Electronic Theses and Dissertations Archive

Date

2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Epidemiology

Committee Chair

Mohamad Abu Naser Titu

Committee Member

Hongmei Zhang

Committee Member

Marian Levy

Committee Member

Xichen Mou

Committee Member

Xinhua Yu

Abstract

Fluoride has long been used to prevent dental caries, questions remain about how to balance its established preventive benefits with potential risks related to excess systemic exposure, particularly during periods of growth and development. Despite longstanding fluoridation policies, contemporary national evidence that jointly examines fluoride exposure, systemic health indicators, and dental outcomes among U.S. youth remains limited. This work examined fluoride exposure and its health effects among U.S. children and adolescents using data from the National Health and Nutrition Examination Survey 2013–2016. The objectives were to characterize fluoride exposure across multiple measures, evaluate whether plasma fluoride derived from drinking-water fluoride is associated with systemic health biomarkers, and assess whether plasma fluoride mediates the relationship between household drinking-water fluoride and dental outcomes. It was hypothesized that most fluoride exposures would remain within current public health benchmarks, that plasma fluoride attributable to drinking-water fluoride would be associated with selected systemic biomarkers, and that plasma fluoride would explain part of the association between water fluoride and dental caries and fluorosis. The first study combined biomonitoring, groundwater fluoride, and community water fluoridation data to describe fluoride exposure in tap water, urine, and plasma among U.S. youth. The second study used an instrumental variable approach, with household tap-water fluoride as an exogenous predictor of plasma fluoride, to estimate associations with cardiovascular, metabolic, electrolyte, hormonal, renal, and hepatic biomarkers. The third study applied mediation analysis to examine whether plasma fluoride mediated associations between household drinking-water fluoride and dental caries experience and fluorosis. Overall, fluoride exposure among U.S. children was generally within established regulatory and clinical thresholds. However, plasma fluoride attributable to tap-water fluoride was associated with lower systolic blood pressure, lower testosterone, reduced estimated glomerular filtration rate, and higher serum sodium and uric acid, with variation across demographic subgroups. Higher drinking-water fluoride showed a modest inverse association with caries experience and a positive association with fluorosis, but plasma fluoride explained little of either relationship.

Comments

Data is provided by the student.”

Library Comment

Dissertation or thesis originally submitted to ProQuest/Clarivate.

Notes

Embargoed until 03-27-2027

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Available for download on Saturday, March 27, 2027

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