Chemical tied to hormonal syndrome
NEW YORK |
NEW YORK (Reuters Health) - Women with polycystic ovary syndrome have increased blood levels of the widely used industrial chemical bisphenol A, a small study finds -- raising the question of whether the compound plays some role in the disorder.
Among 71 women with polycystic ovary syndrome (PCOS), researchers found that on average, they had higher blood levels of bisphenol A, or BPA, compared with 100 healthy women the same age and weight.
The findings, reported in the Journal of Clinical Endocrinology & Metabolism, do not prove that BPA contributes to the ovary disorder.
But the researchers say that future studies should look into that possibility.
PCOS is a hormonal disorder thought to affect up to 10 percent of women of reproductive age. Women with the condition have abnormally high levels of testosterone, leading to problems like irregular periods, acne, excessive body hair and difficulty becoming pregnant.
The underlying cause is not completely clear. Researchers believe there is a genetic component: many women with PCOS have a mother or sister affected by it as well. They also often have elevated levels of the blood sugar-regulating hormone insulin, and experts think that problems in the body's use of insulin may underlie the other hormonal shifts seen in PCOS.
Whether environmental exposures have any role is unknown.
For the new study, researchers focused on BPA because the chemical is a so-called endocrine disruptor with weak estrogen-like activity.
It's also ubiquitous. BPA has been used for decades to make hard plastic containers, including cups and baby bottles, and in the lining of metal food and beverage cans. Research suggests that most people have some amount of BPA in their blood.
Moreover, recent animal studies have suggested that the chemical could play a role in certain cancers, heart disease and abnormal brain development in children. BPA's true effects in humans, however, remain unknown.
It's not clear why women with PCOS had higher blood levels of BPA than their healthy counterparts in this study, according to the researchers, led by Dr. Eleni Kandaraki of Huddersfield Royal Infirmary Hospital in the UK.
There's evidence, they note, that BPA and testosterone may act on each other. Testosterone seems to dampen the activity of an enzyme that helps clear BPA from the body, so it's possible that high testosterone levels cause women with PCOS to have higher BPA concentrations.
On the other hand, Kandaraki's team writes, some research suggests that BPA can indirectly boost testosterone levels.
Animal studies have also hinted that BPA might affect insulin levels in the blood.
Together, this prior research implies "a potential role" for BPA in the development of PCOS in some women, Kandaraki's team writes.
"However, further investigation is required to elucidate the mechanisms linking BPA with PCOS and the possible clinical implications of these (current) findings," they conclude.
So far, the greatest concerns over BPA have centered on its potential health effects on fetuses, infants and young children, whose developing hormonal and nervous systems would be more vulnerable to any harm from the chemical.
Canada and the European Union have banned BPA from baby bottles, and many manufacturers have moved to voluntarily remove the chemical from infant bottles and cups.
Last year, the U.S. National Institutes of Health said it would invest $30 million over two years to further study the human health effects of BPA. The Department of Health and Human Services has advice on its website, at www.hhs.gov/safety/bpa, for people who want to limit their exposure.
SOURCE: bit.ly/dXg8uj Journal of Clinical Endocrinology & Metabolism, online December 30, 2010.
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