Widely Used Plastics Chemical Linked to Testosterone Boost

Greater exposure to BPA associated with slight rise in hormone levels in men, researchers say

THURSDAY, Aug. 26, 2010 (HealthDay News) -- Exposure to the plastics chemical bisphenol A (BPA) can affect men's testosterone levels, a new study has found.

BPA is used in a large number of consumer products, including food and drink containers. A number of countries have moved to ban the use of the chemical in the manufacture of baby bottles and other feeding items.

In the new study, an international team of researchers analyzed data from 715 Italian adults, aged 20 to 74. They found that their average BPA exposure was more than 5 micrograms per day, which is slightly higher than recent estimates for the U.S. population.

Higher BPA exposure was statistically associated with hormone changes in men; specifically, small increases in levels of testosterone in the blood, according to David Melzer, professor of epidemiology and public health at the Peninsula Medical School in Exeter, U.K., and colleagues.

"This is the first big study of BPA from a European country and confirms that 'routine' exposures in the population are not negligible. It also shows that higher exposure to BPA is statistically associated with modest changes in levels of testosterone in men," Melzer said in a news release from Peninsula Medical School.

"This finding is consistent with the evidence from laboratory experiments. However, this is just the first step in proving that at 'ordinary' exposure levels, BPA might be active in the human body. This new evidence does justify proper human safety studies to clarify the effects of BPA in people," Melzer added.

The study was released online Aug. 25 in advance of publication in an upcoming print issue of the journal Environmental Health Perspectives.

A representative of the chemicals industry took issue with the findings.

"Since the biomonitoring data represents exposure only over the last 24 hours, the study cannot establish a cause-effect relationship for any biological event that occurs at an earlier time," Steven G. Hentges of the Polycarbonate/BPA Global Group at the American Chemistry Council, said in a statement. "The small changes in testosterone levels appear to be within normal ranges and there is no indication that these changes are associated with any health effect. Testosterone levels are known to vary significantly throughout the day and seasonally," he added.

Previous research has found that BPA has a similar molecular structure to estrogen and causes disruption of sex hormone signaling in laboratory animals. The controversial chemical has also been linked to thyroid hormone disruption, altered pancreatic beta-cell function (beta cells produce insulin), cardiovascular disease and obesity, according to background information in the news release.

More information

The U.S. National Institutes of Health has more about BPA.

SOURCE: Peninsula College of Medicine and Dentistry, news release, Aug. 25, 2010; statement, Steven G. Hentges, Ph.D., Polycarbonate/BPA Global Group, American Chemistry Council Consumer News