Background: Research suggests that fluoride from dietary and environmental sources may concentrate in calcium-containing regions of the body such as the pineal gland. The pineal gland synthesizes melatonin, a hormone that regulates the sleep-wake cycle. We used population-based data from Cycle 3 (2012-2013) of the Canadian Health Measures Survey (CMHS) to examine associations between fluoride exposure and sleep outcomes.
Methods: The sample included participants aged 16 to 79 years. Fluoride concentrations were measured in urinary spot samples (n=1303) and household tap water among those who reported drinking tap water (n=1016); urinary fluoride was adjusted for specific gravity (UFSG). We used multinomial and ordered logistic regression analyses to examine associations of fluoride exposure with self-reported sleep outcomes, including sleep duration and frequency of sleep problems. Sleep duration was classified as normal, low, or high according to age-based recommendations by the National Sleep Foundation, and frequency of sleep problems were measured on a 5-point scale, ranging from “never” to “all of the time”. Covariates were based on theoretical relevance and included age, sex, ethnicity, body mass index, and household income.
Results: Median (IQR) UFSG and water fluoride concentrations were 0.67 (0.63) and 0.12 (0.38) mg/L, respectively; 32% of participants lived in communities supplied with fluoridated municipal water. A 0.5 mg/L increase in water fluoride level was associated with 34% higher relative risk of reporting sleeping less than the recommended duration [RRR = 1.34, 95% CI: 1.03, 1.73; p = .026]. UFSG was not significantly associated with sleep duration. Water fluoride and UFSG concentration were not significantly associated with frequency of sleep problems. Including chronic health conditions as a covariate did not substantially change the association between water fluoride and sleep duration.
Conclusions: Fluoride exposure may contribute to sleeping less than the recommended duration among older adolescents and adults in Canada.
*Abstract in the Conference Abstract E-Posters at http://fluoridealert.org/wp-content/uploads/isee2020.abstract-e-posters.pdf
J. E. Cunningham, Department of Medicine, McMaster University, Hamilton, Canada
H. McCague, Institute for Social Research, York University, Toronto, ON, CANADA
A. Malin, Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY
J. Riddell, University of Manitoba, Winnipeg, MB, CANADA
D. Flora, Faculty of Health, York University, Toronto, ON, CANADA.
C. Till, Faculty of Health, York University, Toronto, ON, CANADA.