MADELEINE BRAND, host:
This is Day to Day. I'm Madeleine Brand.
ALEX COHEN, host:
And I'm Alex Cohen. Today, a panel of scientists gathered at the Food and Drug Administration is looking into the controversy over Bisphenol A. That's the organic compound found in all sorts of things, including the plastic used in some brands of water bottles. Recent studies have linked Bisphenol A to cancer and obesity. A new study published this morning by the journal of the American Medical Association suggests that people exposed to lots of it are more likely to be diagnosed with diabetes and heart disease. NPR's Allison Aubrey reports.
ALLISON AUBREY: The very first point to make in a story about the possible risks linked to the plastics compound Bisphenol A is that this latest study offers no conclusive answers. It does not prove a cause and effect between some of the microwave dinner trays we've all eaten out of and development of diabetes or heart disease. What the research does do is help scientists understand how this chemical may work in the human body. David Schardt is a staff scientist with the Center for Science in the Public Interest.
Mr. DAVID SCHARDT (Senior Nutritionist, Center for Science in the Public Interest): We don't have a lot of evidence in people about the effects of BPA. This is one of the first studies, and it finds something disturbing. It's suggesting that there may be harm in adults, which we didn't really believe based on the animal studies.
AUBREY: The study published today draws on a survey done by the federal government called the National Health and Nutrition Examination Survey. Basically, researchers identify a group of adults between 18 and 74 who are representative of the U.S. population at large. It asks a series of health-related questions, including which diseases people have been diagnosed with.
A few years ago, participants in this survey also agreed to a urine sample, and researchers tested for a range of compounds, including Bisphenol A. The analysis published today finds that the adults with the highest levels of BPA in their urine were more than twice as likely to report having diabetes or heart disease, compared to adults with the lowest levels of the chemical in their urine.
Researcher David Melzer of the Peninsula Medical School in England directed the study. He says his team never anticipated these associations with these major diseases.
Dr. DAVID MELZER (Epidemiology and Public Health, Peninsula Medical School, Exeter, England): The whole study is surprising in one sense, in that we are interested in the diseases of the 50-and-over age group, and that's originally what we looked at. And then we realized that these associations went into the wider adult populations. And, you know, it just turned out that these signals were just exceptionally strong and exceptionally robust.
AUBREY: Strong and robust, even when his team adjusted for things like weight and smoking. Now, to get a reality check on what these findings mean, we called Ken Portier. He's a statistician with the American Cancer Society and an expert at interpreting these kinds of association studies. We reached him on his cell phone.
I'm wondering if you might help us interpret these findings. What does Dr. Melzer mean when he says that these signals between the diseases he looked at and the plastics exposure are very strong and robust?
Mr. KEN PORTIER (Program Director, Statistics, American Cancer Society): Well, one way of looking at it would be, if you could take two individuals with the same sex, the same age, race ethnicity, level of education, income, body build and cigarette smoking status, and you had one individual that had low levels of BPA and one individual had high levels of BPA, the individual with high levels of BPA would be more likely to also report being a diabetic or having a cardiovascular disease history.
AUBREY: And, of course, that doesn't mean that BPA caused it. It just means there's an association there.
Mr. PORTIER: Correct.
AUBREY: Portier says the findings are certainly strong enough to follow up on. The next step might be to look at another group of the survey participants to see if the associations hold up. David Melzer is scheduled to discuss his findings today at a Food and Drug Administration meeting. The agency has issued a draft proposal on Bisphenol A. It finds that current level of exposure to BPA through food containers is thought to be safe. Allison Aubrey, NPR News, Washington.