You may be familiar with endocrine-disrupting chemicals even if you don’t recognize the term. Bisphenol A (BPA) and phthalates fall into this category of substances capable of interfering with hormones throughout the body. Given that these substances are everywhere—from personal care products to cosmetics to children’s products to floors to medical tubing to food packaging—any potential effects of exposure could have large implications. Case in point: a study finding that levels of BPA and phthalates may correlate to low levels of vitamin D in adults.
The study, published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism, was fairly straightforward. In order to test vitamin D levels, the blood of 4,667 adults was drawn and tested. To examine BPA and phthalate exposure, urine analysis was used to test for substances left over when these chemicals are metabolized. The findings were as follows:
- People with higher levels of phthalate metabolites were more likely to have low levels of vitamin D, with the correlation being strongest in women
- A similar but smaller correlation between BPA and vitamin D was found in women, but did not reach statistical significance in men
- There is no known reason why these chemicals would affect vitamin D, but the authors posit that they may affect the vitamin in a similar way to how they disrupt hormones
What This Means
The findings mean exactly what they say: BPA and phthalate exposure was correlated to lower levels of vitamin D in the blood, and the effect was either reduced or not significant in men depending on the chemical. The main thing to keep in mind is that correlation does not mean causation. More specifically, two extra caveats need to be kept in mind:
- It is unclear whether the participants’ actual vitamin D intake or sun exposure levels were controlled for
- BPA and phthalates are everywhere, which means exposure is a common trait in the US. With this much proliferation, the potential for the findings to be spurious or the result of luck can’t be discounted
Ultimately, while the findings are worth raising an eyebrow over, the authors’ urgings for confirmatory research and more investigation should be heeded.
Johns, L., et. al., “Relationship 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,” The Journal of Clinical Endocrinology & Metabolism, 2016; http://dx.doi.org/10.1210/jc.2016-2134#sthash.j2CDNPcu.dpuf.