Associations of fluoride intake with children's bone measures at age 11.
BACKGROUND
Relationships between fluoride intake and bone health continue to be of interest, as previous studies show conflicting results.


OBJECTIVE
The purpose is to report associations of fluoride intake with bone measures at age 11.


METHODS
Subjects have been participating in the ongoing Iowa Fluoride Study/Iowa Bone Development Study. Mothers were recruited postpartum during 1992-95 from eight Iowa hospitals, and detailed fluoride questionnaires were sent every 1.5-6 months. From these, combined fluoride intakes from water sources (home, childcare, filtered, bottled), other beverages, selected foods, dietary fluoride supplements and dentifrice were estimated at individual points and cumulatively [with area under the curve (AUC)]. Subjects underwent dual-energy X-ray absorptiometry (DXA) scans of proximal femur (hip), lumbar spine and whole body (Hologic QDR 4500A). DXA results (bone mineral content - BMC; bone mineral density - BMD) were related to fluoride intake as revealed by bivariate and multivariable analyses.


RESULTS
The mean fluoride intake estimated by AUC was 0.68 mg (SD = 0.27) per day from birth to 11 years. Associations (Spearman) between daily fluoride intake (mg F/day) and DXA bone measures were weak (r = -0.01 to 0.24 for girls and 0.04 to 0.24 for boys). In gender-stratified, and body size- and Tanner stage-adjusted linear regression analyses, associations between girls' bone outcomes and fluoride intake for girls were almost all negative; associations for boys were all positive and none was statistically significant when using an alpha = 0.01 criterion.


CONCLUSIONS
Longitudinal fluoride intake at levels of intake typical in the United States is only weakly associated with BMC or BMD in boys and girls at age 11. Additional research is warranted to better understand possible gender- and age-specific effects of fluoride intake on bone development.
Levy
Steven M
SM
Department of Preventive and Community Dentistry, College of Dentistry, Carver College of Medicine, Iowa City, IA, USA. steven-levy@uiowa.edu
Eichenberger-Gilmore
Julie
J
Warren
John J
JJ
Letuchy
Elena
E
Broffitt
Barbara
B
Marshall
Teresa A
TA
Burns
Trudy
T
Willing
Marcia
M
Janz
Kathleen
K
Torner
James C
JC
D001827:Body Height / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D001846:Bone Development / Q000187:drug effects*; D002648:Child; D002675:Child, Preschool; D004032:Diet; D005260:Female; D005459:Fluorides / Q000494:pharmacology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016018:Least-Squares Analysis; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D012044:Regression Analysis; D012737:Sex Factors; D018709:Statistics, Nonparametric
D005459:Fluorides