50)
reference: NR
Blood lead (ug/dL):
subject 1: 81 ug/dL at
referral; mean before
EDTA: 45.1(SD16.0);
after chelation: 31.0(9.8)
subject 2: 68 ug/dL at
referral; mean before
EDTA: 43.3 (SD 14.1);
after chelation: 33.7(7.2)
Blood lead (ug/dL) mean
(SD):
<30yr: 22.0(10.4)
30-39 yr: 23.0(11.3)
>40yr: 24.1(9.3)
Lead workers vs. reference: significantly (p < 0.05) covariate-
adjusted lower CD3+CD45RO+ (no.) and higher CD8+ cells (%).
Significant (p < 0.05) association between exposure (categorical:
yes/no) and lower CD3+CD45RO+cells (no.).
Covariates retained: age and cigarette smoking habits.
Blood lead and outcome measures were sampled prior to and 24
hours after 3 CaEDTA treatments (on consecutive days) per week
for 10 weeks. Comparison of mean outcome measures assessed
before and after treatments showed significantly (p < 0.05) higher
IgA, IgG, and IgM; and significantly higher CD8+ T-cells and
CD57+ NK cells after treatment in subject 1. Serum IgG levels in
subject 1 were significantly correlated (r-0.72) with blood lead
concentration.
Significantly higher (p < 0.05) serum IgE levels in blood lead
category (>30 ug/dL) compared to low categories (<10 or 10-29
ug/dL).
O
HH
H
W
-------
o
O
to
O
O
Table AX6-8.2 (cont'd). Effects of Lead on Immune Function in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
to
O
H
6
O
2
O
H
O
O
HH
H
W
Asia (cont'd)
Undeger etal. (1996);
Basaran and Undeger
(2000)
Turkey
NR
Yucesoy etal. (1997a)
Turkey
NR
Yucesoy etal. (1997b)
Turkey
NR
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 25), mean age, 33 yr (22-55);
reference subjects (n = 25) mean age 33 yr
(22-56).
Outcome measures: differential blood cell
counts; lymphocyte phenotype abundance;
serum IgA, IgG, IgM, C3, and C4; neutrophil
chemotaxis (zymosan-activated serum); latex
particle-induced neutrophil phagocytic (latex
particles) respiratory burst (NET reduction)
Analysis: nonparametric and parametric
comparisons of outcome measures for
exposed and reference groups
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 20), ages 39^8 yr; age-
matched reference subjects (n = 12)
Outcome measures: serum cytokines IL-1 p,
IL-2, TNFa, IFN-y
Analysis: parametric and nonparametric
comparison of outcome measures in exposed
and reference groups
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 50), ages 39^8 yr; age-
matched reference subjects (n = 10)
Outcome measures: lymphocyte phenotype
abundance, NK cell cytotoxicity
Analysis: comparison of outcome measures
in exposed and reference groups
Blood lead (ng/dL) mean
(SD):
lead: 74.8(17.8)
reference: 16.7(5.0)
Blood lead (|ig/dL) mean
(SE, range):
lead: 59.4(3.2,42-94)
reference: 4.8(1.0,2-15)
Blood lead (ng/dL) mean
(SE, range):
lead 1 (n = 20): 59.4 (3.2,
42-94)
lead 2 (n= 30): 58.4
(2.5,26-81)
reference: 4.0 (0.4, 2-6)
Workers relative to reference: significantly (p < 0.05) lower serum
IgG, IgM, C3, and C4 levels; lower CD4+ ("T-helper") abundance,
lower neutrophil chemotactic response; no significant difference in
CD20+ (B-cell), CD8+ ("T-suppressor") cell, CD56+ (NK) cell
abundance, or particle-induced NK cell respiratory burst.
Significantly (p < 0.05) lower serum IL-1 p and IFN-y levels in lead
workers compared to controls.
Significantly (p < 0.05) lower CD20+ B-cell (%) abundance in lead
workers compared to controls, no difference in % CD4+ T-cell
abundance.
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to
O
O
Table AX6-8.2 (cont'd). Effects of Lead on Immune Function in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
to
H
6
o
2
o
H
O
Africa
Anetor and Adeniyi
(1998)
Nigeria
NR
Design: cross-sectional cohort
Subjects: adult male "lead workers"
(n = 80), mean age, 36 yr (21-66) and
reference subjects (n = 50), mean age 37 yr
(22-58).
Outcome measures: serum IgA, IgG, and
IgM; lymphocyte count
Analysis: comparison of outcomes measures
in workers and reference group, linear
regression, principal component analysis
Blood lead (|ig/dL) mean
(SE):
lead: 53.6(0.95)
reference: 30.4(1.4)
Significantly lower (p < 0.05) serum IgA, IgG, and total blood
lymphocyte levels; significant associations and interactions between
blood lead and serum total globulins (note high blood lead levels in
reference).
ANOVA, analysis of variance; EDTA, ethylenediaminetetraacetic acid; FMLP, N-formyl-L-methionyl-L-leucyl-L-phenyl-alanine; IFn-y interferon-y; Ig, immunoglobulin A;
LPS, lipopolysaccharide; LT, leukotriene; NET, nitroblue tetrazolium; NK, natural killer; NR, not reported; NSAIDS, non-steroidal anti-inflammatory agents; PHA,
phytohemagglutinin; PMW pokeweed mitogen; SD, standard deviation; SE, standard error; TEL, tetraethyl lead
o
HH
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CHAPTER 6 ANNEX
ANNEX TABLES AX6-9
December 2005 AX6-222 DRAFT-DO NOT QUOTE OR CITE
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Table AX6-9.1. Effects of Lead on Biochemical Effects in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
United States
Piomellietal. (1982)
New York
1976
Design: cross-sectional
Subjects: children (n = 2002), ages 2-12 yr
Outcome measures: EP
Analysis: linear regression
Blood lead (ng/dL)
range: 2-98
Regression equation relating blood lead concentration to EP
(log-transformed):
a = 1.099, p = 0.016, r: 0.509, p < 0.001
Threshold for increase in EP estimated to be: 15.4 ng/dL (95%
CI: 12.9-18.2)
X
to
to
Soldin et al. (2003)
Washington DC
2001-2002
Design: cross-sectional
Subjects: children (n = 4908, 1812 females),
age range 0-17 yr
Outcome measures: EP
Analysis: locally weighted scatter plot
smoother (LOWESS)
Blood lead (ng/dL):
mean (range 1-17 yr):
2.2-3.3
median (1-17 yr): 3
range: < 1-103
EP increases as blood lead concentration increased above 15
mg/dL. A doubling of EP occurred with an increase in blood lead
concentration of approximately 20 ng/dL (a polynomial
expression for EP as a function of blood lead (PbB) is:
EP = -O.OOlS(PbB)3 + 0.1854(PbB)2 - 2.7554(PbB) + 30.911
(r2 = 0.9986)
(derived from data in Table 2 of Soldin et al. (2003)
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Europe
Roels and Lauwerys
(1987)
Belgium
1974-1980
Design: cross-sectional
Subjects: children (n = 143), age range 10-13
yr
Outcome measures: ALAD, urinary ALA, EP
Analysis: linear regression, correlation
Blood lead (ng/dL) range:
children: 15-41
Linear regression for EP (log-transformed) and blood lead
concentration:
a = 1.321, p = 0.025, r = 0.73 (n = 51)
Linear regression for ALA (log-transformed) and blood lead
concentration:
a = 0.94, p = 0.11, r= 0.54 (n = 37)
Linear regression for ALAD (log-transformed) and blood lead
concentration:
a = 1.864, p = -0.015, r = -0.87 (n = 143)
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December 2005
Table AX6-9.1 (cont'd). Effects of Lead on Biochemical Effects in Children
Reference, Study
Location, and Period Study Description Lead Measurement
Latin America
Findings, Interpretation
Perez-Brava et al. Design: cross-sectional;
(2004) Subjects: children (n = 93, 43 males), age
Chile range: 5-12 yrs who attended school near a
NR powdered lead storage facility
Outcome measures: blood Hb and Hct, ALAD
genotype
Analysis: comparison of outcome measures
between ALAD genotype strata
Blood lead (|ig/dL) mean
(SE):
ALADl(n = 84): 13.5
(8.7)
ALAD 2 (n = 9): 19.2(9.5)
Mean blood lead, blood Hct, and Hct not different between ALAD
genotypes (p = 0.13)
X
to
to
ALA, 5-aminolevulinic acid; ALAD, 5-aminolevulinic acid dehydratase; EP, erythrocyte protoporphyrin
H
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H
O
o
H
W
O
O
HH
H
W
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O
O
Table AX6-9.2. Effects of Lead on Biochemical Effects in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Europe
Geimartetal. (1992)
Belgium
NR
Mohammed-Brahim
etal. (1985)
Belgium
NR
Roels and Lauwerys
(1987)
Belgium
1974-1980
Design: cross-sectional cohort
Subjects: adult battery manufacture workers
(n = 98), mean age, 37.7 yr (range 22-55);
reference group (n = 85), mean age 38.8 yr
(24-55)
Outcome measures: blood Hct, blood EP,
urine ALA
Analysis: linear regression
Design: cross-sectional cohort
Subjects: adult smelter and ceramics
manufacture workers (n = 38, 13 females);
reference subjects (n = 100) matched with
worker group by age, sex, and socioeconomic
status.
Outcome measures: blood P5N, EP, ALAD,
R/ALAD (ratio of ALAD before and after
reactivation).
Analysis: comparison of outcome measures
(ANOVA) between lead workers and reference
group; correlation
Design: cross-sectional
Subjects: adults (n = 75, 36 females)
Outcome measures: ALAD, urinary ALA, EP
Analysis: linear regression, correlation
Blood lead (ug/dL) mean
(SD, range):
lead: 51.0(8.0,40-70)
reference: 20.9
(11.1,4.4-30.0
Blood lead (ug/dL) mean
(SD, range):
lead: 48.5(9.1,27.8-66.6)
reference: 14.3 (6.7, 5.6-
33.6)
Urine lead (ug/g creatinine)
mean (SD, range):
lead: 84.0(95.9,21.8-587)
reference: 10.5(8.2,1.7-
36.9)
Blood lead (ug/dL) range:
adult males: 10-60
adult females: 7-53
Significant association between increasing blood lead
concentration and increasing (log) blood EP (a = 0.06, p = 0.019,
r = 0.87, p = 0.0001) or (log) urine ALA (a = 0.37, (3 = 0.008,
r = 0.64, p< 0.0001)
(No apparent analysis of covariables)
Significantly lower (p = NR) P5N in lead workers (males or
females, or combined) compared to corresponding reference
groups.
Correlations with blood lead:
log P5N r = -0.79 (p < 0.001)
log ALAD r = -0.97 (p = NR)
R/ALAD r = -0.94 (p < 0.001)
logEPr=0.86(p = NR)
Correlations with urine lead:
log P5Nr=-0.74 (p = NR)
log ALAD r = -0.79 (p = NR)
R/ALAD r = -0.84 (p < 0.001)
logEPr=0.80(p = NR)
Linear regression for EP (log-transformed) and blood lead
concentration:
adult male (n = 39): a= 1.41, p = 0.014, r = 0.74, p< 0.001
adult female (n = 36): a = 1.23, p = 0.027, r = 0.81, p < 0.001
Linear regression for ALA (log-transformed) and blood lead
concentration:
adult male (n = 39): a = 0.37, p = 0.006, r = 0.41, p < 0.01
adult female (n = 36): a = 0.15, p = 0.015, r = 0.72, p < 0.001
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Table 6-9.2 (cont'd). Effects of Lead on Biochemical Effects in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
to
to
Oi
H
6
o
O
H
O
o
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W
O
O
HH
H
W
Europe (cont'd)
Grandjean(1979)
Denmark
NR
Alessioetal. (1976)
Italy
NR
Coccoetal. (1995)
Italy
1990
Design: longitudinal
Subjects: male battery manufacture workers
(n = 19), mean age 32 yr (range 22-A9)
Outcome measures: EP
Analysis: EP and blood lead for serial
measurements displayed graphically
Design: cross-sectional
Subjects: adult male lead worker (n = 316),
age range NR
Outcome measures: blood ALAD, EP, urine
ALA, CP
Analysis: linear regression, correlation
Design: longitudinal
Subjects: adult male foundry workers
(n = 40), mean age 25.1 yr (SD 2.1, range 21-
28)
Outcome measures: serum total-, HDL- and
LDL-cholesterol, blood Hb, urine ALA,
erythrocyte G6PD
Analysis: comparison of outcomes between
pre-exposure (at start of employment, sample
1) and after 172 (range 138-217, sample 2)
days
Blood lead (ug/dL) median
(range):
Groupl(n=5): 47.7
(22.8-53.9)
group 2 (n = 5): 37.3
(35.2-53.9)
Blood lead (ug/dL) range:
10-150
Blood lead (ug/dL) mean
(range):
sample 1: 10.0(7-15)
sample 2: 32.7(20-51)
Five subjects (group 1) showed declines in EP with declining
blood lead (33-58 ug/dL) over a 10-month period; 5 subjects
(group 2) showed no change in EP with a change in blood lead
concentration (25-54 ug/dL) over the same period.
Regression relating outcomes to blood lead concentration:
ALAD (In-transformed) (n = 169): «3.73, (3 = -0.031, r = 0.871
ALAU (In-transformed) (n = 316): a = 1.25, (3 = 0.014, r = 0.622
UCP (In-transformed) (n = 252): a = 2.18, (3 = 0.34, r = 0.670
EP (log-transformed (males, n = 95): a = 0.94, p = 0.0117
EP (log-transformed (females, n = 93): a = 1.60, p = 0.0143
G6PD levels were unrelated to starting blood lead; however, they
increased in subjects whose blood lead concentration increased
from <30 ug/dL to >30 ug/dL or decreased from >30 ug/dL to <30
ug/dL. Increasing exposure duration was significantly associated
with decreasing magnitude of change in G6PD (sample 1 <30
ug/dL: p = -0.3980, SE 0.1761, p < 0.05; sample 1 >30 ug/dL:
P = -1.3148, SE 0.3472, p < 0.05) and, in the >30 ug/dL subgroup,
increasing blood lead was associated with decreasing magnitude of
change of G6PD (P = -2.0797, SE 0.7173, p < 0.05).
Serum cholesterol levels were unrelated to blood lead
concentration.
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Table 6-9.2 (cont'd). Effects of Lead on Biochemical Effects in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
to
Europe (cont'd)
Francaso et al. (2002)
Italy
NR
Hemberg et al. (1970)
Poland
NR
Design: cross-sectional cohort
Subjects: adult battery manufacture workers
(n = 37, 6 females), mean age 41 yr (SD 7);
reference office workers (n = 29, 8 females),
meanage38yr(SD21)
Outcome measures: lymphocyte DNA strand
breaks, ROS, GSH
Analysis: comparison of outcome measures
between lead workers and reference group
(ANOVA), logistic regression
Design: cross-sectional
Subjects: adult lead workers (n = 166);
reference group (n = 16)
Outcome measures: blood ALAD
Analysis: regression, correlation
Blood lead (ug/dL) mean
(SD):
lead: 39.6(7.6)
4.4 (8.6)
Blood lead (ug/dL) range:
5-95
Covariate-adjusted DNA strand breaks were significantly higher in
lead workers compared to the reference group and significantly
associated with increased blood lead (p = 0.011).
Covariate-adjusted lymphocyte ROS was significantly higher and
GSH significantly lower in the lead workers compared to the
reference group. Lower GSH levels were significantly associated
with increasing blood lead concentration (p = 0.006).
Odds ratios (OR) for DNA strand breaks and lower GSH levels
were significant (lead workers vs. reference):
DNA strand breaks: OR = 1.069 (95% CI: 1.020-1.120,
p = 0.005)
GSH: OR = 0.634 (95% CI: 0.488-0.824, p = 0.001)
ROS: OR = 1.430 (95% CI: 0.787-2.596, p = 0.855)
Covariates retained: age, alcohol consumption and tobacco
smoking.
Linear regression for blood ALAD (log-transformed) and blood
lead concentration (n = 158):
a = 2.274, p = -0.018, r = -0.90, p < 0.001
H
6
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O
H
O
o
H
W
O
O
HH
H
W
Bergdahl et al. (1997)
Sweden
NR
Selander and Cramer
(1970)
Sweden
NR
Design: cross-sectional
Subjects: adult smelter worker (n = 89);
reference groups (n = 24)
Outcome measures: blood lead, erythrocyte
ALAD-bound lead, ALAD genotype
Analysis: comparison of outcome measures
Design: cross-sectional
Subjects: adult battery manufacture workers
(n=177)
Outcome measures: urine ALA
Analysis: regression, correlation
Blood lead (ug/dL):
range 0.8-93
Urine lead (mg/L):
range 1-112
Bone lead (ug/g)
range-19-101
Blood lead (ug/dL) range:
6-90
No association between ALAD genotype and lead measures.
Linear regression for urine ALA (log-transformed) and blood lead
concentration (n = 150):
a = -1.0985, p = 0.0157, r = 0.74
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to
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O
Table 6-9.2 (cont'd). Effects of Lead on Biochemical Effects in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Europe (cont'd)
Wildtetal. (1987)
Sweden
NR
Design: longitudinal
Subjects: adult battery manufacture workers
(n = 234, 37 females) mean age 35 y (range
17-70); reference group (n = 951, 471
females), mean age 39 yr (range 19-67)
Outcome measures: EP
Analysis: analysis of variability over time,
linear regression, correlation
Blood lead (ug/dL) mean
(range):
lead: 10-80
reference:
male: 11.3(8-27)
female: 8.5(5-21)
Linear regression for EP (log-transformed) and blood lead
concentration:
males (n= 851): a= 1.21, (3 = 0.0148, r = 0.72
females (n= 139): a= 1.48, (3 = 0.0113, r = 0.56
Asia
X
to
to
oo
Hsieh et al. (2000)
China
NR
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Jiun and Hsien( 1994)
China
1992
Froometal. (1999)
Israel
1980-1993
Design: cross-sectional
Subjects: Adults in general population
(n = 630, 255 females)
Outcome measures: blood Hb, Hct, RBC
count, ALAD genotype
Analysis: comparison of outcome measures
between ALAD genotype strata
Design: longitudinal
Subjects: adult male lead workers (n = 62),
ages NR; reference group (n = 62, 40 females),
agesNR
Outcome measures: plasma MDA
Analysis: comparison of outcome measures
between lead workers and reference group,
linear regression
Design: longitudinal survey
Subjects: adult male battery manufacturing
workers (n = 94), mean age, 38 yr (SD 9,
range 26-60)
Outcome measures: blood Hb, blood EP
Analysis: multivariate linear regression
Blood lead (ug/dL) mean
(SD):
ALAD l,l(n= 630):
6.5(5.0)
ALAD 1,1/2,2 (n = 30)
7.8 (6.0)
Blood lead (ug/dL) mean
(SD, range):
lead: 37.2
(12.5, 18.2-76.0)
reference: 13.4
(7.5,4.8^3.9)
Blood lead (ug/dL) range of
13-yr individual subject
means
20-61 ug/dL
Mean blood lead not different between ALAD genotype strata
(p = 0.17). RBC count, Hb, Hct not different between ALAD
genotype strata (p = 0.7)
Plasma MDA levels significantly (p < 0.0001) higher
(approximately 2x) in lead workers whose blood lead
concentration 35 ug/dL compared to <30 ug/dL. In subjects with
blood lead >35 ug/dL, blood lead and plasma MDA were
significantly correlated:
blood lead = 9.584(MDA)+24.412 (r = 0.85)
Weak (and probably not significant) covariate-adjusted association
between blood Hb and individual sample blood lead (P = -0.0039,
SE 0.0002), subject average blood lead (P = -0.0027, SE 0.0036),
or blood EP (P = -0.001, SE 0.0007)
Covariates retained in model were age and smoking habits.
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to
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O
Table 6-9.2 (cont'd). Effects of Lead on Biochemical Effects in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
to
to
VO
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Asia (cont'd)
Krisatal-Boneh et al.
(1999)
Israel
1994-1995
Solliway et al. (1996)
Israel
NR
Itoetal. (1985)
Japan
NR
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 56), mean age 43.1 yr (SD 10.6);
reference group (n = 87), mean age 43.2 yr
(SD 8.3)
Outcome measures: serum total-, HDL-, LDL-
cholesterol, HDL:total ratio, triglycerides
Analysis: comparison of outcome measures
between lead workers and reference group
(ANOVA), multivariate linear regression
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 34), mean age: 44 yr (SD 13);
reference subjects (n = 56), mean age 43 yr
(SD 12); cohorts constructed to have similar
age, ethnic characteristics, socioeconomic
status, education level, and occupation
Outcome measures: urinary ALA, erythrocyte
GSH-peroxidase
Analysis: parametric comparison of outcome
measures between lead and reference groups,
correlation
Design: cross-sectional cohort
Subjects: adult male steel (smelting, casting)
workers (n = 712), age range 18-59 yr;
reference (office workers) group (n = 155,
total), age range 40-59 yr
Outcome measures: serum LPO and SOD,
total and HDL-cholesterol, phospholipid
Analysis: comparison of outcome measures
between lead workers and reference group,
correlation
Blood lead (jig/dL) mean
(SD):
lead: 42.3(14.9)
reference: 2.7(3.6)
Blood lead (ng/dL) mean
(SD, range):
lead: 40.7(9.8,23-63)
reference: 6.7(2.4,1-13)
Blood lead (|ig/dL) range:
lead: 5-62
reference: NR
Covariate-adjusted serum total-cholesterol (p = 0.016) and HDL-
cholesterol (p = 0.001) levels were significantly higher in lead
workers compared to reference group. Covariates retained in
ANOVA: age, body mass index, season of sampling, nutritional
variables (dietary fat, cholesterol, calcium intakes), sport activities,
alcohol consumption, cigarette smoking, education, job seniority.
Increasing blood lead concentration was significantly associated
with covariate-adjusted total cholesterol (P = 0.130, SE 0.054,
p = 0.017) and HDL-cholesterol (P = 0.543, SE 0.173, p = 0.002).
Covariates retained: age, body mass index. Stepwise inclusion of
other potential confounders had no effect.
Significantly lower mean erythrocyte GSH-peroxidase activity
(p < 0.005) in and higher urinary ALA (p < 0.001) in lead workers
compared to reference group.
When stratified by age, significantly (p < 0.05) higher serum HDL-
cholesterol and LPO in lead workers, age range 40^9 yr,
compared to corresponding strata of reference group. Serum
lipoperoxide levels increased as blood lead increased above 30
Hg/dL (p = NR), SOD appeared to decrease with increasing blood
lead concentration (p = NR)
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to
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O
Table 6-9.2 (cont'd). Effects of Lead on Biochemical Effects in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
OJ
o
H
6
o
o
H
O
o
H
W
O
O
HH
H
W
Asia (cont'd)
Makinoetal. (1997)
Japan
1990-1994
Moritaetal. (1997)
Japan
NR
Oishietal. (1996)
Japan
NR
Design: longitudinal survey
Subjects: adult male pigment or vinyl chloride
stabilizer manufacture workers (n = 1573)
mean age 45 yr
Outcome measures: blood Hb, Hct, RBC
count
Analysis: parametric comparison of outcome
measures, stratified by blood lead, linear
regression
Design: cross-sectional cohort
Subjects: male lead workers (n = 76), mean
age 42 yr (range 21-62); reference subjects
(n = 13, 6 females), mean age, males 41 yr
(range 26-52), females 45 yr (range 16-61)
Outcome measures: blood NADS, ALAD
Analysis: comparison of outcome measures
(ANOVA) between blood lead categories,
linear regression
Design: cross-sectional
Subjects: adult glass and pigment manufacture
workers (n = 418, 165 females), mean age 33
yr (range 18-58); reference workers (n = 227,
89 females), mean age 30 yr (range 17-59)
Outcome measures: plasma ALA, urinary
ALA
Analysis: linear regression, correlation
Blood lead (ug/dL) mean
(SD, range):
12.6 (2.0, 1-39)
Urine lead (ug/L) mean
(SD, range):
10.2 (2.7, 1-239)
Blood lead (ug/dL) mean
(SD, range)
lead: 34.6(20.7,2.2-81.6)
Blood lead (ug/dL) mean
(SD, range):
lead: 48.5 (17.0,10.3-99.4
reference: 9.6 (3.3, 3.8-
20.4)
Significantly higher (p < 0.001) Hct, blood Hb and RBC count in
blood lead category 16-39 ug/dL, compared to 1-15 ug/dL
category.
Significant positive correlation between blood lead concentration
and Hct: a = 42.95, p = 0.0586 (r= 0.1553, p< 0.001), blood Hb:
a = 14.65, p = 0.0265 (r = 0.1835, p < 0.001) and RBC count a =
457, p = 0.7120 (r = 0.1408, p < 0.001).
Significantly lower (p < 0.01) blood NADS and ALAD in blood
lead categories >20 ug/dL compared to <20 ug/dL, with dose trend
in magnitude of difference.
Significant associations between increasing blood lead and
decreasing blood NADS and ALAD in lead workers:
NADS: a = 0.843, p = -0.00971, r = -0.867, p < 0.001, n = 76
logALAD: a = 1.8535, p = -0.015, r = -0.916, p < 0.001, n = 58
Significant correlation between blood lead concentration and
plasma and urinary ALA (both log-transformed):
plasma ALA: a = 0.327, p = 0.022, r= 0.742
urinary ALA: a = -0.387, p = 0.022, r = 0.711
Significant correlation between plasma and urinary ALA:
a = 6.038, p = 4.962, r= 0.897
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to
O
O
Table 6-9.2 (cont'd). Effects of Lead on Biochemical Effects in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Asia (cont'd)
Sugawaraetal. (1991)
Japan
NR
Kim et al. (2002)
Korea
1996
Lee et al. (2000)
Korea
NR
Design: cross-sectional cohort
Subjects: adult lead workers and reference
group (n = 32, total), ages NR
Outcome measures: plasma and erythrocyte
lipoperoxide and SOD; erythrocyte CAT,
GSH, and methemoglobin
Analysis: comparisons of outcome measures
between lead workers and reference group,
linear regression and correlation
Design: cross-sectional cohort
Subjects: adult male secondary lead smelter
workers (n = 83), mean age: 38.7 yr (SD
10.8); reference subjects (n = 24), mean age:
32.0 (SD 10.8)
Outcome measures: blood Hb, blood ALAD,
blood EP, blood P5N
Analysis: parametric comparison (ANOVA)
of outcome measures between lead workers
and reference group, correlation, multivariate
linear regression
Design: cross-sectional cohort
Subjects: adult male lead workers (n = 95;
secondary smelter, PVC-stabilizer
manufacture, battery manufacture); mean age
42.8 yr (SD 9.3, range 19-64); reference group
(n = 13), mean age 35.1 yr (SD 9.9, range 22-
54)
Outcome measures: urinary ALA, EP
Analysis: correlation
Blood lead (ug/dL) mean
(SD, range):
lead: 57.1(17.6,20-96)
reference: NR
Blood lead (ug/dL) mean
(SD)
lead: 52.4(17.7)
reference: 6.2 (2.8)
Blood lead (ug/dL) mean
(SD, range):
lead: 44.6(12.6,21.4-
78.4)
reference: 5.9 (1.2, 4.0-
7.2)
Significantly (p < 0.01) higher erythrocyte LPO and lower SOD,
CAT and GSH levels in workers compared to reference group.
Erythrocyte lipoperoxide (r = 0.656) and GSH (r = -0.631) were
significantly correlated with blood lead.
Significantly (p < 0.05) lower blood P5N, ALAD, and Hb; and
higher blood EP in lead workers compared to controls.
Significant (p < 0.001) correlations (in lead worker group) with
blood lead: P5N (r = -0.704), log EP (r = 0.678), log ALAD
(r = -0.622).
Significant association between increasing EP and decreasing
blood Hb:
blood lead >60 ug/dL: p = -1.546 (95% CI: -2.387 to -0.704,
r2 = 0.513, p = 0.001)
blood lead <60 ug/dL:
r2 = 0. 177, p = 0.003)
Significant association between increasing P5N and increasing
blood Hb (high blood lead group only):
blood lead > 60 ug/dL: p = 0.222 (95% CI: 0.015 to 0.419,
r2 = 0.513, p = 0.036)
Covariates included in model: P5N, log serum ferritin, log EP
Significant correlation between increasing DMSA-provoked
urinary lead and urinary ALA (r = 0.31, p < 0.002) and EP
(r = 0. 35, p< 0.001).
= -1.036 (95% CI: -1.712 to -0.361,
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to
O
O
Table 6-9.2 (cont'd). Effects of Lead on Biochemical Effects in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
OJ
to
Asia (cont'd)
Schwartz etal. (1997)
Korea
1994-1995
Gurer-Orhan et al.
(2004)
Turkey
NR
Design: cross-sectional
Subjects: adult male battery manufacture
workers (n = 57), mean age 32 yrs (SD 6).
Outcome measures: blood Hb, Hb Ab and
HbA2, ALAD genotype
Analysis: comparison of outcome measures
between ALAD genotype strata
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 20), mean age 35 yr (SD 8);
reference workers (n = 16), mean age 32 yr
(SD9)
Outcome measures: blood ALAD, EP,
erythrocyte MDA, CAT, G6PD, blood
GSH: GSSG
Analysis: comparison of outcome measures
between lead workers and reference group,
correlation
Blood lead (ug/dL) mean
(SD):
ALADl,l(n=38): 26.1
(9.8)
ALAD12(n= 19): 24.0
(11.3)
Blood lead (ug/dL) mean
(SD):
lead: 54.6(17)
reference: 11.8(3.2)
Mean blood lead (p = 0.48) and blood Hb levels (p = 0.34) were
not different between ALAD genotype strata.
Significant correlation between blood lead concentration and blood
ALAD (r = -0.85, p < 0.0001) and EP (r = 0.83, p < 0.001).
Significant correlation between blood lead concentration and
erythrocyte MDA (r = 0.80, p = <0.0001), erythrocyte G6PD
(r = 0.70, p < 0.0001, erythrocyte CAT (r = 0.62, p < 0.001), blood
GSH (r = 0.64, p < 0.0005), blood GSSG (r = 0.67, p < 0.0001).
GSH:GSSG ratio lower (p = NR) in lead workers (3.2), compared
to controls (8.0).
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Suzenetal. (2003)
Turkey
NR
Design: cross-sectional
Subjects: Male lead battery manufacture
workers (n = 72), age range 24-45 yrs.
Outcome measures: blood ALAD, urine ALA,
ALAD genotype
Analysis: comparison of outcome measures
between ALAD genotype strata
Blood lead (ug/dL) mean
(SD, range):
All: 34.5(12.8,13.4-71.8
ALADl,l(n=51)
34.4(13.1,13.4-71.8)
ALAD2(n = 21)
34.9(12.6,19.2-69.6)
Mean blood lead concentration (p = 0.88) and blood ALAD
activity (p = 0.33) were not different between ALAD genotype
strata. Mean urinary ALA was significantly higher (p < 0.05) in
the ALAD 1-1 stratum.
ALA, 5-aminolevulinic acid; ALAD, 5-aminolevulinic acid dehydratase; ANOVA, analysis of variance; CAT, catalase; CP, coproporphryn; DMSA, dimercaptosuccinic acid;
EP, erythrocyte protoporphyrin; G6PD, glucose-6-phosphate dehydrogenase; GSH, reduced glutathione; GSSG, glutathione disulfide; Hb, blood hemoglobin; Hct, hematocrit;
HDL, high-density lipoprotein; LDH, lactate dehydrogenase; LPO, lipoperoxide; MDA, malondialdehyde; NADS, adenine dinucleotide synthetase; OR, odds ratio; P5N,
erythrocyte pyrymidine-5'nucleotidase; R/ALAD, ratio of ALAD activity, before and after reactivation; RBC, red blood cells; ROS reactive oxygen species; SD, standard
deviation; SE, standard estimation; SOD, superoxide dismutase; UCP, urinary coproporphyrin
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to
O
O
Table AX6-9.3. Effects of Lead on Hematopoietic System in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
United States
Liebeltetal. (1999)
Connecticut
NR
Design: cross-sectional
Subjects: children (n = 86, 31 female), ages
1-6 yr
Outcome measures: serum EPO, blood Hb
Analysis: ANOVA of outcome measures
stratified by blood lead, linear regression
Blood lead (ng/dL) median
(range):
18(2-84)
84% <35
Significant association between increasing blood lead concentration
and decreasing serum EPO concentration (P = -0.03, p = 0.02).
Covariates included in model were blood Hb (P = -1.36, p < 0.01)
(age was not included), R2 = 0.224. Predicted decrease in serum
EPO per 10 ng/dL was 0.03 mlU/mL. No significant association
between blood lead and blood Hb.
X
ON
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Schwartz etal. (1990)
Idaho
1974
Design: cross-sectional
Subjects: children (n = 579), ages 1-5 yr,
residing near an active smelter (with
uncontrolled emissions)
Outcome measures: Hct
Analysis: logistic regression
Blood lead (ng/dL) range:
11-164
Significant association between increasing blood lead concentration
and probability of anemia (Hct<35%) (fa: 0.3083, SE 0.0061) and
age(p2: -0.3831, SE 0.1134). A 10% probability of anemia was
predicted to be associated with blood lead concentration of
approximately 20 ng/dL at age 1 yr, 50 ng/dL at age 3 yr, and 75
Hg/dL at age 5 yrs (from Fig. 2 Schwartz et al. (1990).
Regression model relating Hct to blood lead (BL jig/dL) and age
(AGE, yr): Hct=A/(l+exp(p0+PiBL+p2AGE)):
A = 39.42 (SE 0.79, p = 0.0001)
Po = -3.112 (SE 0.446, p = 0.0001)
P! = 0.0133 (SE 0.0041, p = 0.0005)
P2 = -0.2016 (SE 0.0905, p = 0.0129)
Based on above model, a 10% decrease in hematocrit (from 39.5 to
35.5%) is predicted in association with blood lead concentrations of
85, 115, and 145 ng/dL, at ages 1, 3, and 5 yrs, respectively.
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O
Table AX6-9.3 (cont'd.). Effects of Lead on Hematopoietic System in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Europe
Graziano et al. (2004)
(Factor Litvak et al.
(1999,1998)
Yugoslavia
1985-1998
Design: prospective
Subjects: children (n = 311; age range:
4.5-12 yr) from high-lead (smelter/refinery)
and low-lead areas
Outcome measures: blood Hb, serum EPO.
Analysis: multivariate linear regression
(GEE for repeated measures)
Blood lead (|ig/dL) range:
4.5 yr: 4.6-73.1
6.Syr: 3.1-71.7
9.0 yr: 2.3-58.1
Blood lead (jig/dL) means
for ages 4.5 - 12 yrs:
high lead: 30.6-39.3
low lead: 6.1-9.0
Significant association between increasing blood lead concentration
and increasing serum EPO concentration at ages 4.5 (p < 0.0001)
and 6.5 yr (p < 0.0007), with decreasing regression slope with age:
4.5 yr: p = 0.21 (SE 0.043, p = 0.0001); 6.5 yr: p = 0.11 (SE 0.41,
p = 0.0103); 9.5 yr: p = 0.029 (SE 0.033, p = 0.39); 12 yr: p = 0.016
(SE 0.03l,p = 0.60).
Covariates retained in regression model were age (a), blood lead (P),
and blood Hb (y). GEE for repeated measures yielded (Factor-
Litvak et al. 1998, updated from personal communication from
Graziano 07/2005):
y: 0.6097 (95% CL-0.0915, -0.0479; p < 0.0001)
4.Syr: a = 1.3421 (95%CI: 1.0348-1.6194, p< 0.0001), p = 0.2142
(0.1282-0.3003, p< 0.0001)
6.Syr: a= 1.66201.3737-1.9503, p< 0.0001), p = 0.1167 (0.0326-
0.2008, p< 0.001)
9.5 yr: a = 1.7639 (1.4586-2.0691, p< 0.0001), p = 0.0326 (-
0.0346-0.0998, p = 0.1645).
12 yr: a = 1.8223 (1.524-2.1121, p < 0.0001), p = 0.0112 (-0.0359-
0.0584, p = 0.1645).
Based on the GEE, the predicted increase in serum EPO per 10
Hg/dL increase in blood lead concentration (atHb=13 g/dL) \ was:
1.25 mlU/mL (36%) at age 4.5 yr and 1.18 (18%) at age 6.5 y.
Blood Fib levels were not significantly different in children from
high-lead area (mean 25-38 ng/dL) compared to low-lead area
(mean: 5-9 ng/dL).
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Table AX6-9.3 (cont'd). Effects of Lead on Hematopoietic System in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Latin America
Perez-Brava et al.
(2004)
Chile
NR
Design: cross-sectional;
Subjects: children (n = 93, 43 males), age
range: 5-12 yrs who attended school near a
powdered lead storage facility
Outcome measures: blood Hb and Hct,
ALAD genotype
Analysis: comparison of outcome measures
between ALAD genotype strata
Blood lead (ng/dL) mean
(SE):
ALAD1 (n=84): 13.5
(8.7)
ALAD 2 (n= 9): 19.2(9.5)
Mean blood lead, blood Hb, and Hct not different between ALAD
genotypes
X
ON
to
EPO, serum erythropoietin; GEE, generalized estimating equation; Hct, hematocrit; Hb, blood hemoglobin; SE, standard estimation
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
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O
to
O
O
Table AX6-9.4. Effects of Lead on Hematopoietic System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
United States
Huetal. (1994)
U.S.
1991
Design: survey
Subjects: adult male carpentry workers
(n= 119), mean age: 48.6 yr (range: 23-67)
Outcome measures: blood Hct, blood Hb
Analysis: multivariate linear regression
Blood lead (ug/dL) mean
(SD, range):
8.3 (4.0, 2-25)
Bone lead (ug/g) mean
(SD, range)
tibia: 9.8 (9.5,-15-39)
patella: 13.9 (16.6,-11-78)
Significant association between increasing patella bone lead and
decreasing covariate adjusted blood Hb ((3 = -0.019, SE 0.0069,
p = 0.008, R2 = 0.078) and blood Hct ((3 = -0.052, SE 0.019,
p = 0.009, R2 = 0.061). After adjustment for bone lead measurement
error, a 37 ug/dL increase in patella bone lead level (from the lowest
to highest quintile) was associated with a decrease in blood Hb and
Hct of 11 g/L (95% CI: 2.7-19.3 g/L) and 0.03 (95% CI, 0.01 -
0.05), respectively.
Covariates considered: age, body mass index, tibia lead, patella
lead, blood lead, current smoking status, alcohol consumption
Covariates retained: patella bone lead, alcohol consumption, body
mass index.
X
Oi
to
OJ
Oi
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Europe
Osterode et al. (1999)
Austria
NR
Design: cross-sectional cohort
Subjects: adult male lead workers (n = 20),
ages 46 yr (SD, 7); age-matched reference
group (n = 20)
Outcome measures: blood PCV, blood Hb,
serum EPO, blood erythroid progenitor
(BFU-E) cell count, blood pluripotent
progenitor (CFU-GEMM) cell count, blood
granulocyte/macrophage progenitor (CFU-
GM) cell count.
Analysis: parametric and nonparametric
comparison of outcomes between lead
workers and reference group; correlation
Blood lead (ug/dL) mean
(range):
lead: 45.5(16-91)
reference: 4.1(3-14)
Urine lead (ug/L) mean
(range):
lead: 46.6(7-108)
reference: 3.7(2-16)
Significantly lower (p < 0.001) BFU-E counts in lead workers who
had blood lead concentrations >60 ug/dL, compared to reference
group. Significant negative correlation between blood lead or urine
lead and CFU-GM and CFU-E. Serum EPO was not correlated with
Hct in lead workers, however, serum EPO increased exponentially
with decrease in Hct in reference group.
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O
Table AX6-9.4 (cont'd). Effects of Lead on Hematopoietic System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Europe (cont'd)
Gennartetal. (1992)
Belgium
NR
Mohammed-Brahim
etal. (1985)
Belgium
NR
Hajemetal. (1990)
France
NR
Design: cross-sectional cohort
Subjects: adult battery manufacture workers
(n = 98), mean age, 37.7 yr (range: 22-55);
reference group (n = 85), mean age 38.8 yr
(24-55)
Outcome measures: blood Hb, RBC count,
Hct, blood EP
Analysis: linear regression
Design: cross-sectional cohort
Subjects: adult smelter and ceramics
manufacture workers (n = 38, 13 females);
reference subjects (n = 100) matched with
worker group by age, sex, and
socioeconomic status
Outcome measures: blood P5N, EP, ALAD,
R/ALAD (ratio of ALAD before and after
reactivation).
Analysis: comparison of outcome measures
(ANOVA) between lead workers and
reference group; correlation
Design: cross-sectional
Subjects: adult males (n = 129), mean age
36 yr (SD 7.8, range: 24-55), with no
environmental exposure to lead
Outcome measures: erythrocyte membrane
activities of Na+-K+-ATPase, Na+-K+-co-
transport, Na+-Li+-antiport, and passive Na+
and K+ permeability
Analysis: linear regression, correlation
Blood lead (ug/dL) mean
(SD, range):
lead: 51.0(8.0,40-70)
reference: 20.9(11.1,4.4-
30.0
Blood lead (ug/dL) mean
(SD, range):
lead: 48.5(9.1,27.8-66.6)
reference: 14.3 (6.7, 5.6-
33.6)
Urine lead (ug/g creatinine)
mean (SD, range):
lead: 84.0(95.9,21.8-587)
reference: 10.5(8.2,1.7-
36.9)
Blood lead (ug/dL)
geometric mean (95% CI
range):
16.0(15.2-16.8,8.0-33.0)
Hair lead (ug/g) geometric
mean (95% CI range):
5.3 (4.44-6.23, 0.9-60)
Significant association between increasing blood lead concentration
and decreasing blood Hb (P = -0.011, r = 0.22, p = 0.003) or Hct
(P = -0.035, r = 0.24, p< 0.01)
Significant association between increasing blood lead concentration
and increasing blood EP (P = 0.0191, r = 0.87, p = 0.0001)
(No apparent analysis of covariables)
Significantly lower (p = NR) P5N in lead workers (males or females,
or combined) compared to corresponding reference groups.
Correlations with blood lead:
log P5Nr=-0.79 (p< 0.001)
log ALAD r = -0.97 (p = NR)
R/ALAD r = -0.94 (p < 0.001)
logEPr=0.86(p = NR)
Correlations with urine lead:
log P5Nr= -0.74 (p = NR)
log ALAD r = -0.79 (p = NR)
R/ALAD r = -0.84 (p < 0.001)
logEPr=0.80(p = NR)
Na+-K+-co-transport activity negatively correlated with blood lead
concentration (r = -0.23, p = 0.02); linear regression:
a = 583.19, p =-170.70.
Na+-K+-ATPase activity negatively correlated with hair lead
(r = -0.18, p = 0.04); simple linear regression:
a = 3.34, p = -0.02.
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Table AX6-9.4 (cont'd). Effects of Lead on Hematopoietic System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
OJ
oo
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Europe (cont'd)
Poulosetal. (1986)
Greece
NR
Romeo etal. (1996)
Italy
NR
Graziano etal. (1990)
Yugoslavia
1986
Design: cross-sectional cohort
Subjects: adult male cable production
workers who were exposed to lead (worker
1; n = 50, mean age: 37 yr); male cable
workers who had not direct contact with lead
(worker 2, n = 75, mean age: 36. Syr);
reference group (n = 35, mean age: 39 yr)
Outcome measures: blood Hb, Hct
Analysis: simple linear regression in the
form: mean Hct = a+p(individual Hct -
group mean Hct)
Design: cross-sectional cohort
Subjects: adult male lead workers (n = 28),
age range, 17-73; reference group (n = 113),
age range, 21-75 yr
Outcome measures: serum EPO, blood Hb
Analysis: nonparametric comparison of
outcome measures between lead workers and
reference group; correlation
Design: prospective
Subjects: pregnant women (n = 1502) from
high-lead (smelter/refinery) and low-lead
areas
Outcome measures: Hb
Analysis: comparison of outcome measures
between high-and low-lead groups
Blood lead (|ig/dL) mean
(SE):
worker 1: 27.0(0.7)
worker 2: 18.3(0.6)
reference: 21.5(1.5)
Blood lead (ng/dL) mean
(SD, range):
leadl: 32.3(5.6,30^9)
lead 2: 65.1(16,50-92)
reference: 10.4 (4.3, 3-20)
Blood lead (ng/dL) mean
(95% CI):
high lead: 17.1(6.9^2.6)
low lead: 5.1 (2.5-10.6)
Significant association between increasing blood lead and decreasing
Hct:
worker 1: a = 46.50, (3 = -0.170, SE 0.079, p < 0.05
worker 2: a = 44.57, p = -0.180, SE 0.083, p < 0.05
reference: a = 44.69, p = -0.255, SE 0.044, p < 0.001
Significant association between increasing blood lead and decreasing
blood Hb:
worker 1: a = 15.23, p = -0.058, SE 0.028, p< 0.05
worker 2: a = 14.58, p = -0.071, SE 0.034, p < 0.05
reference: a = 14.64, p = -0.087, SE 0.015, p < 0.001
Significantly (p = 0.021) lower serum EPO in lead workers
compared to reference group. No significant (p < 0.05) lead effect
on blood Hb.
Mean blood hemoglobin levels (g/dL) in high-lead group (12.4; 95%
CI: 10.3-14.5) not different from low-lead group (12.3; 95% CI:
10.0-14.7).
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Table AX6-9.4 (cont'd). Effects of Lead on Hematopoietic System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Europe (cont'd)
Graziano et al. (1990)
Yugoslavia
1986
Design: prospective
Subjects: pregnant women (n = 48) from
high-lead (smelter/refinery) and low-lead
areas (6 highest and lowest mid-pregnancy
blood lead concentrations), within each of 4
Hb strata (g/dL): 9.0-9.9, 10.0-10.9, 11.0-
11.9,12.0-12.9
Outcome measures: Hb, EPO
Analysis: ANOVA of outcome measures in
subjects stratified by blood lead and blood
Hb
Blood lead (ug/dL) mean
range for Hb strata
high lead: 16.9-38.6
low lead: 2.4-3.6
Significant effect of blood lead (p = 0.049) and blood Hb (p = 0.001)
on mid-term and term serum EPO (blood lead p = 0.055, Hb
p = 0.009), with significantly lower serum EPO associated with
higher blood lead.
X
ON
to
OJ
VO
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Asia
Hsiao etal. (2001)
China
1989-1999
Hsieh et al. (2000)
China
NR
Design: longitudinal
Subjects: adult battery manufacture workers
(n = 30, 13 females), mean age 38.3 yr
Outcome measures: blood Hb, Hct, RBC
count
Analysis: GEE for repeated measures
(models: linear correlation, threshold
change, synchronous change, lag change);
logistic regression
Design: cross-sectional
Subjects: Adults in general population
(n = 630, 255 females)
Outcome measures: blood Hb, Hct, RBC
count, ALAD genotype
Analysis: comparison of outcome measures
between ALAD genotype strata
Blood lead (ug/dL) mean:
1989: 60
1999: 30
Blood lead ( ug/dL) mean
(SD):
ALAD l,l(n= 630):
6.5(5.0)
ALAD: 1,1/2,2 (n= 30)
7.8 (6.0)
Significant association between increasing blood lead and increasing
RBC count and Hct:
Odds ratios (95% CI):
synchronous change model:
blood Hb (0.95, 0.52-1.78)
RBC count (3.33, 1.78-6.19)
Hct (2.19, 1.31-3.66)
lag change:
blood Hb (1.70, 0.99-2.92)
RBC count (2.26, 1.16-4.41)
Hct (2.08, 1.16-4.41)
Mean blood lead not different between ALAD genotype strata
(p = 0.17). RBC count, Hb, Hct not different between ALAD
genotype strata (p = 0.7)
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O
Table AX6-9.4 (cont'd). Effects of Lead on Hematopoietic System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
J^.
O
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Asia (cont'd)
Froometal. (1999)
Israel
1980-1993
Solliwayetal. (1996)
Israel
NR
Horiguchietal. (1991)
Japan
NR
Design: longitudinal survey
Subjects: adult male battery manufacturing
workers (n = 94), mean age, 38 yr (SD 9,
range: 26-60)
Outcome measures: blood Hb, blood EP
Analysis: multivariate linear regression
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 34), mean age: 44 yr (SD 13);
reference subjects (n = 56), mean age 43 yr
(SD 12); cohorts constructed to have similar
age, ethnic characteristics, socioeconomic
status, education level, and occupation
Outcome measures: blood Hb, RBC count
Analysis: parametric comparison of
outcome measures between lead and
reference groups, correlation
Design: cross-sectional cohort
Subjects: adult male secondary lead refinery
workers (n = 17), mean age: 44.9 yr (range:
24-58); reference male subjects (n = 13),
mean age: 33.5 yr (range: 22-A4)
Outcome measures: RBC deformability
(microfiltration at -20 cm H2O pressure),
RBC count, Hct, blood Hb
Analysis: comparisons of outcome measures
between lead workers and reference group
Blood lead (ug/dL) range
of 13-yr individual subject
means
20-61 ug/dL
Blood lead (ug/dL) mean
(SD, range):
lead: 40.7(9.8,23-63)
reference: 6.7(2.4,1-13)
Blood mead (ug/dL) mean
(SD):
lead: 53.5(16.1)
reference: NR
Urine lead (ug/L) mean
(SD):
lead: 141.4(38.1)
reference: NR
Week (and probably not significant) covariate-adjusted association
between blood Hb and individual sample blood lead (P = -0.0039,
SE 0.0002), subject average blood lead (P = -0.0027, SE 0.0036) or
blood EP (P = -0.001, SE 0.0007).
Covariates retained in model were age and smoking habits.
Significantly lower (p < 0.05) mean RBC count in lead workers
compared to reference group. Significant negative correlation
between blood lead concentration and RBC count (r = -0.29,
p < 0.05). Mean comparison for blood Hb (p = 0.4); correlation with
blood lead concentration (r = -0.05, p = 0.7).
Significantly lower RBC deformability (p < 0.01), RBC count
(p < 0.01) Hct (p < 0.01), and blood Hb (p > 0.001) in lead workers
compared to reference group.
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Table AX6-9.4 (cont'd). Effects of Lead on Hematopoietic System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Asia (cont'd)
Makinoetal. (1997)
Japan
1990-1994
Design: longitudinal survey
Subjects: adult male pigment or vinyl
chloride stabilizer manufacture workers
(n = 1573) mean age 45 yr
Outcome measures: blood Hb, Hct, RBC
count
Analysis: parametric comparison of
outcome measures, stratified by blood lead,
linear regression
Blood lead (ug/dL) mean
(SD, range):
12.6 (2.0, 1-39)
Urine lead (ug/L) mean
(SD, range):
10.2 (2.7, 1-239)
Significantly higher (p < 0.001) Hct, blood Hb, and RBC count in
blood lead category 16-39 ug/dL, compared to 1-15 ug/dL
category.
Significant positive correlation between blood lead concentration
and Hct: a = 42.95, p = 0.0586 (r = 0.1553, p < 0.001), blood Hb:
= 14.65, p = 0.0265 ( r = 0.1835, p < 0.001), and RBC count
a = 457, p = 0.7120 (r = 0.1408, p < 0.001).
Moritaetal. (1997)
Japan
NR
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Kim et al. (2002)
Korea
1996
Design: cross-sectional cohort
Subjects: male lead workers (n = 76), mean
age 42 yr (range: 21-62); reference subjects
(n = 13, 6 females), mean age, males 41 yr
(range: 26-52), females 45 yr (range: 16-
61)
Outcome measures: blood NADS, ALAD
Analysis: comparison of outcome measures
(ANOVA) between blood lead categories,
linear regression
Design: cross-sectional cohort
Subjects: adult male secondary lead smelter
workers (n = 83), mean age: 38.7 yr (SD
10.8); reference subjects (n = 24), mean age:
32.0 (SD 10.8)
Outcome measures: blood Hb, blood ALAD,
blood EP, blood P5N
Analysis: parametric comparison (ANOVA)
of outcome measures between lead workers
and reference group, correlation, multivariate
linear regression
Blood lead (ug/dL) mean
(SD, range)
lead: 34.6(20.7,2.2-81.6)
Blood lead (ug/dL) mean
(SD)
lead: 52.4(17.7)
reference: 6.2 (2.8)
Significantly lower (p < 0.01) blood NADS and ALAD in blood lead
categories >20 ug/dL compared to <20 ug/dL, with dose trend in
magnitude of difference.
Significant associations between increasing blood lead and
decreasing blood NADS and ALAD in lead workers:
NADS: a = 0.843, p = -0.00971, r = -0.867, p < 0.001, n = 76
logALAD: a= 1.8535, p =-0.015, r =-0.916, p< 0.001, n= 58
Significantly (p < 0.05) lower blood P5N, ALAD, and Hb; and
higher blood EP in lead workers compared to controls.
Significant (p < 0.001) correlations (in lead worker group) with
blood lead: P5N (r = -0.704), log EP (r = 0.678), log ALAD (r = -
0.622).
Significant association between increasing EP and decreasing blood
Hb:
blood lead >60 ug/dL: p =-1.546 (96% CI: -2.387 to-0.704,
r2 = 0.513, p = 0.001)
blood lead <60 ug/dL: p =-1.036 (96% CI: -1.712 to-0.361,
r2 = 0.177, p = 0.003)
Significant association between increasing P5N and increasing blood
Hb (high blood lead group only):
blood lead >60 ug/dL: p = 0.222 (96% CI: 0.015 to 0.419,
r2 = 0.513, p = 0.036)
Covariates included in model: P5N, log serum ferritin, log EP
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Table AX6-9.4 (cont'd). Effects of Lead on Hematopoietic System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Asia (cont'd)
Schwartz etal. (1997)
Korea
1994-1995
Design: cross-sectional
Subjects: adult male battery manufacture
workers (n = 57), mean age 32 yrs (SD 6).
Outcome measures: blood Hb, Hb Ab and
HbA2, ALAD genotype
Analysis: comparison of outcome measures
between ALAD genotype strata
Blood lead (|ig/dL) mean
(SD):
ALADl,l(n=38): 26.1
(9.8)
ALADl,2(n= 19): 24.0
(11.3)
Mean blood lead (p = 0.48) and blood Hb levels (p = 0.34) were not
different between ALAD genotype strata.
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ALAD, 5-aminolevulinic acid dehydratase; BFU-E, blood erythroid progenitor; CFR-GM, colony forming unit-granulocyte/macrophage progenitor; CFU-E, colony forming
unit blood-erythroid progenitor; CFU-GEMM, colony forming unit blood-pluripotent progenitor; EP, erythrocyte protoporphyrin; EPO, serum erythropoietin; GEE, generalized
estimation equation; Fib, blood hemoglobin; Hct, blood hematocrit; NADS, nicotinamide adenine dinucleotide; PCV, packed cell volume; P5N, pyrimidine 5'-nucleotidase;
R/ALAD, ratio of ALAD activity, before and after reactivation; RBC, red blood cells
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O
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Table AX6-9.5. Effects of Lead on the Endocrine System in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
United States
Mahaffeyetal. (1982)
Wisconsin, New York
NR
Design: cross-sectional
Subjects: children/adolescents (n = 177),
ages l-16yr
Outcome measures: serum 1,25-OH-D
Analysis: comparison of outcome measures
between age, location and blood lead strata,
linear regression
Blood lead (ng/dL) range:
12-120
Serum 1,25-OH-D levels were significantly (p = 0.05) higher in the
age group 11-16 yr compared to age groups 1-5 or 6-10 yr.
Increasing blood lead (log-transformed) significantly associated with
decreasing serum 1,25-OH-D levels in children 1-5 yr of age
(a = 74.5, p = -34.5, r = -0.884, n = 50)
Dietary calcium: NR
X
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O
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o
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W
O
O
HH
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Rosen etal. (1980)
New York
NR
Sorrelletal. (1977)
New York
1971-1975
Design: cross-sectional
Subjects: children (n = 45), ages 1-5 yr
Outcome measures: serum calcium, PTH,
25-OH-D, 1,25-OH-D
Analysis: comparison of outcome measures
between blood lead strata, and before and
after chelation, correlation
Design: cross-sectional
Subjects: children (124), ages 1-6 yr
Outcome measures: serum calcium,
phosphate, 25-OH-D
Analysis: comparison of outcome measures
between blood lead strata, correlation
Blood lead (ng/dL) mean
(SE, range):
<29(n=15): 18(1,10-
26)
30-59 (n= 18): 47(2,33-
55)
>60 (n = 12): 74 (98, 62-
120)
Blood lead (ng/dL) mean
(SE):
<29(n = 40): 23(1)
30-59 (n = 35): 48(1)
>60(n = 49): 84(5.0)
Significantly higher serum PTH levels and lower 25-OH-D in high-
lead group compared to low-lead group; significantly lower 1,25-
OH-D levels in moderate- and high-lead group compared to low-lead
group. Serum levels of 1,25-OH-D were negatively correlated with
blood lead (high lead: r = -0.71, moderate: r = -0.63, p < 0.01).
After chelation therapy, blood lead decreased and serum 1,25-OH-D
levels increased to levels not significantly different (p > 0.1) from
low-lead group, 25-OH-D levels were unchanged.
Dietary calcium intake (mg/day) mean (SE):
low lead: 800(30)
moderate lead: 780 (25)
high lead: 580(15)
Serum calcium and 25-OH-D were significantly lower in high lead
group (p < 0.001). Significant negative correlation between blood
lead and serum calcium (high lead, r = -0.78, p < 0.001) or calcium
intake high lead, (r = -0.82, p < 0.001) in all three lead strata. Serum
25-OH-D was significantly positively correlated with vitamin D
intake, but not with blood lead.
Dietary calcium intake (mg/day) mean (SE):
low lead: 770(20)
moderate lead: 760 (28)
high lead: 610(20)
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Table AX6-9.5 (cont'd). Effects of Lead on the Endocrine System in Children
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
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to
United States (cont'd)
Siegeletal. (1989)
Connecticut
1987
Design: cross-sectional
Subjects: children (n = 68, 32 female), ages
11 mo to 7 yr
Outcome measures: serum FT4, TT4
Analysis: linear regression
Koo et al. (1991) Design: longitudinal (subset of prospective)
Ohio Subjects: children (n = 105, 56 females), age
NR 21,27, 33 mo
Outcome measures: serum calcium
magnesium, phosphorus, PTH, CAL, 25-OH-
D, 1,25-OH-D, and bone mineral content
Analysis: structural equation modeling
Blood lead (iig/dL) mean
(range):
25 (2-77)
Blood lead (ng/dL)
geometric mean (GSD,
range):
lifetime mean, based on
quarterly measurements:
9.74(1.44,4.8-23.6)
concurrent:
15.01 (1.52,6^4)
maximum observed:
18.53(1.53,6-63)
No significant association between blood lead concentration and
thyroid hormone outcomes. Linear regression parameters:
FT4: a = 1.55 (SE 0.05), (3 = 0.0024 (SE 0.0016), r2 = 0.03, p = 0.13
TT4: a = 8.960 (SE 0.39), p = 0.0210 (SE 0.0127), r2 = 0.04,
p = 0.10
Significant association between increasing blood lead (In-
transformed) and covariate-adjusted decreasing serum phosphorus
(a = 1.83, p = -0.091). No other covariate-adjusted outcomes were
significantly associated with blood lead.
Covariates retained: age, sex, race, and sampling season.
Dietary calcium intake (mg/day)
<600: n = 4(4%)
600-1200: n=58(55%)
>1200: n = 43(41%)
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CAL, calcitonin; FT4, free thyroxine; GSD, geometric standard deviation; 25-OH-D, 25-hydroxyvitamin D; 1,25-OH-D, 1,25-dihydroxyvitamin D; PTH, parathyroid hormone;
RBP, retinal binding protein; SE, standard estimation; TRH, thyroid releasing hormone; TSH, thyroid stimulating hormone; TT3, total triiodothyronine; TT4, total thyroxine;
TTR, transthyretin
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Table AX6-9.6. Effects of Lead on the Endocrine System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
United States
Cullenetal. (1984)
Connecticut
1979
NR
Design: clinical case study
Subjects: adult males with neurological
symptoms of lead poisoning
Outcome measures: serum, FSH, LH, PRL,
TES
Analysis: clinical outcomes in terms of
abnormal values
Blood lead (ng/dL) (range):
66-139
Five subjects with defects in spermatogenesis (including
azospermia), with no change in basal serum FSH, LH, PRL, and
TES.
X
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O
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o
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W
O
O
HH
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W
Robins etal. (1983 Design: cross-sectional
Connecticut Subjects: adult male brass foundry workers
NR (n = 47), age range 20-64 yr
Outcome measures: FT4
Analysis: simple linear regression with
stratification by age and race.
Braunstein et al. Design: clinical
(1978) Subjects: adult male secondary lead smelter
California (n = 12), mean age 38 yr, reference group,
NR (n = 9), mean age 29 yr
Outcome measures: serum EST, FSH, LH,
TES, HCG-stimulated EST and TES, GnRH-
stimulated serum FSH and LH
Analysis: comparisons of outcome measures
between patients symptomatic for lead
poisoning, lead-exposed patients not
symptomatic, reference group
Refowitz (1984) Design: cross-sectional survey
NR Subjects: secondary copper smelter workers
(n=58)
Outcome measures: FT4, TT4
Analysis: linear regression
Blood lead (jig/dL) range:
16-127
Blood lead (jig/dL) mean
(SD):
symptomatic (n = 9):
time of test: 38.7(3.0)
highest: 88.2(4.0)
asymptomatic (n = 4):
time of test: 29.0(5.0)
highest: 80.0(0.0)
reference: 16.1(1.7)
Blood lead (jig/dL) range:
5-60
Significant association between increasing blood lead concentration
and decreasing FT4 (a = 1.22, (3 = -0.0042; 95% CI: -0.0002, -
0.0082; r2 = 0.085, p = 0.048). Significant interaction between race
(black, white) and blood lead. When stratified by race:
black: a = 1.13, p =-0.0051, 95% CI: 0.0007,-0.0095, r2 = 0.21,
p = 0.03)
white: r2 = 0.05, p = 0.27
Strength of association not changed by including age in the
regression model.
Statistically significant (p < 0.05) lower basal serum TES, higher
TES response to HCG, and significantly reduced LH response to
GnRH in workers symptomatic for lead poisoning (including
EDTA-provoked urinary lead >500 ng/24 hr).
No significant association between blood lead and hormone levels:
FT4: a = 2.32, p =-0.0067 (95% CI: -0.18 -+0.0043)
TT4: a = NR, p =-0.28 (95% CI: -0.059 -+0.0002)
No significant association when ratified by race (black, white)
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Table AX6-9.6 (cont'd). Effects of Lead on the Endocrine System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Oi
Canada
Alexander et al. (1998,
1996)
British Columbia
1993
Design: cross-sectional
Subjects: adult male primary smelter workers
(n = 152), mean age 40 yr
Outcome measures: serum FSH, LH, TES
Analysis: multivariate linear regression
Schumacher et al. Design: cross-sectional
(1998) Subjects: adult male smelter workers
British Columbia (n = 151) mean age 40 yr (SD 7.2)
1993 Outcome measures: serum FT4, TT4, TSH
Analysis: linear regression, ANOVA
Blood lead (ng/dL) range
(n=81):
5 (DL)-58 (75th %tile: 29)
Semen lead (jig/dL) range:
0.3 (DL)-17.6
Blood lead (ng/dL) mean:
24.1 (n= 151)
<15(n=36)
15-24(n=52)
25-39 (n = 41)
>40 (n = 22)
No significant association between covariate-adjusted blood lead
and hormone levels (pa0.5) or prevalence of abnormal levels.
Significant association between covariate-adjusted increasing
semen lead concentration and decreasing serum TES ((3 = -1.57,
p = 0.004).
Covariates considered: age, smoking, alcohol, other metals in blood
(As, Cd, Cu, Zn), abstinence days prior to sample collection, and
sperm count.
No significant effect of blood lead (categorical) on covariate-
adjusted or unadjusted FT4 (p = 0.68), TT4 (p = 0.13), TSH
(p = 0.54). No significant association of blood lead with prevalence
of abnormal values of hormones. No significant association
between 10-yr average blood lead and hormone levels or prevalence
of abnormal values.
Covariates considered: age and alcohol consumption.
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O
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Europe
Gennartetal. (1992)
Belgium
NR
Design: cross sectional cohort
Subjects: adult battery manufacture workers
(n = 98), mean age 37.7 yr (SD 8.3, range:
22-55); reference worker group (n = 85),
mean age 38.8 yr (SD 8.7, range: 22-55)
Outcome measures: serum TT3, FT4, TT4,
TSH, FSH, LH
Analysis: comparison of outcome measures
between lead workers and reference group
Blood lead (|ig/dL) mean
(SD, range):
lead: 51.0(8.0,40.0-75.0)
reference: 20.9(11.1,4.4-
39.0)
Urine lead (|ig/g cr) mean
(range):
lead: 57.8(1.95,4.3-399)
reference: 9.75 (2.73,1.45-
77.7)
Mean hormone levels in lead workers and reference group not
different (p = NR); no association between hormone levels and
blood lead or exposure duration quartile.
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Table AX6-9.6 (cont'd). Effects of Lead on the Endocrine System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
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Europe (cont'd)
Assennato et al. (1987)
Italy
NR
Govonietal. (1987)
Italy
NR
Design: cross-sectional
Subjects: adult male battery manufacture
workers (n = 39), mean age 41 yr (SD 10);
reference cement plant workers (n = 18), mean
age 40 yr (SD 10)
Outcome measures: serum FSH, LH, PRL,
TES; urinary 17-ketosteroids
Analysis: parametric comparison of outcome
measures between lead and reference groups
Design: cross-sectional
Subjects: adult male pewter manufacture
workers (n = 78), mean age 35 yr (SD 19,
range: 19-52)
Outcome measures: serum PRL
Analysis: parametric comparison of outcome
measures between blood lead and ZPP strata
Blood lead (ug/dL) mean
(SD):
lead: 61 (20)
reference: 18(5)
Urinary lead (ug/L) mean
(SD):
lead: 79(37)
reference: 18(8)
Blood lead (ug/dL) mean
(SD)/bloodZPP(ug/dL)
mean (SD):
A(n = 22): 28.2(7.1)724.4
(8.7)
B(n=33):
60/3(19.3)7131(107)
C(n= 13):
33.1(6.7)777.0(42.2)
D (n = 8):
49.1(4.2)734.0(4.8)
No significant association (p > 0.05) between blood lead and
hormone levels.
Significantly (p < 0.02) higher serum PRL in high ZPP strata (B and
C, compared to low ZPP strata A).
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W
O
O
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Rodamilans et al. Design: cross-sectional cohort
(1988) Subjects: adult male lead smelter workers
Spain (n = 23), age range 21^4 yr; reference group
NR (n = 20), age range 20-60 yr.
Outcome measures: serum: FSH, LH, TES,
FTES, SHBG
Analysis: comparison of outcome measures
between exposure duration strata
Blood lead (ug/dL) mean
(SD)
lead5yr(n= 10): 76(11)
reference (n = 20): 17.2
(13)
Serum TES (p = 0.01) and FTES (p = 0.001) significantly lower and
SHBG significantly higher (p < 0.025) in >5-yr exposure group
compared to reference group; serum LH was significantly (p < 0.01)
higher in all exposure groups compared to reference group.
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Table AX6-9.6 (cont'd). Effects of Lead on the Endocrine System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Europe (cont'd)
Erfurthetal. (2001)
Sweden
NR
Design: cross-sectional cohort
Subjects: adult male active secondary smelter
workers (n = 62), mean age 43 yr (range: 21-
78) reference worker group (: 26), mean age
43 yr (range: 23-66)
Outcome measures: serum FT3, FT4, TSH,
TES, SHBG; TRH-stimulated serum TSH;
GnRH-stimulated serum FSH, LH, and PRL
Analysis: nonparametric comparison of
outcome measures between lead workers and
reference group; multivariate linear regression
Blood lead (ng/dL) median
(range):
lead: 31.1(8.3-93.2)
reference: 4.1 (0.8-6.2)
Plasma lead (ng/dL) median
(range:
lead: 31.1(8.3-93.2)
reference: 4.1 (0.8-6.2)
Urine lead (ng/g cr) median
(range):
lead: 19.6(3.1-80.6)
reference: 4.1 (2.4-7.3)
Bone (finger) lead (ng/g)
median (range):
lead: 25 (-13-99)
reference: 2 (-21-14)
Basal hormone levels in workers not different from reference group
(p>0.05); age-adjusted basal hormone levels not associated with
plasma lead, blood lead, urine lead, or bone lead. In an age-
matched subset of the cohorts (n = 9 lead workers, n = 11
reference), median GnRH-stimulated serum FSH was significantly
(p = 0.014) lower (77IU/L x hr) in lead workers than in reference
group (162 IU/L x hr). No association between stimulated TSH,
LH, FSH or PRL and lead measures.
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o
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W
O
O
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W
Gustafsonetal. (1989)
Sweden
NR
Campbell etal. (1985)
UK
NR
Design: cross-sectional cohort
Subjects: adult male secondary smelter
workers (n = 21) mean age 36.0 yr (SD 10.4);
individually matched for age, sex, and work
shift (n = 21),
Outcome measures: serum FTES, TTES;
FSH, LH, PRL, COR, TSH, TT3, TT4
Analysis: nonparametric comparison of
outcome measures between lead workers and
reference group, correlation
Design: cross-sectional cohort
Subjects: adult male welders (n = 25);
reference subjects (n = 8) (ages NR)
Outcome measures: plasma ACE, AI, PRA,
plasma ALD
Analysis: linear regression, nonlinear least
squares
Blood lead (ng/dL) mean
(SE):
lead: 39.4(2.1)
reference: 5.0 (0.2)
Blood lead (ng/dL) mean
(SD, range):
35.6(15.3,8-62)
Significantly higher TT4 (p < 0.02) and lower serum FSH
(p = 0.009) in lead workers compared to reference group. When
restricted to the age range <40 yr, lead workers had significantly
higher TT4 (p = 0.01) and lower FSH (p = 0.03), LH (p = 0.04), and
COR (p = 0.04), compared to the reference group.
Significant positive correlation between blood lead concentration
and plasma ALD level (r = 0.53, p < 0.002), PRA (r = -0.76, p <
0.001), AI (r = 0.68, p < 0.002), and ACE (r = 0.74, p < 0.001).
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Table AX6-9.6 (cont'd). Effects of Lead on the Endocrine System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
J^.
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O
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W
O
O
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W
Europe (cont'd)
Chalkeyetal. (1998)
UK
1979-1984
Mason etal. (1990)
UK
NR
McGregor and Mason,
(1990)
UK
NR
Design: cross-sectional
Subjects: adult male primary metal (Cd, Pb,
Zn) workers (n = 19), ages NR
Outcome measures: blood calcium, serum 25-
OH-D, 1,25-OH-D, 24,25-OH-D
Analysis: comparison of outcome measures
(ANOVA) in group stratified by blood lead
and urinary cadmium
Design: cross-sectional
Subjects: adult male lead workers (n = 63),
age range 21-63 yr; reference male subjects
(n = 75), age range 22-64 yr
Outcome measures: serum calcium
phosphate, PTH, 1,25-OH-D
Analysis: comparison of al outcome measures
between lead workers and reference group,
multivariate regression
Design: cross-sectional cohort
Subjects: adult male lead workers (n = 90),
mean age (31.5 yr (SD 11.9); reference
workers (n = 86), mean age 40.6 yr (SD 11.8
Outcome measures: serum FSH, LH, TES,
SHBG
Analysis: comparison of outcome means
between lead workers and reference groups,
multivariate regression, correlation
Blood lead (ug/dL) mean
(SD, range):
47 (21-76)
Blood lead (ug/dL) range:
lead (15-94)
reference: NR
Tibia lead (ug/g)
lead: 0-93
reference: NR
Blood lead (ug/dL) range:
lead: 17-77
reference: <12
After stratification by blood lead and urinary cadmium, serum 1,25-
OH-D levels in strata were significantly different (p = 0.006), with
higher mean values in high blood lead (>40ug/dL)/high blood
cadmium (>0.9 ug/L)/high urine cadmium >3.1 ug/L) stratum
compared to low blood lead (<40ug/dL)/high blood cadmium (>0.9
ug/L)/high urine cadmium >3.1 ug/L) stratum. Serum 24,25-OH-D
levels decreased with increasing urinary cadmium (p = NR)
Significantly higher (p < 0.025) prevalence of elevated 1,25-OH-D
(>2 SD of reference mean) in lead workers (8/63, 13%) compared to
reference group (1/75, 1.3%). Serum levels of 1,25-OH-D
significantly (p < 0.05) higher in lead workers compared to
reference group.
After stratification of lead workers into exposure categories (high:
blood lead >40 ug/dL and bone lead >40 ug/g, low: blood lead <40
ug/dL and bone lead <40 ug/g), serum 1,25-OH-D levels were
significantly (p < 0.01) higher in the high lead group.
Increasing blood lead was significantly (p = NR) associated with
increasing 1,25-OH-D levels (r2 = 0.206; with age and bone lead
included, r2 = 0.218). After excluding 12 subjects whose blood lead
concentrations >60 ug/dL, r2 = 0.162 (p = 0.26).
Age-adjusted serum FSH was significantly (p = 0.004) higher in
lead workers compared to reference group.
Increasing serum FSH significantly (p = NR) associated with blood
lead and age. Increasing serum LH significantly associated with
increasing exposure duration (not blood lead or age).
No significant association between serum TES or SHBG and blood
lead or exposure duration.
No significant difference in prevalence of abnormal hormone levels
between groups.
-------
o
O
to
O
O
Table AX6-9.6 (cont'd). Effects of Lead on the Endocrine System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Latin America
Lopez et al. (2000)
Argentina
NR
Design: cross sectional
Subjects: adult male battery manufacture
workers (n = 75), age range 21-56 yr;
reference group (n = 62), age NR
Outcome measures: serum TT3, FT4, TT4,
TSH
Analysis: comparison of outcome measures
between lead workers and reference group,
correlation
Blood lead (ug/dL) mean
(range):
lead: 50.9(23.3,8-98)
reference: 19.1(7.1,4-39)
Significantly higher serum FT4 (p < 0.01) and TT4 (p < 0.05) in
lead workers compared to reference group. Significant positive
correlation between blood lead and serum TT3 (p < 0.05), FT4 (p <
0.01), TT4 (p < 0.05), and TSH (p < 0.05), for blood lead range 8-
50 ug/dL; and for TSH (p < 0.05) for blood lead range 8-26 ug/dL.
X
ON
to
0.01), but not blood lead (P = 0.00,
NR) in linear regression model that included age, blood lead, and
exposure duration (a = 2.76, r2 = 0.3, p = 0.03).
-------
o
O
to
O
O
Table AX6-9.6 (cont'd). Effects of Lead on the Endocrine System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Asia (cont'd)
Kristal-Boneh et al.
(1998)
Israel
NR
Horiguchi et al. (1987)
Japan
NR
Ng et al. (1991)
China
NR
Design: cross-sectional cohort
Subjects: adult male battery
manufacture/recycling workers (n = 56), mean
age 43.4 yr (SD 11.2); reference workers
(n = 90), mean age 41.5 yr (SD 9.3)
Outcome measures: serum calcium,
magnesium, phosphorus, PTH, 25-OH-D,
1,25-OH-D
Analysis: parametric comparison of outcome
measures between lead workers and reference
group, multivariate linear regression
Design: cross-sectional
Subjects: adult secondary lead refinery
(n = 60, 8 females), mean age 49 yr (range:
15-69)
Outcome measures: serum TT3, TT4, TSH
Analysis: comparison of outcome measures
(method NR), between job categories,
correlation
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 122), mean age 32.6 (SD 8,2,
range: 17-54); reference group (n = 49),
mean age 43.4 yr (SD 13.4, range: 18-74)
Outcome measures: serum FSH, LH, PRL,
TES
Analysis: multivariate linear regression
ANCOVA
Blood lead (ug/dL) mean
(SD, range):
lead: 42.6(14.5,20-77)
reference: 4.5(2.6,1.4-19)
Blood lead (ug/dL) mean
(SD):
male: 31.9(20.4)
female: 13.5(9.5)
Urine lead (ug/L) mean
(SD):
male: 59.3(76.3)
female: 26.0(19.7)
Blood lead (ug/dL) mean
(SD, range):
lead: 35.2(13.2,9.6-77.4)
reference: 8.3 (2.8, 2.6-
14.8)
Serum 1,25-OH-D (p = 0.0001) and PTH (p = 0.042) were
significantly higher in lead workers compared to reference group
Increasing blood lead concentration (In-transformed) was
significantly associated with covariate-adjusted increasing serum
PTH and 1,25-OH-D levels:
PTH: P = 4.8(95%CI: 0.8-8.8, r2 = 0.12)
1,25-OH-D: (3 = 4.8(95%CI: 2.7-6.9, r2 = 0.10)
Occupational lead exposure (yes) significantly associated with
increasing PTH and 1,25-OH-D levels.
Covariates retained: age, alcohol consumption, smoking; calcium,
magnesium, and calorie intake:
PTH: (3 = 7.81 (95%CI: 3.7-11.5)
1,25-OH-D: p = 12.3 (95% CI: 3.84-20.8)
No significant differences (p = NR) between hormone levels in job
lead categories: mean blood lead (ug/dL, SD): 17.9 (10.7), 25.6
(15.4), 49.9 (18.7). No significant correlations (p = NR) between
hormone levels and blood or urine lead levels.
When cohorts were stratified by age serum FSH and LH were
significantly (p < 0.02) higher in lead workers <40 yrs of age
compared to corresponding age strata of the reference group; serum
TES was significantly (p < 0.01) lower in lead workers >40 yr of
age. Covariate-adjusted serum TES were significantly lower (p <
0.01) in lead workers in the > 10-yr exposure duration category,
compared to the reference group. Covariate-adjusted serum FSH
and LH were significantly higher (p < 0.01) in lead workers in the
<10-yr exposure duration category, compared to the reference
group.
Covariates: age and tobacco smoking.
-------
o
O
to
O
O
Table AX6-9.6 (cont'd). Effects of Lead on the Endocrine System in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
60 mo.
Africa
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Tuppurainen et al.
(1988)
Kenya
1984
Design: cross-sectional
Subjects: adult male battery manufacture
workers (n = 176), mean age 34.1 yr (SD 8.1,
range: 21-54)
Outcome measures: serum TT3, FT4, TT4,
TSH
Analysis: multivariate linear regression and
correlation
Blood lead (ug/dL) mean
(SD, range):
55.9(23.8,14.5-133.6)
Increasing exposure duration significantly associated with
decreasing FT4 (r2 = 0.071, p = 0.001) and TT4 (r2 = 0.059,
p = 0.021); regression not improved by including age or blood lead.
Strength of association greater when restricted to workers who had
an exposure duration >7.6 yrs: FT4: r2 = 0.33, p< 0.002; TT4:
r2 = 0.21, p< 0.001.
No significant association between blood lead and hormone levels.
1,25-OH-D, 1,25-dihydroxyvitamin D; 25-OH-D, 25-hydroxyvitamin D; ACE, angiotensin converting enzyme; Al, angiotensin I; ALD, aldosterone; ANOVA, analysis of
variance; CAL, calcitonin; COR, cortisol; cr, creatinine; CSF, cerebral spinal fluid; EDTA, ethylenediaminetetraacetic acid; EST, estradiol; FSH, follicle stimulating hormone;
FT4, free thyroxine; FTES, free testosterone; GnRH, gonadotropin releasing hormone; HCG, human chorionic gonadotropin; LH, luteinizing hormone; NR, not reported; PRL,
prolactin; PTH, parathyroid hormone; RBP, retinal binding protein; SD, standard deviation; SE, standard estimation; SHBG, sex hormone binding globulin; SHBG, sex
hormone binging globulin; TES, testosterone; TRH, thyroid releasing hormone; TSH, thyroid stimulating hormone; TT3, total triiodothyronine; TT4, total thyroxine; TTES,
total testosterone; TTES, total testosterone; TTR, transthyretin; ZPP, zinc protoporphyrin
-------
o
O
to
O
O
Table AX6-9.7. Effects of Lead on the Hepatic System in Children and Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
Children
United States
Saengeretal. (1984)
New York
NR
Design: clinical cases
Subjects: children (n = 26) ages 2-9 yr; age-
matched reference group (n = NR)
Outcome measures: urinary cortisol and 60-
OH-cortisol (CYP3A metabolite of cortisol)
Analysis: comparison of outcome measure
between children who qualified for EDTA
treatment (EDTA provocation >500 jig/24
hr)
Blood lead (ng/dL) mean
(SE, range):
chelated: 46(2,33-60)
not chelated: 42 (3, 32-60)
Urinary lead (ng/24 hr)
mean (SE, range), EDTA-
provocation:
chelated: 991(132,602-
2247)
not chelated: 298 (32, 169-
476)
Significantly lower (~45% lower) urinary excretion of 6P-OH-
cortisol (p = 0.001) and urinary 6p-OH-cortisol: cortisol ratio (p <
0.001) in children who qualified for chelation than in children who
did not qualify and significantly lower than age-matched reference
group. Urinary 6p-OH-cortisol: cortisol ratio was significantly
correlated with blood lead (r = -0.514, p < 0.001), urinary lead, and
EDTA provocation urinary lead (r = -0.593, p < 0.001).
Adults
Asia
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Al-Neamyetal. (2001)
United Arab Emirates
1999
Design: cross-sectional cohort
Subjects: adult male (n = 100) workers (e.g.,
gas pump attendants, garage workers,
printing workers, construction workers),
mean age 34.6 yr (SD 8.0); reference group
(n = 100) matched with lead workers for age,
sex, nationality.
Outcome measures: serum protein, albumin,
ALT, AP, AST, BUN, yGT, LDH
Analysis: comparison of outcome measures
between lead workers and reference group
Blood lead (ng/dL) mean
(SD):
lead: 77.5(42.8)
reference: 19.8(12.3)
Significantly higher serum AP (p = 0.012) and LDH (p = 0.029) in
lead workers compared to reference group (values within normal
range).
-------
o
O
to
O
O
Reference, Study
Location, and Period
Table AX6-9.7 (cont'd). Effects of Lead on the Hepatic System in Children and Adults
Study Description
Lead Measurement
Findings, Interpretation
Adults, Asia (cont'd)
X
ON
to
Hsiao etal. (2001)
China
1989-1999
Satarug et al. (2004)
Thailand
NR
Design: longitudinal
Subjects: adult battery manufacture workers
(n = 30, 13 females), mean age 38.3 yr
Outcome measures: serum ALT
Analysis: GEE for repeated measures
(models: linear correlation, threshold
change, synchronous change, lag change);
logistic regression
Design: cross-sectional
Subjects: adults from general population
(n = 118, 65 female), age range, 21-57 yr
Outcome measures: coumarin-induced
urinary 7-OH-coumarin (marker for
CYP2A6 activity)
Analysis: multivariate linear regression
Blood lead (ug/dL) mean:
1989: 60 (-25-100)
1999: 30 (-10-60)
Urinary lead (ug/g cr)
mean (SD, range):
males: 1.3(1.8,0.1-12)
females: 2.4(1.1,0.6-6.5
Serum lead (ug/L) mean
(SD, range):
males: 4.2 (5.4, 1-28)
females: 3.0 (2.2, 1-12)
No association between blood lead and ALT.
Odds ratios (95% CI):
synchronous change model: 1.25 (0.69-2.25)
lag change: 1.76(0.76^.07)
Significant association between increasing urinary lead and
decreasing covariate-adjusted urinary 7-OH-coumarin (P = -0.29,
p = 0.003) in males, but not in females. Covariates retained: age
and zinc excretion. Significant association in opposite direction
between urinary cadmium and urinary 7-OH-coumarin (P = 0.38,
p = 0.006).
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
yGT, y-glutamyl transferase; 6p-OH-cortisol, 6-p-hydroxycortisol; ALT, alanine aminotransferase; AP, alkaline phosphatase; AST, aspartate aminotransferase; BUN, blood
urea nitrogen; CI, confidence interval; cr, creatinine; EDTA, ethylenediaminetetraacetic acid; GEE, generalized estimating equations; LDH, lactate dehydrogenase; SD,
standard deviation; UAE, United Arab Emirates
-------
o
O
to
O
O
Table AX6-9.8. Effects of Lead on the Gastrointestinal System
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Canada
Holness and Nethercott
(1988)
Ontario
1982-1984
Design: longitudinal
Subjects: adult male demolition workers
(n= 119), age NR
Outcome measures: prevalence of symptoms
Analysis: comparison of prevalence of
symptoms (questionnaire) stratified by job
phase or blood lead
Blood lead (ng/dL) mean
(range):
phase 1: 59(15-99)
phase 2: 30
phase 3: 19
phase 4: 17
Prevalence of reporting of symptoms of abdominal cramps or
constipation increased with increasing blood lead concentration (p <
0.05):
<50 ng/dL: 8%, 6%
50-70 ng/dL: 37%, 42%
>70 ng/dL: 77%, 62%
Caribbean
X
ON
to
Matte etal. (1989)
Jamaica
1987
Design: survey
Subjects: battery manufacture/repair
workers (n = 63), mean age -30 yr (range:
Outcome measures: prevalence of symptoms
Analysis: comparison of GI symptoms
(questionnaire) between blood lead strata
Blood lead (ng/dL)
geometric mean site range:
40-64
Blood lead distribution:
>60: 60%
<60: 40%
When stratified by blood lead, <60 ng/dL (low) or >60 ng/dL (high),
prevalence ratio (high/low) was not significant for abdominal pain
(1.5, 95% CI: 0.5-4.6), or for any other lead symptom (e.g. muscle
weakness).
Asia
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Bercovitz and Laufer
(1991)
Israel
NR
Design: cross-sectional
Subjects: health individuals (n = 12), peptic
ulcer patients (n = 11), and individuals with
heart disease (n = 11) with environmental
exposure
Analysis: one-way ANOVA used to
compare tooth lead concentrations in the
three groups
Tooth lead (|-ig/g dry
dentine) mean (SE):
Healthy: 25.62(10.15)
Peptic ulcer =75.02 (8.15)
Heart disease: 20.30 (2.70)
Tooth lead levels in patients with gastrointestinal ulcers (n = 11),
were significantly higher than that in healthy subjects (p = 0.001)).
Ten of the 11 peptic ulcer patients had a higher lead level than the
health subjects. In these 10 patients, increased severity of the ulcer
and longevity of suffering was associated with increased tooth lead
levels.
There was no significant difference between the tooth lead levels in
the healthy subjects and in the heart disease patients.
-------
o
O
to
O
O
Table AX6-9.8 (cont'd). Effects of Lead on the Gastrointestinal System
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
Oi
to
260.5 vs. <260.5 ug: OR= 1.1
(95% CI: 0.4-2.5)
OR for neuromuscular symptoms were significantly associated with
DMSA-provoked lead (OR = 7.8 (95% CI: 2.8-24.5), but not with
blood lead.
Covariates retained: age, tobacco smoking, and alcohol
consumption.
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Africa
Awad el Karim et al.
(1986)
Sudan
NR
Design: cross-sectional cohort
Subjects: adult male battery manufacture
workers (n = 92), mean age 31.1 yr (SD 8.2);
reference group (n = 40), mean age 33.7 yr
(SD 9.7)
Outcome measures: clinical evaluation
Analysis: comparison of prevalence of
symptoms of lead poisoning between lead
workers and reference group
Blood lead (ug/dL) mean
(SD, range):
lead: 55-81 (mean range
for various jobs), range:
39-107
Blood lead distribution
>80: 23%
40-80: 72%
<40: 5%
reference: 21 (8.5,7.4-
33.1)
Prevalences of abdominal colic (pain) and constipation were 41.3%
and 41.4 % in lead workers and 7.5% and 10%, respectively, in the
reference group.
DMSA, dimercaptosuccinic acid; GI, gastrointestinal; NR, not reported; OR, odds ratio; PAR, population attributable risk; PVC, polyvinyl chloride; SD, standard deviation; SE,
standard error
-------
o
O
to
O
O
Table AX6-9.9. Effects of Lead on the Respiratory Tract in Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Asia
Bagci et al. (2004)
Turkey
NR
Design: cross-sectional cohort
Subjects: adult male battery manufacture and
automobile exhaust repair workers (n = 62),
mean age 32.6 yr; reference hospital workers
(n = 24), mean age 28.8 yr
Outcome measures: VC, FVC, FEVj, PEF,
FEF, MVV
Analysis: comparison of mean outcomes
(ANOVA) between lead workers and
reference group, multivariate (Pearson
partial) correlation
Blood lead (ug/dL) mean
(SD, 95% CI):
battery (n = 22): 36.8(8.1,
33.2-40.3)
exhaust (n = 40): 26.9 (9.2,
24.0-29.9)
reference (n = 24): 14.8
(3.0,13.5-16.1)
Battery manufacture workers had significantly lower FEV (p <
0.05), FEV: VC ratio (p < 0.05), FEV: FVC ratio (p< 0.01), FEF
(p < 0.01), and MVV (p < 0.01) compared to the hospital workers.
Significant negative (partial) correlation between blood lead and
FEV/FVC (r = -0.31, p = 0.006) and FEF (r = -0.30, r = 0.009),
adjusted for age, cigarette smoking, and exposure duration.
X
ON
to
ANOVA, analysis of variance; CI, confidence interval; FEF, forced expiratory flow; FEV, forced expiratory volume; FVC, forced vital capacity; MVV, maximum voluntary
ventilation; PEF, expiratory peak flow; SD, standard deviation; VC, vital capacity
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
-------
o
O
to
O
O
Table AX6-9.10. Effects of Lead on Bone and Teeth in Children and Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
12 yr (18,460)
Outcome measures: number of caries (dfs,
DPS, DMFS)
Analysis: multivariate linear regression and
logistic regression
Blood lead (|ig/dL)
geometric mean (SE):
2-5 yr: 2.90 (0.12)
6-1 lyr: 2.07 (0.08)
> 12 yr: 2.49 (0.06)
Increasing blood lead concentration (log-transformed) significantly
associated with covariate adjusted increases in dfs:
2-5 yr: 0 = 1.78 (SE 0.59, p = 0.004)
6-1 lyr: (3= 1.42 (SE 0.51, p = 0.007)
and increases in DFS:
6-11 yr: p = 0.48 (SE 0.22, p = 0.03)
>12yr: p = 2.50 (SE 0.69, p< 0.001)
and increases in DMFS:
> 12 yr: p = 5.48 (SE 1.44, p = 0.01)
Odds ratio (OR) for caries (> 1 DMFS, ages 5-17 yr) and population
attributable risk (PAR) in association with 2nd or 3rd blood lead
tertiles, compared to 1st tertile were:
1st tertile (<1.66 |ig/dL)
2nd tertile (1.66-3.52 |ig/dL): OR 1.36 (95% CI: 1.01-2.83); PAR
9.6%
3rd tertile (>3.52 |ig/dL): OR 1.66 (95% CI: 1.12-2.48); PAR 13.5%
For an increase of blood lead of 5 |ig/dL, OR 1.8 (95% CI: 1.3-2.5)
Covariates retained were age, gender, race/ethnicity, poverty income
ratio, exposure to cigarette smoke, geographic region, educational
level of head of household, carbohydrate and calcium intakes, and
dental visits.
-------
o
O
to
O
O
Table AX6-9.10 (cont'd). Effects of Lead on the Gastrointestinal System in Children and Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
X
ON
to
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Children, United States (cont'd)
Schwartz etal. (1986)
U.S.
1976-1980
Gemmel et al. (2002)
Boston/Cambridge, MA
NR
Design: cross-sectional national survey
(NHANES II)
Subjects: ages <7 yr (n = 2,695)
Outcome measures: variables of stature,
including height, weight, and chest
circumference
Analysis: multivariate weighted linear
regression
Blood lead (|ig/dL) range:
5-35
Design: cross-sectional
Subjects: children (n = 543), ages 6-10 yr
Outcome measures: number of caries (dfs,
DPS)
Analysis: multivariate linear regression
Blood lead (|_ig/dL) mean
(SD, max):
urban (n = 290): 2.9 (2.0,
13)
rural (n= 253): 1.7(1.0,7)
Blood lead levels were a statistically significant predictor of
children's height (p < 0.0001), weight (p < 0.001), and chest
circumference (p < 0.026), after controlling for age in months, race,
sex, and nutrition.
Height: p = -0.119 (SE 0.0005)
Weight: p = -1.0217 (SE 0.08) for log-transformed blood lead
Chest circumference: p = -0.6476 (SE 0.077) for log-transformed
blood lead
There are several explanations for the inverse correlation between
blood lead and growth in children. First, blood lead level may be a
composite factor for genetic, ethnic, nutritional, environmental, and
sociocultural factors. Second, nutritional deficits that retard growth
also enhance lead absorption. Finally, there may be a direct effect of
low level lead on growth in children.
Increasing blood lead (In-transformed) was significantly associated
with covariate-adjusted number of caries (dfs + DFS) (In-
transformed) in the urban (P = 0.22, SE 0.08, p = 0.005) group, but
not in the rural group (P = -0.15, SE 0.09, p = 0.09). When dfs
numbers were stratified by permanent or deciduous teeth, the blood
lead association in the urban group was significant for deciduous
teeth
(P = 0.28, SE 0.09, p = 0.002), but not for permanent teeth (P = 0.02,
SE 0.07, p = 0.8).
Covariates retained: age, sex, ethnicity, family income, education of
female guardian, maternal smoking, frequency of tooth brushing,
firmness of toothbrush bristles, and frequency of chewing gum.
-------
o
O
to
O
O
Table AX6-9.10 (cont'd). Effects of Lead on the Gastrointestinal System in Children and Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Children, United States (cont'd)
Campbell et al. (2000)
New York
1995-1997
Design: retrospective cohort
Subjects: children (n = 154), ages 6.9-12 yr
Outcome measures: prevalence of caries
(dfs, DMFS)
Analysis: multivariate logistic regression
Blood lead (|ig/dL) mean
(range):
10.7(18.0-36.8)
(measured at ages 18 and
37 mo)
Covariate-adjusted odds ratios for caries in association with blood
lead <10 or > 10 |-ig/dL, were:
permanent teeth (DMFS): OR 0.95 (95% CI: 0.43-2.09)
deciduous teeth (dfs): OR 1.77 (95% CI: 0.97-3.24)
Covariates retained: age, grade in school, number of tooth surfaces at
risk. Other covariates explored, that had no effect on strength of
association with blood lead were: sex, ethnicity, and oral hygiene
score.
X
Oi
to
Oi
O
H
6
o
O
H
O
o
H
W
O
O
HH
H
W
Adults
United States
Dye et al. (2002)
U.S.
1988-1994
Design: cross-sectional national survey
(NHANES III)
Subjects: adults in general population (n =
10,033; 5,255 females), ages 20-69 yr
Outcome measures: symptoms of
periodontal bone loss (attachment loss,
periodontal pocket depth)
Analysis: multivariate linear regression
Blood lead (|ig/dL)
geometric mean (SE,
range):
2.5(0.08)(2.36%>10)
Increasing blood lead (log-transformed) was significantly associated
with increasing prevalence of covariate-adjusted dental furcation
(P = 0.13, SE 0.05, p = 0.005). Covariates retained: age, sex,
race/ethnicity, education, smoking, and age of home. Smoking
status interaction was significant when included in the model as an
interaction term (P = 0.10, SE 0.05, p = 0.034). When stratified by
smoking status, association between dental furcation and blood lead
was significant for current smokers (P = 0.21, SE 0.07, p = 0.004)
and former smokers (P = 0.17, SE 0.07, p = 0.015), but not for
nonsmokers (P = -0.02, SE 0.07, p = 0.747).
Europe
Tvinnereim et al.
(2000)
Norway
1990-1994
Design: cross-sectional
Subjects: 1,271 teeth samples collected by
dentists in all 19 counties in Norway
Analysis: Student's t-test comparing metal
concentrations in teeth with caries, roots, and
in different tooth groups
Tooth lead (|ig/g tooth)
geometric mean (SD,
range):
1.16(1.72,0.12-18.76)
Also examined mercury, cadmium, and zinc. All tooth groups had
higher lead concentrations in carious than in non-carious teeth. The
geometric mean lead concentration in carious teeth was 1.36 |ig/g
compared to 1.10 |_ig/g (p = 0.001).
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Table AX6-9.11. Effects of Lead on Ocular Health in Children and Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
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Children
Latin America
Rothenberg et al..
Mexico
1987-1997
2002 Design = longitudinal (subset of prospective)
Subjects: children (n = 45, 24 female), ages
7-1 Oyr
Outcome measures: ERG
Analysis: comparison of outcome measures
between blood lead tertiles (ANOVA for
repeated measures)
Blood lead (|_ig/dL) median
(range) at 85-124 mo:
1st tortile: 4.0 (2.0^.5)
2nd tortile: 6.0(5.0-6.5)
3rd tortile: 7.5 (7.0-16.0)
Blood lead (|_ig/dL) median
(range), maternal at 12 wk
of gestation =
1st tortile: 4.0 (2.0-5.5)
2ndtertile: 8.5(6.0-10.0)
3rdtertile: 14.0(10.5-32.5)
Significant association between increasing maternal blood lead at 12
wk of gestation and increasing ERG a-wave (p = 0.025) and b-wave
amplitude (p = 0.007), with significant increases in a-wave in the 2nd
blood lead tortile (6.0-10.0 |ig/dL), and a-wave and b-wave in the 3rd
blood lead tortile (10.5-32.5 |ig/dL), compared to the 1stblood lead
tertile.
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O
H
O
o
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W
O
O
HH
H
W
Adults
United States
Schaumberg et al., 2004
Massachusetts
1991-2002
Design = longitudinal (subset of Normative
Aging Study)
Subjects: adult male (n = 642), mean age 69
yr (range: 60-93)
Outcome measures: cataract diagnosis
Analysis: multivariate logistic regression,
odds ratio (vs. 1st quintile)
Blood lead (|ig/dL) median
(range):
5(0-35)
Bone lead (|ig/g) median
(range):
patella: 29 (0-165)
tibia: 20 (0-126)
Significant covariate adjusted odds ratio (OR) for cataracts in 5
tibia bone lead quintile (31.0-125 |ig/g): OR 3.19 (95% CI: 1.48-
6.90, p = 0.01). OR for cataracts were not significantly associated
with patella bone lead (5th quintile: 43.0-165 |ig/g): OR 1.88 (95%
CI: 0.88^.02) or blood lead (5th quintile: 8.17-35.0 |ig/dL): OR
0.89 (95% CI: 0.46-1.72, p = 0.73).
Covariates retained: age, smoking, history of diabetes, daily intake
of vitamin C, vitamin E, and carotenoids.
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Table AX6-9.11 (cont'd). Effects of Lead on Ocular Health in Children and Adults
Reference, Study
Location, and Period
Study Description
Lead Measurement
Findings, Interpretation
Adults
Europe
Cavallerietal., 1982
Italy
NR
Design = cross-sectional cohort
Subjects: adult male vinyl chloride pipe
manufacture workers, exposed to lead
stearate (n = 35), mean age 45 yr (SD 14,
range: 21-59); reference group (n = 35)
matched for age, smoking, and alcohol
consumption.
Outcome measures: visual field
Analysis: comparison of outcome measures
between lead workers and reference group
Blood lead (|_ig/dL) mean
(SD, range):
lead: 46 (14, 21-82)
reference: 23 (4, 21-37)
Urine lead (|-ig/L) mean
(SD, range):
lead: 71 (18, 44-118)
reference: 30(5,21^12)
Visual sensitivity was significantly (p = 0.003) lower in lead workers
compared to the reference group; however, visual sensitivity index
was not significantly associated with blood or urine lead. Mesopic
field scotoma prevalence was 10 of 35 (28%) in lead workers and
0% in the reference group.
X
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to
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to
ERG, electroretinogram
H
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O
H
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W
O
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HH
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W
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CHAPTER 6 ANNEX
ANNEX SECTION AX6-10
December 2005 AX6-263 DRAFT DO NOT QUOTE OR CITE
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1 The analyses fitting both the linear and log-linear models assumed that the error in the
2 response variable was constant across the range of values of the independent variable.
3 Violations of this assumption (heteroscedasticity) could potentially bias the estimated slope of
4 the model. Two models were considered:
5
6 Linear model: IQ = 90.0 - 0.4 x (blood lead level - 10.0), and
7 Log-linear model: IQ = 90.0 - 4.0 x [ln(blood lead level) - ln(10.0)].
8
9 The standard deviation of IQ was assumed to be equal to 15 x (blood lead level / I0)h
10 where h is the heteroscedasticity factor. When h = 0 there is no heteroscedasticity, and when h =
11 1 the standard deviation is proportional to the value of the blood lead. The value of h = 1 would
12 be comparable to the situation where there is a lognormal error.
13 The linear regression models described above were simulated for a sample size of
14 200 subjects and a lognormal distribution of blood lead levels with a geometric mean of 10.0
15 and a geometric standard deviation of 1.5. For each set of models and values of h, 100,000
16 simulations were performed.
Table AX6-10.1. Average Estimated Slopes for Linear and Log-linear Models in the
Presence of Heteroscedasticity
Heteroscedasticity
(h)
0.0
0.5
1.0
Linear Model
(True slope = -0.4)
-0.400
-0.400
-0.399
Log-Linear Model
(True slope = -4.0)
-4.00
-4.00
-4.01
17 The simulations indicated that any presence of heteroscedasticity would have no
18 noticeable bias on the estimation of the slopes of the models.
December 2005 AX6-264 DRAFT DO NOT QUOTE OR CITE
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