October 28th, 2010
03:01 AM ET
Add another potential problem to the list: A new study of Chinese factory workers suggests that very high levels of BPA exposure may decrease sperm count and contribute to other sperm-related problems in men.
The findings aren't surprising. BPA—which can be found in some baby bottles and water bottles, as well the linings of food and beverage cans—is known to be a so-called endocrine disruptor that functions "like a weak estrogen" and blocks male sex hormones (including testosterone), says the lead author of the study, De-Kun Li, M.D., a reproductive and perinatal epidemiologist at Kaiser Permanente's division of research, in Oakland, California.
Health.com: 4 things that mess with your hormones
"Human studies have been the missing link," Li says.
In the new study, which appears in the journal Fertility and Sterility, Li and his colleagues collected urine and semen samples from 218 factory workers, some of whom worked in facilities that make BPA or epoxy resin and were therefore regularly exposed to very high levels of the chemical.
Compared with men whose urine was BPA-free, those who had detectable levels of BPA were four times more likely to have a below-average sperm count, three times more likely to have fewer "live" sperm than average, and two times more likely to have below-average sperm quality (motility).
In previous studies conducted in the same population, Li's team found a similar association between BPA exposure and erectile dysfunction, among other sexual problems.
Health.com: Study links BPA in plastics to erectile dysfunction
The findings don't prove cause and effect, however, and it's not clear how relevant they are for men in the U.S. who aren't exposed to unusually high levels of BPA. Although the researchers did find a connection between BPA levels and sperm problems in men who were exposed to BPA only in the general environment (rather than the workplace), it's possible that the study population differs from the U.S. population in key ways.
Still, the study seems likely to serve as ammunition for advocates and public health officials who favor restrictions on BPA.
Health.com: 12 ways to remove (and avoid) toxics in your home and body
From around the web
About this blog
Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.