Background: Fluoride can affect reproductive health in animals and is associated with later pubertal development and decreased testosterone production in adolescent and adult males. However, effects of fluoride on female reproductive health and pubertal development are unclear. Therefore, we examined associations of fluoride exposure with reproductive health outcomes among adolescent females in the United States.
Methods: The sample included participants from The National Health and Nutrition Examination Surveys (2013 to 2016) who were aged 16-19. There were 524 and 460 participants who had plasma fluoride and household tap water fluoride measurements respectively, at least one reproductive health outcome examined and complete covariate data. We applied covariate adjusted survey-weighted linear or logistic regression to examine associations of fluoride exposure with age of menarche, menstrual cycle regularity, or log2 transformed serum sex steroid hormone levels. Covariates included age, race/ethnicity, body mass index and the ratio of family income to poverty. Participants taking sex hormone medication were excluded from relevant analyses (n=46 and n=41 for plasma and water fluoride samples respectively).
Results: Median (IQR) water and plasma fluoride levels were 0.48 (0.53) mg/L and 0.34 (0.30) umol/L respectively. An IQR increase in water fluoride was associated with a 3.3 month earlier first menstrual period (B= -0.28, 95%CI: -0.54, -0.02, p = 0.05). Additionally, we observed a significant interaction between plasma fluoride and race/ethnicity in association with age of menarche (p = 0.01). For non-Hispanic black females, each IQR increase in plasma fluoride was associated with a 5-month earlier age of menarche (B=-0.42, 95%CI: -0.61, -0.23, p < 0.001).
Conclusion: Chronic low-level fluoride exposure may influence reproductive health outcomes in adolescents. These findings, as well as whether non-Hispanic black females are uniquely vulnerable to potential reproductive impacts of fluoride, should be explored in prospective studies.
This abstract was presented at the virtual 32nd Conference of ISEE, ORAL SESSION 35.
Authors affiliation: Icahn School of Medicine at Mount Sinai, New York, NY.