CLARITY – Just Another Study?

Steven Hentges, Ph.D
Tuesday, March 13, 2018 SAFETY
You may have already heard that the U.S. National Toxicology Program recently released
the results of an important new study on BPA known as the CLARITY Core study. One
reason it’s important is because the goal of the study was to resolve any remaining
uncertainties about the safety of BPA, which has been a controversial topic for quite sometime.
With that goal in mind, a key conclusion in the study report is that “BPA produced minimaleffects that were distinguishable from background.” In a statement released in conjunction
with the report, Dr. Stephen Ostroff, Deputy Commissioner for Foods and Veterinary
Medicine at the U.S. Food and Drug Administration (FDA) stated: “our initial review
supports our determination that currently authorized uses of BPA continue to be safe forconsumers.”
You’re forgiven if you glossed over this news because it may have sounded like déjà vu allover again. Another day, another study you might have thought. After all, countlessstudies have been conducted on BPA leading to claims that it’s safe, it’s not safe, and justabout everything in between.
But not all studies are created equal, and this one is anything but equal to any of thepreceding studies on BPA. By design, the scope of this study is truly unprecedented.
The study was designed to evaluate several important concerns about how BPA may act in
the body. One concern is that exposure to BPA early in life, in particular during sensitive
developmental stages, may lead to health effects that only occur much later in life. To
address this concern, the laboratory animals were dosed with BPA starting in pregnancy
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regardless of when the dosing occurred.
A second concern is that low doses of BPA, in particular in the range of actual human
exposure, might cause health effects even though higher doses do not cause healtheffects. This counterintuitive relationship between dose and health effect is known
scientifically as a “non-monotonic dose-response” relationship (NMDR). To address thisconcern, five groups of animals were given a very wide range of BPA doses, from low
doses close to actual human exposure to levels about 250,000 times higher. Any NMDR
relationships that occurred would have been observed.
A third concern is that BPA may act in the body as an estrogen to disrupt normal hormonal
functions and result in health effects. To address this concern, two groups of the animals
were given doses of a known estrogenic compound to ensure that the animals weresensitive to estrogenic effects.
Finally, size does matter in this type of study. If the study is too small, the study results
may not be robust and the study goals will not be met. In the CLARITY Core study, all of
the groups with lifetime BPA exposure included 46-50 animals. The result is that the study
is statistically powerful, meaning that we can have confidence in the validity of the results.
Although the nature of science is that more research is always possible, the goal of theCLARITY Core study was to resolve remaining uncertainties about the safety of BPA. Thatgoal was certainly met, which is why FDA could confidently reaffirm the safety of BPA. As
concisely stated on FDA’s website: “Is BPA safe? – Yes.” In light of the results of theCLARITY Core study, and the strengths of that study, FDA’s conclusion seems sound.

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