Is bisphenol A to blame for rise in male anomalies?

February 1, 2009

A material used in plastic baby bottles and other products, which has been associated with such health risks as reproductive system abnormalities, prostate cancer, and obesity, could be banned this year, according to a professor at the University of Missouri, Columbia.

Frederick S. vom Saal, PhD, a noted researcher in developmental biology, says proposed legislation by federal lawmakers led by Rep. Edward Markey (D-MA) would ban the use of bisphenol A (BPA) in many consumer products.

The FDA, which has come under fire from consumer advocates, lawmakers, and some scientists for not taking immediate steps to ban BPA, is rethinking its position regarding the chemical's potential health risk. In a letter to a member of its Science Board dated Dec. 3, 2008, the FDA states that it plans "a large research effort" that will assess the effects of the material in laboratory animals.

Dr. vom Saal asserts that mounting evidence shows that BPA is a potential health hazard and refers to animal studies that indicate the chemical may mimic estrogen, advancing the onset of puberty and increasing the risks of prostate cancer and other conditions. (Dr. vom Saal recently co-authored a review of the current literature on this topic in Environmental Research [2008; 108:127-30]). Seven million pounds of bisphenol A are produced per year, and tons of products containing the chemical are dumped in landfills, which can result in groundwater contamination. Because of the potential ecological hazard, the total health impact on the population will not be known for decades, Dr. vom Saal says.

"You can say that BPA is the asbestos of the 21st century," Dr. vom Saal said.

Opponents of BPA hope the United States follows the lead of Canada, which last October banned the use of baby bottles made with the material. BPA is found in polycarbonate plastic used to harden plastic and in the resins used to line metal food cans.

Last August, the FDA released a draft report based on lab tests in rodents, stating that infants and adults who are exposed to BPA levels via certain products do not face exposure at toxic levels. The draft assessment concludes that the small amounts of BPA that leach into milk or food from containers aren't dangerous to humans.

However, because of questions from researchers, including Dr. vom Saal, the FDA convened a panel of independent science advisers in September to look again at the possible health effects of BPA in consumer products. The advisory panel made headlines a month later when it chastised the FDA for using only two industry-sponsored trials from a widening pool of studies examining BPA use in products.

Caleb Nelson, MD, MPH, instructor in urology at Harvard Medical School in Boston, says the urologic community is concerned over the rising prevalence of male reproductive development problems in many parts of the world, including cryptorchidism, hypospadias, testicular cancer, infertility, and poor sperm quality.

Dr. Nelson says the magnitude of the health risk that BPA poses is unclear, due to the difficulty in demonstrating a minimum level above which the chemical is directly harmful to humans. The question, he says, is whether endocrine disruption in humans is related to exposure to certain environmental chemicals.