The public has recently been warned about the chemical compound Bisphenol A (BPA), commonly used in plastic packaging for food and beverages. To correspond with a Food and Drug Administration (FDA) hearing on BPA, the September 17 issue of JAMA contains a report that finds an association between higher levels of urinary BPA and cardiovascular disease, type 2 diabetes and liver-enzyme abnormalities.
Two million metric tons of BPA were produced worldwide in 2003, making it one of the world’s highest production-volume chemicals. Experts also expect an annual increase in demand of 6% to 10% for this ubiquitous compound found in the plastic of several consumer products. Researcher David Melzer, M.B., Ph.D. (Peninsula Medical School, Exeter, U.K.) and colleagues note that, “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.” Although animal studies have shown adverse effects to create concern over low-level exposure in humans, researchers still lack enough data to detect low-dose effects with sufficient statistical power. This new study is unique in that it analyzes effects of BPA levels in a large population while also exploring “normal” levels of BPA exposure.
To investigate the relationship between urinary BPA concentrations and the health status of adults, Melzer and colleagues employed data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004. The sample consisted of 1,455 adults, age 18 through 74 years, with measured urinary BPA concentrations.
Statistical models that controlled for factors such as age and sex suggested that on average, BPA concentrations were higher in participants who reported diagnoses of cardiovascular diseases and diabetes. Further, a 39% increase in the odds of reporting diabetes and cardiovascular disease (including angina, coronary hear disease, or hear attack combined) was associated with only a 1-Standard Deviation (SD) increase in BPA concentration. Splitting the data into quartiles of BPA concentration revealed that participants in the highest 25% of BPA concentration had about 3 times the odds of cardiovascular disease and 2.4 times the odds of diabetes compared to participants in the lowest 25% of BPA concentration.
Finally, the researchers established a link between higher BPA concentrations and clinically abnormal concentrations for three liver enzymes.
“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,” conclude the researchers. “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.”
An accompanying editorial to the article was written by Frederick S. vom Saal, Ph.D. (University of Missouri, Columbia) and John Peterson Myers, Ph.D. (Environmental Health Sciences, Charlottesville, Va.). They write:
“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 good news is 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, even while awaiting confirmation of the findings of Lang et al, decreasing exposure to BPA and developing alternatives to its use are the logical next steps to minimize risk to public health.”
Association of Urinary Bisphenol A Concentration With Medical Disorders and Laboratory Abnormalities in Adults
Iain A. Lang; Tamara S. Galloway; Alan Scarlett; William E. Henley; Michael Depledge; Robert B. Wallace; David Melzer
JAMA (2008). 300(11):1303-1310.
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Written by: Peter M Crosta