B.P.A. associated with obesity in children
by Keith Nunes
NEW YORK — Children and adolescents who had higher levels of urinary bisphenol A (B.P.A.) had “significantly” increased odds of being obese, according to a study published in the September 19 issue of the Journal of the American Medical Association (JAMA).
Leonardo Trasande, M.D., of the New York University School of Medicine, presented the findings of the study at a JAMA media briefing today.
Dr. Trasande and colleagues conducted a study to examine the association between urinary B.P.A. concentrations and body mass in children. The study consisted of a cross-sectional analysis of a nationally representative sub-sample of 2,838 participants, ages 6 through 19 years, randomly selected for measurement of urinary B.P.A. concentration in the 2003-2008 National Health and Nutrition Examination Surveys. Body mass index (B.M.I.) was used to classify participants as overweight or obese.
The median (midpoint) urinary B.P.A. concentration for participants in the study was 2.8 nanograms per milliliter. The prevalence of obesity was 17.8% and overweight 34.1%.
The B.P.A. concentrations of the participants were divided into quartiles. Controlling for a variety of factors such as 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 B.P.A. quartile had a lower estimated prevalence of obesity (10.3%) than those in quartiles 2 (20.1%), 3 (19%), and 4 (22.3%).
Compared with the first quartile, participants in the third quartile had approximately twice the odds for obesity. Participants in the fourth quartile also had higher odds of obesity.
Further analyses showed the association to be statistically significant in only one racial subpopulation, white children and adolescents. The researchers also found that obesity was not associated with exposure to other environmental phenols commonly used in other consumer products, such as sunscreens and soaps.
The authors noted that in experimental studies, B.P.A. 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. But in their conclusion, they were less specific, saying, “Urinary B.P.A. concentration was significantly associated with obesity in this cross-sectional study of children and adolescents. Explanations of the association cannot rule out the possibility that obese children ingest food with higher B.P.A. content or have greater adipose stores of B.P.A.”
Steven G. Hentges, Ph.D., of the Polycarbonate/B.P.A. Global Group for the American Chemistry Council, said in response to the study, “Attempts to link our national obesity problem to minute exposures to chemicals found in common, everyday products are a distraction from the real efforts under way to address this important national health issue. Due to inherent, fundamental limitations in this study, it is incapable of establishing any meaningful connection between B.P.A. and obesity. In particular, the study measures B.P.A. exposure only after obesity has developed, which provides no information on what caused obesity to develop.
“The authors themselves state: ‘Obesity develops over time, and causation cannot be inferred from a cross-sectional association of urinary B.P.A. concentration…’ The authors further state that their work is ‘at best hypothesis generating,’ indicating that this study is speculative and might, at most, be the basis for conducting additional studies.
“More relevant to actual, real-world safety is the recent, robust research funded by the Environmental Protection Agency and conducted by scientists at the government’s Pacific Northwest National Laboratory, Centers for Disease Control and Prevention and Food and Drug Administration. Consistent with previous human and animal studies, the Pacific Northwest study indicates that, because of the way B.P.A. is processed in the body, it is very unlikely that B.P.A. could cause health effects at any realistic exposure level. Furthermore, regulators from Europe to Japan to the United States have recently reviewed hundreds of studies on B.P.A. and repeatedly supported the continued safe use of B.P.A.”