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bisphenol a

Science Suppressed:
How America became obsessed with BPA

 

 

The NTP draft report
This tendency to cherry pick and over-interpret was also evidenced by how the Journal Sentinel reported the conclusions of a draft report on BPA by the National Toxicology Program on April 16, 2008:

“For the first time, the federal government said Tuesday that a chemical found in commonly used products such as dental sealants, baby bottles and aluminum cans is potentially dangerous to human development and reproduction.

The new report by the National Toxicology Program heightens concern about Bisphenol A, a chemical found in the bodies of 93% of Americans recently tested. It overrides conclusions reached by a panel in November that found minimal concern that bisphenol A could cause prostate and breast problems or early puberty for young children or those who were exposed to the chemical in the womb.
 
‘The possibility that bisphenol A may alter human development cannot be dismissed,’ the report says.

The report is a compilation of the work of two panels convened last year by the National Institutes of Health. One was made up of scientists with expertise in bisphenol A. The other was a panel of scientists with no direct expertise in the chemical.”

The paper turned to a spokesperson from the Natural Resources Defense Council, and Frederick vom Saal, to comment on the draft’s significance:

“Scientific experts on bisphenol A said the findings should force the FDA to reconsider an earlier ruling that the chemical is safe for all to use.

‘This leaves the FDA with little wiggle room,’ said Frederick vom Saal, a researcher at the University of Missouri and one of the nation's leading experts on Bisphenol A. "Their position of no concern looks ridiculous in light of these new assessments.”

The specific reporting on the NTP draft is somewhat misleading. As the NTP notes:

“The Draft NTP Brief on Bisphenol A is not a quantitative risk assessment, nor is it intended to supersede risk assessments conducted by regulatory agencies. The Draft NTP Brief on Bisphenol A is intended to serve as an environmental health resource for the public, as well as regulatory and health agencies.”

In other words, its goal is to give a qualitative assessment, which makes it, perhaps, harder to determine what the risk is. The NTP uses five categories of “concern” in non-technical language and in order of worry: negligible concern, minimal concern, some concern, concern, and serious concern. The brief was based on the conclusions of an expert panel, public comments, and additional scientific papers not used by the panel of experts (either because they had been dismissed or because they were published after the panel convened).

The draft report concluded that there was

  1. some concern for neural and behavioral effects in fetuses, infants, and children at current human exposures.
  2. some concern for bisphenol A exposure in these populations based on effects in the prostate gland, mammary gland, and an earlier age for puberty in females.
  3. negligible concern that exposure of pregnant women to bisphenol A will result in fetal or neonatal mortality, birth defects, or reduced birth weight and growth in their offspring.
  4. negligible concern that exposure to bisphenol A causes reproductive effects in non-occupationally exposed adults and minimal concernfor workers exposed to higher levels in occupational settings.

The “bottom line” according to the NIEHS website on whether BPA affect human development or reproduction?

“Possibly. Although there is no direct evidence that exposure of people to bisphenol A adversely affects reproduction or development, studies with laboratory rodents show that exposure to high dose levels of bisphenol A during pregnancy and/or lactation can reduce survival, birth weight, and growth of offspring early in life, and delay the onset of puberty in males and females. Recognizing the lack of data on the effects of bisphenol A in humans and despite the limitations in the evidence for "low" dose effects in laboratory animals, the possibility that bisphenol A may impact human development cannot be dismissed. More research is needed.”

As Michael D. Shelby, PhD, director of the National Toxicology Program's Center for the Evaluation of Risk to Human Reproduction told WebMD, the evidence from rodent studies was “very limited,”

“But our conclusion was that we couldn't dismiss the possibility that similar effects might occur in humans. This is a very controversial area with obvious differences in the way different groups have interpreted the data. We have tried to do it in as scientifically sound and thorough means as we could. Even in the areas where we've expressed some concern, the literature is not consistent on the endpoints reported. Some people find these effects; others may not, and their relevance to effects on human health -- there's still some uncertainty about that. That's why we didn't have a lower or higher level of concern in our conclusions.”

As already noted, a couple of months later the European Food Safety Authority – along with several environmental and health agencies in European countries dismissed the research that the NTP used to justify “some concern” as being poorly done. And the Food and Drug Administration appeared to reach the same conclusion by the same route, much to the fury of the Journal Sentinel and the signatories of the Chapel Hill Consensus.

The paper spent a lot of time trying to show that the FDA relied on industry-funded studies to justify its position, but as the paper never cites the actual studies in any of its reporting and appears to use no scientific or statistical criteria to decide whether the conclusions are robust or not on any given scientific study – apart that is from adducing rigor to, and relying on interpretation from, the designated “experts” on BPA such as vom Saal – it will suffice to say that the FDA’s position simply mirrors that of Europe, NSF International’s risk assessment, Germany’s risk assessment, etc.

Again, one can think of many interesting questions a reporter could have asked, namely, why is there a difference between multiple quantitative risk assessments – independent and governmental, domestic and international, and even industry-funded (for the sake of convenience, this analysis has ignored the numerous industry-funded assessments, from Gradient and Harvard’s Center for Risk Analysis, which all concur with the no risk view of BPA ) compared to the one qualitative risk assessment.

It’s worth noting the paper’s suggestion that chemical regulation is in the hands of people who are not “experts” in the specific chemicals being regulated as if there weren’t general scientific and statistical principles underlying chemistry, toxicology, and risk evaluation. This appears to be a rather bald rhetorical attempt to invalidate any findings that do not include the work of the Chapel Hill Consensus – because only those signatories are “experts” on BPA. And this, in turn, results in a rhetorical situation where anyone who testifies to BPA’s safety is not an “expert,” even if they have actually done research on BPA, because the real “experts” have found it dangerous. In other words, the Journal Sentinel ends up protecting its sources and, therefore, its investigation by engaging in a PR offense.

One could have imagined the Journal Sentinel going beyond the magic circle of sourcing that went from vom Saal to other Chapel Hill signatories to the activist groups and then back to vom Saal. But the paper never took that journalistic leap. It was trapped by its thesis. It was no longer engaged in journalism, but had joined the magic circle as a true believer, a source of novel “scientific” research, an “independent” activist group that was only interested in the public good.

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