The United States Food and Drug Administration (FDA) made decisions about the safety of bisphenol A (BPA) based on incomplete data, according to information presented during the Endocrine Society’s virtual conference, held October 23, 2018.
BPA is an endocrine-disrupting industrial chemical used in a wide range of consumer products, including plastic bottles, metal cans, toys, and medical equipment. Present in the bodies of over 96% of Americans, the BPA compound mimics estrogen within the body by binding to estrogen receptors. As of 2014, roughly 100 epidemiologic studies have shown that BPA exposure is linked to negative health effects, including polycystic ovary syndrome, behavioral problems in children, and abnormal liver function.
Laura Vandenberg, PhD and Heather Patisaul, PhD of the Endocrine Society discussed and disagreed with the FDA’s current position on BPA safety. They argued the FDA’s most recent literature analysis on BPA only considered a narrow view of existing research; for example, “within the neurotoxicity section, they identified 36 studies, and none were identified as being useful for risk assessment except for 1.” This restricted consideration was similar in 14 other clinical endpoints.
Dr Vandenberg and Dr Patisaul went on to discuss the latest data from the extensive Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA) study. CLARITY-BPA was designed to reach a consensus on the health effects of BPA exposure, specifically for the purpose of risk assessment by regulatory agencies like the FDA. This study involved scientists from the National Toxicology Program, FDA, and multiple academic institutions.
CLARITY-BPA used animal models receiving 5 different doses of BPA from gestational development through adult life. Unexposed subjects as well as positive controls receiving ethinyl estradiol were included in the study for comparison. Significant effects were observed in groups receiving low-dose BPA, including mammary adenocarcinoma, prostatic inflammation, kidney nephropathy, and increased body weight in older females.
According to the Endocrine Society, these core study results of CLARITY-BPA were “dismissed by the FDA because [either] they were not observed at high doses, or because they were only observed in one group.” There is “an expectation that with increasing dose, there should be an increase in an effect,” explained Dr Vandenberg. Though this model is applicable to toxins, endocrine-disrupting chemicals like BPA do not show linear relationships between dose and effect (ie, at a lower dose, BPA acts more like estrogen, whereas at a higher dose it is suppressed).
“When you think about reproducibility in the broad sense — you look at the effects the FDA found at low-dose, you look at the effects the CLARITY investigators found at low-dose, and you go back and look at the existing literature — you see a very clear picture of BPA-produced effects on brain and behavior, female reproductive system, and cardiovascular system,” added the researchers.
For clinicians, the researchers suggested having open dialogues with patients about BPA and chemicals in general. “Just because something is on a store shelf doesn’t mean that it’s safe,” said Dr Patisaul, adding that Environmental Working Group’s Healthy Living smartphone application is a good resource for patients to help navigate the grocery store for safer products. In addition, the Endocrine Society is currently developing tools for clinical practice that will include how to talk to patients about endocrine-disrupting chemicals like BPA.
Final integrated data for CLARITY-BPA is expected to be available by fall 2019.
Is BPA safe? Clearing up misinformation around the CLARITY-BPA study [virtual news conference]. Endocrine Society. October 23, 2018. Accessed October 23, 2018.