If the plastic additive bisphenol A is dangerous to health, you'd expect to see problems in people who work with lots of the stuff.
Greg Baker/AP, file
Chinese smokestacks in winter.
Chinese smokestacks in winter. Greg Baker/AP, file
So Kaiser Permanente epidemiologist Dr. De-Kun Li and some other scientists took a look at men working in Chinese factories that made BPA or used it to produce the sorts of resins that line cans of food. For comparison, they studied men in factories in the same Chinese cities that didn't use BPA.
The results of the five-year study? Men exposed to high levels of BPA on the job had a much greater chance of sexual problems than men who weren't. Reductions in sexual desire and sexual satisfaction were about four times more likely. Erectile difficulties were 4.5 times more likely. And problems with ejaculation were seven times more likely.
It's the first time evidence has shown men exposed to BPA at work can develop sexual problems because of it, the authors wrote. The chemical resembles the hormone estrogen and that's fueled worries that even very small amounts of BPA can cause harm.
To be sure, factory workers exposed to BPA in the study faced levels 50 times higher than those experienced by the average American male. "Because the BPA levels in this study were very high, more research needs to be done to see how low a level of BPA exposure may have effects on our reproductive system," Dr. Li said in a statement. "This study raises the question: Is there a safe level for BPA exposure, and what is that level?"
The scientists' findings appear in the journal Human Reproduction. Their work was funded by the US National Institute of Occupational Safety and Health.
Update: The American Chemistry Council, a trade group, said in a statement that the study "provides interesting new information" but that its relevance to consumers is limited because they use products exposing them to "minute amounts of BPA."