Study Links Chemical BPA to Health Problems
Wednesday, September 17, 2008
The first large study in humans of a chemical widely used in everyday plastics has found that people with higher levels of bisphenol A had higher rates of heart disease, diabetes and liver abnormalities, a finding that immediately became the focus of the increasingly heated debate over the safety of the chemical.
The research, published yesterday in the Journal of the American Medical Association by a team of British and American scientists, compared the health status of 1,455 men and women with the levels of the chemical, known as BPA, in their urine.
The researchers divided the subjects into four statistical groupings according to their BPA levels and found that those in the quartile with the highest concentrations were nearly three times as likely to have cardiovascular disease than those with the lowest levels, and 2.4 times as likely to have diabetes. Higher BPA levels were also associated with abnormal concentrations of three liver enzymes.
Although the researchers described them as preliminary, the findings were the buzz of a public hearing the Food and Drug Administration held yesterday to discuss whether BPA is safe for continued use in food packaging and liquid containers.
"This is the nail in the coffin," Frederick vom Saal, a reproductive scientist at the University of Missouri at Columbia and one of the first to document evidence of health problems in rodents exposed to low doses of BPA, said outside the FDA meeting in Rockville. "This is a huge deal."
On Capitol Hill, Sen. Charles E. Grassley (R-Iowa) cited the study as he opened an investigation of the way the FDA has regulated the chemical, joining several Democrats, led by Rep. John D. Dingell (Mich.), who have been looking into whether chemical manufacturers unduly influenced the agency's stance.
One of the authors of the new study, David Melzer of the Peninsula Medical School in Exeter, England, briefed the FDA gathering about the research.
He said that the study did not prove that BPA causes health problems and that additional studies are needed. "This needs to be replicated as soon as possible, and we need to understand the mechanism," he said.
Data on the health status of the study subjects, who ranged in age from 18 to 74, came from the Centers for Disease Control and Prevention. The BPA levels in the study were below those the government deemed safe.
Trade groups representing the chemical industry and metal can producers dismissed the results.
"Due to inherent limitations in study design, this new study cannot support a conclusion that bisphenol A causes any disease," Steven G. Hentges of the American Chemistry Council said in a statement. "The weight of scientific evidence continues to support the conclusion of governments worldwide that bisphenol A is not a significant health concern at the trace levels present in some consumer products."
The FDA regulates the compound's use in plastic food containers, bottles, tableware and the plastic linings of food cans. In light of the controversy surrounding the chemical, the agency is reviewing its policy. It issued a draft statement last month that repeated its position that BPA is safe for food and beverage packaging, but it also tapped six outside scientists to review the scientific literature and make a recommendation to agency officials, who are expected to make a final decision on BPA next month. Yesterday's hearing before the six scientific advisers was the public's chance to offer testimony.
Laura Tarantino, director of the FDA's Office of Food Additive Safety, said her agency has no reason to think that BPA in food packaging and liquid containers is unsafe. "We have confidence in the data we've looked at to say that the margin of safety is adequate," she said, adding that consumers can take steps to reduce their exposure to the chemical.
More than 100 studies have linked BPA exposure to health effects in animals. The FDA maintains that BPA is safe largely on the basis of two studies funded by the chemical industry, a fact that was repeatedly cited at yesterday's forum.
"We're concerned that the FDA is basing its conclusion on two studies while downplaying the results of hundreds of other studies," said Amber Wise of the Union of Concerned Scientists. "This appears to be a case of cherry-picking data with potentially high cost to human health."
The FDA's position on BPA runs counter to a report by another federal agency, the National Toxicology Program, which found "some concern" that BPA may cause developmental problems in the brains and hormonal systems of children.