v>EPA
820-R-10-017
Fluoride:
Dose-Response Analysis
For Non-cancer Effects
Fluoride-Related Skeletal Effects:
Evaluations of Key Studies
Health and Ecological Criteria Division
Office of Water
January, 2008
U.S. Environmental Protection Agency
Washington, D.C.
-------
TABLE OF CONTENTS
ACKNOWLEDGMENTS 3
INTRODUCTION 4
STUDY SUMMARIES 5
January, 2008
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ACKNOWLEDGMENTS
This document was prepared by Oak Ridge National Laboratory, Oak Ridge, Tennessee, under work assignment
2006-014, underthe U.S. EPA IAGNumber DW-89-9220971. The Principal EPA Scientist is Joyce M. Donohue,
Ph.D., Health and Ecological Criteria Division, Office of Science and Technology, Office of Water, U.S.
Environmental Protection Agency, Washington, DC.
The summaries included in this report were prepared by C. Wood, S. Milanez, D. Glass, S. Garcia, S. Goldhaber,
and V. Dobozy of Oak Ridge National Laboratory (ORNL). Summary reviewers included J.M. Donohue and T.
Duke of the Health and Ecological Criteria Division, Office of Science and Technology, Office of Water, U.S.
EPA; and D. Glass, D. Opresko and A. Watson of ORNL.
The Oak Ridge National Laboratory is managed and operated by UT-Battelle, LLC., for the U.S. Department of
Energy under Contract No. DE-AC05-OOOR22725.
January, 2008
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INTRODUCTION
Prior to initiating the dose-response analysis for fluoride-related skeletal effects, the Office of Water
(OW) critically evaluated the studies that had been cited and utilized by the National Research Council
(NRC, 2006) in their report Fluoride in Drinking Water: A Scientific Review of EPA 's Standards.
Additional studies identified in the OW initial literature search (2006) were also evaluated. This
document is a compilation of the study evaluations arranged alphabetically by the name of the lead
author. Critical information fields examined and summarized include endpoint studied, type of study
and population studied, exposure period and assessment, characterization of study groups, analytical
methods and study design, parameters monitored, statistical methods employed, results (including
critical tables and figures) authors' conclusions, critical references and definitions, profiler's appraisal,
and critical review of the profiler's assessment. Studies of fluoride-related skeletal effects identified and
added to the dose-response analysis for the non-cancer effects document after its external peer review
were not evaluated in this fashion.
January, 2008
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STUDY SUMMARIES
Fluoride-Related Skeletal Effects:
Evaluations of Key Studies
January, 2008
-------
Bharati, P., A. Kubakaddi, M. Rao and R.K. Naik. 2005. Clinical symptoms of dental and skeletal
fluorosis in Gadag and Bagalkot districts of Karnataka. J. Hum. Ecol., 18(2): 105-107.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
ANALYTICAL METHODS:
STUDY DESIGN
PARAMETERS
MONITORED:
STATISTICAL METHODS:
RESULTS:
Dental fluorosis
Dental and skeletal fluorosis
Case control
India/ 6 villages in Gadag and 2 villages of Bagalkot District: 532 male and female subjects
surveyed from 6 villages in the Mundargi taluk (Gadag district) and 300 male and female
subjects surveyed from 2 villages in the Hungund taluk (Bagalkot district). Ten percent of
the households from each village were chosen for the study with at least one member of the
household exhibiting fluorosis. All members of the households chosen were part of the
study sample.
PROFILER'S NOTE: The ages or range of ages of the participants were not included in
the study report.
None described
Not described.
PROFILER'S NOTE: The profiler assumes since all members of the household were
included in the study that some of the participants (i.e. parents) had received long-term
exposures to the fluoride levels.
Only fluoride levels in drinking water were provided. Water in the Mundargi taluk ranged
from4.0to 10.5 ppm (Bharati and Meera Rao, 2001; Bharati, 1996) and water in the
Hungund taluk ranged from 2.04 to 3.2 ppm (Kubakaddi, 2001).
PROFILER'S NOTE: The applicability of this study for use in developing United States'
guidelines is limited as the values of fluoride exposure are much higher than those found
typically in the U.S. drinking water supply.
Participants were only assessed for the exposure to fluoride through the drinking water.
Analytical methods were not described. Only ranges for the fluoride level in the water were
provided; no other water parameters were measured.
The study was conducted in 6 villages of Mundargi taluk (Gadag district) and 2 villages of
Hungund taluk (Bagalkot district) in India that historically had fluoride levels ranging from
2.04 to 10.5 ppm fluoride. In each village, 10% of the households were selected with the
criteria for selection being that one person in the family was affected with fluorosis. A
checklist was developed using available literature and consultation with a nutritionist to
record the clinical symptoms of fluorosis. The symptoms were recorded by personally
interviewing each individual in the families chosen and by observations with the help of
local doctors. The symptoms were then tabulated and percentages calculated.
No parameters used for scoring either the dental or skeletal fluorosis were described. The
dental fluorosis was observed by examination (see Table 1) and the skeletal fluorosis by
clinical symptoms described by the participants (see Table 2).
No statistical methods were described.
Table 1 below is copied directly from Bharati et al. (2005). In Mundargi taluk, out of 532
participants, 328 (61.65%) had either dental fluorosis (25%), skeletal fluorosis (5.45%) or
January, 2008
-------
Skeletal fluorosis
both (3 1.20%). Among the 300 participants of Hungund taluk, 194 (64.67%) had either
dental fluorosis (35%), skeletal fluorosis (17%) or both (12.67%). In the Mundargi taluk,
browning of the teeth was the most common symptom of dental fluorosis followed by pain
and pus in teeth. Ninety five subjects had pitting and swelling and 86 participants had lost
their teeth. In Hungund taluk, lack of luster was the most common symptom followed by
browning of teeth with about 6 participants having lost their teeth. Overall, dental fluorosis
was more severe in Mundargi.
TiW* 1 Siinptem nf ilrntalfluoioT among rlie fluuiufii 'ub|«t< iiumMandaigi undhuugiuid falnk
.',np. ,», ^'".J',1 lUvm.'Kr „-•>•
'. J -.iMJit Jfil
M-, J.T, f™;n ,•? ljul, ,,-,-., F.VI ' '/; (...« 9n,c,,,J
L cl * " o C5.j".-tv "1 """ ^J 4i I1' 4 i >cii~ L 1 o* "4 ifin>«l-~
?"kite iirJiw-< 4'~ J( 4_ °* " 'f* 1tij S-^ -H 1 ~~ ji 1 2 Aft 4 ! -*^ '
B*~ ' vmre ' it_ -«in i i_> 4iixif> "" f I'
B'u'nni.K i OH. '""< ->"ui ./ r" ;t,4 Hi 2 "if I~M "41 : i
md y i
It^Lii s HSL l^c-^ti *^ti"Ji 3 tw 41^ n4 1 1 ^sf t i i ^j 1 1 i
L • Ttee-li tldl ~ . 4^ ,i " i ' u ytijd "^, i 5 'l<1
- LJC "f-. ij_e cftl° let iltlepja m '. 3* s1 1J1J. kl
PROFILER'S NOTE: The profiler agrees that the number of more severe findings were
observed in the higher fluoride area, Mundargi taluk; however, if the authors had provided
the data based on age groups and length of exposure, more useful information for
establishing a dose response would have been available for evaluation. Also, more details
in how the authors determined signs and symptoms are needed.
Table 2 below is copied directly from Bharati et al. (2005). For skeletal fluorosis, tingling
and numbness of extremities, back pain and bending were observed in a high number of
females in both areas. Males in both areas had more joint and knee pain. A higher
percentage of females were unable to walk properly or do normal work compared to males
in Hungund but the opposite was true in Mundargi taluk. Overall, skeletal fluorosis was
more severe in Mundargi taluk (the high-F communities).
Tahlt 2; ^iniitomr- of "4;e!rfal ftioi osr among flnot-oric *olij«T5 fiomMuntfat §i and Hiuignncl taluk
•n-pw.,.- :>.f,w, .-fjuvii ca-i:
FemaM TosA
'Ju-^flf, a-r,^ 'u<;,n,vur. JJ,,1C,m' V.™-fllYl Hvr»l
H,ii"f :im 4i4ii'it' J!>i*l '? ~ *' <>4 _••> .i" ftl * jii."" J4" "Si? v i
^k^i it.Vr j HIT 1 "^ „ J s n ij ^ ^ 1 '^^' 2no i1 ! 4il *^
''tfL* t _' J 4 M >S ~i4i i 1 '' i .5i: "4 Jil *-.
Bei l\r«i r 1 ~~ llv13 J. 1J15 :.'?• 2ti" '•' jil i,
T Hr""-tT all prcp»-- 1 il-i _i 2 t ' 'ir 3 . "Si J'l"^1 s-"i4h_
Eo-i-ilez - -il "4 4' ll^i
Laii'i-' JTI in i' - 1 ^ - I'M i. :t_!1 i *ni LI ji 1 "i
E\d mi* Tc ir m
'tu-*uzc.j--i... - 1(1.08) - - - 1(0.52)
KL t nle^1 11 - - - !>M il'
iTH ^r-]rB- 1 "> - - - li".''1
s mr;vW,.ii)l li' - i'C'iSl - l^1.
i" HI ' JrIJ,.""..«"J .* " » 31 ^"'•43! - ~i" IV
FtZu..e . [uicirlir i uiikiVie "e J '5-
- LJI ^i '"« 'j ji.e ::tl e j 1 • ect^ liie H J ma. r T ^ aipti J
PROFILER'S NOTE: The profiler agrees that the number of more severe findings were
observed in the higher fluoride area, Mundargi taluk; however, giving the data based on age
groups and length of exposure would have provided more useful information in establishing
January, 2008
-------
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
PROFILER'S Initials/date
REMARKS DFG/1-07
PROFILER'S ESTEM.
NOEL/NOAEL
PROFILER'S ESTEM.
LOEL/LOAEL
POTENTIAL SUITABILITY
FOR DOSE-RESPONSE
MODELING:
a dose response.
Also, more details in how the symptoms were determined are needed.
The people of Mundargi and Hungund taluk consuming water containing more than 2 ppm
of fluoride were suffering from both dental and skeletal fluorosis. Major symptoms of
dental fluorosis included lack of luster, browning, pain, pus and untimely loss of teeth.
Skeletal fluorotic symptoms observed included tingling and numbing of extremities, pain in
joints and knee, bending, stiff limbs, stiff vertebral column and unable to carry out the
routine duties. Preventative measures in these villages in the form of a supply of safe
drinking water and/or defluoridation of water is needed.
Bharati, P. 1996. Nutritional status and occurrence of fluorosis in selected villages of
Mundargi Taluk in Dharwad District. PhD. Thesis, University of Agricultural Sciences,
Dharwad.
Bharati, P. and Meera Rao. 2001. Epidemiology of fluorosis in Dharwad district. Journal of
Human Ecology. 14 (1): 3742.
Kubakaddi, A.B. 2001. Epidemiology of fluorosis and educational intervention in Hungund
Taluk. M.H. Sc. Thesis, University of Agricultural Sciences, Dharwad.
PROFILER'S NOTE: The two references that are thesis publication are not likely to be
retrieved.
The study severely lacked details that could have been used for developing a dose response.
The ages of the participants including their length of exposure to the fluoride, actual
fluoride levels measured in the water (including analysis techniques), details on other
sources of fluoride, using a widely-accepted method for measuring the degree of fluorosis
and applying statistical techniques to the data were either not performed or not provided.
Application of the findings of this report to exposure conditions in the United States is
limited, as the levels of F concentration in US domestic drinking water are usually much
lower.
Despite the incomplete documentation and limited application of these findings to the US
domestic drinking water debate, this paper adds background information to the limited
dataset on skeletal fluorosis. No other sources of F, such as food or tea, etc., were reported
in Bharati etal (2005).
Focus of the study was on documenting the clinical signs of fluorosis. Water fluoride levels
for the individual households were not reported, and no evaluation was made of
confounding factors. Although the data did show that the community with lower fluoride
levels had fewer cases of severe fluorosis, the data are insufficient for a dose-response
analysis. Further, the populations studied are not comparable (regarding dental hygiene and
diet) to North American domestic water consumers.
The study is not suitable for developing a NOAEL for fluorosis.
The study is not suitable for developing a LOAEL for fluorosis.
Not suitable ( ), Poor (X), Medium ( ), Strong ( )
PROFILER'S NOTE: This study supports the hypothesis that the incidence of decayed and
missing teeth is increased when dental fluorosis is severe, especially in areas where access
to dental care is poor. There is a dramatic difference between the two populations for decay
and other severe dental problems.
Although this study lacks details and is incomplete, the results could possibly be combined
January, 2008
-------
CRITICAL EFFECT(S):
with more robust studies for weight-of-evidence that participants exposed to >2 ppm
showed signs of dental and skeletal fluorosis, noting that a key piece of information missing
was length of exposure.
Dental and skeletal fluorosis
January, 2008
-------
Cao, J., Y. Zhao, J. Liu, R. Xirao, S. Danzeng, D. Daji and Y. Yan. 2003. Brick tea fluoride as a
main source of adult fluorosis. Food and Chemical Toxicology, 41: 535-542.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
Stage 1, 2 and 3 skeletal fluorosis
Cross-sectional survey
Tibet/Naqu County (Northern Tibet plateau): 1 1 1 (53 males and 58 females), 30-78
year old adults residing in either one Tibetan Buddhism temple, one nursing home, or
two pastoral villages.
none
Actual duration that the population was exposed was not included; however, the study
stated that the risk of developing early signs of skeletal fluorosis is associated with a
fluoride intake of >10 mg/day for> lOyears (Sub-committee on the 10th Edition of the
RDAs Food and Nutrition Board Commission on Life Science, National Research
Council 1989) and the average estimated intake for the adults in the study was 12
mg/person/day.
The 111 participants came from four groups with similar food habits in Naqu County,
Tibet. They were either Lamas from a Buddhist temple, elders in a nursing home or
herdsmen from two different pastoral villages. The use of brick tea is very prevalent in
the area and is an important part of the diet. (Brick tea is a densely compressed block
of tea leaves, which is then shaved into hot water and steeped as a beverage, or used as
a broth for cooked or parched grains such as barley).
The main source of fluoride exposure in the area is through the consumption of brick
tea. Tables 1 and 2 are copied directly from Cao et al. (2003) and indicate all factors
that are possible contributors to fluoride exposure in the area. Local water supplies and
industrial air pollution (nonexistent in this part of Tibet) were eliminated as significant
sources of ingested fluoride.
I
l::mt'o:ime:Uiil fluoride !s\ei in Nnqu Cuaitt) itng Kg or tnt !)
Satnpi". N /"±^
D;i:iLi;M waa-r IS (UOitj.W
Suit 5 tU2±)l.ll
C OM dung 5 l>.12±fU)V
Ua:!cy tlimi 5 H.2I±«.IIM
\\rural "loaf 5 lUSill.U
Ikvl and mutton 5 It.ti7±ti.li|
Uri^k ten 4 V.W±J7
/atnlw 4 4.:>±n.V4
Haiteral f jii 4 XJili.hi
1
i'oui' daily ilaondi: intake of adult-; in Naqu t ojtit> inia'pciscwi 'Jay!
Bu::e:cd Hour Bed" it-id /am ha 1'otai
ft'a niii'toii
1 intake Cti:t-.U'.u*i\f "",« S.fU 3.M tl.ll) OJI2 II.1)1)
fi? .O U.S (I.I UHi
PROFILER'S NOTE: Both buttered tea and zamba (a parched barley food staple) use
10
January, 2008
-------
ANALYTICAL METHODS:
STUDY DESIGN:
PARAMETERS
MONITORED:
STATISTICAL METHODS:
RESULTS:
Skeletal fluorosis
brick tea in their preparation.
The fluoride levels for water, brick tea, brick tea-water, soil, fuel, food and some urine
samples were determined with or without pre-treatment by using a fluoride-ion
selective electrode method. This method was described by the Chinese Public Health
Ministry, "The Manual of Preventing Endemic Fluorosis" (Dept. of Endemic Disease
Prevention 1991; Cowell 1977; Itai and Tsunoda 2001)
The study was conducted to examine the prevalence of skeletal fluorosis in adults
living in the Naqu County area of Tibet where, earlier, Cao et al. (2000) identified
dental fluorosis in children. One hundred eleven adults, > 30 years old, from four
different sites were selected by a randomized sampling method. The level of fluoride in
the water, fuel, soil, food, brick tea, brick tea-water and urine were determined. For the
fluoride level in food, daily food intake was measured for 3 consecutive days; from
these data, a mean daily total fluoride intake was calculated. Physical examinations
evaluating for skeletal fluorosis using a standardized set of non-invasive physical signs
commonly associated with the disease (e.g., fingers could not touch the shoulder,
middle finger could not touch the contralateral ear, etc.) were performed with subjects,
and individual radiographs were performed on those that presented with 3 or more
physical signs.
Environmental sources were measured for fluoride concentrations and included, water,
fuel (cow dung), soil, and food.
Participants were evaluated for skeletal fluorosis on physical examination for the
presence of the following physical limitations according to the Standard of Endemic
Fluorosis (Cao, SR 1992): (i) fingers could not touch the shoulder because of
restricted elbow flexing; (ii) hands up could not reach 180°; (iii) the middle finger
could not reach the contralateral ear; (iv), the thumb could not reach the lower angle
of the contralateral scapular; (v) the heels were raised when squatting; (vi) the patient
essentially could not squat; (vii) 45-90° kyphosis; (viii) restricted flexing and/or
hands up of extremities; (ix) paralysis.
Forty two of the 99 patients demonstrating more than three of the physical signs were
also radiographed to confirm diagnosis, and some of the 42 also had their urine tested
for fluoride concentration. Radiographs were performed according to the
recommendations in the Chinese National Standard "Criteria of Skeletal Fluorosis X-
Ray Diagnosis" (Public Health Ministry 1976).
The student's t-test was applied for inter-group comparison.
Tables 4, 5 and 6 are copied directly from Cao et al. (2003) to indicate the prevalence,
age range of those affected, severity of skeletal fluorosis, and the radiographic findings.
The tables indicate more prevalence and severity of signs as the adults became older,
and that 83% of all the participants had some form of skeletal fluorosis. The most
common radiographic change was trabecular changes to the interosseous membrane
which occurred in 86% of those diagnosed with skeletal fluorosis.
TiU«4
A.ge dis'liifeeikiis for sigim of mtsise s.kdetal (feorays
Ag® grOTjs ^'€Mi"3 Cam with thrre ta titaeitetm ofpo^iiiw stigim Total
5te$ 3 Itfflm 4 flam 5 tarn 6 Iffitm ? ftaim i llmrn 9 Item
39-3* M31000004
F3000000 -1
«M» M } 3 1 J 0 0 0 8
F 3 I I 0 it a 9 S
541-59 M 4 1 32000 12
f 3 S 3 3 0 0 0 It
150-78 M 3 3 6 4 3 2 2 23-
F 15 5 1 (t 1 2 1 30
11
January, 2008
-------
, rl Ihi ',* ca <*» ot r.iJi '
Shige ",
j'.'jrlyi
Sup.- II
( mJva need i
Sttge III
llalci
Total
'rutoluliw
45"-,
Uhk *
M iiu r=( h fETtf HK. feitur--. mH f>pine
til trid. l.i Up-- kdct il Hu T M-V
irnh;--ij
tKsittiu
me ttt i-himn
rhH-ml-n \rtKui ir
T hvrnilmi: Toiai
PROFILER'S NOTE: The prevalence of the skeletal fluorosis with more than 3
positive signs increased with age and was most prominent in those aged 60-78. The
radiographic findings correlated well with the physical findings indicating physical
signs were a good diagnostic (and non-invasive) tool for screening patients.
STUDY AUTHORS'
CONCLUSIONS:
In Naqu County, Tibet, the total daily fluoride intake in adults was estimated to equal
12 mg, with 99% coming from brick-tea containing foods. The occasional urinary
fluoride level was 5.73 mg/L and the incidence of adult skeletal fluorosis among
subjects examined was 89% by physical examination and 83% by radiographic
diagnosis.
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
Cao, J, Y. Zhao, and J. W. Liu. 2000. Fluoride in the environment and brick-tea-type
fluorosis in Tibet. Journal of Fluoride Chemistry, 106, 93-97.
Cao, S.R. 1992. Standards of endemic fluorosis. Fluoride Research Letters, 7 (1), 29-
36.
Cowell, D.C. 1977. Automated fluoride ion determination. Determination of urine
fluoride ion levels. Annals of Clinical Biochemistry. 14(5), 269 — 274.
Department of Endemic Disease Prevention. 1991. Chinese Health Ministry. The
manual of preventing endemic fluorosis. Chinese Endemic Disease Preventative
Research Center, Harbin.
Itai, K. and H. Tsunoda. 2001. Highly sensitive and rapid method for determination of
fluoride ion concentrations in serum and urine using flow injection analysis with a
fluoride ion-selective electrode. Clinica Chimica Acta, 308 (1-2), 163-171.
National Research Council. 1989. RDAs: Fluoride subcommittee on the tenth edition of
the RDAs food and nutrition board commission on life sciences. Washington D.C., pp.
235-240.
Public Health Ministry, China. 1976. Criteria for bone fluorosis, x-ray diagnosis
(GB 16397-1996). Chinese Standards Press, Beijing, p. 6.
PROFILER'S
REMARKS
Initials/date
DFG
12/15/2006
The profiler felt the study design was adequate. Based on previous evidence of
pediatric dental fluorosis in the region (Cao et al. 2000), the area was revisited to assess
skeletal fluorosis in adults. The study used standardized methods for evaluating
physical signs, and also relied on two methods of diagnosis (physical limitations and
radiographs). The study showed a positive correlation between adult exposures to an
estimated 12 mg F/da and adverse skeletal fluorosis. The study helped provide a
LOAEL but could not be used for a dose-response study by itself, because only one
exposure concentration was identified.
12
January, 2008
-------
PROFILER'S ESTIM.
NOEL/NOAEL
PROFILER'S ESTIM. LOEL/
LOAEL
POTENTIAL SUITABILITY
FOR DOSE-RESPONSE
MODELING:
CRITICAL EFFECT(S):
The NOAEL could not be determined in this study.
It is unclear where the actual LOAEL occurs, as only a single estimate of adult daily
ingestion was calculated (e.g., 12 mg F/person/day); no distribution or range of intake
was presented by the authors. Adverse skeletal fluorosis findings were identified at 12
mg F/person/day; this estimation is limited by the short-term duration of observation (3
consecutive days of food intake).
Not suitable ( ), Poor (X), Medium (), Strong ( )
Although the study does not use the correlation of fluorosis with a source applicable to
the U.S. population, it still provides a thorough study indicating that long-term
exposure to fluoride concentrations approximating of 12 mg F/person/da is associated
with advanced to late-stages skeletal fluorosis. The study is also a good example of
evaluating all sources of possible fluoride intake as the drinking water alone did not
possess fluoride concentrations sufficient to cause skeletal fluorosis.
Skeletal fluorosis graded II (advanced) or greater.
13
January, 2008
-------
Goldman SM, Sievers ML, Templin DW. 1971. Radiculomyopathy in a southwestern Indian due to skeletal
fluorosis. Ariz Med. 28(9):675-7.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
ANALYTICAL METHODS:
STUDY DESIGN
PARAMETERS
MONITORED:
STATISTICAL METHODS:
RESULTS:
Physical Examination
Skeletal fluorosis, fluorotic radiculomyopathy
Case report
Arizona, Gila Bend; 55-year old Papago Indian male admitted to the Phoenix Indian Medical Center
on May 2, 1969, for evaluation of possible pulmonary tuberculosis. Long standing severe weakness
of both legs was attributed to trauma from an accident 10 years earlier.
Not applicable in case report.
Lifetime (55 years)
Samples of the water from the patient's drinking source were evaluated by the Arizona State Health
Department and found to contain 5.2 to 7.8 ppm fluoride. A random sample of this water, analyzed
by two methods by Dr. Leon Singer of the University of Minnesota at the time of the tooth analysis
revealed a fluoride content of 4.04 ppm and 4.27 ppm.
Subject had a history of drinking large quantities of water with a fluoride concentration 4-8 ppm; he
also drank hot tea. Two additional practices further elevated the high water fluoride concentration:
boiling water for hot tea, and keeping his drinking water supply in open containers for several days,
permitting evaporation in the low humidity climate in Arizona.
Method used by Arizona State Health Department to measure fluoride water levels not reported. Two
methods were used by Singer; ion electrode method and diffusion isolation with colorimetric
analysis.
A 5 5 -year old Papago Indian male from Arizona was admitted to the Phoenix Indian Medical Center
on May 2, 1969 for evaluation of possible pulmonary tuberculosis. He had a lifetime history of
drinking large quantities of water with a high fluoride concentration (from 4 to 8 ppm); he also drank
hot tea. He was examined and x-rays were taken to determine bone density of the spine, ribs, and
pelvis. Laboratory tests included VDRL, hemoglobin, hematocrit, serum calcium, phosphorus,
alkaline phosphatase and acid phosphatase. Chemical analysis for fluoride was determined in an
extracted tooth. A diagnosis of fluorotic radiculomyopathy was made.
The physical examination assessed muscle tone, range of motion, and neurological abnormalities. X-
rays were taken to evaluate bone density, evidence of fractures, and sagittal diameters of the cervical
and lumbar spine. Laboratory tests included VDRL for syphilis, hemoglobin, hematocrit, serum
calcium, phosphorus, alkaline phosphatase and acid phosphatase. Chemical analysis for fluoride was
determined in an extracted tooth.
Statistical analysis was not performed on this one patient.
The subject had bilateral flexion contractures of both knees and elbows. The range of knee motion
was 80-95° on the right and 80-140° on the left. Limitation of abduction and rotation of the shoulders
was noted. The neck and spine were completely rigid. Muscle tone was normal, but sensation to light
touch and pin prick was decreased over the dorsum of the right foot. He was unable to stand without
assistance.
Laboratory tests revealed nonreactive VDRL, and normal hemoglobin, hematocrit, and serum
calcium, phosphorus, alkaline phosphatase, and acid phosphatase.
14
January, 2008
-------
Skeletal fluorosis
Dental fluoride content
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
PROFILER'S Initials/date
REMARKS SJG/
10/26/07
X-ray examination revealed generalized increased bone density of the spine, ribs, and pelvis,
suggestive of skeletal fluorosis, and accompanying osteophytosis. No evidence of previous vertebral
fracture was noted. The sagittal diameters of both the cervical and lumbar spine were below the 90%
tolerance levels, as summarized in Tables 1 and 2 copied directly from Goldman et al. (1971).
TABLE 1
S*pttal MMMte rf CervteaJ Spinal Canal
80* minimal Lowest normal Press*
tolerance Itaiiti Hmitf (mm) patients
for «tft*l (wording to Bwn&ure-
dimeter {mm} Whotay1} iwnl*
(according to
Ifinck') ._
CM 16.8 W If
C-2 16,1 W }g
C-3 14.3 16 10
C-4 14.1 14 9.5
C-5 13.9 14 11
TABLE 2
Sagittal Diameter oC the Lumbar Spine
W& tolerant* fails Pwsenl patient's
for saettlJ diameter (mm) ijieasur*™#wt» {mm}
{awowing to Hiuek")
L-l IB I*
L-2 IS 12 t
L~3 17 1-1-S
L-4 » 13
L-5 18 i2
Chemical analysis of the extracted tooth revealed the following fluoride levels: bulk canal, 614 ppm;
a calculus from the crown, 4838 ppm; a supragingival calculus, 5299 ppm. Tooth analysis confirmed
fluorosis.
PROFILER' S NOTE: Normal tooth values for fluoride were not presented for comparison.
The patient was exposed to prolonged (55 years) excessive fluoride in drinking water (4-8 ppm). He
presented with neurological deficits and severe weakness in both legs. Fluorosis was confirmed in an
extracted tooth in which fluoride content ranged from 614 to 5299 ppm, depending on the part of the
tooth. Syphilis was ruled out by the VDRL test.
The characteristic vertebral changes of skeletal fluorosis and severe osteophytosis were probably the
basis for the patient's neurological deficits. Although trauma may have precipitated his
radioculomyopathy, the neurological symptoms are adequately explained by the marked narrowing of
the sagittal diameter of the cervical and lumbar spinal cord and the vertebral osteophytosis secondary
to fluorosis. Neurological deficits occurred as a manifestation of spinal cord and nerve root bony
compression.
Skeletal fluorosis occurs in only a small percentage of those with prolonged ingestion of water with
excessively high fluoride content, and radiculomyopathy is rare among those who develop skeletal
fluorosis. This case is of regional importance since fluorosis is endemic to Arizona. The authors stress
that water fluoridation programs (at 1 ppm) have no potential for causing skeletal or neurological
complications as reported in this case due to the low fluoride concentrations.
VDRL: A blood test for syphilis (VDRL stands for Venereal Disease Research Laboratory)
Hinck VC, Hopkins CE, Savara BS. 1962. Sagittal diameter of the cervical spinal canal in children.
Radiology. 79: 97-108.
Wholey MH, Bruwer AJ, Baker HL Jr. 1958. The lateral roentgenogram of the neck. Radiology.
71(3): 350-6.
The study design does not aid in the development of a dose response to fluoride with respect to
skeletal fluorosis. The objective of the study was to report the second documented case (as of 1971)
of fluorotic radiculomyopathy in a single patient with prolonged ingestion of water with a fluoride
concentration of 4-8 ppm. The patient's symptoms and neurological deficits are presented well and x-
15
January, 2008
-------
PROFILER'S ESTEM.
NOEL/NOAEL
PROFILER'S ESTEM.
LOEL/LOAEL
POTENTIAL
SUITABILITY FOR DOSE-
RESPONSE MODELING:
CRITICAL EFFECT(S):
ray examination provides evidence of narrowing of the sagittal diameter of the cervical spinal canal
and lumbar spine below the tolerance limits. Although the case is interesting and novel, it has some
limitations. Laboratory tests did not support or contradict the diagnosis of fluorotic
radiculomyopathy, except to rule out syphilis (VDRL test). The authors do not explain the rationale
behind the chosen laboratory tests, nor do they present normal values for fluoride in teeth for
comparison. Because the diagnosis is so novel, it would have been more compelling if other potential
diagnoses were presented for consideration and then ruled out based on the presented evidence.
Study design was not suitable for development of a NOAEL.
Study design was not suitable for development of a LOAEL.
Not suitable (X), Poor (), Medium (), Strong ()
The study presented a rare case of fluorotic radiculomyopathy as a progression of skeletal fluorosis in
one patient with prolonged exposure (55 years) to fluoride in the drinking water at 4-8 ppm.
Skeletal fluorosis and radiculomyopathy
16
January, 2008
-------
Kurttio, P., N. Gustavsson, T. Vartiainen, and J. Pekkanen. 1999. Exposure to natural fluoride in
well water and hip fracture: a cohort analysis in Finland. Am. J. Epidemiol. 150: 817-824.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
Skeletal (hip) fracture
Retrospective cohort (based on hospital discharge record linkage )
Finland/Southeast and Southwest: 144,627 persons (66,742 men; 77,885 women) from
Finland, born in 1900-1930, who from at least 1967-1980 lived at the same address in a
rural village or area where >90% of population did not use municipal water (e.g.,
private well-water users). Their incidence of hip fracture was recorded for 1/1/81-
12/3 1/1994, and is presented in Table 1 according to gender, age on 1/1/81, occupation,
and geographic area of residence. Persons were excluded who had a hip fracture
between 1/1/78 and 12/3 1/80 or whose main diagnosis was not hip fracture, and only
the first hip fracture was tabulated.
TABLE t Description of the study vibjwli who had livtd at teas! (torn 1967 to 1i80 outsid* mynretpftl
dfiatuflt water sources in Finland
*,,„ ^"-''"""'''1^1-^
fin '«. H>(, " 1* H(
f m^t^l^S t»«5GturEu> <')- ,f^ * ip f**t!i«r
RS ^^\ ~ 5T " ~4N?rl '' * ** 'M
yi «S UBiS It (I ft H/it,>, (Oil (1 fl
f.fUVt lt,
T>, 80 €17"* .i.'tt 6,1 tf«>JS 388 11'
Adin!mst*M!u*> ^ruet, Uimffieradl 15^G 3F' 10 5,92ie f33 22
i-Oilfel'^ctiftn fr<$us!oE 5 tra^^Oift^fOn °H$S# sMl] 14 3 3tt1 'i^s 1C
',«mina. lo.csbs, fis.non 41023 69S '* ,17efl« t,201 31
Uitvivmn nal* V!> 39 2",rcu t BIS 66
Geaqfap^u area
1 4,1 "XI It* 13 ^.382 M2 SJ
2 IBfK 74 '» Vli? )"*.> <3
3 10(133 tw> 8 K'Vfi 43? 40
4 b,?SG !1b ?•>):'? tj^i ^
6 1Clf> j»'j 0 H.CO* 1.50.
Water concentrations of F were determined potentiometrically from untreated samples.
Individual F exposures were estimated for each cohort member based on their location
17
January, 2008
-------
ANALYTICAL METHODS:
STUDY DESIGN
PARAMETERS
MONITORED:
STATISTICAL METHODS:
RESULTS:
Fluoride concentration and
hip fractures
and using a database of groundwater fluoride measurements (8,927 wells) by the
Geological Survey of Finland (Lahermo et al 1990). The interpolation method of a
moving weighted median was used to smooth the concentrations to obtain a regular grid
of estimated fluoride concentrations. The grid was 2x2 km2 and the window radius
was 42 km. The nearest accepted grid value for each member of the cohort was found
using the quad-tree algorithm. The estimates made by this method were compared to
fluoride measurements from a national study in 1990-1991of 1,41 1 wells that
geographically represented all of Finland.
Other fluoride sources included food and toothpaste, which were estimated in Finland
as 0.6 and 0.08 mg/day, respectively, based on work by other investigators. These
extraneous fluoride sources were not accounted for in the data analysis.
Water fluoride concentrations were measured potentiometrically (no further description
provided).
The study cohort consisted Finns born in 1900-1930, who from at least 1967-1980 lived
in the same rural area. Finland was divided into 8 areas along the longitudes of 2.5°,
25.5°, and 28.5°, and latitudes of 62.2° and 65.0° as a crude adjustment for possible
effects of the geographic area of residence. The date of birth, gender, and place of
residence, residence history, and occupation in 1970, 1975, and 1980 were obtained for
each person from the Population Census of Statistics Finland. Occupation was used as
a measure of socioeconomic status, although these data was unavailable for 59% of the
subjects.
The subjects' incidence of hip fracture was recorded for 1/1/81-12/31/1994, based on
the Hospital Discharge Registry (linked with personal identification numbers). Persons
were excluded who had a hip fracture between 1/1/78 and 12/3 1/80 or whose main
diagnosis was not hip fracture, and only the first hip fracture was tabulated. The effect
of the water fluoride concentration on the risk of hip fractures was analyzed for men
and women separately, and for either all ages (50-80) combined, or for 5-year age
increments. The statistical methods used are described below ("Statistical Methods").
First hip fractures, per data obtained from the Hospital Discharge Registry of Finland.
Age at the beginning of follow-up (i.e. as of 1/1/81) was the basis for subdividing the
cohort into age groups. The number of "person-years" (in Tables 2 and 3) was
calculated for the period beginning on 1/1/81 and ending with date of the hip fracture
diagnosis, the date of death, or 12/3 1/94. Cox's regression was used to determine the
crude and adjusted (age, area, occupation) rate ratios and confidence intervals (CI).
Age was adjusted for as a continuous variable (similar risk estimators obtained if age
was class variable) and fluoride concentration was analyzed as both a continuous and
stratified variable.
The estimates of fluoride concentrations ranged from below 0.05 mg/L (detection limit)
to 2.4 mg/L, and most of the subjects lived in areas where water fluoride was estimated
as <0. 1 mg/L. There was a correlation of 0.7 1 between the analyzed and estimated well
water concentration, and the latter "tended to be 0.7 times less than the measured
fluoride concentration in a well." This diluted the effects of the highest fluoride
concentrations.
Hip fracture incidence clearly increased with age, and was higher in females than males
in all age groups. When all ages were combined for each gender, there was no
correlation (age or area-adjusted) between the rate ratios (RR) of hip fractures and water
fluoride concentration, whether fluoride concentration was treated as a stratified
variable (Table 2) or a continuous variable (age-adjusted and age-area-adjusted RRs for
men were 0.97 and 0.90, respectively, and for women were 1.07 and 1.10, respectively).
18
January, 2008
-------
l&SliE 2. H@Jg ratios (RR) ao0 t "1? 085 061 118 07? D?1,1Un
Ofii-ioo we SVM/ r i;i t ;e i m *s» 103 081.132
1 10-1 SO 3.' P?,751 t4t ufl'j OM 1"! 067 04609'
>t -,l> IB »vr IBM 1*3 J7> 181 09P OBI. 1,6P
Worws
510 "650 5E4621 3 T.I 1 0 10
0 11-0 W 775 21MH37 351 106 CM7 1 1" 0<5," O.W, 1 0?
031-050 14? 34617 210 1.^ t iU 1,46 II,1 093, t. 34
051 100 "ff f644fl (M i 21 1 06 1 AJ 1 f» C>9f. 1..11
1 10 ! W US .W497 '(1:7 1 Id M..14U 1 OR 088,1.12
~1 i>0 47 'i 7W iu) 1JO Ol»16U 108 06(1. » 46
Analysis of the subjects stratified by age (six 5-y
the crude and adjusted (age, area) RR for men aj
women aged 50-65 were above 1.0, as shown in
, M«n
a.*-! ?s-
2 I
|s £^ ll M
If '- T f T T f f| '*
^" l_-^«p-^*^--^^=!s-|- ^i
| «. ir-; t ii* | as.
00 DA,,
ear increments), however, found that
;ed 50-59 were below 1.0, whereas for
Figure 3.
T
(l'^T~-^c 1 1
-I— — SatJ_— «««,— — -A
1 -±— ^A^B^r-J- -^-y_
5
-------
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
PROFILER'S
REMARKS
Initials/date:
SM
1/19/07
PROFILER'S ESTIM.
NOEL/NOAEL
PROFILER'S ESTIM. LOEL/
LOAEL
POTENTIAL SUITABILITY
FOR DOSE-RESPONSE
MODELING:
CRITICAL EFFECT(S):
Kurttio et al. (1999) concluded that fluoride (in the drinking water) had a slight, non-
significant protective effect against fractures in men aged 50-64, but was associated
with an increased risk of hip fracture in women aged 50-64 as of 1/1/81 (the
beginning of the follow-up period). The adjusted RR was 2.09 (95% CI 1.16, 3.76)
for women who were exposed to the greatest fluoride concentrations (>1.5 mg/L) as
compared to women exposed to the lowest fluoride concentrations (< 0. 1 mg/L). No
correlation was found between fluoride concentration and hip fracture in the older
subjects (65-80 years old), possibly due to other more prominent risk factors at higher
ages (e.g. age-related changes in calcium absorption, fluoride metabolism, hormonal
status, etc.).
The weighted median smoothing method of estimating well water fluoride
concentrations tended to underestimate the actual fluoride concentrations and diluted
the effects at the highest fluoride concentrations, which might have biased the ratio
estimates toward the null. Although the effects of possible confounders such as
nutrition and physical activity were not addressed, the overall effect of geographic
location and occupation were small.
Lahermo, P, M Ilmasti, R Juntunen et al. 1990. Geochemical Atlas of Finland, Part 1.
Hydrogeochemical survey of Finnish ground waters, (in Finnish). Geological Survey of
Finland, Helsinki.
This was a well-conducted study that clearly showed that in the Finnish population, the
incidence of hip fracture increased with age, and was particularly higher in younger
females (aged 50-65 years) exposed to drinking water >1.5 mg/L than males in all age
groups (50-80 years old) or older women. The major confounder was that the subjects,
who were up to 80 years old, had to have lived in the same rural location for only 13
years of their life (1967-1980). Other drawbacks were that the water fluoride
concentrations were generally underestimated, and that too broad of a concentration
range was included in the highest exposure group (i.e. >1.5 mg/L).
Information and references provided in Kurttio et al (1999) are pertinent to relative
source contribution analysis. Known risk factors such as alcohol
consumption/smoking/low body weight were not controlled.
A NOAEL cannot be assigned based on the provided data.
A LOAEL cannot be assigned based on the provided data.
REVIEWER'S NOTE: Nevertheless, the paper points out that drinking water
concentrations >1.5 mg F/L are positively associated with an increased relative risk of
hip fracture in adult women aged 50-65 (the "younger" cohort). The elevated relative
risk for this fluoride water concentration and age class is not statistically significant
based on the reported 95% confidence intervals, but is a finding of concern.
Not suitable (x ), Poor ( ), Medium ( ), Strong ( )
Skeletal (hip) fracture
20
January, 2008
-------
Leone, N.C., Stevenson, C.A., Hilbish, T.F., Sosman, M.C. 1955. A roentgenologic study of a human
population exposed to high-fluoride domestic water: A ten-year study. Am. J. Roentgenol. Radium Ther.
Nucl. Med. 74(5):874-85.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
ANALYTICAL METHODS:
STUDY DESIGN
Bone changes (density; osteoporosis; coarsened trabeculation; hypertrophic change)
Cohort (prospective)
1 16 white adults, 15 to 63 years old at study initiation (1943), residing for at least 15
years in a high-fluoride area (Bartlett, Texas) where water fluoride level was 8 ppm.
121 white adults, 15 to 63 years old at study initiation (1943), residing for at least 15
years in a low-fluoride area (Cameron, Texas) where water fluoride level was 0.4 ppm.
All participants had a minimum of 15 years of residence (exposure) in the respective
towns at study initiation in 1943. The average length of exposure was 37 years in the
high-fluoride area and 38 years in control area. Follow-up studies were conducted after
a 10 year interval, in 1953.
In 1943, 237 participants were selected based on minimum residence of 15 years in
Cameron or Bartlett, Texas, where naturally occurring fluoride content of the water was
0.4 ppm or 8 ppm, respectively. No other sources of fluoride exposure were considered,
besides prolonged fluoride ingestion from drinking water.
In 1953, 47 of the original participants moved from the immediate study areas, 22 from
Bartlett and 25 from Cameron, predominately of the younger age groups. These
'removed' participants were located and similar roentogenographic studies were made
in all but 10 cases.
Roentgenograms were made in 1943 and repeated on the same subjects with matching
views in 1953. Individual medical histories, physical examinations, and laboratory data
were correlated with roentgenograms.
The method used for measuring the fluoride concentrations in the water was not
reported; no other water quality parameters were measured.
The primary objective of the study was to present roentogenographic findings of a ten
year study of 237 white adults (15 to 63 years old) residing in a high-fluoride area
(Bartlett, Texas, 8 ppm F) or in a control area (Cameron, Texas, 0.4 ppm F), and to
describe the findings that might be ascribed to prolonged ( >15 years) fluoride ingestion.
Roentgenograms were made in 1943 and were repeated on the same individuals with
matching views ten years later to enable comparative study of the individuals in each
group with themselves and of those in a high-fluoride group with those in a low-fluoride
group. The roentogenographic findings were correlated with individual medical
histories, physical examinations, and laboratory data to evaluate the presence or absence
of any detectable effects in the individual, in the groups, or in the various age categories.
Bone fracture histories, arthritis and systemic conditions which might be associated with
roentgenographic findings were tabulated. There were no significant differences in these
conditions within the study groups.
The roentgenograms were made at the Scott and White Clinic, Temple, Texas, under the
immediate supervision of the same Chief of Service in 1943 and in 1953. A 500 ma.
roentgenographic unit with rotating anode tube was used on both occasions. Emphasis
was placed on bone detail. Anteroposterior roentgenograms of the dorsal and lumbar
spine and the pelvis, showing the proximal third of each femur, were made for each
patient in 1943 and again in 1953. When bone changes were found (e.g., increased
21
January, 2008
-------
PARAMETERS
MONITORED:
STATISTICAL METHODS:
RESULTS:
Bone changes
(bone density, coarsened
trabeculation, osteoporosis)
bone density, coarsened trabeculation, hypertrophic change, ligamentous calcification) a
roentogenographic bone survey was made, consisting of the following views: a lateral
skull (stereo), cervical spine; left upper arm, forearm and hand; and right femur, lower
leg, and foot. These regions represent those in which the earliest or most definite
manifestations of fluoride effects might be seen if present.
Most of the "removed" participants were transported to the Scott and White Clinic,
where they were examined in the same manner and with the same equipment as the
other participants. No attempt was made to evaluate the "removed" participants
separately because no comparable roentogenographic differences were noted in these
persons from either area.
Bone density changes refer to increased or decreased density in the presence or absence
of coarsened trabeculation. Hypertrophic changes were recorded if they were moderate
(2+), severe-limited (3+), or severe-generalized (4+). Some hypertrophic change is a
normal finding, especially in aged persons, and was not considered as a possible
fluoride effect when change was moderate. Roentgenographic evaluation included a
correlation with individual histories and physical examinations.
Evaluations were made on the basis of age, sex, activity, study area, and elapsed time.
Details of data analysis were reported in an earlier paper (Leone et al. 1954) and not
included in the current study.
Table 1 was copied directly from Leone et al. (1955) and summarizes roentgenographic
bone changes in subjects residing in the control (Cameron) and high-fluoride (Bartlett)
areas over a ten-year interval. A limited number of subjects from both areas showed
some degree of bone change, but these changes were minimal. High concentrations of
fluoride in the drinking water did not uniformly produce detectable bone changes. Only
one new case of increased bone density was found in the high-fluoride area at the end of
the ten-year period.
Of the original Bartlett cohort, 16 exhibited bone changes in varying degrees in 1943; in
1953, 9 of the 16 showed no further bone change, 4 showed an increase in bone density,
and 3 a decrease in density toward a "normal" appearance. One new case of increased
bone density was recorded. Of the cases designated as 'increased density' only 2 could
be considered frank abnormalities. In Cameron (control area), there were 4 cases of
increased density, 2 cases of increased coarsened trabeculation, and 8 new cases of
osteoporosis during the ten year period, as compared with 1 new case of osteoporosis in
Bartlett. During the 10-year interval, 4 Bartlett participants showed increased coarsened
trabeculation without increased bone density.
Increased bone density occurred predominately in persons over the age of 45.
Decreased bone density in those who showed an increased density in 1943 is of interest
as a transition from a dense bone structure to less dense appearing bone ten years later.
22
January, 2008
-------
TABLE I
It >K> i I- t !-('\MI K!l\ lUnRIUI »lllli
R<;_;
B.ntlt'tt C.imcion
Nnmlv Numlti'!
•\l>rHiniiaht\ } StucHCif: J^v ^tsuhi'tl" t'~
4 [ 4
I :?
I
2 j JO
I}ttre.-t,,c.ii
C )>itooj>iiri>sis
t'oirscned frahecula-
fi(K) («ifh(«it in-
irtMMil hum. den-
sity) I 12
H \pertrotlire cli.utgi'f ;
** tralto uhuot , LsJudirn* £»,f «>pr.rt4»> ihsrKi
ili's k nc nev* i ,^c s Mn< F6 .isrd byn^ Ut'nMf^ in i ^* 1.
H nssss, but sstH i ' &r*jpor<»s3*».
^ OiJ% , t*< > %iih '\rv4re fns itul*' > j4" i -tntl *\rnrr * |, 5 lie1'.si
i',-.i (,4+' iff 'nrlllJf.1.
PROFILER'S NOTE: Results reported in the text do not appear to be clearly tabulated
in Table 1._ "In Cameron, there were 4 cases of increased density, 2 cases of increased
coarsened trabeculation, and 8 new cases of osteoporosis during the ten year period"
It is unclear whether these values are for 1943 or 1953; there were 4 cases of bone
density changes in 1943 with 3 increased cases and 1 decreased case in 1953; similarly,
there were 2 cases of coarsened trabeculation in 1943 and 3 cases in 1953. However, it
is clear that 8 new cases of osteoporosis were found in 1953 (10 cases in 1953 versus 2
cases in 1943). "During the 10-year interval, 4 Bartlettparticipants showed increased
coarsened trabeculation without increased bone density. " From Table 1, it seems that
there were 2 new cases of coarsened trabeculation in 1953 (14) compared to 1943 (12).
Case reports
Four cases were presented to represent the changes observed.
Increased density and coarsened trabeculation: A 72-year old white male, resident of
Bartlett for 33 years showed an increase in the total density of the bone throughout the
entire lumbar spine and pelvis. The change involved a coarsening of the trabeculae
halfway between the normal pattern and the thickened denser trabeculae in classic
Paget's disease. The process was uniform through all bone and not localized. A similar
view 10 years later showed no apparent change in the amount or character of this
abnormality.
Minimal increased density with coarsened trabeculation: The case of a 71 -year old
white male, resident of Bartlett for 59 years, was presented as typical of the majority of
positive cases in the series. The lumbar spine and pelvis showed a slight, but distinct
increase in the total density of the bones with coarsening of trabeculae, most evident in
the sacrum and not distinct in any other portion of the pelvic bones. There also was
definite ossification of the right sacrotuberous ligament, somewhat more extensive in
1953 than in 1943. There was no change in the degree of density when the 1943 and
1953 films were compared.
Increased bone density and coarsened trabeculation with a decrease in bone density 10
years later: A case of unusual medical interest is that of a woman with increased bone
density and coarsened trabeculation in 1943 with a decrease in bone density to a point
more closely resembling 'normal' bone 10 years later. Several such cases were noted in
23
January, 2008
-------
Bone fluoride content
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
the series. A 59-year old white female, resident of Bartlett for 39 years, showed a
marked increase in the total bone density in 1943, particularly in the vertebrae, sacrum,
and around the sacroiliac joints. There was definite coarsening of the trabeculae in the
lumbar spine, pelvis, and femurs. In the 1953 films, the increased density previously
noted had decreased appreciably and the trabecular pattern has lost much of its
coarsening. There were small bony spurs or ossifications in the region of the
sacrotuberous ligaments, and one sacrospinous ligament, slightly more pronounced.
Changes may have been due to postmenopausal osteoporosis.
5 0-year fluoride exposure without bone effects: An 84-year old female resident of
Bartlett with known exposure to a high level of naturally occurring fluorides for 50
years, and a resident of the high-fluoride area immediately adjacent to Bartlett for the
rest of her life (total exposure of 84 years to 4-8 ppm F) presented with no evidence of
increased bone density, coarsened trabeculation, or other significant roentgenographic
bone changes. This patient was the mother of one of the participants (not an original
subject herself in 1943) and is included to illustrate that a lifetime of exposure to high-
fluoride levels does not necessarily produce changes often described as 'fluoride bone
effects' or produce recognizable bone changes in all of those who are exposed.
Roentgenographic examinations in 1943 and 1953 on a patient who died after the 1953
examination showed a moderate degree of increased bone density with some coarsened
trabeculation. Chemical analysis of the bones showed approximately six times the
fluoride content (0.6 mg. per cent) of the same bone from individuals from non-fluoride
regions (as determined by FJ. McClure, National Institute of Dental Research). No
histologic changes could be linked to fluoride exposure.
The following types of roentgenographic bone conditions were seen in subjects
ingesting water with 8 ppm fluoride for long periods:
o Increased bone density with or without coarsened trabeculation, with a 'ground
glass' appearance.
o Coarsened trabeculation, showing lines of stress, without increased bone
density.
o Increased thickening of cortical bone and periosteum with equivocal narrowing
of bone marrow spaces.
The data demonstrate that ingestion of water containing up to 8 ppm fluoride produces
no deleterious bone changes: no unusual incidence of bone fractures, arthritis,
hypertrophic bone changes or exostoses, or interference with fracture healing; no cases
of 'poker spine' and no evidence of associated functional or systemic effects.
Excessive fluorides in a water supply may produce roentgenographic evidence of bone
changes, but the observable changes:
o Occur in only a select few (-10-15% of those exposed)
o Are slight, often difficult to recognize, and in most cases equivocal in degree
o Are not associated with other physical findings, except for dental mottling in
persons who resided in the high-fluoride area during the tooth formative
period (birth to 8 years old)
o Cannot be definitely ascribed to excessive fluorides alone
o Do not necessarily occur even though the fluoride content of bone may be 6
times that of 'normal' bone.
There is some indication that the ingestion of excessive fluoride in water may, on
occasion, have a beneficial effect in adult bone, as in counteracting the osteoporotic
changes of the aged.
Not applicable (cited reference is included in NRC fluoride report)
24
January, 2008
-------
FOUND IN NRC (2006)
PROFILER'S
REMARKS
Initials/date
SJG/11/1/07
PROFILER'S ESTIM.
NOEL/NOAEL
PROFILER'S ESTIM. LOEL/
LOAEL
POTENTIAL SUITABILITY
FOR DOSE-RESPONSE
MODELING:
CRITICAL EFFECT(S):
Overall, the study was well-conducted and had adequate study design, with some
limitations in the presentation of results. The study design does not aid in the
development of a dose response to fluoride with respect to bone changes, such as
changes in bone density, coarsened trabeculation, osteoporosis, or hypertrophic change.
The objective of the study was to present roentogenographic findings of a ten year study
of 237 white adults residing in a high-fluoride area (8 ppm F) or in a control area (0.4
ppm F). Overall, it appears that prolonged ( >15 years) ingestion of water containingip
to 8 ppm fluoride produces bone changes such as increased bone density (16-17 vs. 4
cases) and coarsened trabeculation (12-14 vs. 2-3 cases) in a greater number of subjects
compared to a group exposed to negligible amounts of fluoride in their water.
The paper does not stand alone; that is, statistical methods were presented in an earlier
article (Leone et al. 1954). Thus, the statistical significance of the results is unclear. The
authors report that bone changes were evident in only about 10-15% of the exposed
study population, but whether or not there was a significance difference compared to the
control group is not reported. Furthermore, the summarized results in Table 1 did not
readily correspond to reported results in the text. Several cases were presented as case
reports to illustrate the changes typical in the study; however, this does not provide any
statistical power in evaluating the effects of fluoride on bone.
Study design was not suitable for development of a NOAEL.
Study design was not suitable for development of a LOAEL.
Not suitable (X), Poor ( ), Medium ( ), Strong ( )
While the study was well-conducted, the study design was not conducive to provide
data for a dose-response. The study suggested that prolonged ingestion of 8 ppm
fluoride in water produces bone changes such as increased bone density and coarsened
trabeculation in a greater number of subjects compared to a control group (0.4 ppm F),
but the effects were sometimes equivocal.
Increased bone density; coarsened trabeculation
25
January, 2008
-------
Li, Y., Liang, C, Slemenda, C.W., Ji, R., Sun, S., Cao, J., Emsley, C.L., Ma, F., Wu, Y., Ying, P.,
Zhang, Y., Gao, S., Zhang, W., Katz, B.P., Niu, S., Cao, S., and Johnston, C.C. 2001. Effect of long-
term exposure to fluoride in drinking water on risks of bone fractures. Journal of Bone and
Mineral Research. 16(5): 932-939.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
POPULATION STUDIED:
CONTROL
POPULATION:
POPULATION STUDIED:
POPULATION STUDIED:
POPULATION STUDIED:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
Bone fracture
Cohort
1363 adults, 62.6 ± 9.3 years old (41.8% male) with long term residence in a Chinese community
with 0.25-0.34 ppm fluoride in the drinking water; mean total daily fluoride intake was 0.73 mg
F/day.
1407 adults, 62.7 ±9.1 years old (47.0% male) with long term residence in a Chinese community
with 0.58-0.73 ppm fluoride in the drinking water; mean total daily fluoride intake was 1.62 mg
F/day.
1370 adults, 62.5 ± 9.0 years old (43.7% male) with long term residence in a Chinese community
with 1.00-1.06 ppm fluoride in the drinking water; mean total daily fluoride intake was 3.37 mg
F/day.
1574 adults, 63 .6 ± 8.8 years old (44.5% male) with long term residence in a Chinese community
with 1.45-2.19 ppm fluoride in the drinking water; mean total daily fluoride intake was 6.54 mg
F/day.
1051 adults, 64.0 ± 9.0 years old (43.3% male) with long term residence in a Chinese community
with 2.62-3.56 ppm fluoride in the drinking water; mean total daily fluoride intake was 7.85 mg
F/day.
1501 adults, 61.3 ± 8.4 years old (52.4% male) with long term residence in a Chinese community
with 4.32-7.97 ppm fluoride in the drinking water; mean total daily fluoride intake was 14.13
mg F/day.
A minimum of 25 years of continuous residence in the study community and a lifelong exposure
to the specified fluoride level in drinking water was required of each participant. Mobility in the
countryside is almost nonexistent so the history of fluoride exposure in individuals is relatively
easy and reliable.
Six groups of a total of 8266 male and female subjects, > 50 yearsld, were recruited randomly
from rural communities in China where water fluoride concentration in the drinking water
ranged from 0.25 to 7.97 ppm and total daily fluoride intake ranged proportionally from 0.73 to
14. 13 mg F/day. There was virtually no fluoride exposure from other sources such as fluoride
supplements and fluoride containing dentifrice, mouth rinse, or use of infant formula.
IXF " 1. &>; * v. ri- D\-, •, - vv CT-^.-I-
PM* " SH- -'- Rf:I" "*' • lit C •!,€,-«, . T-.^i1 Y>-T''
?- !• •'<-"'•.: C »•• Til' vrii ••'•!; Di n;i,T-«i W VF*
ij'v\f T.'.'w F iTT'is- a A*c *' fxrf M3,!fr~.'f
j [ 2^-'".'.:- 1353 d2?±L-'i* -IS
; c -".>:»." 143" 6] ~ ± f i •«",:>
5 L70-: C5 BTt> «-:±c; -5.-
- L.-5-I.'.P 15"4 >S 1 ± £ i ~^~
r> 1 'S,!-},:-'} ;C"".L 64 } ± f ; -5 3
6 4SI-"P 1501 >S1 ? ± ^ r'".4
1 >SME ± S.D.
26
January, 2008
-------
FK- I
a'r-n .11
"t", SAsi; £ucr:&i .<;:£*« m
*ng Viisr in ;K Cfcr-s p
EXPOSURE
ASSESSMENT:
Data collected from each subject included medical history and demographic information, bone
fractures, physical activity as determined using the Chinese standard (National Standards 1995),
tea drinking, cigarette smoking, and alcohol consumption. Information regarding bone fracture
included: subject age, fracture site, frequency, and circumstances associated with the fracture.
Medical records and X-rays were obtained where possible, or an X-ray was taken to verify the
serf-reported bone fracture.
ANALYTICAL
METHODS:
For each site, samples of drinking water were collected and analyzed for fluoride using the direct
method with a combination fluoride-specific electrode (no.96-909-00, Orion Research, Inc.,
Boston, MA). Eight additional elements in drinking water also were analyzed: calcium,
selenium, aluminium, lead, cadmium, iron, zinc, and arsenic. A modified International
Organization for Standardization ISO method was used to determine the fluoride content in
ambient air (Ando et al. 1998). Surveys were conducted to ensure no other potential sources of
fluoride exposure (e.g., pollution, dentifrice, etc.) in the study populations.
The dietary fluoride and brewed tea samples were analyzed using a modified method of Taves
(1968); calcium and protein were determined using Chinese National Standard procedures
(1991).
STUDY DESIGN
The purpose of the study was to determine the prevalence of bone fracture, including hip
fracture, in six Chinese populations with water fluoride concentrations ranging from 0.25 to 7.97
ppm; a total of 8266 male and female adults, >50 years of age, were included in the study.
Drinking water was the only major source of fluoride exposure in the study populations. A
minimum of 25 years of continuous residence in the study community and a lifelong exposure to
the specified fluoride level in drinking water was required of each participant. Residency was
determined by three measures: objective assessment by checking the Family Registry Book, an
official document issued by the government; a subject survey questionnaire; and confirmation by
village officials familiar with the subject.
Surveys indicated that the environment, culture, ethnic background, social structure, and
economic conditions of these populations had not changed significantly during the past several
decades. Ethnic backgrounds and level of physical activity were similar among the six
populations.
Parameters evaluated included fluoride exposure, prevalence of bone fractures, demographics,
medical history, physical activity, cigarette smoking, and alcohol consumption. For those
reporting bone fractures, additional information was collected: fracture site (22 sites using an
illustrative drawing of the human body); subject age; frequency of each fracture; and
circumstances associated with the fracture including cause (eight categories), location (six
categories), ground condition, and fall or without fall. Family history of hip fractures and
information on falls within the last year also was collected. Medical records and X-rays were
obtained where possible. For those without records, an X-ray was taken to verify the self-
reported bone fracture.
27
January, 2008
-------
PARAMETERS
MONITORED:
STATISTICAL
METHODS:
RESULTS:
Overall fracture
(since age 20 years)
A 3 -day dietary survey and analysis for dietary intake of calcium, protein, and fluoride were
conducted in a randomly selected 10% of subjects to ensure that all study populations had
adequate nutrition and to determine fluoride exposure from diet.
Parameters evaluated included fluoride exposure, prevalence of bone fractures, demographics,
medical history, physical activity, cigarette smoking, and alcohol consumption.
For each class of fractures, the bivariate relationship was first examined between fracture rate
and several demographic and lifestyle variables including gender, current cigarette smoking
status, consumption of alcohol, physical activity level on the job, age, and body mass index
(BMI). Comparisons were made using %2 tests for categorical variables and t-tests for
continuous variables. Dose-dependent analyses were performed using a multiple logistic
regression model, which was used to compare fracture rates across fluoride levels, while
adjusting for demographic and lifestyle variables, which were significant in the bivariate
analysis. Adjusted odds ratios (ORs) were calculated based on the coefficients in the multiple
logistic regression models. The data analyses were adjusted for water calcium, aluminium,
selenium, lead, cadmium, iron, zinc, and arsenic by including them individually in the logistic
regression model for overall fractures.
Analysis defined subjects as to whether they had the fracture or not and did not use the count of
multiple fractures in the same subject.
For all statistical tests, the level of statistical significance was set at p<0.05.
There were 53 1 subjects reporting fractures; so the prevalence of overall bone fracture in the
entire study population was 6.42%; 99. 1% of these reported fractures were verified by X-ray.
The mean ages of subjects with fracture were 63.4, 64.2, 63.5, 66.1, 64.6, and 62.1 years for
groups 1-6, respectively. Statistical analysis showed that group 4 differed significantly from
group 6, indicating that subjects with bone fracture were slightly younger in the population of the
highest fluoride in drinking water, but the effect was not dose dependent.
Table 2 was copied directly from Li et al. 2001 and presents the prevalence of overall bone
fracture since age 20 years for each fluoride level as well as the odds ratios (OR) and p values
from the multiple logistic regression model adjusted for age and gender. Both the populations
with the lowest (0.25-0.34 ppm) and the highest (4.32-7.97 ppm) fluoride concentrations showed
a significantly higher prevalence of overall fractures (p=0.0 1) than those residing in areas where
water fluoride was 1.00-1.06 ppm, where the lowest prevalence of overall fractures was found.
No significant differences were found among the groups with fluoride levels ranging from 0.58-
3.56 ppm (groups 2, 3, 4 and 5).
TABLE 2. EFFECT OF FLUOSIDE ETI IXE nt"i Drr;M\ T \\ "~EX T Pin ^_E c >T ^TEALL FRACTUEI SINCE THE AGE
A- 20 fEtf " ^ < -IT'S pup I-TIU
Water F (ppm) 11 " . • ' "' n OR" f Valuer
0.25-0.34 1 11 101 7.41 1.50 0.01
0.58-0.73 14 1 90 440 1.25 0.17
1.00-1.06 1 -< 70 5.11 1.00 —
1.45-2.19 I1-" 95 6M 1.17 0.33
2.62-3.58 1 i 64 6.09 1.18 0.35
4. ,32»? ..97 11 III 7.40 1.47 0.01
3 Values relatiYe to f ia i ft 1 t "> p ^IB ftooiide group, ad|iwfe4 fee sge and gender using multiple logistic regression.
In general, the trend of fracture prevalence in relation to the water fluoride concentration
approximates a U-shaped pattern (Figure 2, copied directly from Li et al. 2001).
28
January, 2008
-------
FIG. I P evrf
dntiong f r:-r
JeiiCf of ;• en_
;ii :i\ Chnwe j .
1'bJ'. .'42-3.86 4.32-7.97
rrd-n
?- ..n-i fli i-ni-e t.3ii;eiit.it.3ii in
cnc "ince fV ae«- cf 20 " e:-n
Table 3 was copied directly from Li et al. 2001 and summarizes results frombivariate analysis.
Age, gender, alcohol consumption, and physical activity level were significant factors for the risk
of overall bone fractures. Subjects with fractures were significantly older (pO.Ol) than those
without fractures. More males suffered fractures than females (pO.Ol), and subjects who
consumed alcohol had more fractures (pO.Ol) than non-drinkers. Gender and alcohol
consumption were highly correlated, with 46.9% of males and 4.3% of females reported drinking
alcohol. The level of physical activity had a significant effect (p=0.05); excessively strenuous or
lack of activity increased the risk of fractures. No significant effect of cigarette smoking
(p=0. 15) or BMI (p=0.80) on overall fracture rates was detected. Only calcium (p=0.044) and
iron (p=0.032) showed a significant relationship with fracture but neither one (nor any of the
other analyzed elements) altered the results concerning the six fluoride groups.
TABLE 3. BWAMAIE ASSOCIATIONS or OVERALL BONE FRACTCRB RISKS SINCE THE AGE. OF
20 YEARS WITH CATEGORICAL FACTORS
Variable
Category
Subjects
Fracture (%)
f Valve
Gender
Cigarette smoking
Alcohol consumption
Physical activity
Male
Female
Yes
No
Yes
No
Very little
Light
Moderate
Heavy
Ejdretaely
3771
4495
3100
516(5
1960
6299
652
2532
4157
912
11
7.48
5.54
6.94
6.12
8.52
5.76
7.98
5.53
6.54
7.13
18.18
<0.01
0.15
<0.01
0-05
Hip fracture
(since age 20 years)
Table 4 was copied directly from Li et al. 2001 and presents the prevalence of hip fractures since
age 20 years in the six populations and the results of the multiple logistic regression model. A
total of 56 subjects (of 8266) reported hip fractures, resulting in a prevalence of 0.68%.
Bivariate analysis showed that subjects with hip fracture were significantly older (mean age 68.5
vs. 62.7 years) and thinner (mean BMI 21.2 vs. 22.6) than those without fractures (p<0.01 for
both). No significant effects were detected for gender, cigarette smoking, alcohol consumption,
and the level of physical activity. After adjusting for age and BMI, the risk of hip fracture was
significantly higher in the highest fluoride group (4.32-7.97 ppm) than the population with 1.00-
1.06 ppm fluoride, which had the lowest prevalence.
29
lanuary, 2008
-------
TABLE 4. EFTECT or FLUORIDE EXPOSURE FROM DRINKING WATET >" ^te ±~ LE _F H.P FK. < TORE •» six CHINESE
POPULATIONS SINCE THE AGE uc 2' i YEAT
H'oter
n (surveyed)
p Kite"
0.25-034
0.58-0.73
1.00-1.06
1.45-2.19
2.62-3.56
432-7.9?
1363
1407
1370
1574
1051
1501
14
18
n jo
I1
Hi
0.15
0.34
0.02
a Values r
to tile l.OG- to l.CNS-ppm ftsoiide grasp. adjusted for iiie i i BI II i i-ij mi t fib -* ^ le
In general, the hip fracture prevalence was stable up to 1.06 ppm of fluoride and then appeared to
rise, although it did not attain statistical significance until the water fluoride concentration
reached 4.32-7.97 ppm (Figure 3, copied directly from Li et al. 2001).
FIG. 3 Pifii.pii:e ,->f
fu nl mg ^ate7 HI ,i\ vliiE
i jn;eiitoitLjii L.
Overall fracture
(since age 50 years)
Table 5 was copied directly from Li et al. 2001 and summarizes prevalence of overall bone
fracture since the age of 50 years, including odds ratios (ORs) and p values. There were 311
people with fractures, resulting in 3.76% overall prevalence. There was a similar trend in the
relationship between water fluoride level and overall fractures when evaluated from age 20
years, but less pronounced. Only the highest fluoride group (4.32-7.97 ppm) had a significantly
higher risk for fractures, after adjusting for age, than the group with 1.00-1.06 ppm of fluoride.
TABLE 5. EFFECT OF FLUORIDE EXPOSURE FROM DIKIONG WATER. ON PREVALENCE OF OVERALL FRACTURES M Six
CHINESE POPULATIONS SINCE THE AGE or 50 YEARS
OR'
p Value"
0.25-034
0.58-0.73
1.00-1.06
1.45-2.19
2.62-3.56
4.32-7.97
1363
1407
1370
1574
1051
1501
59
45
45
52
3S
72
4.33
3.20
3.28
3.30
3.62
4JO
1.33
0.97
1.00
0.96
1.04
1.59
0.16
0.87
* Values rditive to tlie 1.00- to 1.06~ppm fluoride gromp, adjured fsi age using multiple logistic regression.
Table 6 was copied directly from Li et al. 2001 and summarizes results from the bivariate
analysis. Age remained a risk factor; subjects with fractures were significantly older than
subjects without fractures. The level of physical activity also was significant (p=0.03) in relation
to fractures. No significant effects were observed for gender, cigarette smoking, alcohol
consumption, and BMI.
30
January, 2008
-------
TABLE 6, BIYAPJATE ASSOCIATION or OVERALL BONE FRACTURE RISES SINCE THE AGE OF
SO YEARS WITH CATEGORICAL FACTORS
Csiegon-
Subjects
Fracture flit
p Vahm
Gender
Cigarette smoking
Alcohol consumption
Phyacai activity
Male
Female
Yes
No
Yes
No
Very little
Light
Moderate
Heavy
Extremely strenuous
3771
4495
3100
5166
I960
6299
652
2532
4157
912
11
3.61
3.89
3.29
4.05
3.98
3.70
5.2!
3.71
3.58
3.5!
18.18
0.52
0.08
0.59
0.03
STUDY AUTHORS'
CONCLUSIONS:
Based on the data collected from this investigation, it is concluded that long-term fluoride
exposure from drinking water containing 4.32 ppm or more increases the risk of overall fracture
as well as hip fracture. The prevalence of overall bone fractures was lowest for populations
living in areas of approximately 1.00 ppm of fluoride. Thus, water fluoride levels of 1.00-1.06
ppm decrease the risk of overall fractures relative to negligible fluoride in water; however, there
does not appear to be a similar protective benefit for the risk of hip fractures. The U-shaped
effect of water fluoride observed in bone fractures was not observed in the hip fracture data. The
prevalence of hip fractures was stable until the water concentration reached 1.45-2.19 ppm.
Additionally, fractures are influenced by other factors, such as age, gender, alcohol consumption,
and physical activity.
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE
NOT FOUND IN NRC
(2006)
National Standards (1995). Levels of labor intensity. Chinese National Standard GB 3869-83,
Beijing, China.
Ando, M, Tadano, M, Asanuma, S., Tamura, K., Matsushima, S., Watanabe, T., Kondo, T.,
Sakurai, S., Ji, R., Liang, C., and Cao, S. (1998). Health effects of indoor fluoride pollution
from coal burning in China. Environmental Health Perspectives 106: 239-244.
Taves, DR. (1968). Separation of fluoride by rapid diffusion using hexamethyldisiloxane.
Talanta 15: 969-974.
Standard Department of Chinese Academy of Preventative Medicine (1991). Standard
compilation of environment, school and radiation health. Chinese Standard Publishing House,
Beijing, China, pp. 278-338.
PROFILER'S
REMARKS
Initials/date
SJG/
9/25/07
Overall, the study was well-conducted and had adequate study design, considering several
aspects to confirm exposure, reported fractures, and confounding factors. The study design aids
in the development of a dose response to fluoride with respect to risk of overall bone fracture and
hip fracture. The objective of the study was to determine the prevalence of bone fractures in six
cohorts of older adults (>50 years old) from rural communities in China with long-term exposure
to different fluoride concentrations in the drinking water (0.25-0.34 ppm; 0.58-0.73 ppm; 1.00-
1.06 ppm; 1.45-2.19 ppm; 2.62-3.56 ppm; and 4.32-7.97 ppm). Analysis of water samples
confirmed fluoride concentrations and considered eight other elements (calcium, selenium,
aluminium, lead, cadmium, iron, zinc, and arsenic). There were no significant differences among
groups concerning other potential sources of fluoride (e.g., diet, supplements, or air), ethnic
backgrounds, level of physical activity, or occupation.
The data suggest an optimal beneficial window of fluoride intake for bone health as
approximately 1.00 ppm. There was an increased risk of overall bone fractures and hip fractures
in the highest exposure group (4.32-7.97 ppm). Further, the risk for overall fractures decreased in
the population with 1.00-1.06 ppm compared to the lowest exposure group with negligible
fluoride in the water (0.25-0.34 ppm). Factors that influenced bone fracture risk included age,
gender, alcohol consumption, and physical activity.
When considering odds ratios (ORs) presented in the tables above, it may not be appropriate to
conclude that the risk of hip fracture is more sensitive to water fluoride concentration as
31
January, 2008
-------
PROFILER'S ESTIM.
NOEL/NOAEL
PROFILER'S ESTIM.
LOEL/LOAEL
POTENTIAL
SUITABILITY FOR
DOSE-RESPONSE
MODELING:
CRITICAL EFFECT(S):
compared to overall fractures the number of hip fractures in the present study is relatively small.
Further, the total number of people with fractures was relatively small, making it impossible to
sort out all potential confounding factors individually.
Study design was suitable for development of a NOAEL for bone fracture. No statistically
significant effects on overall bone fracture or hip fracture prevalence were observed at fluoride
levels <3.56 ppm in the drinking water. Water fluoride levels at 1.00 -1.06 ppm decreases the
risk of overall fractures relative to negligible fluoride in water (>0.58 ppm resulted in
statistically similar results).
Study design was suitable for development of a LOAEL for bone fracture. Long-term fluoride
exposure from drinking water containing >4.32 ppm fluoride increases the risk of overall bone
fractures and hip fractures. Water fluoride levels at 1.00 -1.06 ppm decreases the risk of overall
fractures relative to negligible fluoride in water (<0.34 ppm resulted in increased prevalence of
overall fractures).
Not suitable (), Poor ( ), Medium ( ), Strong (X)
The study was well-conducted, and the study design was conducive to provide data for a dose-
response bone fracture risk. The study indicated that long-term fluoride exposure from drinking
water containing 4.32 ppm or more increases the risk of overall fracture as well as hip fracture.
The prevalence of overall bone fractures was lowest for populations living in areas of
approximately 1.00 ppm of fluoride.
Prevalence of overall bone fracture and hip fracture
32
January, 2008
-------
Reid IR, Cundy T, Grey AB, Home A, Clearwater J, Ames R, Orr-Walker BJ, Wu F, Evans MC, Gamble GD, and
King A. 2007. Addition of monofluorophosphate to estrogen therapy in postmenopausal osteoporosis: a
randomized controlled trial. J Clin Endocrinol Metab. 92(7): 2446-52. Epub 2007 Apr 17.
ENDPOINT STUDIED:
Bone mineral density (BMP)
TYPE OF STUDY:
Randomized control trial (double-blind)
POPULATION STUDIED:
(MET)
41 postmenopausal women with osteoporosis. Subjects received daily doses of 20 mg elemental
fluoride and 600 mg calcium. 15 subjects discontinued the study due to personal reasons or illness.
CONTROL POPULATION:
(Placebo)
39 postmenopausal women with osteoporosis. Subjects received daily doses of placebo containing
600 mg calcium. 14 subjects discontinued the study due to death, personal reasons or illness.
EXPOSURE PERIOD:
Duration of follow-up in the study was 3.1±1.3 years in the placebo group and 2.9±1.7 in the MFP
group.
EXPOSURE GROUPS:
80 postmenopausal women with osteoporosis were recruited from a hospital clinic. They were
required to have at least one vertebral fracture (i.e., a reduction in the anterior, middle, or posterior
relative height of a vertebra of more than 3 standard deviations in relation to the vertebra-specific
normal values or a bone mineral density (BMD) T-score in the lumbar spine (L2-4) of <-2.5). All
subjects had been receiving estrogen for at least 12 months prior to study entry. Subjects were
ineligible if they had disorders of calcium metabolism other than osteoporosis, thyroid or hepatic
dysfunction, or serum creatinine X).20 mmol/L. No subjects had previously used calcitonin or
fluoride and none had used bisphosphonates in the previous year. Subjects received
monofluorophosphate (20 mg F/day) with calcium (600 mg/day, 50% citrate and 50% gluconate) or
placebo (calcium only), in addition to 500 mg calcium carbonate supplement and estrogen therapy.
Table 1: Characteristics of Study Subjects at Baseline
n
Age (years)
Weight (kg)
Height {cm}
Calcium intake (mg''d|
Current smokers
BMO T-score
Lumbar spine
Femoral neck
Total body
Prevalent vertebral fractures
Duration of estrogen use (years!
Placebo
41
65.0(7.1)
60.0 (9.8)
157.9(6.6)
890 (460)
4(10%)
-2.56 (0.92!
-1 .98 (0,83)
-2.50(1.07)
26 fractures in1 2 women
2.5 (2.2)
MFP
39
85.5 (7.3)
60.4(11)
157.8(4.8)
1030(570)
7(19%)
-2.49(1.19)
-1.78(0.82)
-2.31 (0.94)
23 fractures in 7 women
2.3 (2.0)
Data are mean (SD). There were no significant differences between tl
groups.
EXPOSURE
ASSESSMENT:
Serum fluoride concentrations were monitored. Bone mineral density (BMD) was assessed at trial
entry and annually. Bone turnover markers were assessed using standard methods (Reid 2004).
Lateral radiographs of the thoracic and lumbar spines were performed at trial entry and annually.
Bone biopsies were performed at the end of the study in 7-9 subjects from each group.
ANALYTICAL METHODS:
Fluoride levels were maintained by tablet and not analyzed for content.
STUDY DESIGN
Prior to study entry, a full medical history was taken, dietary calcium intake was assessed using a food
33
January, 2008
-------
PARAMETERS
MONITORED:
STATISTICAL METHODS:
RESULTS:
Bone Mineral Density
frequency questionnaire and physical activity was assessed by questionnaire. Height and weight were
measured at study entry and every 6 months using a Harpenden stadiometer and an electronic balance,
respectively.
Women were randomized to receive tablets of calcium (TRIDIN, RottapharmSpA, Monza, Italy) with
or without glutamine monofluorophosphate. Tablets were taken with the morning and evening meals
and provided daily doses of 20 mg of elemental fluoride and 600 mg of calcium. Compliance was
checked at each clinic visit by tablet counts. All patients also took nightly supplements of 500 mg of
calcium carbonate. Subjects continued on their estrogen regimen, usually continuous conjugated
equine estrogens (03. -0.625 mg/day) plus medroxyprogesterone acetate (2.5-5 mg/day). Vitamin D3
(400-800 lU/day) was given to any patient whose serum 25-hydroxyvitamin D level was <50 nmol/L,
either initially or at the annual checks. Patients were seen at trial entry, at 3 and 6 months, and then
semi-annually to 4 years.
Mean trial medication compliance (based on tablet counts) was 86% (±17.3) in the placebo group and
81% (±15.2) in the MFP group.
Serum fluoride concentrations (at least 12 hours after last MFP dose) were monitored at each visit,
with the intention of maintaining levels <12.5 |amol/L. Results were monitored by a staff member
who had no contact with the participants; all other study personnel and the study participants were
blinded to treatment allocation.
Bone mineral density (BMD), bone turnover markers, and lateral radiographs of the thoracic and
lumbar spines were monitored. Bone biopsies were performed at the end of the study in 7-9 subjects
from each group.
Bone mineral density (BMD) was assessed at trial entry and annually using a Lunar DPX-L dual
energy x-ray absorptiometer. Separate scans of the total body, lumbar spine in the anteroposterior
projection, third lumbar vertebra in the lateral projection, proximal femur and distal forearm were
undertaken. For lumbar spine scans, only those vertebral bodies demonstrated not to be fractured on
plain radiographs were included in the analysis.
Bone turnover markers were assessed using standard methods (Reid 2004).
Lateral radiographs of the thoracic and lumbar spines were performed at trial entry and annually,
using a film-tube distance of 100 cm. An incident vertebral fracture was defined as a decrease in an
anterior, middle, or posterior vertebral height of >20%md >4 mm.
Continuous variables (e.g., BMD, biochemical measurements) were analyzed using a mixed models
approach to repeated measures (Proc Mixed). Significant interaction effects were further explored
using the method of Tukey to preserve an overall 5% significance level. Time to first fracture was
compared between treatment and control arms using a proportional hazards model, and results
presented as the hazard ratio and 95% confidence interval (CI). Fractures were expressed as fractures
per 1000 patient-years at risk, and the incidences compared between groups assuming a Poisson
distribution. All analyses were performed using procedures of SAS version 9.1 (SAS Institute Inc,
CaryNC).
The study was powered to assess effects on lumbar spine BMD and on vertebral fractures. A study of
this size has >90% power to detect a difference in the absolute change in lumbar spine BMD between
treated and control groups of at least 5%. Based on figures from Riggs (1982), 80 subjects yield a
power of 90% to detect this difference (oc=0.05) and a power of 80% to detect a halving of fracture
numbers.
PROFILER'S NOTE: The information regarding power of sample size does not specify whether the
original sample size (n =39, 41) or the final sample size after subjects discontinued participation
(n=25, 26) was used for the calculations.
Figure 1 was copied directly from Reid et al. (2007) and shows an increase in BMD for lumbar spine
34
January, 2008
-------
Biochemical Parameters
(L2-4 in the anteroposterior projection, AP) (pO.OOO 1), third lumbar vertebra in the lateral projection
(L3 lateral) (pO.OOOl), and femoral
neck (p=0.015). P values are for the treatment-time interaction
over the trial period. In the AP projection, the MFP group increased 22% whereas the placebo group
was only 6% above baseline at
the end of the study. These changes were most marked in the
trabecular bone, as reflected in the L3 (lateral) projection; MFP group increased 49%, compared to
2.5% in placebo group. In the femoral neck, BMD increased 4.6% above baseline by year 4 in the
MFP group and decreased slightly in the placebo group.
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Table 2 was copied directly from Reid et al. (2007) and summarizes serum biochemistry and urine
calcium during the study. Serum calcium, phosphate, 25-hydroxyvitamin D and 1,25-hydroxyvitamin
D and urine calcium showed no significant between-group changes during the study. Parathyroid
hormone levels were comparable at baseline, subsequently tended to be higher in the MFP group
(p=0.06), but only reached significance at year 3 (placebo value slightly lower in year 3). Serum
fluoride levels were maintained at ~7 |amol/L in the MFP group.
Table 2: Serum Biochemistry and Urltw Calcium During Study
Analyle
Fluoride {pmol/L}
Total Calcium
(mmoVU
Phosphate
(mmo!''L)
25-hydroxyvitamin
D (nmol/L)
1,25-hydroxy-
vitamin D (pmol/L}
Parathyroid
Hormone (pmol/L)
Urine Calcium
(mmoi/day)
Baseline
Placebo
2.7 (0.7)
8.29
(0.12)
1.1 (0.1)
73(34)
105 (33)
3.8(1.7)
4.3 (2.7)
MFP
2.8(1.1)
2.29
(0.08)
1.1 (0.1)
83 (30)
105(35)
3,6(1.5)
4.1 (2.4)
Ywr1
Placebo
3.2(1.2)
2.31
(0.09)
1.1 (0.2)
71 (30)
94 (31)
3,0(1.3)
4.3 (2.3)
MFP
8.7 (2.2)
2.3S
S0.09)
1.1 (0.2)
70 (26)
102(36)
3.7(1.8)
4.9 (3.1)
Y«>r2
Placobo
3.1(1.2)
2.30
(0.09)
1.2(0.2)
72 (33)
90(41)
3,1(1.7)
4.4 (2.2)
MFP
6.9 (2.9)
2.32
(0.14)
1.2(0.2!
70 (29)
91 (31)
3.8(1,7)
4.8 (2.4)
Years
Placebo
3.0 (0.8)
2.31
(0.09)
1,2(0.2)
60 (27)
B4 (29)
2.7(1.1)
4.2(1.8)
MFP
7.2(2.6)
2.30
(0.07)
1.2(0.2)
59(27)
98(23)
3.7(1.8)*
4.7 (2.6)
Year 4
Plaoabo
3,1 (1.3)
2,27
(0,07)
1.2(0.1)
S9 (24)
79 (34)
3.0 (1.3)
4.3 (2.3)
MFP
7.3 (2.3)
2.31
(0.12)
1.2(0,2)
61 (21)
87 (43)
3.4 (1.5)
4,6 (2,5)
Data are mean (SO)
* significantly different between-groups, P=0.01.
Serum fluoride concentrations were significantly higher in the MFP group at all timepoints after baseline.
There were no other significant differenoes between-§roups
PROFILER'S NOTE: Data points are not evident for years 2 and 3 for osteocalcin, P1NP or pCTX in
Figure 3. It is unclear whether data was collected for these time points and whether 'sustained'
effects on all bone formation markers would become significant if these values were included since
the general trend is similar for ALP.
36
January, 2008
-------
Fractures
The vertebral fracture rate for the placebo group was 60.3 per 1000 patient-years compared to 9.8 per
1000 patient-years for the MFP group. A Poisson regression gives an incidence rate ratio of 0.12
(95% CI, 0.06-0.23, pO.Ol). Analysis of the time to first vertebral fracture showed a hazards ratio of
0.20 (95% CI, 0.05-1.30). Six non-vertebral fractures occurred in the MFP group and 2 in the placebo
group, giving a hazards ratio of 3.3 (95% CI, 0.8-12.0).
Height loss tended to be greater in the placebo group (0.46±0.10 cm) compared to the MFP group
(0.24±0.10 cm) at 4 years, but this was not significant over the whole study period (p=0.45).
Bone Biopsies
Figure 4 was copied directly from Reid et al. (2007) and indicates histomorphometric assessments of
bone biopsies after 4 years of treatment with either placebo (n=9) or MFP (n=6). Medians for each
group are shown as solid lines, and the upper limit of normal in postmenopausal women as horizontal
dotted lines. Values for both parameters were different between-groups (p<0.01). In one MFP subject
whose biopsy was not quantifiable, there was evidence of hyperosteoidosis. Osteoid surface and
osteoid volume were above the reference ranges in 4 of the remaining 6 MFP subjects, but were
within normal range in all placebo subjects. Thus, 5 MFP-treated subject and none of the placebo-
treated subjects had hyperosteoidosis (significantly different between-groups, p=0.005). Osteomalacia
was evident in 3 of the MFP-treated subjects.
Figure 4
65-
O 45-
4S 40-
^ 35-
CO 30-
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"O 20-
£ 15-
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£
-------
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
PROFILER'S
REMARKS
Initials/date
SJG/
10/12/07
PROFILER'S ESTEM.
NOEL/NOAEL
PROFILER'S ESTEM.
LOEL/ LOAEL
POTENTIAL
SUITABILITY FOR DOSE-
RESPONSE MODELING:
CRITICAL EFFECT(S):
subjects evaluated. In 2 of 7, these values were within normal range, but in 2 others the diagnostic
criteria for osteomalacia were met.
The present findings indicate that despite increases in BMD, abnormal mineralization contributing to
fracture risk still occurs with elemental fluoride doses as low as 20 mg/day. Therefore, it is
inappropriate to recommend the widespread use of the dosing regimen employed in the current study.
Much lower doses should be assessed to find a safe dose window for the use of this powerful anabolic
agent.
Reid IR, Davidson JS, Wattle D, Wu F, Lucas J, Gamble GD, Rutland MD, and Cundy T. (2004).
Comparative responses of bone turnover markers to bisphosphate therapy in Paget's disease of
bone. Bone 35: 224-230.
Riggs BL, Seeman E, Hodgson SF, Taves DR, O'Fallon WM. (1982). Effect of the
fluoride/calcium regimen on vertebral fracture occurrence in postmenopausal osteoporosis. N Engl
JMed 306:444-450.
Overall, the study was well-conducted and had adequate study design. The study design aids in the
development of a dose response to fluoride with respect to increased bone mineral density and
interference with bone mineralization. The objective of the study was to determine the anti-fracture
efficacy of fluoride in low doses combined with an antiresorptive agent in postmenopausal women
with osteoporosis who had been taking estrogen for >1 year.
Serum fluoride was elevated in the MFP-treated group after 1 year of treatment without changes in
other serum biochemistry parameters. There were progressive increases in BMD in the MFP-treated
group as measured in the trabecular bone of L3 (49%), the lumbar spine (22%), and the femoral neck
(4.6%), as well as in total body scans and their subregions (particularly trunk). The increases in BMD
are well documented and confirm fluoride's anabolic action on bone. Bone formation markers
(osteocalcin, P1NP, ALP) increased during the study in the MFP group whereas no change was
observed in bone resorption (PCTX). Data values for years 2 and 3 were missing from the graphs for
all bone markers except ALP, so the effects at theses time points are unclear. The hazards ratio for
vertebral fractures was 0.20, suggesting decreased fracture risk, and 3.3 for non-vertebral fractures,
suggesting increased fracture risk. However, the sample size for these events was small so the authors
cited similar results from the literature to support the findings. Moreover, in a few subjects (n=7-9)
bone biopsies in the MFP group indicated hyperosteoidosis in 5/7 subjects and osteomalacia in 2/7
subjects. Therefore, fluoride at 20 mg/day is beyond the therapeutic window due to interference with
bone mineralization.
Study design was not suitable for development of a NOAEL.
Study design was suitable for development of a LOAEL for bone mineral density and fracture risk.
Fluoride at 20 mg/day increases BMD in the total body as well as in specific bones (trabecular bone
of L3, the lumbar spine, and femoral neck) and subregions (e.g., trunk). Interference with bone
mineralization contributing to fracture risk also occurs at 20 mg fluoride/day.
Not suitable (), Poor (X), Medium (), Strong ()
The study was well-conducted, but only one dose level was used (20 mg/day); the study design was
conducive to contribute data for LOAEL for BMD and fracture risk together with other data from the
literature. Effects were noted at 20 mg/day but a lower dose level also may increase fracture risk.
Bone mineral density; osteomalacia
38
January, 2008
-------
Riggs BL. Hodgson SF. O'Fallon WM. Chao EY. Wahner HW. Muhs JM. Cedel SL. Melton LJ III. 1990. Effect of
fluoride treatment on the fracture rate in postmenopausal women with osteoporosis. N Engl J Med. 322(12):802-9.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
ANALYTICAL METHODS:
STUDY DESIGN
Skeletal fracture, bone mineral density
Prospective, randomized, double-blind, placebo-controlled clinical trial
101 white women, 50 to 75 years of age, with postmenopausal osteoporosis who were patients at the Mayo
Clinic (Rochester, MM) received 75 mg sodium fluoride and 1500 mg elemental calcium per day.
101 white women, 50 to 75 years of age, with postmenopausal osteoporosis who were patients at the Mayo
Clinic (Rochester, MM) received placebo tablets and 1500 mg elemental calcium per day.
The women were treated for 4 years.
The 202 patients who were enrolled in the study were fully ambulatory, postmenopausal women with
documented osteoporosis but no evidence of an associated disease or a history of use of any drug known to
cause osteoporosis. The criteria for osteoporosis were diffuse osteopenia on spinal x-rays, one or more
vertebral fractures, and a bone mineral density (BMD) value for the lumbar spine below the normal range
for premenopausal women. About 1000 patients or patients' medical records at the Mayo Clinic were
screened for the above criteria to find volunteers to enroll in the study.
At the time of recruitment, 153 of the women were receiving treatment for their osteoporosis: calcium
supplements ± vitamin D ± estrogen; vitamin D ± estrogen. None of the women had ever received sodium
fluoride or diphosphonate drugs. Before the start of the study, treatment was discontinued for three months
in women receiving calcium supplements, vitamin D, or both and for six months in those receiving
estrogen.
The treatment group received 75 mg sodium fluoride and 1500 mg elemental calcium daily and the control
group received placebo and 1500 mg elemental calcium daily.
Treatment was by the oral route.
Serum and urinary calcium levels were measured by atomic -absorption spectrophotometry. Serum levels of
phosphate, creatinine, and alkaline phosphatase and urinary levels of phosphate and creatinine were
measured by routine methods. Serum bone Gla-protein (BGP, osteocalcin) and parathyroid hormone levels
and urinary cyclic AMP were measured by radioimmunoassay. Serum and urinary fluoride levels were
measured by a glass-electrode method. Urinary hydroxyproline levels were measured colorimetrically
after fractionation by high performance liquid chromatography (HPLC). The glomerular filtration rate was
estimated by measuring creatinine clearance.
The BMDs of the lumbar spine, femoral neck, and femoral intertrochanteric region were measured by dual
photon absorptiometry. The bone mineral content of the shaft of the radius was measured by single photon
absorptiometry.
Vertebral fractures from T4 through L5 were assessed by quantitative biplanar radiography. Total vertebral
height and total lateral area of the vertebral bodies were summed and recorded as continuous variables. All
measurements were made by a person unaware of the patient's treatment assignment.
The 202 women were randomly assigned to treatment or placebo groups, with 101 women in each group.
The composition of the groups was balanced according to the number of vertebral fractures at base line, the
BMD ofthe lumbar spine, the dosage of any previous estrogen treatment, and the interval after the
discontinuation of previous treatment for osteoporosis. The treatment group received sodium fluoride (75
mg per day, given as 30-mg tablets three times daily and twice daily on alternate days) and the control
group received a placebo tablet identical in appearance. Both groups received divided doses of calcium
carbonate equivalent to 1500 mg of elemental calcium per day. The women were treated for 4 years,
during which they were evaluated every six months. There was no formal exercise program, though they
39
January, 2008
-------
PARAMETERS
MONITORED:
STATISTICAL METHODS:
RESULTS:
Bone mineral density
were encouraged to be active. Dietary calcium intake was assessed in interviews with a dietician and by
review of a 7-day diet diary. Changes in calcium intake were evaluated at the end of the study.
BMD measurements of the lumbar spine and radius were made at base line and every six months, and
those for femur every two years. Roentgenography of the lumbar and thoracic vertebra was performed at
base line and yearly. Blood and 24-hour urine samples were collected for various biochemical
measurements. Side effects were assessed during evaluations, specifically gastric pain or distress, nausea or
vomiting, joint pain, stiffness or swelling, neurological symptoms, and hair loss. When side effects
occurred, fluoride treatment was stopped until the symptoms cleared and then treatment was resumed with
a 15 mg reduction in the daily dose of fluoride or placebo (Profiler's note: composition of placebo was not
reported).
Serum and urinary biochemical measurements, side effects, BMD, vertebral and nonvertebral fractures
were monitored.
Fracture rates and confidence limits were expressed as fractures per 100 person-years. Relative risk was
defined as the ratio of the number of fractures per person-year in the patients receiving fluoride to those
receiving placebo. Binary logistic analysis was used to assess differences between groups with respect to
the number of women in whom new fractures developed during treatment. The dependent variable in this
analysis was whether at least one new fracture occurred during treatment. Patients were grouped into
categories according to the rate of occurrence of new fractures, and an ordered categorical analysis
(proportional-odds model) with the logistic-regression model was performed. To assess the effect of
treatment on the rate of occurrence of first new fractures, the Cox proportional-hazards model was used.
Side effects were assessed by binary logistic regression and Cox proportional-hazards modeling.
The rates of change in BMD (% change per year) at each site were calculated as the slope of a least-squares
regression line of successive measurements of BMD for each patient, divided by its intercept and
multiplied by 100. This ratio was used as the dependent variable in weighted multiple regression models to
assess the effect of treatment on these rates of change. The weights were the variance estimates of the
ratios.
In each analysis, the results were adjusted for stratification variables and significant (p<0.05) covariates
and interactions. Covariates included: base line values for age; number of years since menopause; height
and weight; calcium intake; type of previous treatment; number of fractures; initial BMD at various sites;
serum and urinary fluoride, calcium, phosphorous, and creatinine levels; serum parathyroid hormone, bone
Gla-protein, and alkaline phosphatase levels; urinary excretion of cyclic AMP and hydroxyproline; and
hemoglobin.
In all analyses, the results are for all available data for the 202 patients who entered the trial, regardless of
full 4 year completion of the study.
The following changes in BMD (or bone mineral content in the case of the radial shaft) were reported
(Table created by Profiler from text results). The difference between treatment and placebo rates was
significantly different (pO.OOOl) from zero at all sites reported.
Site % Change per year (95% CI) Rate difference (95% CI)
Fluoride
Lumbar spine 8.2 (5.5 to 10.9)
Femoral neck 1 .8 (-0.7 to 4.2)
Femoral -1.8 (-1.4 to 5.1)
intertrochanteric region
Radial shaft 1.8 (-3.3 to 0.3)
Placebo
0.4 (-1.6 to 2.5) 7.8 (6.0 to 9.5)
-0.9 (-3 .4 to 1.6) 2.6 (1.7 to 3. 6)
-0.7 (-3.7 to 2.3) 2.5 (1.1 to 4.0)
0.4 (-1.7 to 1.1) -1.4 (-2.0 to 0.08)
Figures 2 and 3 were copied directly from Riggs et al. 1 990. During the four years of the trial, there was a
cumulative increase in BMD of 35% for the lumbar spine (Figure 2), 12% for the femoral neck, and 10%
for the femoral intertrochanteric area, and a decrease of 4% for the radial shaft (Figure 3) in the fluoride
group compared to the placebo group.
40
January, 2008
-------
Oft*
*]«
pp 2. y«wrt
Fmvio Ur»yn 1S««J CMM) ana (h» Pt»c«to Group
riguto 3. Mokfl 1 .'. SE| 8orw Dsnyiy al Itio Pemorat Fruchanter,
Fomoral Nncfc, wd flartial Shall IP the Ftowtoe (Voup Dr-
ctei 3«s f»e PSac*c Gwup (Open Or ta'-i
Skeletal fractures
(nonvertebral)
Table 4 was copied directly from Riggs et al. 1990 and summarizes all nonvertebral fractures that occurred
during treatment. In the fluoride group, a total of 12 fractures occurred in 6 1 women; of these, 40 fractures
were complete and 32 were incomplete. In the placebo group, there were 24 fractures in 24 women; 22
were complete, and 2 were incomplete. The rates of fracture per 100 person-years in the fluoride group
were 232, 12.9, and 10.3 for total, complete, and incomplete fractures, respectively; the rates in the
placebo group were 7.4, 6.8, and 0.6, respectively. The fluoride-treated patients had nonvertebral fractures
3.2 times more often than those given placebo. The total nonvertebral fractures occurred more frequently
(p<0.02) and in more women (p<0.0 1) in the fluoride group than the placebo group. The number of
incomplete fractures (p<0.0005) and the number of women who had them (p<0.0005) were higher in the
fluoride group than in the placebo group. There were no differences between groups for complete fractures.
4 N«nw»rfetwal Ffaetyt«s ounni the Study in lha Women with Qsltopofosis m
the I'luonte and Psawte l-koups.
Radius i'C«iB" frair
Hunwic,
Rib
Tifctt
« jtli
il('i»
i\H
iMtrt
10)
III; 4»4>
> (hi lull
lint') * «*"«
no*
* M)
I i!i
(4)
All
111 I
>ii?i
Ifi (i(
•wt fottafcj «•»(«» «-S. woBip fjr nulw
Skeletal fractures
(vertebral)
Table 5 was copied directly from Riggs et al. 1990 and shows the rates of vertebral fracture per person-year
of follow-up, according to year of treatment and over the entire 4-year trial. The risk of vertebral fracture
was similar in both groups. The 15% reduction in the number of women over the entire trial who had new
vertebral fractures in the fluoride group compared to the placebo group was not significant (p=0.32).
41
January, 2008
-------
Clinical findings
Table S. Vertebral Fractures dyrif»g the Siudy Period in the Worrier* with Osteoporosis
m the Fluoride and Placebo Groups *
PMWM* UUMI *
t 87 56
i KI ;v
i f>7 ?6
4 r* «3
Eiw.re ^0 1 1 lh
pen^d
*Ttefr Imiilnbe* ui wtfleh-sl Irsaitf
CMfidkBCC i£lt£r\Kl
Figure 4 also was copied directly froi
have new vertebral fractures during t
treatment to the time of first new vert
model, p=0.41).
100
I "
1
it
*B
1
IL
e
S »
n
c
Figure *
Groups
In a prof
witi adjij
theoomf
mated re
place
RELATIVE Rrifc,
P&imi**- Nl> Uh M> W MjUAi**-
88.7 63 t W » 91.1 C.B 147(0 4-5 ij
«I4 ?'« H* 36 ft K 46.3 f».5Siffl*,M)
bt, *t 4t> 4 bt M 68 i *J.S 0.*4 iCI y t S)
"fill «.« JH 16^ 1103 52.5 O.RSiflto 1?)
s» *#ai ar-s^si^J iHflj aj jeariy vm*s. Raises shpwm iMT |ser ItXi |»ffif5^jjj- ^Bila O deiwtes
n Riggs et al. 1990 and shows the proportion of women who did not
le treatment period. There were no significant differences with
ebral fracture (proportion-hazards model, p=0.34; proportional-odds
^
^"^
— Fa»orWfe
^
•wmmumm.
1 2 S 4
, Proportion of Women in lite Ftoonde and Placebo
Afc* Did Not Have New Vertebra! Fractures during the
Four- Year Study Period
wriional4>azarcte rnodel ot the time to Ihe Met fracture,
stment (or the viriabtes ussd as ecwanates to baJanoe
walion of the groups al tcgsfcnBnt assignment the e»t»-
lative risk in the ftuori* groyp as compared wlfi the
Ax) group was 0.82 {95 percent confidence intervnl,
O.SSto 1.23).
The clinical characteristics of the 202 women at baseline are provided in Table 1. There were no
significant differences between the two groups for covariates at baseline. Of the 202 enrolled, 135 (66 in
the fluoride group, 69 in the placebo group) completed the 4-year trial. Reasons for discontinuation were
side effects (n=10), personal reasons (39), development of other illnesses (10), death (6), or loss to follow-
up (2). As assessed by tablet count, the median dosage of sodium fluoride at the end of the study was 1 1
mg/day. The dosage distribution was as follows: >75 mg/day (n=25), 6574 mg/day (36), 55-64 mg/day
(18), <55 mg/day (13), not determined (9). The median dosage of supplemental calcium was 1329 and
1305 mg/day in the fluoride and placebo groups, respectively (not significant).
42
January, 2008
-------
Table 1 Chnical Characlenslici of (rip Women m thp FhHWlrtu awl f1«.t*b GHJMJA .1!
Ltf*.
mmc s-Hisi>3|HiJie
-.MVP ,<<>ig»w rf
-1! t»'i > "i
2*i rt ,'- .7.
nice tnita? >enrtrtjl
HI-*- fr.<
Ltunka t\
W ••", i">-
**,'••* m !"^c *c ,i» ». act's
Biochemical
measurements
The biochemical characteristics of the 202 women at baseline are provided in Table 2.
Table 2 Bi«:hpmKa( Chaf8etpr»sties of the Women In ihe art
Groups at Base Line
Srmrni
Allut
Huor «t
t'»w*f> ojihmin iw
IfaiurY jffc,m*is-e i
t. fltalltt* '|«
c'nln wf (.ifwi! ill til rjn
Z*)
Tft 1% .,74,
1 4 UJ4-'iij7i
I* H i ? *• ^ ^»
fi4 (ftl-C-'i
'4 r> l> tl *i
j? i2?-M>i
14 sit-221
1M |l?ft-l«l>
MS '5 6 6 i>
ri MN'th
I* , ^ « PI M
-,,'» ; ;; ^4^1
During the trial, the mean serum alkaline phosphatase concentration increased by 15.6 U/liter (pO.OOOl)
(Profiler's note: the units provided in the baseline table are not the same), and the mean serum bone Gla-
protein concentration increased by 5.2 ng/liter (pO.OOOl) in fluoride -treated women compared to those
taking placebo. Serum and urinary fluoride levels increased (pO.OOOl) in the fluoride group (Figure 1,
copied directly from Riggs et al. 1990). Serum calcium, phosphorous, and parathyroid hormone
concentrations, the urinary excretion of calcium, and the creatinine clearance did not change significantly.
43
January, 2008
-------
Safety
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
PROFILER'S Initials/date
REMARKS SJG/12/15/07
^•mm
| n i- __JL_____J______1____L_
i
t •,. „, , „- - - „,-,-,
8 "
£ « • *"
f ««• • K.
w / ^s^
r 't
SSM*^!** p^ rrt wn fw*!i»4 *^fc tl,"
M .if H* ^ l^fc I* =*
«j*fe »•»«• IL'V* *£**«
Carim ju.il. mutw* 1? * .7 » ." IW < f ? n
wf^raa^
UiMnunrrgiMl MMtttiiy. •* ¥ ill >," it>nMi)» -' *i
&ib£$ti&
lir»,tf~f HUfwry fain uf tte Auvt* H jM d i W H«1 1 1 M 4 »(
nv flwm^fc' ^me^ ^ssi UH psnjr^ WM% s>l ^Itv*. *if , *sd tt»- prifctf^f /j*t«r to" ^ '^
wpflifems iflw^vnl
f&«» |^l»fe i»d fcif! BW WW'^iBfl I)'S(WIWt
The data from this study suggests that fluoride treatment increases cancellous bone mass (e.g., lumbar
spine), but deceases cortical-bone mass (e.g., radial shaft) and increases skeletal fragility. Combined, these
effects result in a slight trend toward a decrease in fracturing of the vertebral bodies (predominately
composed of cancellous bone) but an increase in fracturing at sites containing either predominantly cortical
bone or similar amounts of cortical and cancellous bone. Thus, although there was an increase in
cancellous-bone mass, the findings do not support the clinical efficacy of the fluoride-calcium regimen for
the treatment of osteoporosis.
None to report.
This prospective, randomized, controlled, double-blind study followed 202 postmenopausal women with
osteoporosis who were treated with sodium fluoride or placebo over the course of 4 years. The study found
44
January, 2008
-------
PROFILER'S ESTIM.
NOEL/NOAEL
PROFILER'S ESTIM.
LOEL/ LOAEL
POTENTIAL SUITABILITY
FOR DOSE-RESPONSE
MODELING:
CRITICAL EFFECT(S):
that when compared to women in the placebo group, women treated with 75 mg/day of fluoride had more
side effects (placebo: 24; fluoride: 54 women), including gastric symptoms and lower extremity pain;
increased serum alkaline phosphate and bone Gla-protein, and serum and urinary fluoride levels; increased
BMD in the lumbar spine (35%; predominately cancellous bone), femoral neck (12%), and femoral
intertrochanteric region (10%; both sites of mixed cortical and cancellous bone); decreased bone mineral
content in the radial shaft (-4%; predominately cortical bone); and increased incidence of nonvertebral
fractures (placebo, 24; fluoride: 72 fractures). The slight decrease in the relative risk (0.85) of vertebral
fractures in the fluoride group compared to the placebo group was not significant. Thus, although bone
mass increased, particularly in the lumbar spine, the risk of nonvertebral fractures also increased.
One-third (67) of the patients failed to complete the full treatment period; however, the dropout rate was
similar in both groups and the data analysis included all randomized patients, so the impact was unlikely to
bias the results. Because there have been conflicting conclusions from other studies, the conclusions drawn
here are for the conditions of this study only.
Study design was not suitable for development of a NOAEL.
Study design was suitable for development of a LOAEL for bone mineral density and fracture risk.
Fluoride at 75 mg/day increases BMD in sites with predominately or mixed cancellous bone (lumbar spine,
femoral neck, femoral intertrochanteric region). Nonvertebral fracture risk also occurs at 75 mg
fluoride/day.
Not suitable (), Poor (X), Medium (), Strong ()
The study was well-conducted, but only one dose level was used (75 mg/day); the study design was
conducive to contribute data for LOAEL for BMD and fracture risk. Effects were noted at 75 mg/day but a
lower dose level also may increase fracture risk.
Skeletal fractures, bone mineral density
45
January, 2008
-------
Sauerbrunn BJ, Ryan CM, Shaw JF. 1965. Chronic fluoride intoxication with fluorotic
radiculomyelopathy. Ann Intern Med. 63(6):1074-8.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
ANALYTICAL METHODS:
STUDY DESIGN
PARAMETERS
MONITORED:
STATISTICAL METHODS:
Skeletal fluorosis and Fluorotic radiculomyelopathy
Case report
64-year old white male with the following history: birth to 7 years in Calhoun, GA; 43 years on farms
in southwestern Ellis County and the Grand Prairie area of Dallas County, TX, drinking well water
containing 2.4 to 3.5 ppm fluoride; at age 50, he moved to the Grapevine area of Tarrant County, TX.
The patient suffered from persistent polydipsia.
Not applicable in case report.
The patient's exposure from birth until age 7 was unknown, but records showed the water supply in
Calhoun, GA was not artificially fluoridated at the time he lived there. Drinking water seems to have
been his only source of fluoride intake, with exposure for 43 years to water with fluoride
concentrations ranging from 2.4 to 3.5 ppm.
A 64-year old white male was admitted to Veterans Administration Hospital in McKinney, TX on
May 1 1, 1962 because of severe respiratory distress and semi-coma. He had been a complete invalid
and in a nursing home for a year.
Medical records, including physical examinations, laboratory findings and x-rays, were evaluated
from hospitalizations at McKinney in 1950, 1954, 1955, 1959, 1961 and finally in 1962. An autopsy
was performed upon death. Medical history was obtained by questioning the patient's sister who had
lived with him for 35 years. The records of the patient's brother were reviewed following admission
to the VA hospital at McKinney in 1955 at age 61.
Records from the GA State Department of Health showed the water supply in Calhoun, GA was not
artificially fluoridated until 1957; natural fluoride content was not reported. Data from the TX State
Department of Health on chemical analyses of public water systems (1953- 1959) showed that wells
in southwestern Ellis County may contain up to 3.5 ppm fluoride; in the Grand Prairie area, 2.8 ppm
(90% of wells above 2.4 ppm); and in the Grapevine area, 2.4 ppm in wells and 2.2 ppm in the
distribution system. Analytical methods were not reported.
A 64-year old white male was admitted to Veterans Administration Hospital in McKinney, TX on
May 1 1, 1962 because of severe respiratory distress and semi-coma. He had been a complete invalid
and in a nursing home for a year.
Medical records, including physical examinations, laboratory findings and x-rays, were evaluated
from hospitalizations at McKinney from 1950 until his final admission in 1962. An autopsy was
performed upon death, with attention to the skeletal system, urinary system, brain and lung. Medical
history, including potential fluoride exposure, was obtained by questioning the patient's sister who
had lived with him for 35 years. Drinking water seems to have been his only source of fluoride
intake, with exposure for 43 years to water with fluoride concentrations ranging from 2.4 to 3 .5 ppm.
The records of the patient's brother were reviewed for comparison.
The following parameters were monitored: skeletal x-rays; neurological signs (e.g., pain, cramping,
stiffness, or weakness of limbs or joints; Babinski and Hoffmann's reflexes; muscular atrophy);
laboratory tests (e.g., serum calcium and phosphorus, acid phosphatase, alkaline phosphatase,
nonprotein nitrogen, blood urea nitrogen, creatinine; cerebrospinal fluid examination and
electroencephalogram, and renal function tests); and bone and liver fluoride content upon death.
Statistical analysis was not performed on this one patient.
46
January, 2008
-------
RESULTS:
Physical Examination
Skeletal findings
Laboratory findings
Bone and liver fluoride
content
In 1 950, the patient complained of pain and cramping in the left leg and of weakness and stiffness of
all limbs for several years. He had polydipsia and polyuria for at least 20 years. Physical findings
included moderate kyphosis, stiffness of the knee and ankle joints, spastic weakness of all
extremities, and ankle and patellar clonus. Bilateral Bibinski's and Hoffmann's signs were present.
Hypalgesia was found over both feet. Fasciculations were noted in both shoulders and arms.
A cystometrogram revealed a hypertonic bladder and spastic external sphincter. The patient's fluid
intake and output of urine varied from 4 to 10 liters/24-hour period. (Profiler note: it is unclear
whether this amount of fluid intake was only during the hospital admission period or an indication of
past consumption over the patient's lifetime). The principal disorder was thought to be due to
amyotrophic lateral sclerosis.
In 1954, the patient was readmitted due to acute epididymitis and intermittent retention of urine of 1
month's duration. His bladder was distended and the neurological signs of spastic quadraparesis had
increased since 1950. The patient's neurological disorder was thought to be caused by spinal cord
compression due to extrinsic pressure from an unidentified disease of bone. The polyuria was
considered to represent diabetes insipidus.
Admissions in 1955, 1959, and 1961 showed increasing functional urinary obstruction and
progression of crippling skeletal disease. On the final admission in 1962, the patient was critically ill
with pneumonia and shock; his condition deteriorated and he died on the third day after admission.
Skeletal x-rays in 1950 revealed increased size and density of long bones and of the vertebrae.
Calcification of the paravertebral and sacrospinous ligaments was noted. Skull films showed a
normal sella turcica and diffuse internal hyperostosis with obliteration of diploe. Minimum to
moderate narrowing of the foramen magnum was described. X-rays in 1954 showed increasing bone
density.
Autopsy revealed the following: the sternum, calvarium, and vertebrae were extremely dense. There
was no spongy bone between the tables of the skull; the cranial vault was 2.5 cm thick and uniformly
white and dense throughout. The anterior fosse showed massive protuberances of bone. The clinoid
processes were white, thick, and homogenous. The vertebral column was massive. The spinal cord
showed no gross abnormalities. Multiple sections of vertebral bone showed marked thickening of
trabeculae. The marrow spaces were markedly narrowed. Osteoblastic reaction was noted in several
areas.
Laboratory findings in 1950: serum calcium, 9.7 to 1 1.6 mg/100 ml; serum phosphorus, 3.1 to 3.7
mg/100 ml; acid phosphatase, 0.3 Bodansky units/100 ml; alkaline phosphatase, 3.1 Bodansky
units/100 ml; nonprotein nitrogen, 29 to 54 mg/100 ml; blood urea nitrogen, 1 1 to 12 mg/100 ml;
creatinine, 1.9 mg/100 ml; aphenolsulphonphthaleintest showing 3 6% excretion in the first 30
minutes and 52% in 1 hours. A Fishberg concentration test showed a maximum specific gravity of
1.008. Maximum urea clearance was 44 ml/min. Cerebrospinal fluid examination and
electroencephalogram showed normal findings.
Laboratory findings in 1955, 1959, and 1961: Serum calcium, phosphorous and potassium levels
were normal in each of these admissions. In 1961, serum alkaline phosphatase was elevated on three
occasions at 15.1, 11.3, and 12.3 Bodansky units/100 ml. Serum creatinine was 2.54 mg/lOOml.
Maximum urine specific gravity was 1.010.
Autopsy revealed the following: The pituitary gland, anterior and posterior lobes, and parathyroids
appeared normal. A culture of the lung revealed Staphylococcus aureus. The bladder, ureters and
calyces were dilated. Acute inflammatory changes were noted in the renal pelves. Chronic
inflammation was noted in the renal parenchyma, and hyaline casts were seen in dilated tubules.
A lexicological study (from the laboratory of Morton Mason, University of Texas Southwestern
Medical School, Dallas, Texas) indicated an elevated bone fluoride content of 610 mg/100 g of dried
bone and a liver fluoride content of 6. 1 mg/100 g of dried liver. The analytical method was a
microdiffusion method for determination of fluorides, according to Frere (1962).
47
January, 2008
-------
Supporting evidence of
fluoride exposure
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
PROFILER'S Initials/date
REMARKS SJG/
11/12/07
PROFILER'S ESTEM.
NOEL/NOAEL
PROFILER'S NOTE: The normal values for fluoride content ion the bone and liver were not
presented for comparison.
The patient's brother was admitted to the VA hospital at McKinney in 1955 at age 61. A review of
records and x-rays of the spine showed evidence of osteoarthritis but none of osteosclerosis. His teeth
were described as discolored, pitted, ridged, and worn, but there was no evidence of caries. His
sister, who lived with him for 35 years, also had mottled teeth.
The patient reported here showed most of the features of the cases of fluorotic radiculomyelopathy
reported from India by Singh et al. (1963) and Siddiqui (1955), notably crippling fluorosis with
marked neurological complications. Acroparesthesias, root pain, and muscular wasting are attributed
to compression of anterior roots. Spastic weakness, exaggerated deep tendon reflexes, and extensor
plantar reflexes follow spinal cord compression. Patchy sensory changes and occasionally a definite
sensory level are found.
The laboratory findings indicated defective renal concentrating function, possibly as a consequence of
functional urinary tract obstruction resulting from cord compression. Abnormalities of bladder
function have been noted by others and are not unusual when advanced fluorosis is complicated by
radiculomyelopathy.
In the post-mortem inquiry, no evidence was found to suggest self -medication, industrial exposure, or
dietary idiosyncrasy. Drinking water with fluoride concentrations from 2.4 to 3 .5 ppm for 43 years
seems to have been his only source of fluoride intake. Although these levels of fluoride have not been
thought to result in clinically detectable fluorosis except for mottled teeth, this relationship appears to
be for individuals with normal water consumption. The risk and degree of fluorosis may also depend
on the quantity of water consumed. This is suggested by the findings in this patient who developed
severe crippling fluorosis while his brother, who drank the same water, showed only mottling of the
teeth. The brothers were exposed to the same water for the same period of time, had the same diet,
lived under similar environmental conditions, but differed by the excessive water intake by this
patient. The bone content of fluoride in this patient is also much greater than the amount predicted
from the fluoride content of his drinking water (Profiler' s note : normal value not indicated) . Thus, it
appears that the probable cause for fluoride intoxication was prolonged polydipsia.
Prolonged polydipsia may be hazardous to persons living in areas where the levels of fluoride in
drinking water are not those usually associated with significant fluorosis.
Frere, FJ. 1962. A microdiffusion method for determination of fluorides. Microchem. J. 6: 167.
Singh A, Jolly SS, Bansal BC, Mathur CC. 1963. Endemic fluorosis. Epidemiological, clinical and
biochemical study of chronic fluorine intoxication in Panjab (India). Medicine 42:229-46.
The study design does not aid in the development of a dose response to fluoride with respect to
skeletal fluorosis. The objective of the study was to report the case of fluorotic radiculomyelopathy
in a single patient with prolonged and excessive ingestion of water with a fluoride concentration of
2.4 to 3.5 ppm. The patient's symptoms and neurological deficits are presented well and x-ray
examination provides evidence of increased vertebral size, marked osteoarthritis, and characteristic
calcification in the distal portion of the both sacrospinous ligaments. Autopsy confirmed increased
bone density and bone protuberances; thickening of trabeculae and narrowed marrow spaces; and
elevated bone and liver fluoride content. Decreased renal function is evident and, together with
excess water intake (polydipsia), may have increased the risk of fluorosis.
Although the case is interesting and novel, it has some limitations. The authors do not explain the
rationale behind the chosen laboratory tests, nor do they present normal values for fluoride in bone
and liver for comparison. Furthermore, it is not stated whether or not the patient also had mottled
teeth, indicative of fluoride exposure and dental fluorosis, like his siblings.
Study design was not suitable for development of a NOAEL.
48
January, 2008
-------
PROFILER'S ESTEM.
LOEL/ LOAEL
POTENTIAL
SUITABILITY FOR DOSE-
RESPONSE MODELING:
CRITICAL EFFECT(S):
Study design was not suitable for development of a LOAEL.
Not suitable (X), Poor (), Medium (), Strong ()
The study presented a rare case of fluorotic radiculomyelopathy as a progression of skeletal fluorosis
in one patient with prolonged exposure (43 years) to fluoride in the drinking water at 2.4 to 3.5 ppm.
Skeletal fluorosis and radiculomyelopathy
49
January, 2008
-------
Sowers, M., Whitford, G.M., Clark, M.K., and Jannausch, M.L. 2005. Elevated Serum Fluoride
Concentrations in Women Are Not Related to Fractures and Bone Mineral Density. J Nutr.
135: 2247-2252.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
(High-fluoride)
POPULATION STUDIED:
(High-calcium)
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
ANALYTICAL METHODS:
Skeletal fractures; bone mineral density; serum fluoride levels
Prospective cohort
526 women (54.8±0.80 years old) residing in a small, predominately Caucasian, American
(USA) community with high-fluoride concentration (2 10.4 |j,mol/L) and below national
average calcium concentration (0.375 mmol/L) in the water supply.
406 women (54.1±0.91 years old) residing in a small, predominately Caucasian, American
(USA) community with high-calcium concentration (9.375 mmol/L) in the water supply and
fluoride levels (52.6 |amol/L) consistent with the national average.
368 women (55.9±0.96 years old) residing in a small, predominately Caucasian, American
(USA) community with fluoride (52.6 nmol/L) and calcium (1.500 mmol/L) concentrations
in the water supply consistent with the national average.
The exposure period was based on the number of years residing in each community
(categorized into tertiles: 0-13 years; 14-27 years; 27-79 years). Fluoride levels in the 210.4
|j,mol/L communities have been augmented by water treatment since 1958. Bone fracture
incidence and site were recorded every 6 months for 4 years.
Data collection was initiated in 1300 women, aged 20-92 years, living in 3 communities with
diverse mineral content in the water supplies. The communities were similar with respect to
size (<2000 residents per community), racial and ethnic mix (>95% Caucasian), mean
income, and primary occupations. A community census identified women >18 years old who
were ambulatory (able to climb 3 steps without assistance), and able to provide informed
consent. There were no additional selection criteria. Study participation rates among eligible
women were 70%, 79%, and 8 1% in the high-fluoride, high-calcium, and control
communities, respectively. There was no significant difference in mean ages among the 3
communities. The fluoride and calcium concentrations in each community were as follows:
High-fluoride community. F: 210.4 |jmol/L = 4 mg/L; Ca: 0.375 mmol/L = 15 mg/L
High-calcium community. F: 52.6 |amol/L = 1 mg/L; Ca: 9.375 mmol/L = 375 mg/L
Control community. F: 52.6 |j,mol/L = 1 mg/L; Ca: 1.500 mmol/L = 60 mg/L
The fluoride content in the high-fluoride community was naturally occurring due to the
geology of the area. In the other communities, fluoride levels were augmented by water
treatment. The communities are small, so blending and processing of waters from more than
one source do not occur.
Individual serum fluoride concentrations and bone mineral density (BMD) of the femoral
neck, lumbar spine, and distal radius were measured. Serf-reported fractures were confirmed
by medical record abstraction.
Fluoride intakes were based on reported water and water-based beverage consumption and
duration of residence in the community. Additional sources of calcium intake (water, diet,
and supplement) were considered.
The University of Iowa Hygienic Laboratory, the state public health laboratory, has
monitored the calcium and fluoride concentrations in these communities since 1938; the
concentrations have varied only slightly over that period. The analytical methods were not
50
January, 2008
-------
STUDY DESIGN
PARAMETERS
MONITORED:
STATISTICAL METHODS:
reported.
This study relates serum fluoride concentrations, which reflect individual fluoride exposures,
to BMD and bone fractures. The study population consisted of 1300 female residents, >18
years old, of 3 small, predominately Caucasian, communities in which the water fluoride and
calcium concentrations were as follows: control. 52.6 |amol F/L; 1.50 mmol Ca /L; high-
calcium: 52.6 |amolF/L; 9.375 mmol Ca/L; or high-fluoride: 210.4 |j,molF/L; 0.375 mmol
Ca/L. Subjects were interviewed for fluoride and calcium intake. Fluoride intakes were
based on water and water-based beverage consumption and duration of residence in the
community. Additional sources of calcium intake (water, diet, and supplement) were
considered. Serum fluoride and osteocalcin concentrations, bone mineral density (BMD),
and fracture incidence and site were assessed as follows:
Serum fluoride was analyzed using an ion-specific electrode (Model 9409, Orion Research)
and a miniature calomel reference electrode coupled to a potentiometer after overnight
diffusion using a modification of the hexamethyldisiloxane-facilitated diffusion of Taves
(Taves 1969, Whitford 1996). The CV was <5%. Serum osteocalcin concentrations were
measured using the Instar™ RIA (radio-immunoassay). The inter- and intra-assay variation
was < 10%.
BMD of the femoral neck and lumbar spine and total body bone calcium were measured by
dual X-ray densitometry (DEXA-Lunar; DPX-L™, analysis software version 1.3y). BMD
of the distal radius was measured using single-photon densitometry. Measurements of BMD
at the various sites allowed for assessment of different effect of fluoride in bone that is more
cortical, as in the radius, or more trabecular, as in the lumbar spine. Calibration was
performed daily and a lumbar spine phantom was scanned weekly. The CV for DEXA was
<1.5% for the femoral neck site.
Participants reported the site of any bone fracture, date of occurrence and, if appropriate, the
facility where the fracture was treated using a postal card every 6 months for 4 years.
Fracture status was confirmed at treatment facilities by abstracting medical records and
securing available copies of images.
Other measures included: height and weight to calculate body mass index (BMI; (weight
(kg)/height (m2)); serf-reported menopause status ( >12 months cf amenorrhea); medication
use; and total time (min) per week of activity.
Individual serum fluoride concentrations were analyzed by ion-specific electrode. Serum
osteocalcin concentrations were measured by radio-immunoassay (RIA). Bone mineral
density (BMD) of the femoral neck and lumbar spine (predominately trabecular bone) and
total body bone calcium were measured by dual X-ray densitometry. BMD of the distal
radius (predominately cortical bone) was measured using single-photon densitometry. Serf-
reported fractures were confirmed bv medical record abstraction.
Continuous variables were evaluated for normality and transformations undertaken when
appropriate. General linear models were used to estimate group means and test for pair-wise
significant differences between groups. To show the association of serum fluoride with
duration of residence in the community, serum fluoride values were categorized into
quartiles with the lowest quartile acting as the reference category. Duration of residence was
classified into tertiles (1-13, 14-26, 27-77 years) with the first category acting as the
reference. Serum fluoride concentrations were calculated for each cell and compared using
ANOVA.
Multiple variable regression models were fit with quadratic terms centred about their means.
These models were built by identifying the relation between fluoride exposure and BMD and
then including other variables (e.g., age, BMI, and menopause status) based onp-values for
individual terms O.05. Logistic regression analyses were used to assess the association
between risk of osteoporotic fractures and serum fluoride concentration, BMD, age, body
size, and medications. In all regression analyses, serum fluoride was a log-transformed
51
January, 2008
-------
RESULTS:
Serum fluoride
continuous variable; indicator variables represented the high-calcium and high-fluoride
communities, with the control community as the reference.
Tables 1 and 2 were copied directly from Sowers et al. (2005). Table 1 summarizes the
characteristics of the study populations according to water mineral content. Serum fluoride
concentrations were highest in the high-fluoride community. The mean serum fluoride
concentration was 32% greater in the high-fluoride community (2. 1 1 |amol/L) compared
with that in the control community (1 .60 |amol/L) and 73% greater than that in the high-
calcium-community (1.22 |amol/L).
TABLE 1
Characteristics of women, aged 20-92 y, in communities according to water mineral concentration,
with comparisons across community designations^
Community
Variable Control High-calcium High-fluoride P-value
n 368 406 526
Age,y 55.940.96 54.1 ± 0.91 54.8 0.80 NS2
Serum fluoride, lunollL 1.60 ±0.04" 1.22*0.05= 2.11 0.05" 0.0001
Dally calcium intake, mg 754 ± 20" 1001 ±25* 679 16= <0.0001
Dally water fluoride intake, pmol/L 63.65*2.63" 40.50*1.58= 192.52 6.84" <0.0001
BMD, 9/cm*
Lumbarspine 1.179 ±0.0110 1.197*0.0104 1.195 0.009 NS
Femoral neck 0.914 * 0.0084 0.912 * 0.0083 0.912 0.007 NS
Distal radius 0.651 * 0.0053" 0.656 * 0.0057-° 0.667 0.004' 0.05
BMI, kglrrf 27.85 ± 0.33 28.56 ± 0.31 28.30 0.27 NS
Osteocalcin, nmol/L 0.385 ± 0.012= 0.446*0.011" 0.434 0.010° 0.0005
Fracture, n (%)
Osteoporotte 5 (1.4) 14'(2.3) 15 (2.9) 0.01
Nonosteoporotic 11 (3.2) 14 (3.4) 16 (3.1) NS
Current smoking, n (%) 31 (10.8) 51 (16.2) 58 (15.4) 0.02
Thiazlde antihypertensive. n (%) 22(7.7) 22(7.0) 38(10.1) 0.02
Use in previous 12 mo, n(%) 13(4.5) 16(5.1) 23(6.1) 0.01
Hormone replacement, n (%) 2 (0.7) 17 (5.4) 16 (4.3) 0.01
Physical activity, n {%) <0.0001
<40min/wk 98 (27) 79 (19) 248 (47)
40-150 min/wk 142 (38) 137 (34) 156 (30)
>150mln/wk 128(35) 190(47) 122(23)
1 Values are means * SE or n (%). Means in a row with superscripts without a common letter differ, P < 0.05.
2 NS, nonsignificant; P ^ 0.05.
Table 2 ranks serum fluoride concentrations related to years of residence in each community.
Serum fluoride concentrations increased with greater years of residency in the high-calcium
community (4th quartile) and in the high-fluoride community (3rd quartile).
TABLE 2
Quartiles of serum fluoride concentration related to years of residence in the community (by tertiles)
according to community water supply mineral concentration'1
Serum fluoride concentration
Quartile 1 Quartile 2 Quartile 3 Quartile 4
Years of residence (tertiles) <25% 25-50% 50-75% >75%
ti/noi/L
Control community
710-13(30%) 0.76 0.04 1.32 0.03 1.68 0.03 2.60 ± 0.18
7213-27(31%) 0.80 0.04 1.29 0.02 • 1.69 0.02 2.58 ± 0.14
7327-77(38%) 0.79 0.04 1.33 0.02 1.73 0.02 2.54*0.11
High-calcium community
710-13(38%) 0.55 0.02 0.92 0.02 1.23 0.02 1.84 0.13'
7213-27(31%) 0.57 0.02 0.89 0.02 1.27 0.02 2.27 0.13
7327-79(30%) 0.55 0.03 0.93 0.02 1.27 0.02 2.24 0.10
High-fluoride community
710-13(33%) . 0.84 0.03 1.47*0.03 2.09 ± 0.05 3.87 0.33
7213-27(33%) 0.91 0.04 1.43 ±0.03 2.15 ±0.04 3.78 0.24
73 27-78 (33%) 0.91 0.04 1.45 * 0.03 2.27 ± 0.04" 3.97 0.18
1 Values are means ± SE, total n = 1300. * Different from 72, * P < 0.01 . " Different from 72, P < 0.001.
PROFILER'S NOTE: The profiler agrees that the serum fluoride concentrations in the high-
fluoride community were higher than the values from the control and high calcium
communities; however, serum fluoride levels do not appear to be related to the number of
years of residency in the communities. If serum fluoride concentrations increased with the
number of years of exposure in a given community, greater values in each serum fluoride
quartile in the 27-77 year fertile compared to the 0-13 or 13-27 year tertiles would be
expected. Only one quartile in each of the high-calcium (4th quartile) and high-fluoride (3rd
quartile) communities showed statistical significance, thus the lexicological relevance is
52
January, 2008
-------
Bone mass density (BMD)
Skeletal fractures
Serum osteocalcin
questionable.
The BMD of the distal radius, mainly cortical bone, was significantly higher (2.5%) in the
high-fluoride community compared with the control community. BMD of the lumbar spine
or femoral neck did not differ among communities (Table 1).
Table 3 was copied directly from Sowers et al. (2005) and lists results from multiple-variable
regression models relating serum fluoride and BMD. There were no statistically significant
associations of serum fluoride concentrations and BMD measures. Other variables (age,
BMI, osteocalcin concentration, thiazide antihypertensive use, oral contraceptive use,
hormone therapy use, menopause status and physical activity) explained 50% of the
variation in the BMD at the femoral neck and distal radius, and 32% of the variation in the
BMD at the lumbar spine.
TABLE 3
^-Coefficients and variance
-------
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
PROFILER'S
REMARKS
Initials/date
SJG/2/19/07
PROFILER'S ESTEM.
NOEL/NOAEL
and in the high-fluoride communities, respectively, compared with women in the control
community (Table 1).
This study measured multiple variables including serum fluoride concentration, fluoride
exposure, assessment of bone metabolism, and fluoride interactions with other important
bone factors including age, body size, menopause status, and medications. Neither serum
fluoride concentrations nor the duration of residency in communities with known water
fluoride concentrations predicted incident osteoporotic fractures in women 20-92 years old.
A substantial fluoride exposure gradient was found among the communities, as indicated by
both the serum concentration and the duration of residency in the communities. The
measures of fluoride exposure used in this study, and at the amounts identified, were not
associated with osteoporotic fractures or with BMD, particularly after adjustment of
covariates including age, body size (BMI), thiazide use, hormone use, and menopause status.
There were no independent associations of fluoride exposure with BMD at the 3 measured
bone sites. BMD was higher in the distal radius of residents of the high-fluoride community;
BMD of the vertebrae or femoral neck did not differ among communities.
The authors conclude that within the range of these exposures and variables, the risk of
deleterious bone-related outcomes was not related to fluoride exposure. At 210.4 |amol F/L
in the drinking water, there is little evidence of a bone demineralization defect associated
with low BMD or fracture.
Taves, D.R. 1969. Determination of submicromolar concentrations of fluoride in bio logical
samples. Talanta 15: 1015-1023.
This was a well-conducted and designed study. Serum fluoride, BMD and skeletal fractures
were monitored. The study indicated higher individual serum fluoride levels in the
community with 2 10.4 |amol F/L in the water supply. There was an increase in distal radius
BMD in the high-fluoride community and increased osteoporotic fracture frequency in the
high-fluoride and high-calcium communities, with an association between the high-fluoride
or high-calcium communities and BMD of the distal radius (p-coefficient: 0.020, p=0.01 1;
and p-coefficient 0.018, p=0.01 1, respectively). There was only a weak association between
serum fluoride and BMD in the femoral neck and lumbar spine (P-coefficient 0.01 1, p=0. 13;
and p-coefficient 0.0 19, p=0. 12, respectively). After adjustment for covariates, no
association was found between serum fluoride levels and osteoporotic fractures (RR 1. 16,
p=0.66) or between the high fluoride community and fractures (RR=2.55, p=0.07). Thus,
serum fluoride levels in subjects of the community with 210.4 |j,mol F/L in the water supply
were not statistically associated with fracture incidence.
Some weaknesses of the study included the following:
Serum fluoride levels may not be a suitable biomarker for bone fluoride levels. The profiler
disagrees that a substantial fluoride exposure gradient was found, as indicated by the
duration of residency in the communities. Further, it is unclear whether smoking status,
which differed among communities, was included in the regression models. Other
unidentified confounders may be contributing to the results since some effects (i.e., increased
osteoporotic fracture frequency; an association with BMD of the distal radius) were
observed in both the high-fluoride and high-calcium communities; moreover, the RR for
osteoporotic fractures was 3.01 (p=0.04) in the high-calcium community. Finally, fracture
incidence and risk associated with fluoride-based measures was not broken down by age;
although mean age among communities did not differ, it is unclear whether limiting
regression models to certain ages (e.g., 20-40, 41-60, 61-80) would yield different risk ratios.
Limited data for dose-response analysis; however, results indicate that fluoride levels of 4
ppm in drinking water may not increase risk of fractures.
Based on the risk of osteoporotic fracture, the estimated NOAEL is 2 10.4 |amol F/L (4
54
January, 2008
-------
PROFILER'S ESTEM.
LOEL/ LOAEL
POTENTIAL SUITABILITY
FOR DOSE-RESPONSE
MODELING:
CRITICAL EFFECT(S):
mg/L) in the drinking water.
After adjustment for covariates, an estimated LOAEL could not be established.
Not suitable ( ), Poor ( ), Medium (x), Strong ()
This was a well-conducted and designed study, with only a few limitations. The study
indicated the following results in the community with 210.4 |amol F/L in the water supply:
higher individual serum fluoride levels; increased distal radius BMD; and increased
osteoporotic fracture frequency (also noted in the community with 52.6 |amol F/L and 9.375
mmol Ca/L); an association between the high-fluoride (or high-calcium) communities and
BMD of the distal radius. Nevertheless, after adjustment for covariates, no association was
found between serum fluoride levels and osteoporotic fractures (RR 1. 16, p=0.66) or
between the high fluoride community and fractures (RR=2.55, p=0.07).
Skeletal fracture incidence and site; bone mineral density
55
January, 2008
-------
Sowers, M.R., Wallace, R.B., and Lemke, J.H. 1986. The relationship of bone mass and fracture
history to fluoride and calcium intake: a study of three communities. Am. J. Clin. Nutr.
44:889-898.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL
POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE
ASSESSMENT:
ANALYTICAL
METHODS:
STUDY DESIGN:
Skeletal fractures and bone mass in adult women
Cross-sectional baseline survey (May - August, 1983 and 1984) of bone mass and skeletal
fractures in women supplied with drinking water of high and low F content and different calcium
concentrations. REVIEWER'S NOTE: This study was followed during 1988-89 and published
in Sowers etal. (1991)
PROFILER'S NOTE: The study authors' hypothesis was that higher fluoride intake would
result in greater bone mass and fewer fractures. The findings did not support the hypothesis.
US/Iowa: 827 adult women in three rural communities in northwest Iowa; participants had lived
in the community at least 5 years; ages at the beginning were 20-80 years for the high fluoride
group and 20-35 and 55-80 years for both low and high calcium groups; all individuals were
ambulatory, not knowingly pregnant, and had not experienced wrist or forearm fractures in the
previous two years. The communities were similar with respect to population size (less than
2000 persons), age distribution, proportion foreign born, mean income, and occupational
categories; all eligible women were of northern European heritage. Completion rates were high,
with >77% of eligible women completing the study in each community.
Community with relatively low fluoride (1 mg F/L) and low calcium (67 mg Ca/L) in the
municipal water. Demographics were similar to the study population.
PROFILER'S NOTE: 1 mg/L F is optimally fluoridated water and is not really considered low
fluoride except in comparison to 4 mg/L F.
Participants had lived in the high fluoride community for 5-77 years at the beginning of the study.
The communities were chosen based on municipal water supplies containing either high natural
fluoride (4.0 ± 0.1 mg F/L with 15 ± 3 mg Ca/L), high calcium (375 ± 8 mg Ca/L), or low
calcium (60 ± 4 mg Ca/L as reported); the low and high calcium water supplies were treated to 1
mg fluoride/L.
The exposure assessment consisted solely of measured fluoride concentrations in drinking water
and estimated fluoride concentrations of water-based beverages (frozen juices, powdered drink
mixes, coffee, and tea). Water and water-based beverage intake was assessed in a 24-hour recall
survey and in a water intake section of a questionnaire. Fluoride content in foods was not
evaluated and non-dietary sources of fluoride were not measured.
Each individual was asked to recall her previous 24-hour intake of food and beverage during an
interview. Nutrient values, including calcium, were assigned to coded foods and beverages
using the US Department of Agriculture Food Composition Tape # 456. A supplemental
program was developed to assign vitamin D values to foods and beverages based on information
from published food composition tables (Southgate and Southgate 1978) and other information
sources about fortified products.
Inorganic constituents of the community water supplies were determined at the University of
Iowa Hygienic Laboratory (the state public health laboratory) according to most current methods
(APHA 1976). No further information was given regarding the methods for analyzing fluoride
and calcium in drinking water. Water sampling and testing had been performed approximately
every 5 years since 1938.
Bone mass was studied in adult women in three rural communities supplied with water of
differing mineral (F and Ca) content. Mid-radius bone mass of women whose community
56
January, 2008
-------
PARAMETERS
MONITORED:
STATISTICAL
METHODS:
RESULTS:
Diet assessment
Drinking water
characteristics
Bone mass in baseline
study (Sowers et al.
1986)
drinking water contained naturally occurring high fluoride (4 mg F/L) and low calcium (15 mg
Ca/L) was compared to bone mass of women living in two demographically similar communities
where the fluoride level of the treated drinking water was 1 mg F/L but the Ca concentration
varied considerably (375 mg Ca/L or 60 mg Ca/L).
Bone mass was measured using a Norland 278 photon absorptiometer with an I125 source
(Cameron and Sorensen 1963, Cameron et al. 1968). Bone mass was expressed as the bone
mineral to bone width ratio (g/cm2) of the radius.
Each participant was measured for height, weight, triceps skinfold thickness, and mid-arm
circumferences. Responses to questions regarding demographic information, reproductive
history, medication and nutritional supplement use, smoking, alcohol use, medical history,
fracture history, and sunlight exposure were recorded.
Normality of variance was evaluated with univariate analysis. Variables with highly skewed
distributions were logic transformed (nutrient intakes) or categorized. Chi-square tests were
used to determine if subjects were demographically homogeneous. Analysis of covariance
with multiple comparison tests was used to generate and compare mean nutrient intakes and
physical measurements by community. Associations between levels of bone mass and factors
such as medication use and dietary fluoride and calcium intakes were tested using multiple
regression analysis. Probability of fracture history in relation to community fluoride exposure
considering important covariates such as perimenopausal estrogen and current thiazide use as
well as interactions was evaluated using stepwise multiple logistic regression analysis.
PROFILER'S NOTE: Thiazide is a diuretic used in the prevention of urinary calculi.
Composite diet analysis performed by means of a 24-hr recall interview indicated that water was
the primary source of fluoride intake.
TABLE 1
Selected mineral characteristics of wells providing the drinking water of three rural {kmograpMcaiiy-simtlar
communities in northwest Iowa*
NjiafaJ Fre$tf£ti€) 0^
Due Mean Cilrium range Duotvde Trawif to ttaiuiicn
Coffiatyfliiy drilled Dspih csldym smienl {min-ma*} !c*el 1 mi/L ssnee 193$
f mg/L mg/L mg/L
High fluoride < 1938 1211 15 14-19 4.00 No 6
High calcium
WelW 1960 600 351 336-370 0.35 Yes 6
Well 12 1938 660 360 345-390 0.40 n
Low calcium
Well#l I960 230 70 66-7! 0,20 Yes 6
Well #2 1S48 230 65 62-68 0,20 9
* Data Source: University of Iowa Hygienic Laboratory.
Mid-radius bone mass did not differ among women aged 20-35 years in the three communities.
However, women 55-80 yr living in the high fluoride community had significantly less (25%)
mean mid-radius bone mass than women living in either the low or high calcium communities.
When adjusted for estrogen and thiazide use as well as total calcium intake (including water,
food, and supplement), vitamin D intake and muscle area, levels of bone mass from women in
the high fluoride community were slightly lower (< 2%) but did not attain statistical
significance (Fig 2). Findings were similar using bone mineral (g) or bone width (cm) instead
of bone mass (g/cm2) as the variable of interest.
PROFILER'S NOTE: Total calcium and Vit D intake were estimated from respondent
questionnaire, as described in the methods section above.
57
January, 2008
-------
Skeletal fractures
Dose Response
0.8-
1 OJ-
1
m
O
"S.
aj
CD
0.5-
\
» tow CcWurn x "'., \
*•» '•', \
« High Cokftim \ '""-X
\ \
• H\^ Fluoride v \
"V \
20 25 30 35 40 45 50 55 60 65 70 75 80
Age
FIG 2 ^ conramurt ulf mon rrrd-fswJtus hone m«i of stamen ^dusted for a?f, humors musdr area, e^ragM
d SNJ82IOT
ujrvf (n MSJS, *<( -,«< m wS1 « v» TtiM liiMtitisp i tiMb^«> a.- iivtt n w i.iu u*.i% JJ •nunai
Fracture history was determined from subject interview and was evaluated by community of
residence (Table 3). Among women aged 20-35 yr, no community differences were observed
in the history of fracture frequency. Women 55-80 yr living in the high fluoride community
reported significantly more lifetime and current fractures than did women in the high calcium
or low calcium communities.
REVIEWER'S NOTE: Fracture history and medical history information was obtained by
subject interview; there is no evidence that individually reported fracture history was
confirmed with medical records or other more objective evidence.
TABLE 3
Frequency of fractures among women living in three communities whose drinking waters have differing levels of
fluoride and calcium
High Sittorkk High odciMm tow o&ciMm
Type of franutt Number » Number «t Number » tew»
Women 55-80 n - 200 n=I7J n=!5l
Ever had a fmcture 92 46* 61 35% 55 36% p- 0.0660
Sites of fracture *
hip, wrist, spine 31 16% IS 9% 18 12% p = QJ40«
other sites 61 30% 46 26% 46 24%
Fracture in past 1C yr 57 29% 24 14% 20 , 13% p- 0,0001
Site of fracture in the past 10 yr
hip, wrist, spine 3 2% 2 1% 3 2% p^ 0,0006
other sites 54 27% 22 13% 17 11%
Women 20-35 n = SS » = 43 n = 43
Ever had a fracture 27 31% 12 28* 9 21% p = 0,4«<»
Sites of fracture
hip, wrist, spine 6 7% 1 2% I 2% p - O.S436
other sites 21 24% II 26% 8 19%
Fracture in
past 10 >r B 9% 1 7% 5 i 1% p « 0.7599
Sites of fracture in past 10 yr
hip, wrist, spine _______
other sites 8 9% 3 7% 5 11% p = 0,7599
To estimate fluoride intake, years of residence multiplied by reported typical beverage
consumption (expressed as quartiles of the distribution) was related to bone mass. Mean
bone mass
of women in the upper quartile of fluoride exposure tended to be significantly
less (p = 0.0665) than mean bone mass of women in the third quartile and slightly, but not
statistically, less than the mean value of women in the second quartile. This relationship is
observed following adjustment for age, humeral muscle area, current thiazide use,
history of estrogen use, and menopausal state. The quartile categorization of fluoride
exposure was not associated significantly with an increased probability of recent or
58
January, 2008
-------
Interaction with calcium and
vitamin D
Demographics
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE
NOT FOUND IN NRC
(2006)
PROFILER'S Initials/date
REMARKS CSW
12/18/2006
and
1/22/2007
PROFILER'S ESTIM.
NOEL/NOAEL
PROFILER'S ESTIM.
LOEL/LOAEL
POTENTIAL
lifetime fracture history after considering the important covariants.
Premenopausal women with lower calcium and vitamin D intakes (determined by recall
interviews) and greater fluoride intake (n = 16) had significantly lower mean bone mass
than mean values of women in the low fluoride/low calcium, low fluoride/high calcium,
and high fluoride/high calcium intake groupings (0.715±0.017 vs 0.744±0.004, p =
0.0470). No consistent interactions of the three nutrients in relation to bone mass were
observed in postmenopausal women after considering important covariants.
No differences in demographics were found among the women in the three communities.
"We observed no protective effect with higher fluoride intake. Bone mass was lower in older
women from the high fluoride community though not statistically so; these women reported
significantly more fractures. There was no observed community difference in young women's
bone mass or fracture history. Young women in the high fluoride community consuming
calcium and vitamin D in excess of 800 mg/day and 400 lU/day, respectively, had significantly
better bone mass (p < 0.05) than their peers."
PROFILER'S NOTE: The study authors' hypothesis was that higher fluoride intake would
result in greater bone mass and fewer fractures. The findings did not support the hypothesis.
American Public Health Association. Standard methods for the examination of water and
wastewater, 14th ed. Washington, DC: American Public Health Association, 1976.
Cameron, J.R. and Sorenson, J.A. 1963. Measurements of bone mineral in vivo: an improved
method. Science 142:230-232.
Cameron, J.R., Mazess, R.B., and Sorensen, J.A. 1968. Precision and accuracy of bone mineral
determination by direct photon absorptiometry. Invest. Radiol. 3 : 141-150.
Southgate, P.P.A. and Southgate, D. A.T. 1978. McCance and Widdowson's the composition of
foods, 4th ed. Amsterdam: Elsevier/North-Holland Biomedical Press.
This study was well conducted and controlled for factors such as age and estrogen use.
The most pronounced effect appeared to be in older women ( >55 years) with high fluoride (4
mg/L) content of their drinking water. This group had the lowest bone mass and the greatest
number of fractures.
Good comparison to communities with low fluoride and either high or low calcium content of the
drinking water.
Doses could not be reconstructed based on the data presented.
In the baseline study, overall mean drinking water calcium levels in the low and high
communities were reported in the text as 60 and 375 mg/L, respectively. However, the mean
ranges (based on 6-1 1 measurements in two wells) given in the table were 65-70 and 35 1-360
mg/L so clearly the overall mean is outside the range. In the follow-up study (Sowers et al. 1991)
the overall mean for the low calcium water is 67 mg/L which is reasonable based on the data
presented in the first report (1986). It may be that the overall mean for the high calcium value is
a typo as it appears that it should be about 355 mg/L. This discrepancy does not affect the
conclusions of either paper.
Could not be determined
Could not be determined.
Not suitable ( ), Poor (X), Medium ( ), Strong ( )
59
January, 2008
-------
SUITABILITY FOR
DOSE-RESPONSE
MODELING:
CRITICAL EFFECT(S):
A positive correlation was found between years of residence and lower bone mass and number of
fractures. Dose was estimated by years of residence and reported beverage consumption.
However, the study authors stated only that significance was found for "women in the upper
quartile of fluoride exposure" but corresponding doses were not given for each quartile. Thus, a
range of doses could be calculated from the residence time and estimated intake data presented,
but it is unknown at which dose statistical significance is attained.
Skeletal fracture, bone mass
60
January, 2008
-------
Sowers, M.R., Clark, M.K., Jannausch, M.L., and Wallace, R.B. 1991. A prospective study of bone
mineral content and fracture in communities with differential fluoride exposure. Am. J.
Epidemiol. 133:649-660.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL
POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE
ASSESSMENT:
ANALYTICAL
METHODS:
STUDY DESIGN
Skeletal fractures and bone mass in adult women
Five-year follow-up study (1988 and 1989; N = 684) after the initial cross-sectional baseline
survey (May - August, 1983 and 1984; N = 827) of bone mass and skeletal fractures (see
Sowers et al 1986 for baseline study documentation).
US/Iowa: Adult women in three rural communities in northwest Iowa; participants had lived in
the community at least 5 years and consumed the community water supply; ages at the
beginning were 20-80 years for the high fluoride group and 20-35 and 55-80 years for both
low and high calcium groups; all individuals were ambulatory, not knowingly pregnant, and
had not experienced wrist or forearm fractures in the previous two years. The communities
were similar with respect to population size (less than 2000), age distribution, proportion
foreign born, mean income, and occupational categories; all eligible women were of northern
European heritage. Of those participating in the baseline study (Sowers et al. 1986), 81.5-85%
participated in the follow-up.
Community with low fluoride (1 mg/L) and low calcium (67 mg/L) concentrations in the
community water. Demographics were similar to the other study populations.
Participants had lived in the high fluoride (4.0 mgF/L with 15 mgCa/L) community for 5-77
years at the beginning of the baseline study (Sowers et al. 1986). The current study was a
follow-up five years after the baseline study. Residence duration for the other 2 communities
was not reported.
The communities were chosen based on community water supplies with either naturally high
fluoride (4.0 mg F/L with 15 mg Ca/L), high calcium (375 mg Ca/L), or low calcium (67 mg
Ca/L); the low and high calcium water supplies were treated to 1 mg fluoride/L.
The exposure assessment consisted solely of measured fluoride concentrations in drinking
water and estimated fluoride concentrations of water-based beverages (frozen juices,
powdered drink mixes, coffee, and tea). Water and water-based beverage intake was assessed
in a 24-hour recall survey and in a water intake section of a questionnaire. Fluoride content in
foods was not evaluated and non-dietary sources of fluoride were not measured.
Each individual was asked to recall her previous 24-hour intake of food and beverage during
an interview. Nutrient values, including calcium, were assigned to coded foods and beverages
using the US Department of Agriculture Food Composition Tape #456. A supplemental
program was developed to assign vitamin D values to foods and beverages based on
information from published food composition tables (Southgate and Southgate 1978) and other
information sources about fortified products.
Inorganic constituents in community water supplies were determined at the University of Iowa
Hygienic Laboratory (the state public health laboratory) according to methods recommended
in APHA (1976). No further information was given regarding the methods for analyzing
fluoride and calcium in drinking water.
Bone mass and relative fracture risk were studied in 684 adult women aged 20-80 years and
residing in three rural communities supplied with differing mineral (F and Ca) content in
community water, as follow-up to a baseline study of similar design (Sowers et al 1986; N =
827). Mid-radius bone mass and fracture history of women living in a community whose
municipal drinking water had naturally-occurring high fluoride (4 mg F/L) were compared to
those of women living in two demographically similar communities where the fluoride level of
the treated drinking water was 1 mg F/L and the Ca content varied (375 or 67 mg Ca/L).
61
January, 2008
-------
PARAMETERS
MONITORED:
STATISTICAL
METHODS:
RESULTS:
Diet assessment
Drinking water
characteristics
Bone mass
Bone mass was measured using a Norland 278 photon absorptiometer with an I125 source
(Cameron and Sorensen 1963, Cameron et al. 1968). Bone mass was expressed as the bone
mineral to bone width ratio (g/cm2) of the radius. In addition, femoral bone mass was
measured using a Norland 2600 Dichromatic dual-photon densitometer with a gadolinium- 153
source; femoral bone mass was measured only in women who were post menopausal, were
capable of reclining to a flat position, did not have hip pins, and were sufficiently lean to fit
under the scanner arm.
Each participant was measured for height, weight, triceps skinfold thickness, and mid-arm
circumferences. Responses to questions regarding demographic information, reproductive
history, medication and nutritional supplement use, smoking, alcohol use, medical history,
fracture history, and sunlight exposure were recorded.
Normality of variance was evaluated with univariate analysis. Variables with highly skewed
distributions were logic transformed (nutrient intakes) or categorized. Chi-square tests were
used to determine if subjects were demographically homogeneous. Analysis of covariance
with multiple comparison tests was used to generate and compare mean nutrient intakes and
physical measurements by community. Associations between levels of bone mass and
factors such as medication use and dietary intakes were tested using multiple regression
analysis.
Probabilities of fracture between baseline and follow-up in relation to community fluoride
exposure were evaluated using stepwise logistic regression analysis (important covariates
such as age, Quetelet index (wt/ht2), calcium intake, vitamin D intake, and interactions were
evaluated). Estimates of relative risk with 95 percent CIs were calculated from beta
coefficients and standard errors.
Composite diet analysis performed by means of a 24-hr recall interview indicated that water
was the primary source of fluoride intake. Calcium and vitamin D intakes were assessed as
described above in "Exposure Assessment."
Drinking water in the higher fluoride community had a naturally occurring fluoride
concentration of 4 mg F/L and a calcium concentration of 1 5 mg Ca/L. Drinking water in the
higher calcium community had a calcium concentration of 375 mg Ca/L and was fluoridated
to a concentration of 1 mg F/L. The "control" community had drinking water that was
fluoridated to 1 mg F/L and an average calcium concentration of 67 mg Ca/L.
Mean radial bone mass, by community, in adult women age 20-35 yr, adjusted for age and
Quetelet index is given in Table 2. No significant differences by community in mean radial
bone mass measurement were observed at baseline. At follow-up, young women in the
higher fluoride community had significantly lower mean bone mass values than did women
in the control and higher-calcium communities. The mean loss of radial bone (absolute
difference or percentage of loss) was greater in women of the higher-fluoride community
than in women of the control and higher-calcium communities.
62
January, 2008
-------
TABLE 2, Mean radial bone mass in women aged 20-35 years at baseline {1983/1984), by community, in
wrai Iowa communittes with different water mineral characteristics
Adjusted* walye
plor
(Utterenee m
means
Baseline (1983/1984) radial bore mass
-------
Dose response
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE
NOT FOUND IN NRC
(2006)
PROFILER'S Initials/date
wrist, spine, or hip; or for multiple fractures were found between the higher-calcium
community vs the control community.
TABli 6, Rink of fraeturt In » S-year period (1(83/1984- 1988/1 989) among women of three rural Iowa
communities with differences 'm the mineral content of their community water supplies, by age group and
community
Relative risk* {95% confidence interval)
WmBWrty Fracweofhip, Fraetyrtsat
any fracture ^^ m $^ng m-|j^ ^
Women aged 20-35 yssra af baselinef
Control — J —
Higher-calcium 0,36(0.03-3.63) 0.30(0.04-3.39)
Higher-fluoride 1,81(0.45-8,22) 2.70(0.16-6.28)
women agetf 55 -SO years at baseline
Control — — —
Higher-calcium 1.84(0.70-3.37) 1.80 {0,7 1-3 .40} 1.60(0.71 -3.41 )
Higher-fluoride 2.1 1(1 .01-4.431 2,20(1.07-4.69) 2.20(1.04-4.5?)
* Adjusted for age and Ouetetet index, (weight (Sg)/hejgrit (mf ). .
| There were no multiple fractures "m this age group.
t Referent
1 netatiw rish adjusted for taselne radial bone mass - 1 .99 (95 percent eonfMaw interval 0,95-4 .20J,
In the higher fluoride community, fluoride dose (years of residence multiplied by daily
intake from beverages) was positively correlated with increased risk of fracture. The
relative risk of fracture in postmenopausal women with a fluoride exposure less than the
median was 1.9 (95 percent CI 0.88-4.0), while those postmenopausal women with an
exposure greater than the median had a relative risk of 2.6 (95 percent CI 1.2-6.0) when
compared with premenopausal women. These relative risks were adjusted for age and
Quetelet index.
Bone mass and fracture risk were similar between the control and higher-calcium
communities such that a dose-response could not be evaluated.
PROFILER'S NOTE: These data were given in the text with no additional details on dose
calculation or the median value.
Residence in the higher-fluoride community was associated with a significantly lower radial
bone mass in premenopausal and postmenopausal women, an increased rate of radial bone
mass loss in premenopausal women, and significantly more fractures among
postmenopausal women. For women in the higher fluoride community, aged 55-80 yr, the
5-year relative risk of any fracture or of wrist, spine, or hip fracture was increased compared
to the control community.
REVIEWER'S NOTE: Sowers et al (1986) tested alternate explanations (mean body size,
oral contraceptive use, Ca intakes), which were all found to be similar between observed
communities. The authors admit that skeletal observations may be related "either to fluoride
exposure or other unique but unknown factors." The authors further observe that the
increased incidence (not statistically significant) of fractures in young adult women further
suggests that the fracture observation in older women is not an artifact or due to the age
cohort.
American Public Health Association. Standard methods for the examination of water and
wastewater, 14th ed. Washington, DC: American Public Health Association, 1976.
Cameron, J.R. and Sorenson, I A. 1963. Measurements of bone mineral in vivo: an improved
method. Science 142:230-232.
Cameron, J.R., Mazess, R.B., and Sorensen, J.A. 1968. Precision and accuracy of bone
mineral determination by direct photon absorptiometry. Invest. Radiol. 3:141-150.
This study was well conducted and controlled for such factors as age and estrogen use; a large
64
January, 2008
-------
REMARKS
csw
12/19/2006
PROFILER'S ESTIM.
NOEL/NOAEL
PROFILER'S ESTIM.
LOEL/ LOAEL
POTENTIAL
SUITABILITY FOR
DOSE-RESPONSE
MODELING:
CRITICAL EFFECT(S):
percentage of those women participating in the baseline study also participated in the follow-
up study (Sowers et al 1991).
The most pronounced effect appeared to be in older women ( >55 years) with high fluoride (4
mg/L) content of their drinking water. This group had the lowest bone mass and an increased
risk of fractures. However, younger women in the high fluoride community had an increase in
bone loss over the five years between baseline and follow-up.
Good comparison to communities with low fluoride and either high or low calcium content of
the drinking water.
Doses could not be reconstructed based on the data presented.
In the baseline study, overall mean calcium levels in the low and high communities were
reported in the text as 60 and 375 mg/L, respectively. However, the mean ranges (based on 6-
1 1 measurements in two wells) given in the table were 65-70 and 35 1-360 mg/L; clearly, the
overall means for the low and high communities are outside the reported range. In the follow-
up study (Sowers et al. 1991) the overall mean for the low calcium water is 67 mg/L which is
reasonable based on the data presented in the first report (1986). It may be that the overall
mean for the high calcium value is a typo as it appears that it should be about 355 mg/L. This
discrepancy does not affect the conclusions of Sowers et al (1986, 1991).
"Control" community would be more accurately termed the "reference" community.
Could not be determined.
Could not be determined.
Not suitable ( ), Poor (X), Medium ( ), Strong ( )
A positive correlation was found between years of residence and lower bone mass and number
of fractures. Dose was estimated by years of residence and reported beverage consumption.
However, the study authors stated only that an increased risk of fracture was found for
"postmenopausal women with an exposure greater than the median" but a corresponding dose
was not given.
Skeletal fracture, fracture risk, bone mass
65
January, 2008
-------
Stevenson, C.A. and Watson, A.R. 1957. Fluoride osteosclerosis. Am. J. Roentgenol. Radium Ther. Nucl.
Med. 78(l):13-8.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
ANALYTICAL METHODS:
STUDY DESIGN
PARAMETERS
MONITORED:
Skeletal fluorosis (fluoride osteosclerosis)
Retrospective
23 patients, aged 44 to 85, primarily from Texas and Oklahoma and presenting with a diagnosis of
fluoride osteosclerosis.
No control population was examined in this study.
Each of the 23 patients lived his entire life (44 to 85 years) in the same fluoride bearing area in which
he was born, with drinking water containing 4 to 8 ppm fluoride.
Medical records from the Scott and White Clinic in Texas were evaluated between 1943 and 1953. A
total of approximately 170,000 roentgen examinations of the spine and pelvis made on patients
primarily from Texas and Oklahoma yielded 23 cases of fluoride osteosclerosis. Each of the 23
patients lived his entire life (44 to 85 years) in the same fluoride bearing area in which he was born,
with drinking water containing 4 to 8 ppm fluoride.
This group presented nothing in common except roentgenographic changes in their osseous systems.
There was no unusual incidence of anemia, arteriosclerosis, arthritis, back stiffness, renal disease, or
biliary calculi.
Medical records, including roentgen examinations of spine and pelvis, were evaluated. Osseous
changes and pelvic ligament calcification were graded on a 1 to 4 scale.
Data for measuring the fluoride concentrations in the drinking water supplies were not included in the
study report. Water quality parameters were not measured.
Medical records from the Scott and White Clinic in Texas were evaluated for the eleven year period
from 1943 to 1953. A roentgenologic diagnosis of fluoride osteosclerosis was recorded on 23
patients' records from a total of approximately 170,000 roentgen examinations of the spine and pelvis
made onpatients primarily from Texas and Oklahoma. No cases reported by the U.S. Department of
Health, Education, and Welfare are included.
All patients were given complete clinical examinations including serology, sedimentation rate, red
and white blood cell counts, hemoglobin, blood urea, and routine urine studies. The physicians who
examined the patients were familiar with dental fluorosis, but were unable to determine any
relationship between the roentgenologic findings and the patients' disease processes or symptoms.
There was no chemical analysis of bone for fluorine content. The diagnosis was based on bone
changes as reported by Roholm, bone changes observed in cattle exposed to extremely high toxic
doses of fluorides, and on bone changes noted in a few Bartlett, Texas (8 ppm fluoride drinking
water) residents who were examined during Public Health Service surveys. The autopsy of a patient
who had typical roentgenographic findings of fluoride osteosclerosis revealed bone fluoride content
six times the normal amount expected. This information, plus the fact that this group of patients had
been drinking water with high fluoride content for many years permitted the authors to assume that
the diagnosis was correct, especially since these changes are not observed in individuals not exposed
to fluorides.
Osseous changes were graded on a 1 to 4 scale, with grade 1 showing bone density of a very minimal
degree, and grade 4 showing bone density of an extreme degree. Pelvic ligament calcification was
graded with grade 1 representing minimal calcification in either the sacrotuberous or sacrospinous
ligaments, and grade 4 showing calcification extending about 6 cm from the ischium towards the
sacrum.
66
January, 2008
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STATISTICAL METHODS:
RESULTS:
Fluoride osteosclerosis
STUDY AUTHORS'
CONCLUSIONS:
Statistical analysis was not performed.
Table 1 was copied directly from Stevenson and Watson (1957) and summarizes the age, fluoride
content of the drinking water, degree of osseous changes and pelvic ligament calcification for all 23
patients with a diagnosis of fluoride osteosclerosis. Osseous changes were noted in these patients only
when water contained fluoride at 4 to 8 ppm. Pelvic ligament calcification closely paralleled the
degree of bone, with 15 of the 23 patients having calcification of the sacrospinous and sacrotuberous
ligaments. The calcification began at the ligamentous attachment in the pelvis, was usually bilateral
and extended towards the sacrum for distances up to 6 cm. The entire length of the ligaments did not
calcify, and no instance of calcification at the sacral end of the ligaments was observed. Because of
the nature of this type of sclerotic process with associated pelvic ligament involvement and the
absence of any abnormal blood changes, the differential diagnosis of fluoride osteosclerosis from
other diseases producing increased bone density was not difficult.
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-------
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
PROFILER'S
REMARKS
Initials/date
SJG/
11/14/07
PROFILER'S ESTEM.
NOEL/NOAEL
PROFILER'S ESTEM.
LOEL/LOAEL
POTENTIAL
SUITABILITY FOR DOSE-
RESPONSE MODELING:
CRITICAL EFFECT(S):
sacrotuberous ligaments is a distinct aid in the diagnosis of fluoride osteosclerosis.
None to report.
The study design does not aid in the development of a dose response to fluoride with respect to
skeletal fluorosis. The objective of the study was to evaluate the systemic effects of excessive
fluorides in drinking water by reviewing medical records on file at the Scott and White Clinic from
1943 to 1953 for cases of fluoride osteosclerosis. Avery small number of cases were found, 23 from
a total of approximately 170,000 x-ray examinations of the spine and pelvis. The authors state that
"since no clinical correlation or significance could be attached to the roentgenologic findings, the
validity of the roentgen diagnosis of fluoride osteosclerosis may be questioned." They base their
diagnosis on bone changes reported by Roholm, bone changes observed in cattle exposed to high
fluoride, and bone changes noted in some subjects exposed to up to 8 ppm fluoride in their drinking
water.
Fifteen of the 23 patients were exposed to 4 to 8 ppm fluoride in the drinking water, while exact
fluoride exposure for 8 of the 23 was unknown, but they drank from shallow wells in known fluoride
areas. The degree of skeletal fluorosis varied from minimally increased bone density (9 with grade 1
osseous change) to 'extreme' (11 with grade 4), with few having moderate changes (grade 2-3). The
authors conclude that "calcification of the sacrospinous and sacrotuberous ligaments is a distinct aid
in the diagnosis of fluoride osteosclerosis," but it should be noted that calcification of ligaments
occurs in more advanced stages of skeletal fluorosis than increased bone density, so is not a
diagnostic tool. Indeed, 8 of the 23 cases presented here did not have any detectable pelvic ligament
calcification.
Although physicians who examined these patients were stated to be familiar with dental fluorosis, it
is not stated whether or not the patients also had mottled teeth, indicative of fluoride exposure and
dental fluorosis.
Study design was not suitable for development of a NOAEL.
Study design was not suitable for development of a LOAEL.
Not suitable (X), Poor (), Medium (), Strong ()
The study presented 23 cases of skeletal fluorosis, diagnosed as fluoride osteosclerosis and
characterized by increased bone density with or without pelvic ligament calcification, in patients with
prolonged exposure (44 to 85 years) to fluoride in the drinking water at 4 to 8 ppm.
Skeletal fluorosis (fluoride osteosclerosis, including increased bone density and pelvic ligament
calcification)
68
January, 2008
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Susheela, A.K. and M. Bhatnagar. 2002. Reversal of fluoride induced cell injury through
elimination of fluoride and consumption of diet rich in essential nutrients and antioxidants.
Molec. Cell Biochem. 234/235: 335-340.
ENDPOINT STUDIED:
TYPE OF STUDY:
POPULATION STUDIED:
CONTROL POPULATION:
EXPOSURE PERIOD:
EXPOSURE GROUPS:
EXPOSURE ASSESSMENT:
ANALYTICAL METHODS:
STUDY DESIGN:
Dental and skeletal fluorosis; fluoride in serum, urine, and drinking water, and health
symptoms of people with fluorosis.
Prospective cohort
India/New Delhi and neighboring states: 10 people (6 males, 4 females, aged 8-60) with
clinical manifestations of fluorosis, who lived in rural areas.
None
Unknown
10 people who were exposed to excessively high levels of fluoride in their drinking water
and/or in their food, which resulted in their clinical diagnosis of fluorosis.
Fluoride levels in the blood, urine, and drinking water were measured using an ion
selective electrode. Exposure prior to the study initiation was not quantified, but was
confirmed by establishing that the subjects' drinking water had high fluoride levels, and
by evaluating tooth discoloration in children of the family, joint stiffness, and finding a
family history of gastrointestinal (GI) complaints that would disappear 10-15 days after
switching to safe low-fluoride water.
During the one-year intervention program, the subject's clinical symptoms and the
fluoride levels in the drinking water, blood, and urine were monitored and reported at 1-3
unspecified time points (impact assessments).
The only information provided regarding other possible sources of fluoride exposure was
that three of the patients (who had relatively low fluoride in their drinking water) ingested
food contaminated with fluoride.
Fluoride levels in the serum, urine, and drinking water were measured using ion selective
electrode technology.
Ten subjects with clinical manifestations of fluorosis were referred to the study
investigators by clinicians from hospitals in New Delhi, India, and from neighboring
states. The clinical diagnosis of fluorosis was made in hospitals on the basis of the
people's case histories, clinical complaints, forearm X-rays, and by testing fluoride levels
in their blood, urine, and drinking water. In rural areas without diagnostic facilities,
fluorosis was diagnosed after first determining that the drinking water had high fluoride
levels. Then the following were evaluated: tooth discoloration of children in the family,
joint stiffness by three physical tests in the subject (ability to bend over and touch the toes
without bending the knees; to touch the chest with the chin; and to touch the back of the
head with the hands), and a family history of GI complaints, which would disappear 10-15
days after switching to safe water.
Once fluorosis was confirmed, the subjects participated in an intervention protocol, which
consisted of drinking safe defluoridated water from village sources or home filtration with
activated alumina, and nutritional counseling to avoid high-fluoride foods and to consume
adequate vitamins C, E, and other antioxidants. Subjects were monitored for up to a year
afterwards at three unspecified intervals (i.e., impact assessments), at which time their
serum, urine, and health status were assessed. Evaluated health manifestations included
GI complaints, muscular weakness, polyurea, polydypsea, and pain and rigidity in the
joints). A single value was provided for the water fluoride concentration during
69
January, 2008
-------
PARAMETERS
MONITORED:
STATISTICAL METHODS:
RESULTS:
Fluoride levels in the
drinking water, serum, and
urine of fluorosis patients
Health symptoms of
fluorosis patients
STUDY AUTHORS'
CONCLUSIONS:
DEFINITIONS AND
REFERENCES CITED IN
PROFILE THAT ARE NOT
FOUND IN NRC (2006)
PROFILER'S Initials/date
REMARKS SM/1/10/07
intervention, with no description of how/when the value was obtained.
Subjects were monitored for levels of fluoride in serum, urine, and drinking water, and
health symptoms on 1 -3 occasions for up to a year after the beginning of fluoride
intervention.
No statistical analysis was conducted.
In all subjects, serum and urine fluoride levels progressively decreased over the course of
the one-year intervention period, as shown in Table 1. For 2/10 of the subjects (1 and 2),
serum fluoride was reduced to levels considered normal (0.02 mg/L). Urinary fluoride
levels were still above those considered normal (0. 1 mg/L) for all subjects by the third
(last) impact assessment. Water fluoride concentration during the intervention period was
significantly lower than prior to intervention for 7 of the 10 subjects, and was unchanged
for the remaining three subjects, who ate food contaminated with fluoride.
Fs^fe Flu rid \<* Utiitafrnt 'itiifhi twis before and duriog tntCTvratioH
Patientn* Himril in Jrmhng 'frter imi_ ti Fiui id«~ n M.™ Hmi. Ji l-tu ind™ in urm |mc 1
I* lure lukr i"iiu n Puiia^nl i lit! ii fa tua uiti r cnti n I'uruumt nliu i ButfiR i ikr i"nlm During i i r \.n I n
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Pemui^ibii liiait Htim id" m f}n hug ^ it^r 1 'Img 1 trie *"" rmihipp r linnlut tlwu dt m ^rtin l'i'2i it. L |c^] N nnal upc itmit J lluiindi in
urine;! lmtl[M]I> Imp it i s> mi-ut '1 uj uumiiunil »nh llonntl-
All 10 patients had complete recovery of their health symptoms by the end of the third
impact assessment, as shown in Table 2. Recovery was the quickest for GI complaints,
with 70% of the participants reporting a recovery at the first impact assessment.
Symptoms were ameliorated more quickly in subjects who drank low-fluoride water and
had nutritional supplements, as compared to those who only drank the low-fluoride water.
"b c "" HI iillh tntpr 11 fat* c\j.s * 1 h tht-pjranc m = HM
Maiiii1* l-ilmn., pi r at ittln ti u P^R "nta JL ro \ °r Juitnc i ti n ^nts tti
Ixti^a mkr toll n Pimpuita id^tr int tiiul -vrnplunf !'«( ~« ]'>M
IIu lilar^.ilns.^, Hi 4* n i i^kt-nx ^r
Pfl un J ^U 2* ('f i mi 1 t m ti
Fut dip-*.! U 21 4fi I nipli t r^ r
fdm in1neidiH tuth I'Hnt *n t 'il < ^-ilpltE n> •". r
Susheela and Bhatnagar (2002) concluded that fluorosis can be reversed. Removing
fluoride sources and a diet containing essential nutrients and antioxidants can significantly
improve health (i.e. reduce fluoride toxicity) and reduce fluoride in the urine and serum of
fluorosis patients. This was shown in 10 patients who had complete recovery of a variety
of clinical symptoms and lower urine and serum fluorine after reducing their intake of
fluoride in the drinking water.
The study unambiguously showed that reducing water fluoride intake led to decreased
fluoride levels in the serum and urine of fluorosis patients, as well as recovery from a
number of health symptoms that appeared to be fluorosis-induced.
70
January, 2008
-------
PROFILER'S ESTEM.
NOEL/NOAEL
PROFILER'S ESTEM. LOEL/
LOAEL
POTENTIAL SUITABILITY
FOR DOSE-RESPONSE
MODELING:
CRITICAL EFFECT(S):
The data may be useful for estimating the levels of serum fluoride associated with adverse
health effects.
Insufficient data were provided, however, for a quantitative dose-response assessment of
water fluoride levels and fluorosis in the subjects, or of the decrease of urinary and serum
fluoride with time. For example, there were no quantitative estimates of the cumulative
fluoride intake of the 10 subjects, and the time at which the serum and urine were
collected were not provided. Also, the study had no reference control group.
Cannot be determined from this study.
Cannot be determined from this study.
Not suitable (x), Poor ( ), Medium ( ), Strong ( )
Data were insufficient for a quantitative dose-response assessment of water fluoride levels
and fluorosis, or for the decrease of urinary and serum fluoride with time. No reference
control group was provided.
Increased serum and urinary fluoride levels, associated with adverse health symptoms (GI
complaints, muscular weakness, polyurea, polydypsea, and pain and rigidity in the joints).
71
January, 2008
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72 January, 2008
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