Many plastic containers such as water jugs, bottles, and food containers contain a compound termed bisphenol A (BPA) that is used as a coating to protect the lining. BPA is also used in some dental fillings and for the restoration of tooth cavities. Recently, there has been much controversy regarding the safety of the compound when humans are exposed at a low level. BPA has some hormonal effects and can cause metabolic derangements. Animal studies have shown that it can cause developmental problems in the genito-urinary tract, effect prostate and breast tissue, and produce aggression and hyperactivity. We have recently discussed the finding that dental fillings containing BPA are associated with behavioral problems in children. In Canada and Europe, BPA is considered toxic and the use of BPA in baby bottles is banned. The United States Food and Drug Administration (FDA) has also recently banned the use of BPA in baby bottles and sippy cups. Regardless of the ban in baby products, BPA continues to be used in other products where it can exert its negative health effects on humans.
Researchers, led by Dr. Leonardo Trasande from New York University School of Medicine, have found that bisphenol A is associated with childhood obesity. The results of their study were published online in the Journal of the American Medical Association. The researchers conducted a cross-sectional analysis of 2,838 study participants aged 6 through 19 years who were enrolled in the National Health and Nutrition Examination Surveys. The study participants were tested for urinary BPA concentration. Body mass index converted to sex and age standardization was used to determine those who were overweight and obese. The researchers found that urinary BPA concentration was significantly associated with obesity in children and adolescents. Even after controlling for confounding variables (race/ethnicity, age, caregiver education, poverty to income ratio, sex, serum cotinine level, caloric intake, television watching, and urinary creatinine level) the association remained for white children, but not for blacks or Hispanics.
The authors wrote, “To our knowledge, this is the first report of an association of an environmental chemical exposure with childhood obesity in a nationally representative sample. The association was evident when exposure and outcome were modeled in a number of different ways. For example, compared with the lowest quartile of urinary BPA concentration, values in the second, third, and fourth quartiles showed a substantial elevation in the odds of obesity, controlling for an array of potential confounders”.
The authors theorized, “Obese children may drink more canned or bottled beverages, or eat more canned food, and thus have higher urinary BPA levels. Similarly, although we adjusted for excessive caloric intake and television watching —2 lifestyle-associated risks for childhood obesity—it may be that sedentary children consume foods high in BPA. Obese children could also have higher urinary BPA concentrations because BPA is stored and released from adipose tissue. We cannot rule out these alternative explanations in a cross sectional design”.
The authors concluded, “Advocates and policy makers have long been concerned about BPA exposure. We note the recent FDA ban of BPA in baby bottles and sippy cups, yet our findings raise questions about exposure to BPA in consumer products used by older children. Last year, the FDA declined to ban BPA in aluminum cans and other food packaging, announcing ‘reasonable steps to reduce human exposure to BPA in the human food supply’ and noting that it will continue to consider evidence on the safety of the chemical”.
This study highlights an association with childhood obesity and BPA, but it does not provide evidence for a cause and effect relationship. Taken together with previous findings of the negative health consequences of BPA exposure, this study adds to the evidence that BPA is harmful to both children and adult. The health effects of BPA should be investigated even further. Future studies may provide substantial evidence of a causal relationship for the negative health effects of BPA. Additional studies may influence the FDA to place more strict regulation on the use of BPA or even ban its use as has occurred in both Canada and Europe.
Leonardo Trasande el al. “Association Between Urinary Bisphenol A Concentration and Obesity Prevalence in Children” JAMA 2012;308(11):1113-1121. doi:10.1001/2012.jama.11461