Study Links Plastic Chemical To Heart Disease, Diabetes
Higher levels of urinary bisphenol A (BPA), a chemical compound commonly used in plastic packaging for food and beverages, is associated with cardiovascular disease, type 2 diabetes and liver-enzyme abnormalities, according to a study by an international research team that included a University of Iowa researcher.
The study, led by David Melzer, Ph.D., of Peninsula Medical School, Exeter, U.K., and co-authored in part by Robert Wallace, M.D., UI professor of epidemiology, will be published in the Sept. 17 issue of the Journal of the American Medical Association (JAMA).
"Up until now, there has been very little data linking BPA with human disease," Wallace said. "This study finds a correlation between people with higher urinary BPA levels and two serious diseases - cardiovascular disease and diabetes."
BPA is one of the world's highest production-volume chemicals, with more than two million metric tons produced worldwide in 2003 and an increase in demand of 6 percent to 10 percent annually, according to the article. BPA has been used for many years for making certain plastics and resins in many consumer products but has been controversial in recent years.
"Widespread and continuous exposure to BPA, primarily through food but also through drinking water, dental sealants, dermal exposure, and inhalation of household dusts, is evident from the presence of detectable levels of BPA in more than 90 percent of the U.S. population," the authors write. Evidence of adverse effects in animals has created concern over low-level chronic exposures in humans, but there is little data of sufficient statistical power to detect low-dose effects. This is the first study of associations with BPA levels in a large population, and it explores "normal" levels of BPA exposure.
The researchers examined associations between urinary BPA concentrations and the health status of adults, using data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004. The survey included 1,455 adults, age 18 through 74 years, with measured urinary BPA concentrations.
The researchers found that average BPA concentrations, adjusted for age and sex, appeared higher in those who reported diagnoses of cardiovascular diseases and diabetes. A 1-Standard Deviation increase in BPA concentration was associated with a 39 percent increased odds of cardiovascular disease (angina, coronary heart disease or heart attack combined) and diabetes.
When dividing BPA concentrations into quartiles, participants in the highest BPA concentration quartile had nearly three times the odds of cardiovascular disease compared with those in the lowest quartile. Similarly, those in the highest BPA concentration quartile had 2.4 times the odds of diabetes compared with those in the lowest quartile.
In addition, higher BPA concentrations were associated with clinically abnormal concentrations for three liver enzymes. No associations with other diagnoses were observed.
These findings add to the evidence suggesting adverse effects of low-dose BPA in animals.
"This is an association, not a causal finding, but it requires further study," Wallace said. "Most regulators may say that long-term, low-level exposure to BPA isn't harmful, and they may be right, but there is enough evidence here to suggest more research needs to be done."