Women with the problem had higher levels of BPA, but study can't confirm cause-and-effect, experts say
MONDAY, June 21 (HealthDay News) -- There may be more troubling news about the ubiquitous plastics chemical bisphenol A (BPA): Women with polycystic ovary syndrome have higher levels of the chemical in their bloodstream, a study finds.
The ovaries of women with polycystic ovary syndrome (PCOS) develop multiple "cysts" -- immature follicles bunching together in lumps --and the condition can raise the risk of several conditions including infertility, heart disease and type 2 diabetes.
In women with PCOS, higher BPA levels were also associated with elevated levels of male hormones, according to new research that was presented at the annual meeting of the Endocrine Society in San Diego.
And a second abstract, also being presented at the meeting, found that male rats exposed to BPA in the womb and while suckling suffered long-term testicular dysfunction.
The findings add to the burgeoning, if not-yet-definitive, evidence that BPA may have adverse health effects in humans.
BPA has been found in many plastic products, including baby bottles and sippy cups (although most baby bottles manufactured for the U.S. market no longer contain BPA), as well as metal linings of some cans.
The chemical, which acts similarly to the female hormone estrogen, has come under close scrutiny in the past several years, with studies linking it to a host of health and developmental problems.
In January, the U.S. Food and Drug Administration and other U.S. health agencies announced that they were pledging $30 million toward short- and long-term research aimed at clarifying the health effects of BPA.
Most of the current data is from laboratory animals and shows subtle effects of BPA on heart disease, sexual dysfunction, cancer, diabetes and hyperactivity, as well as human studies which, among other things, suggest a link between the chemical and aggression in toddler girls. There is also concern that it could have an effect on the developing fetus.
The authors of the first study, from the University of Athens Medical School in Greece, compared blood BPA levels in 71 women with PCOS and 100 healthy women.
Levels of BPA in the blood of healthy-weight women with PCOS were 60 percent higher as compared with controls. BPA levels were 30 percent higher in obese women with PCOS.
And the higher the BPA level, the higher the levels of male hormones.
But, cautioned Dr. Diana Wu, a clinical fellow in reproductive endocrinology and infertility at Center for Reproductive Health, University of Cincinnati, "This is an association study," cautioned Dr. Diana Wu,. "You can't really determine cause-and-effect."
The second study found that male rats whose mothers were fed BPA while they were pregnant and then breastfeeding produced less testosterone than mice who had not been exposed to BPA.
The effects lasted into adulthood and after exposure had been stopped.
The exposure levels were below those considered safe by the FDA and the Environmental Protection Agency, the authors stated.
"We used very low doses compared to levels that the population is exposed to," said study lead author Dr. Benson T. Akingbemi, associate professor of anatomy and developmental biology at Auburn University's College of Veterinary Medicine in Auburn, Alabama. "And the effects due to BPA that were caused early in development remained into adulthood."
While this study may have looked at low levels, many BPA animal studies use BPA levels well beyond what humans would normally experience, thus making the totality of the evidence, "controversial," Wu said.
In the meantime, one representative of the chemicals industry defended BPA's overall safety.
A statement from Steven Hentges, executive director of the Polycarbonate/BPA Global Group at the American Chemistry Council pointed out that, "Recent reviews of the science have continued to support the safe use of BPA in food contact applications. In January, 2010, the FDA weighed in on BPA, noting that additional studies on BPA are underway. Principal deputy commissioner Joshua Sharfstein stated, 'If we thought it was unsafe, we would be taking strong regulatory action.'" He added that other global regulatory bodies, Health Canada, have recently completed scientific evaluations and found BPA safe in canned food products and beverages.
There's more on BPA research at the U.S. National Institute of Environmental Health Sciences.
SOURCES: Benson T. Akingbemi, D.V.M., Ph.D., associate professor, anatomy and developmental biology, College of Veterinary Medicine, Auburn University, Auburn, Ala.; Diana Wu, M.D., clinical fellow, reproductive endocrinology and infertility, Center for Reproductive Health, University of Cincinnati Health; June 21, 2010, statement, Steven Hentges, Ph.D., executive director, Polycarbonate/BPA Global Group, American Chemistry Council, Arlington, Va.; June 20 and 21, 2010, presentations, Endocrine Society annual meeting, San Diego
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