A chemical in plastic bottles is linked with impotence

Factory workers in China who were exposed to high doses of a chemical widely used in hard plastic bottles reported high rates of sexual problems, a study has found.

Heavy exposure at work to BPA (bisphenol A) was linked with impotence and lower sexual desire and satisfaction, according to the study, which adds to concerns about the chemical's effects on ordinary consumers.

The men studied were exposed to about 50 times more BPA than the average American man, said the researcher Dr De-Kun Li. "We don't know whether typical doses have similar effects."

Li, a reproductive and perinatal epidemiologist at the Kaiser Permanente research division in Oakland, California, said people shouldn't be alarmed, but that it would be wise to limit exposure to BPA while scientists look for any effects at low doses. The US government recently announced new funding for research on BPA.

Li is senior author of the study, published online on Wednesday in the journal Human Reproduction and funded by the National Institute for Occupational Safety and Health.

BPA is used in a wide range of consumer products, including some hard plastic bottles and the linings of food and drink cans. Some makers of baby bottles have said they have stopped using it. About 90% of the US population have detectable levels in their urine.

Scientists worry that BPA exposure may harm the reproductive and nervous systems and perhaps increase prostate and breast cancers. Last year a preliminary study linked BPA with the risk of heart disease and diabetes.

The FDA said last year that the tiny amounts of BPA in bottles and cans were not dangerous, but it is now reviewing that position after criticism from its scientific advisers.

For the new research, Li and colleagues studied 164 factory workers in China exposed to high levels of BPA, compared with 386 other men in the same town who either worked in other factories or were married to women factory workers. The scientists measured BPA exposure by sampling the air and interviewed the workers about their sexual function.

Compared with the other workers, the men exposed to BPA were about four times as likely to have difficulty getting an erection, about seven times as likely to report difficulty ejaculating, and about four times as likely to report lower sexual desire or to be unhappy with their sex life.

The effects were strong and clearly linked to exposure, said Linda Birnbaum, director of the National Institute of Environmental Health Sciences, who wasn't involved in the research. The results are consistent with animal studies and should be followed up in the general population, she said. The institute said last month that it would spend more on BPA research, bringing the total to 30 million dollars over two years.

Steven Hentges, a BPA expert with the American Chemistry Council, an industry group, said the work was probably not relevant to consumers: the workers breathed in the chemical or got it on their skin, whereas consumers get it through food, so their bodies can get rid of it. Li said the workers may have been exposed not only by breathing and skin contact but also by swallowing contaminated powder and food, and that he didn't know which route mattered most in the Chinese factories.