In a confusing study from the Journal of Clinical Endocrinology & Metabolism, researchers compared 71 women with polycystic ovary syndrome (PCOS), a hormonal disorder affecting up to ten percent of women of reproductive age, to 100 healthy women of the same age and weight and found that women with PCOS had higher levels of bisphenol A (BPA) in their blood. Women with PCOS have unusually high levels of testosterone and may suffer from such symptoms as irregular periods, acne, excessive body hair or difficulty in becoming pregnant. The study authors claim that BPA may increase the risk of PCOS by indirectly boosting testosterone levels or conversely, it may be that the high testosterone levels found in PCOS patients diminish the effectiveness of clearing BPA from the body.
Regardless, the study author's evidence for these hypotheses is shamefully lacking, says ACSH’s Jonathan Leaf. “The data for the study falls easily within the margin of error. In other words, they didn’t have any statistically significant results, although the article summary indicates that they did,” Leaf notes. “What’s more, they report that BPA levels in their test subjects were typically at or below one part per billion. These are the minutest of trace levels. Do the researchers actually think these tiny quantities could be playing a role in causing PCOS?”
ACSH's Dr. Gilbert Ross, likewise, thinks that the Journal of Endocrinology & Metabolism has undercut its scientific credibility by publishing this study. “How could a substance like BPA lead to PCOS,” he asks, “when this disorder is associated with excessive androgenic activity, not with the female hormone estrogen, which is what BPA is always accused of disrupting — albeit without evidence of such effects? I also wonder how a study without any significant findings could be published by JCEM — did it not go through any peer-review? Has JCEM become a political platform now instead of an academic journal?”
Not to be outdone by their anti-BPA colleagues, anti-phthalate researchers meanwhile published a study in the journal Occupational and Environmental Medicine in which they claim that women with workplace exposure to phthalates and pesticides have an increased probability of taking six months or more to conceive, and that their children are more often of low birth weight. Yet, after analyzing 3,719 women who were pregnant between 2002 and 2006, the study authors admit that the overall numbers for this association were small.
Dr. Ross notes that the data on exposure to the targeted chemicals were constructed out of whole cloth by some magical use of an invented statistic called “job-exposure matrix,” nicknamed JEM by the authors. “The women studied did not report exposure to pesticides or phthalates, but the JEM ‘linked reported job title to workplace chemical exposure within jobs according to expert judgement.’” He wonders: “Does this look like super-fudged data to anyone else?” In any event, he asks, given that the results were at best slight, why even bother publicizing the study?
“This is junk science,” laments ACSH’s Dr. Elizabeth Whelan. “Every day we hear about another study saying how bad BPA and phthalates are even though they have been used completely safely for over fifty years and are essential to the production of important products and medical devices. Why don’t journalists take the time to cover this instead of wasting time on these small and statistically dubious studies?”