Community water fluoridation is a key public health intervention, yet ongoing debates about systemic risks call for evidence on fluoride exposure. We analyzed NHANES 2013–2016 biomonitoring data to assess fluoride exposure in children and adolescents aged 0–19 years. We calculated the proportion of children with fluoride levels in relation to guidelines from the United States Environmental Protection Agency (USEPA), World Health Organization (WHO), and Centers for Disease Control and Prevention (CDC). Biomonitoring data was obtained from the National Health and Nutrition Examination Survey (NHANES). Median water fluoride concentration was 0.50 (95% CI: 0.35, 0.64) mg/L for males, 0.49 (95% CI: 0.35, 0.63) mg/L for girls, 0.49 (95% CI: 0.35, 0.63) for the <3 age group, and 0.50 (95% CI: 0.36, 0.64) for the 18–19 age group. Median urine fluoride concentration was 0.56 (95% CI: 0.51, 0.62) mg/L for males, 0.46 (95% CI: 0.41, 0.50) for girls, 0.59 (95% CI: 0.50, 0.62) for the age group 6–8, and 0.51 (95% CI: 0.42, 0.60) for the 18–19 age group. Of the children, 99.96% were below the EPA’s enforceable 4.0 mg/L limit, 99.05% below the EPA’s 2.0 mg/L limit, and 98.6% below the WHO 1.5 mg/L standard. For urinary fluoride, 88.1% were within the CDC reference range of 0.2–<3.2 mg/L. We found that water fluoride levels did not vary across age and sex groups, but urine fluoride levels changed. Results indicate that most children remain within regulatory agencies’ guidelines.

Plasma fluoride reflects fluoride exposure from multiple sources. Fluoride exposure and health outcome observational studies are susceptible to confounding