Cover-up vs. Scientific Progress

Has There Been a Conspiracy to Hide BPA Dangers?

Bisphenol A (BPA) is a widely used chemical product found in plastic bottles and containers, food cans, and a host of other sources. There has been a long-standing debate about the extent to which humans are exposed to BPA and whether it is harmful. About 93% of people six years and older have detectable levels of BPA in their urine, but the FDA has taken the position that the amount of BPA detected is too small to be harmful. FDA did ban the use of BPA in infant formula, baby bottles, and sippy cups in 2017.

         Against this reassurance about the benign nature of BPA exposure, there have been persistent reports about health harms. BPA is known to bind to several hormone receptors and has therefore been called a “hormone disrupter.” Scientists academic institutions linked it in animal and epidemiological studies to a variety of disorders, including infertility, diabetes, obesity, and some tumors. Advocacy groups have persistently pointed to evidence that BPA is toxic.

BPA is present in many products we use everyday, including plastics that hold food and beverages. It leaches into those products and we consume them (image: Shutterstock).

         In order to bridge the gulf between regulatory agency reassurance and academic and advocacy group warnings, several federal science agencies initiated the CLARITY-BPA Program. The program involves research done at a federal laboratory and the laboratories of 14 grantees conducting research at independent academic institutions. The final CLARITY-BPA report should be released soon. A draft report from the government’s arm of the study failed to find any toxic effects from BPA in laboratory animals.

New Study Finds Higher Exposure Levels

         Now, however, a new wrinkle has been introduced into the entire BPA controversy. A study published last December in the respected British journal Lancet Diabetes & Endocrinology reported that levels of BPA in adults may be much higher than previously reported. The study’s publication was unsurprisingly followed by headlines such as “Human exposure to BPA systematically underestimated”. One website declared that “Human exposure to bisphenol A (BPA) may have been underestimated as a result of a ‘flawed’ analytical technique commonly used to measure levels in urine”.

         It would be understandable for people to leap to the conclusion that the “government” has been deliberately covering up the possible harms to human health of BPA. Words like “systematically” and “flawed” sound as if FDA and other regulatory agencies are at fault and even imply that they somehow conspired to knowingly minimize the effects of BPA. The motive, some assert, is to protect the business interests of the many industries that use BPA in their manufacturing processes.

The Reasons Behind the Differing Views of BPA Safety

         While we too have been very concerned lately about the roll-back of many federal environmental and health regulations, seemingly at the behest of commercial interests, the situation with the new BPA study is more nuanced and deserves some explanation. In the end, it turns out to be more a matter of a scientific advance than a deliberate cover-up.

BPA is present in plastic beverage containers. How harmful that is to our health is a matter of debate in the scientific community (image: Shutterstock).

         First, why has there been a controversy all along about the effects of BPA? The traditional way that regulatory agencies like FDA and EPA determine if something is toxic to humans is to feed it to rats and other laboratory animals in higher and higher doses, examining the effects on each organ of the animals’ bodies at each dose level. Inevitably, they eventually reach a level that causes some kind of harm to the rats, like a tumor that does not occur in animals fed placebo. The scientists at FDA then calculate how much of the substance a human would have to be exposed to in order to match the dose in rats that caused the problem. If that amount is far greater than a human could possibly ever encounter, the substance is declared to be safe. That is the case so far with FDA’s assessment of BPA. This kind of study is called a “guideline study ” and must be conducted in accordance with a strict set of rules, called “Good Laboratory Practice” (GLP).

         But academic institution scientists may work the problem from a different angle, called “hypothesis testing”. Instead of looking at every organ of the body, the academics might start with a hypothesis like “this substance can cause the kind of damage to DNA that is associated with cancer in humans.” They then use advanced molecular techniques to see if there is a dose of the substance that does indeed damage DNA in the predicted way. Often, that does turns out to be lower than the dose a regulatory agency has found to be harmful to laboratory animals. Academic scientists often insist that the GLP rules are too restrictive and present barriers to probing for potential harms. They assert that their methods are more sensitive to picking up potential toxicities, but regulatory agencies disagree, insisting instead that non-GLP studies lack the rigor necessary to reach meaningful conclusions.

         It remains to be seen whether CLARITY-BPA will resolve this divide in methodologies and opinions. But once again, finding that we may all harbor higher levels of BPA than we knew about means that doses previously considered too high to be indicative of likely toxicity may not hold.

New Technologies Mean New Findings

         Pouring through the very technical study in Lancet: Diabetes & Endocrinology, what we see is that the scientists have developed a completely new laboratory method for detecting BPA in human urine. The method traditionally used to measure BPA levels is called an “indirect method,” whereas the scientists in the new report developed a “direct method” and concluded that “ Importantly, because estimates of human exposure have been based almost exclusively on data from indirect methods, these findings provide compelling evidence that human exposure to BPA is far higher than has been assumed previously.”

         Two things are very disconcerting to many of us about the BPA story. First, it is hard for us to know what to make of disagreements among highly qualified and well-meaning scientists. The GLP rules that academic scientists seem to dislike are an attempt to ensure that toxicology studies are performed according to rigorous standards. They are not an attempt to hide evidence. On the other hand, academic scientists have the flexibility to use novel methods to search for evidence of human health harms and these may or may not accord with GLP standards. This is not an easy thing for most of us to adjudicate.

         Second, no one likes to read headlines that the basis for a long held scientific finding may be wrong. Science often advances only when new technologies are developed that permit greater insights into biological processes. Positron emission tomography (PET), CRISP-R, and genome wide assessment studies (GWAS) are just a few of the many technological advances developed since the late 20th-century that have revolutionized what we know about the ways that cells and organs work. In this case, a not quite so dramatic advance in technology potentially enables us to have better information about BPA levels and may be a game-changer, but it has nothing to do with conspiracies to hide data. Rather, it follows the usual trajectory of science—a new discovery can invalidate what we previously knew (or thought we knew).

         What would be amiss, however, is if scientists, both academic and regulatory, fail to follow-up the new study with work that takes into account its findings and determine if indeed we are being exposed to toxic levels of BPA.[1] There is ample precedent for industry to try to derail such investigations. Until we had powerful epidemiological tools, it was not possible to understand that cigarette smoking causes lung cancer. Until computer modeling became more powerful, the extent of global warming was not apparent. But once those things became clear, there was an outrageous delay in accepting the findings and working to mitigate their implications for human health and survival.

         If BPA turns out to be worse than FDA thought, it is indeed upsetting that so many of us have been exposed to so much of it for so many years. Rather than rushing to cast blame, the way to deal with a  situation like this, however, is two-fold: first, fund research that develops the technologies that give us important new insights and second, act on findings as soon as they are confirmed. It will be extremely interesting to see how the regulatory community reacts to the finding in the Lancet paper. We will follow that along with you and report on what happens in future commentaries.

[1] Incidentally, as we pointed out last month, Critica strongly recommends against the use of disposable plastic beverage containers because they pose a significant environmental hazard.

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