Higher levels of 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 in the September 17 issue of JAMA.
Bisphenol A (BPA) is one of the world's highest productionvolume chemicals, with more than two million metric tons produced worldwide in 2003 and annual increase in demand of 6 percent to 10 percent annually.
Such was the concern abut the chemical that Wal-Mart announced back in April that it would stop selling baby bottles made with BPA in its U.S. stores early next year. Meanwhile, the Food and Drug Administration cites other studies that indicate the chemical is safe. The new study takes issue with that view.
"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.
Researchers from Peninsula Medical School, Exeter, U.K., 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 (SD) 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.
"Using data representative of the adult U.S. population, we found that higher urinary concentrations of BPA were associated with an increased prevalence of cardiovascular disease, diabetes, and liver-enzyme abnormalities. These findings add to the evidence suggesting adverse effects of low-dose BPA in animals. Independent replication and follow-up studies are needed to confirm these findings and to provide evidence on whether the associations are causal," the authors conclude. "Given the substantial negative effects on adult health that may be associated with increased BPA concentrations and also given the potential for reducing human exposure, our findings deserve scientific follow-up."
In an accompanying editorial, Frederick S. vom Saal, Ph.D., of the University of Missouri, Columbia, and John Peterson Myers, Ph.D., of Environmental Health Sciences, Charlottesville, Va., wrote that, "since worldwide BPA production has now reached approximately 7 billion pounds per year, eliminating direct exposures from its use in food and beverage containers will prove far easier than finding solutions for the massive worldwide contamination by this chemical due its to disposal in landfills and the dumping into aquatic ecosystems of myriad other products containing BPA, which Canada has already declared to be a major environmental contaminant."
The two note that that government action to reduce exposures may offer an effective intervention for improving health and reducing the burden of some of the most consequential human health problems.
"Thus," they concluded, that even while awaiting confirmation of the findings of the study, "decreasing exposure to BPA and developing alternatives to its use are the logical next steps to minimize risk to public health."
