Environmental Factor, August 2007, National Institute of Environmental Health Sciences
Advisory Panel Weighs in on Bisphenol A
By Eddy Ball
In its first step toward drawing conclusions about the human health risks of Bisphenol A (BPA), the National Toxicology Program (NTP) has released the findings of its Center for the Evaluation of Risks to Human Reproduction (CERHR) Expert Panel Evaluation held August 6 - 8, 2007 in Alexandria, Va. The panel was composed of 12 independent scientists who reviewed more than 500 scientific studies on BPA to assess the potential reproductive and developmental hazards of the estrogen-like chemical, which is used in the manufacture of polycarbonate plastics and epoxy resins. The panel's meeting was open to the public.
NTP emphasizes that the findings of its expert panels do not necessarily reflect the views of the NTP. The panel used a five-point scale, ranging from "negligible" to "serious," to rate the level of its concerns about the effects of exposure to the compound on human health:
- The panel's greatest level of concern was directed towards possible neural and behavioral effects caused by BPA exposure in utero. The panel expressed "some" concern for these types of effects, a level of concern that falls in the middle of the five-point scale.
- "Minimal" characterized the panel's level of concern that exposure to BPA in utero causes effects on the prostate or potentially causes accelerations in puberty. Likewise, the experts expressed minimal concern that children's exposure to BPA potentially causes accelerations in puberty.
- "Negligible" described the panel's degree of concern that exposure to BPA in utero produces birth defects and malformations in pregnant women and fetuses. The expert panel also had negligible concern that adverse reproductive effects may follow exposures in the general adult population to BPA.
The expert panel report will be finalized and available for public comment in fall 2007. The NTP will take the report into consideration as it reaches its own conclusions about BPA, using the same categories for level of concern as the panel used. The NTP will express its conclusions, which may differ from the panel's, in a document referred to as the NTP brief. During 2008 CERHR expects to release the NTP-CERHR monograph on BPA, which will consist of the NTP brief, the expert panel report and all public comments on that report. The center will solicit public comment on the brief and submit it for independent peer review prior to completing its report.
A Statement on BPA by 38 Independent Scientists
A statement, signed by 38 scientists, is the outcome of another meeting sponsored by NIEHS Division of Extramural Research & Training, the National Institute of Dental and Craniofacial Research, the Environmental Protection Agency and Commonweal held in Chapel Hill, NC, November 28 - 29, 2006. (See eFactor report Expert Panel Debates Health Risks of BPA). The meeting produced five review articles on specific aspects of BPA research with statements on the strength of the data, in addition to the consensus statement that integrated the data across research areas.
is now in press for the online issue of Reproductive Toxicology 24(2).
In the statement, BPA research scientists agreed that the range of exposures that most Americans experience are higher than those that cause a wide range of adverse health effects in animals. Although they recognized the short-comings of the current body of research and called for expanded investigations into the human health risks, they concluded, "The wide range of adverse effects of low doses of BPA in laboratory animals exposed both during development and in adulthood is a great cause for concern with regard to the potential for similar adverse effects in humans."
The group included several NIEHS grantees and two NIEHS representatives, DERT Administrator Jerry Heindel, Ph.D., and Laboratory of Molecular Toxicology Supervisory Biologist Retha Newbold. The group called for increasing research on human health risks based on the "extensive evidence from laboratory animal studies, particularly when common mechanisms that could plausibly mediate the responses are known to be very similar in the laboratory animal models, wildlife and humans."
The statement about the human health risks of BPA differed from conclusions in a European Food Safety Authority report released in January 2007, which found no risk to human health at current exposure levels.
(Note: The October 1 issue of the eFactor will feature a report on the Future Research on Endocrine Disruption Conference scheduled for August 27-29, 2007 in Durham. The conference is sponsored by the NIEHS Division of Extramural Research and Training and U. S. Environmental Protection Agency.)