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Sept. 16, 2008 -- For the first time, the controversial plastic chemical bisphenol A has been linked to serious health problems -- heart disease and diabetes -- in people.
Bisphenol A, also called BPA, is used in polycarbonate plastic -- hard plastic used in products including some baby bottles and refillable water bottles -- and in epoxy resins, which line some canned goods and are also in dental composites and sealants. Bisphenol A isn't found in softer plastics, such as single-serving water bottles.
A new study links high urinary levels of bisphenol A to a history of heart disease or diabetes, and to abnormally high concentrations of liver enzymes.
The study doesn't prove that bisphenol A caused those problems. But the findings are "disturbing," says David Schardt, MS, senior nutritionist of the Center for Science in the Public Interest. The plastics industry, on the other hand, stands by bisphenol A's safety.
The findings, published in The Journal of the American Medical Association, were presented today at an FDA public hearing on bisphenol A. Here's what you need to know about the new bisphenol A study.
Most bisphenol A studies have been done in lab tests on rodents. The new study is all about humans.
The researchers checked government data on heart disease, diabetes, and bisphenol A in 1,455 U.S. adults age 18-74.
As part of a national health study done in 2003-2004, participants provided urine samples and were asked if they had ever been diagnosed with cardiovascular disease -- heart attack, coronary heart disease, or chest pain (angina) -- or diabetes.
People with the highest urinary levels of bisphenol A were more than twice as likely to report ever being diagnosed with cardiovascular disease or diabetes, compared to people with the lowest urinary levels of bisphenol A. High urinary levels of bisphenol A were also linked to abnormal concentrations of liver enzymes.
To put the heart disease and diabetes findings in perspective, those conditions were relatively rare: 79 people reported a history of heart disease and 136 reported a history of diabetes.
The study didn't directly test bisphenol A to see if caused health problems, so it doesn't prove that bisphenol A was to blame.
Still, the results held regardless of factors including age, sex, race, smoking, and BMI (body mass index). But the researchers didn't adjust for all possible influences, including family history of heart disease or diabetes.
David Melzer, MB, PHD, worked on the new bisphenol A study. He's a professor of epidemiology and public health at Peninsula Medical School at England's University of Exeter.
People with high urinary levels of bisphenol A probably weren't exposed to extreme levels of bisphenol A, according to Melzer.
"It looks as if what people were exposed to was way lower than what is considered the safe level at the moment," Melzer tells WebMD. But he adds that it's not clear where their bisphenol A came from.