WASHINGTON, DC, September 16, 2008 (ENS) - For the first time, scientists have linked higher concentrations of the chemical bisphenol A in human urine with diagnoses of cardiovascular disease and diabetes.
Bisphenol A is widely used in epoxy resins lining food and beverage containers and in hard plastic baby bottles and drinking water bottles. Evidence of adverse health effects in animals exposed to low doses of the chemical has generated concern over low-level chronic exposures in humans.
The study by American and British scientists was published today on the website of the "Journal of the American Medical Association."
The first study of associations with bisphenol A levels in a large population, it explores "normal" levels of exposure to the chemical
Led by David Melzer, Ph.D., of Peninsula Medical School, Exeter, U.K., the study was co-authored in part by Robert Wallace, M.D., University of Iowa professor of epidemiology.
"Up until now, there has been very little data linking BPA with human disease," Wallace said. "This study finds a correlation between people with higher urinary BPA levels and two serious diseases - cardiovascular disease and diabetes."
In addition, the study found that higher concentrations of the chemical were associated with clinically abnormal concentrations for three liver enzymes.
The study is based on analysis of bisphenol A concentrations and health status in the general adult population of the United States, using data from the National Health and Nutrition Examination Survey 2003-2004. Participants were 1,455 adults aged 18 through 74 with measured urinary BPA concentrations.
"This is an association, not a causal finding, but it requires further study," Wallace said. "Most regulators may say that long-term, low-level exposure to BPA isn't harmful, and they may be right, but there is enough evidence here to suggest more research needs to be done."
The study was released in time for a meeting of scientific advisers to the U.S. Food and Drug Administration today in Rockville convened to hear and discuss the agency's draft assessment of bisphenol A for use in food contact applications such as water bottles and can linings.
At the meeting, FDA scientist Laura Tarantino repeated the agency's long-standing position that exposure to the chemical is safe.
"A margin of safety exists that is adequate to protect consumers, including infants and children, at the current levels of exposure," she told the meeting.
"Widespread and continuous exposure to BPA, primarily through food but also through drinking water, dental sealants, dermal exposure, and inhalation of household dusts, is evident from the presence of detectable levels of BPA in more than 90 percent of the U.S. population," the authors write.
"Evidence of adverse effects in animals has created concern over low-level chronic exposures in humans, but there is little data of sufficient statistical power to detect low-dose effects," they write.
Past animal studies have suggested reproductive and hormone-related health problems from bisphenol A.
The American Chemistry Council, which represents the chemical industry, says the new study is a statistical analysis that attempts to correlate urinary concentrations of bisphenol A, which reflect very recent exposure, with the incidence of cardiovascular disease and diabetes.
The council argues that the onset and development of these diseases occurred over time periods well before the bisphenol A exposure measurements were made.
"Because of this and other inherent limitations, the study is not capable of establishing a cause and effect relationship between bisphenol A and these health effects," the council said, adding that more research is needed.
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