An epidemiological study in the journal Fertility and Sterility finds a link between exposure to bisphenol A (BPA) and sub-par sperm.
BPA has been called out before for its effects on reproduction, but most findings have come from mouse models. This study used human men. The researchers found that men with high levels of BPA in their urine also had four times the risk of low sperm count, and two times the risk of having low sperm motility.
Why would BPA bring down sperm, and should we worry?
BPA is thought to mimic estrogen in the body and therefore interrupt the functioning of androgens (male hormones). Semen production is dependent on these male hormones.
The men in the study were Chinese factory workers, who were exposed to much higher levels of BPA than the average person. But even for the control group (who didn’t work in a factory), the BPA – sperm correlation held.
In the high BPA group, the average level of the chemical was 38.7 micrograms of BPA per liter of urine. The average U.S. male levels are 2.3 micrograms per liter. But current FDA guidelines say 2,687.5 micrograms per liter is okay.
Another study earlier this year used U.S. men recruited from a fertility clinic and found the higher the BPA, the lower the sperm concentration and quality — these were not unusually high BPA-exposed men, like in the current study.
BPA is found in hard plastic bottles, metal food container linings, dental sealants and more. Millions of dollars have been poured into studying its effects, because preliminary findings suggest it’s harmful. But we still don’t have a clear answer, because it’s hard to tease apart chemical exposures (we have so many in our systems all the time), and while we find associations all the time, clear cause and effect is a different story.
The National Institute of Occupational Safety and Health funded this research.
More from Heather Turgeon