THE AGRICULTURAL HEALTH STUDY:

Collaborative Health and Exposure Research for the Agricultural Community

Kent Thomas1, Ruth Allen2, Dale Sandler3, Aaron Blair4, Jane Hoppin3, Cynthia Hines5, Michael Alavanja4

1U.S, EPA Office of Research arid Development, 2U.S. EPA Office of Pesticide Programs,

3National Institute of Environmental Health Sciences, "National Cancer Institute, 5National Institute for Occupational Safety and Health

The Agricultural Health Study

The AHS is a collaborative research effort sponsored by several federal agencies with
support from academic institutions and research organizations

The AHS is a comprehensive prospective epidemiological study on agricultural populations
that is designed to:

—	Measure cancer and non-cancer health risks in the agricultural community

—	Examine associations between use of agricultural chemicals, other agricultural
exposures, and disease

—	Determine factors that promote good health in the community

Over 55,000 licensed pesticide applicators and 34,000 spouses were enrolled in Iowa and
North Carolina from 1993 to 1997

Follow-up of health and agricultural practices in the cohort is ongoing

Agricultural Health Study Collaborators

Leading the Epidemiological Studies

National Cancer Institute

National Institute of Environmental Health Sciences
University of Iowa - Iowa AHS Field Station
Battelle CPHRE - North Carolina AHS Field Station
Westat-AHS Coordinating Center



Leading the Exposure Studies

U.S. EPA, ORD, National Exposure Research Laboratory
National Institute for Occupational Safety and Health
Battelle Columbus and CPHRE University of Iowa
RTI International Southwest Research Institute



Supporting the Epidemiological and Exposure Studies

U.S. EPA Office of Pesticide Programs, Health Effects Division

Science Issues and Research Impact

Epidemiological Studies

Science Issues

Despite low mortality and cancer incidence rates overall, farmers may experience excess risk of specific cancers
and other adverse health outcomes. Farmers, their families, and other pesticide applicators may have contact
with a variety of potentially hazardous substances (e.g., pesticides, solvents, fuels, oils, exhaust, dust). Previous
epidemiologic studies in agricultural populations have been limited by inadequate or retrospective exposure
information. Limitations of these previous studies are being addressed through the Agricultural Health Study.

Anticipated Impact

The Agricultural Health Study is designed to identify occupational, lifestyle, and genetic factors that may affect
the rate of diseases in agricultural populations. This study will provide information that agricultural workers can
use in making decisions about their health and the health of their families. Results from the study will inform risk
assessments and mitigation decisions, and will provide information for agricultural safety training and education.
The impact will extend beyond agricultural populations to other populations where pesticide exposures may occur.

Exposure Studies

Science Issues

Information derived from the epidemiological study questionnaires
is used to investigate associations between pesticide exposure
and specific diseases. Exposure measurement data are needed to
assess and refine these questionnaire-based exposure classification
procedures. Identifying and understanding key exposure factors can
also guide development of improved exposure reduction strategies.

Anticipated Impact

This research will improve exposure and health risk assessments
in the AHS epidemiological study. The results may also provide
information on how pesticides can be handled more safely to reduce
the exposures to farm-workers and their families.

AHS Research Results

Health Outcome Results

AHS researchers are examining health outcomes and their possible
associations with agricultural exposures. Many health outcome studies
have been published in peer-reviewed scientific journals. More information
about these results can be found at www-aohealth-orG.

Examples of findings to date:

•	Members of the AHS cohort experienced a 50% lower mortality rate
compared to the general population in Iowa and North Carolina over a
follow-up period of about 5 years (Blair et al., 2004)

•	The AHS cohort experienced a lower rate of overall cancer incidence; rates
of a few cancers appear elevated, including multiple myeloma and cancers
of the lip, gallbladder, ovary, prostate, and thyroid, but numbers for many of
these cancers are small (Alavanja et al., in press)

•	The incidence of prostate cancer among pesticide applicators in the AHS is
slightly higher (14%) than it is for other men in North Carolina and Iowa; the
risk increased with increasing use of methyl bromide (Alavanja et al., 2003)

•	Exposure to diesel exhaust and solvents are the strongest risk factors for
wheeze in the AHS cohort while raising farm animals, particularly poultry,
and the use of several pesticides are also associated with wheeze (Hoppin
etal., 2002, 2003, and 2004)

Exposure Study Results

The U.S. EPA led the AHS Pesticide Exposure Study which examined exposure to
2,4-D or chlorpyrifos for 84 AHS pesticide applicators in Iowa and North Carolina, and
for a subset of participating applicator family members. Some preliminary results are
described below; data analysis is ongoing.

The NIOSH led the Orchard Fungicide Exposure Study which examined the exposure
to selected fungicides for 74 AHS participants from farms in North Carolina and Iowa.
Data collation and analysis is currently underway.

Some preliminary results from the EPA Pesticide Exposure Study:

•	Significant correlations were found between measured exposures and exposure
intensity derived from questionnaire information

•	Chlorpyrifos exposures were higher for liquid products compared to granular products.

•	Differences in exposure were observed for different work practices

•	Significant correlations were found between urinary biomarker concentrations and
dermal exposure levels

•	Low urinary biomarker concentrations were found for most applicator spouses and
children; significant correlations were observed between applicator and spouse urine
concentrations for 2,4-D

Communicating with the Agricultural Community and Stakeholders

Research scientists from federal agencies and the Iowa and North Carolina AHS Field Stations have developed and implemented plans for communicating with
study participants and other stakeholders using a variety of products and dissemination methods to reach a wide audience.

Disclaimer: Although this work was r£viewsd by
the U.S. EPA and approved for publication, it may not
necessarily reflect official Agency policy. The findings
and conclusions in this report are those of the authors
and do not necessarily represent the views of the
National Institute for Occupational Safety and Health.

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