More Evidence Links BPA to Childhood Obesity
Study finds preteen girls who had high levels of common chemical were twice as likely to be overweight
In laboratory studies, BPA produces many of the molecular hallmarks of obesity. It makes fat cells bigger, it blocks the function of a protein called adiponectin, which protects against heart disease, and it disrupts the balance of testosterone and estrogen -- hormones that are important for maintaining a healthy body mass.
One expert found the study results troubling.
"Clearly, unhealthy diet and physical activity are still the leading causes of the childhood obesity epidemic worldwide, but this study adds further concern to the notion that environmental chemicals may be independent contributors," said Dr. Leonardo Trasande, an associate professor of pediatrics, environmental medicine and health policy at NYU Langone Medical Center, in New York City.
In a study of more than 2,800 U.S. children published last year in the Journal of the American Medical Association, Trasande reported that boys and girls who were exposed to higher levels of BPA were more likely to be obese than those exposed to lower levels of the chemical. That was true even after they took into account how many calories kids ate, how much TV they watched and household income.
Still, he said, neither of these studies can prove that BPA causes children to become obese. One explanation could be that obese kids eat more packaged and processed foods, which in addition to having more fat and calories could also contain more BPA. Another explanation is that obese kids may have higher levels of BPA because the chemical is stored in body fat, Trasande said.
Other studies that follow children as they grow are needed to clarify the nature of the association.
The American Chemistry Council, a trade group that represents the interests of the chemicals industry, said in a statement that the new study did little to shed light on the true causes of childhood obesity.
"Attempts to link our national obesity problem to minute exposures to chemicals found in common, everyday products are a distraction from the real efforts underway to address this important national health issue," the statement from the council said. "Due to inherent, fundamental limitations in this study, it is incapable of establishing any meaningful connection between BPA and obesity. In particular, the study measures BPA exposure only after obesity has developed, which provides no information on what caused obesity to develop, a limitation noted by the study's authors."