Chemical BPA in food linked to childhood obesity
Many factors are responsible for the current obesity epidemic in the United States. Now, another possible causative factor has been discovered by researchers affiliated with New York University. They conducted a study to determine whether bisphenol A (BPA), an industrial chemical that is present in many hard plastic bottles as well as metal-based food and beverage cans since the 1960s, is associated with childhood obesity. They published their findings on September 19 in the Journal of the American Medical Association (JAMA).
The researchers note that in adults, elevated urinary BPA concentrations are associated with obesity and coronary artery disease. They add that it is logical to assume that BPA exposure could be linked to childhood obesity; however, the medical literature does not contain sufficient evidence in this regard. Therefore, they set out to examine associations between urinary BPA concentration and body mass outcomes in children.
The study group was comprised of a nationally representative subsample of 2,838 participants aged 6 through 19 years randomly selected for measurement of urinary BPA concentration in the 2003-2008 National Health and Nutrition Examination Surveys. The main outcome measures were body mass index (BMI), which was used to classify participants as overweight (BMI at or above the 85th percentile for age/sex) or obese (BMI at or above the 95th percentile).
The researchers found that the average urinary BPA concentration was 2.8 ng/mL. Among the study group, 1,047 (34.1%) were overweight and 590 (17.8%) were obese. Controlling for race/ethnicity, age, caregiver education, poverty to income ratio, sex, serum cotinine level, caloric intake, television watching, and urinary creatinine level, children in the lowest urinary BPA quartile had a lower estimated prevalence of obesity (10.3%) than those in quartiles 2 (20.1%), 3 (19.0%), and 4 (22.3%). Similar patterns of association were found in multivariable analyses. Obesity was not associated with exposure to other environmental phenols commonly used in other consumer products, such as sunscreens and soaps. The researchers found significant associations between urinary BPA concentrations and obesity among whites but not among blacks or Hispanics.
The researchers found that urinary BPA concentration was significantly associated with obesity in this cross-sectional study of children and adolescents. They cautioned that the findings do not necessarily indicate that BPA plays a role in the development of obesity and that it is possible that obese children and adolescents ate food with higher BPA concentrations than thinner children or that they have higher amounts of BPA stored in fat tissue.
Last July, the Food and Drug Administration (FDA) banned the use of BPA in baby bottles and sippy despite the fact that manufacturers had already stopped using the chemical because of health concerns. However, the FDA stopped short of banning use of the chemical in metal can liners and other plastics because they did not have adequate proof that exposure to low levels of BPA through diet are unsafe. The FDA plans to review the new research as “part of its ongoing evaluation of the safety of BPA.” However, it also noted that it “sees substantial uncertainties with respect to the overall interpretation of many published studies, and, particularly, their potential implications for human health effects of BPA exposure.”
BPA is still used in many plastics and metal can liners; however many companies are phasing out use of the chemical. Campbell Soup Co. has said it expects most of its soup cans to be BPA-free by July 2013. BPA is used to make an epoxy for the lining of more than 85% of cans produced each in the US, according to the North American Metal Packaging Alliance, an industry group representing can makers.