Sperm Quality Declines After Exposure to Plastic Chemical BPA
Bisphenol-A, a chemical used for decades to make plastic food containers and baby bottles, was linked to lower sperm quality in men, researchers said.
A five-year study of 514 Chinese workers compared those with detectable levels of BPA in their urine, ranging from high to low, and those with undetectable amounts, according to results appearing today in the journal Fertility & Sterility. Men with measurable levels had two to four times the risk of lower sperm concentration, sperm count, vitality and motility.
This is the first human study to show a relationship between semen quality and BPA levels in urine, after animal studies showed similar associations, said De-Kun Li, an epidemiologist at Kaiser Permanente’s division of research in Oakland, California. The U.S. Environmental Protection Agency and the Food and Drug Administration said earlier this year that they will study the potential health effects of BPA. On Oct. 14, Canada declared the chemical a toxic substance.
“BPA damages your sperm, that’s the very obvious message,” Li said in a telephone interview. “Sometimes people may not care about semen quality, but they should -- it may lead to birth defects and infertility.”
The U.S. National Toxicology Program lists BPA as presenting a “negligible concern” that exposure will cause reproductive effects in adults who aren’t vulnerable to it because of their jobs. The NTP also has “minimal concern” that workers exposed to BPA will show effects, according to the agency’s website.
Ed Kang, a spokesman for the federal program, didn’t respond to a phone call and an e-mail requesting comment.
More Studies
The FDA said in January that it supports additional studies, by governmental and nongovernmental researchers, to provide information and address uncertainties about the safety of BPA, said Michael Herndon, a spokesman for the agency.
Dale Kemery, a spokesman for the EPA, said the agency was still examining the chemical, and “no single study is likely to be the sole driver or determinant of action,” according to an e-mailed statement.
Today’s study found that men with detectable levels of BPA in their urine also showed more than three times the risk of lowered sperm concentration and vitality, more than four times the risk of a lowered sperm count, and twice the risk of lowered motility, compared with men without BPA in their urine.
When the study authors eliminated the men who were exposed to BPA in workplaces, the average study participant had BPA exposure of 1.4 micrograms per gram of urine. The average U.S. male has 2.3 micrograms per gram, Li said.
Children’s Health
The FDA’s staff found in a 2008 report that food packaged in material containing BPA is safe. Scientists advising the agency said later that the FDA produced a flawed assessment and urged more research. Because BPA is a reproductive, developmental and systemic toxicant in animal studies, questions have emerged about its potential effects on children’s health.
To minimize exposure, the Health and Human Services Department recommends that people discard scratched baby bottles and infant feeding cups and avoid putting boiling water in bottles and cans that contain BPA.
Nestle SA and Energizer Holdings Inc. were among six manufacturers that said they stopped using BPA, as of January 2009, when making baby bottles and feeding cups for the U.S. market, according to the health department.
BPA blocks the effects of androgens, or male hormones, and it acts as a mild estrogen, said Li, the lead author on today’s study.
“Up until two years ago, some of the arguments we heard were that we only have animal studies showing it’s bad,” Li said. “Our study is adding the weight of human evidence to show that those effects demonstrated in animal studies are being supported by human studies.”
To contact the reporter on this story: Elizabeth Lopatto in New York at elopatto@bloomberg.net.
To contact the editor responsible for this story: Reg Gale at rgale5@bloomberg.net.
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