Children and adolescents who have higher concentrations of urinary bisphenol A (BPA), a manufactured chemical found in plastics and consumer products, have significantly higher odds of being obese, study results suggest.
Those with the highest concentration of BPA were more than twice as likely to be obese as those who had the lowest levels (odds ratio=2.53; 95% CI: 1.72- 3.74; P<0.001), Leonardo Trasande, MD, of New York University, and colleagues reported in the Journal of the American Medical Association.
The association between BPA and obesity was strongest among white children, with those with the highest urinary concentrations four times more likely to be obese than those with the lowest urinary concentrations (OR=4.08; 95% CI: 1.66-10.00, P=0.003).
“In experimental studies, BPA exposure has been shown to disrupt multiple metabolic mechanisms, suggesting that it may increase body mass in environmentally relevant doses and therefore contribute to obesity in humans,” the researchers wrote, noting that previous studies on the topic have involved only adults.
So Trasande and colleagues conducted a cross-sectional analysis of a nationally representative subsample of 2,838 participants aged 6 through 19 years in the 2003-2008 National Health and Nutrition Examination Studies, randomly selected for urinary BPA concentration measurement. Participants were then classified into quartiles based on BPA concentrations.
The median urinary BPA concentration was 2.8 ng/mL; 34.1% were overweight and 17.8% were obese.
Children in the fourth and highest quartile of BPA urinary concentration had an adjusted obesity prevalence of 22.3% (95% CI: 16.6%-27.9%) compared with a 10.3% prevalence among those in the first and lowest quartile of BPA concentration (95% CI: 7.5%-13.1%), the researchers found.
The correlation between BPA urinary concentration and obesity were significant for children in the second (OR= 2.22; 95% CI: 1.52- 3.23), third (OR=2.09; 95% CI: 1.48- 2.95) and fourth quartiles (OR=2.53; 95% CI: 1.72- 3.74, P<0.001 for all) compared with those in the first and lowest quartile.
Neither Hispanic, nor non-Hispanic black children with elevated concentrations of urinary BPA had a significantly increased risk for obesity, the researchers found.
The researchers cautioned that they are unable to infer causation using a cross-sectional study design, as obesity develops over time, but called for further studies to evaluate elevated urinary BPA concentrations and obesity in white children.
In July 2012, the FDA banned the use of BPA in baby bottles and sippy cups, but not in aluminum cans and other food packaging. However, the agency has noted that it will continue to consider evidence on BPA’s safety.
“Carefully conducted longitudinal studies that assess the associations identified here will yield evidence many years in the future,” the researchers concluded.