Fluoride Exposure Linked to Changes in Sleep Cycle, Study Suggests

Fluoride exposure may be associated with changes in sleep cycle regulation and sleep behaviors among older adolescents, according to a study published in Environmental Health.

Data from the National Health and Nutrition Examination Survey was collected in order to analyze adolescents who had plasma fluoride and water fluoride measures and were not prescribed medication for sleep disorders. The researchers also investigated relationships between fluoride exposure and self-reported sleep patterns or daytime sleepiness.

“Many benefits of fluoride have been reported for oral health and it is regarded as a major public health achievement,” noted the authors. “Fluoride from environmental sources accumulates preferentially in the pineal gland which produces melatonin, the hormone that regulates the sleep-wake cycle. However, the effects of fluoride on sleep regulation remain unknown."

The research assessed adolescents at an average age of 17. The data revealed that the median (IQR) water fluoride concentration was 0.27 mg/L and the IQR plasma fluoride concentration was 0.29 μmol/L, respectively. Furthermore, an IQR increase in water fluoride was associated with 1.97 times higher odds of reporting symptoms suggestive of sleep apnea, according to the study. The increase in water fluoride was also associated with a later bedtime by 24 minutes, a later morning wake time by 26 minutes, and among males, a 38% reduction in the odds of reporting snoring.

The results also explained that water fluoride concentrations were associated with higher odds of reports of snorting, gasping, or stopping breathing while sleeping at night. Some of the data suggested higher water fluoride concentrations may be associated with frequent daytime sleepiness, however, more studies would be necessary to confirm.

“The high accumulation of fluoride in pineal gland hydroxyapatite (among those chronically exposed) points to a plausible mechanism by which fluoride may influence sleep patterns. In adults, pineal gland fluoride concentrations have been shown to strongly correlate with degree of pineal gland calcification,” explained the authors. “Interestingly, greater degree of pineal calcification among older adolescents and/or adults is associated with decreased melatonin production, lower REM sleep percentage, decreased total sleep time, poorer sleep efficiency, greater sleep disturbances and greater daytime tiredness.”

The authors suggest additional studies to be conducted in order to investigate the effects of fluoride on sleep patterns and to identify windows of vulnerability for potential effects.

Reference

Malin A, Bose S, Busgang S, et al. Fluoride exposure and sleep patterns among older adolescents in the United States: a cross-sectional study of NHANES 2015—2016 [published online December 9, 2019]. Environmental Health. doi: 10.1186/s12940-019-0546-7