OAKLAND, CA — Two weeks after Canada officially declared bisphenol-A (BPA) to be toxic, new research suggests high exposure to the chemical can lead to poor semen quality.
It is the latest blow to the reputation of BPA, a chemical used in a variety of applications, including hard plastics and the lining of canned food. It is so ubiquitous that it has been detected in the urine of more than 90 percent of the U.S. population and 91 percent of Canadians.
In animal studies, BPA, which mimics estrogen, has been shown to impact the male reproductive organs and interfere with male sex hormones. In humans, BPA exposure has been associated with male sexual dysfunction, according to two previous studies from Kaiser Permanente Division of Research.
In the latest five-year study published in the journal Fertility and Sterility, scientists from the Kaiser Permanente Division of Research examined 514 Chinese factory workers, comparing those with high urine BPA levels against men with low urine BPA levels. The results revealed that those with high BPA levels in their urine were up to four times more likely to have poor sperm quality, although urine BPA was not linked to volume or abnormal sperm.
"Compared with men without detectable urine BPA, those with detectable urine BPA had more than three times the risk of lowered sperm concentration and lower sperm vitality, more than four times the risk of a lower sperm count, and more than twice the risk of lower sperm motility," Dr. De-Kun Li, the report's lead author, said in a statement Thursday.
The workers' high level of BPA exposure far exceed that of the average American, the American Chemical Council countered in a statement Thursday.
"This study of Chinese workers with high exposure to BPA is of limited relevance to consumers who, by contrast, are exposed to only very low levels of BPA," said Steven Hentges, from the ACC's Polycarbonate/BPA Global Group. "Studies from the U.S. Center for Disease Control and Health Canada have shown that typical consumer exposure to BPA, from all sources, is more than 1,000 times lower than government-established safe intake levels."
The study suggests, however, that the sperm of those with low BPA exposure, similar to levels among U.S. men, were still impacted, with quality declining as exposure increases.
Image CC licensed by Flickr user stevendepolo.