BPA and Obesity: Is This Connection Real?

A Best Evidence Review

Charles P. Vega, MD


January 14, 2013

In This Article

Description of the Study

Researchers examined data from the National Health and Nutrition Surveys between 2003 and 2008 in order to evaluate the relationship between urinary BPA concentrations and obesity. The current study focused on children and adolescents between the ages of 6 and 19 years, with 2838 subjects providing data for study analysis. The comprehensive nature of the survey allowed researchers to adjust their main study outcome to account for race/ethnicity, age, caregiver education, poverty-to-income ratio, sex, serum cotinine level, caloric intake, television watching, and urinary creatinine level. The cohort was fairly balanced in terms of sex and age, and 62.0% of participants were non-Hispanic white. The study featured children from a spectrum of family income levels.

Overweight among study participants was defined by sex- and age-adjusted z scores for body mass index (BMI) at or above the 85th percentile, while obesity was defined by a score at or above the 95th percentile. Using these definitions, 34.1% of the children in the current study were overweight, and 17.8% were obese.

The median urinary BPA concentration was 2.8 ng/mL. Non-Hispanic black children had higher median concentrations of BPA compared with white children, while Mexican American children had lower concentrations of BPA. BPA was also lower among children whose parents were at either extreme of educational attainment. Caloric intake and television viewing did not affect BPA levels.

The adjusted prevalence values for obesity were 10.3%, 20.1%, 19.0%, and 22.3% in each successive increasing quartile based on BPA concentration. Compared with the lowest quartile of BPA concentration, the respective odds ratios for obesity in each successively higher quartile were 2.22 (95% confidence interval, 1.53-3.23), 2.09 (1.48-2.95), and 2.53 (1.72-3.74), respectively. There was a similar interaction in examining the relationship between BPA quartiles and BMI z scores.

Further analysis demonstrated that BPA was a significant variable in predicting the risk for obesity among white children only. However, race and ethnicity did not affect the relationship between BPA and increasing BMI. The association between BPA and obesity was stronger among boys than girls. In addition, other urinary phenol metabolites were generally unrelated to the prevalence of obesity, which suggests a specific effect of BPA in promoting obesity.