Endocrine-Disrupting Chemicals Associated With Reduced Vitamin D Levels

Environmental exposure to phthalates and bisphenol A (BPA) may impact circulating 25-hydroxyvitamin D (25[OH]D) levels in adults, according to recent research published in the Journal of Clinical Endocrinology & Metabolism.¹

“Nearly every person on the planet is exposed to BPA and another class of endocrine-disrupting chemicals called phthalates, so the possibility that these chemicals may even slightly reduce vitamin D levels has widespread implications for public health,” Lauren Johns, MPH, a PhD candidate at the University of Michigan School of Public Health in Ann Arbor, stated in a press release.² “Vitamin D plays a broad role in maintaining bone and muscle health. In addition, low vitamin D levels have been implicated in outcomes of numerous conditions such as cardiovascular disease, diabetes and cancer.”

Johns and colleagues evaluated urinary data from 4667 men and women, taking note of urinary BPA, urinary creatinine, urinary phthalate metabolites, and serum 25(OH)D. The data were obtained from the 2005-2006, 2007-2008, and 2009-2010 cycles of the National Health and Nutrition Examination Survey (NHANES).

The researchers analyzed urinary BPA levels and 11 phthalate metabolites above the limit of detection in at least 50% of patients. They also measured total 25(OH)D levels, which included sum 25-hydroxyvitamin D₂ and 25-hydroxyvitamin D₃.

Of the phthalate metabolites analyzed, there was a positive association with monoethyl phthalate, and di(2-ethylhexyl) phthalate (DEHP) carried an inverse association with total 25(OH)D after adjusting for gender with a significant inverse relationship seen in molar sum of DEHP metabolites. Specifically, researchers found a 1.90% decrease in total 25(OH)D for each interquartile range increase (95% CI, –3.64 to –0.17).¹

There was significant inverse association between BPA exposure and lower 25(OH)D levels among women in the cohort, but this association was not seen in men. The researchers noted there was a 3.71% decrease in total 25(OH)D levels per interquartile range increase for these women (95% CI, –6.41 to –1.02).¹

“More research is needed into why an association exists, but it is possible that endocrine-disrupting chemicals alter the active form of vitamin D in the body through some of the same mechanisms that they use to impact similar reproductive and thyroid hormones,” John D. Meeker, MS, ScD, senior author of the study, stated in the release.² “Confirmatory studies are needed to show whether this association exists in other populations.”

Disclosures: This research was supported in part by the Intramural ResearchProgram of the National Institutes of Health, NationalInstitute of Environmental Health Sciences. Funding was alsoprovided by the National Institute of Environmental Health Sciences,National Institutes of Health. The researchers report no conflicts of interest.

References

1. Johns LE, Ferguson KK, Meeker JD. Relationships Between Urinary Phthalate Metabolite and Bisphenol A Concentrations and Vitamin D Levels in U.S. Adults: National Health and Nutrition Examination Survey (NHANES), 2005–2010. J Clin Endocrinol Metab. 2016. doi:10.1210/jc.2016-2134.
2. Endocrine-disrupting chemicals may alter active form of vitamin in body [press release]. Washington, DC: Endocrine Society News Room; September 20, 2016. https://www.endocrine.org/news-room/current-press-releases/chemical-exposure-linked-to-lower-vitamin-d-levels. Accessed September 21, 2016.