CHICAGO - Chinese factory workers exposed to high levels of the plastics chemical BPA had low sperm counts, according to the first human study to tie it to poor semen quality.
The study is the latest to raise health questions about bisphenol-A and comes two weeks after Canada published a final order adding the chemical to its list of toxic substances.
Whether the relatively low sperm counts and other signs of poor semen quality translate to reduced fertility is not known. Study author Dr. De-Kun Li, a scientist at the Kaiser Permanente Division of Research in Oakland, Calif., noted that even men with extremely low sperm counts can father children.
But Li said finding that BPA may affect sperm is troubling because it echoes studies in animals and follows his previous research in the same men that linked BPA exposure with sexual problems.
If BPA exposure can reduce sperm levels, "that can't be good" and means more study is needed to check for other harmful effects, Li said.
The study was published online yesterday in the journal Fertility and Sterility. The National Institute of Occupational Safety and Health funded the research.
BPA is used to make resins and strengthen plastics and is found in many consumer products: hard plastic bottles, metal food container linings, dental sealants and eyeglasses. Most Americans' urine contains measurable levels of BPA.
Steven Hentges of the American Chemistry Council, an industry group, said the study in China "is of limited relevance" to U.S. consumers, who typically are exposed to very low BPA levels that pose no health threat.
The study involved 130 Chinese factory employees who worked directly with materials containing BPA and 88 workers who didn't handle it and whose exposure was similar to that of typical U.S. men.
Low sperm counts were found in workers who had detectable levels of bisphenol-A in their urine. The lowest sperm counts were in men with the highest levels of BPA.