Published: Jun 12, 2013 | Updated: Jun 13, 2013
By Cole Petrochko , Staff Writer, MedPage Today
Action Points
- Higher urine concentrations of the plastic component bisphenol-A (BPA) in older girls were associated with a twofold risk of weight in the 90th percentile, a study found.
- Note that the relationship between urine BPA concentration and overweight was significantly linear.
In girls ages 9 to 12, a higher urine concentration of the plastic component bisphenol-A (BPA) was more likely to put them in the 90th percentile on weight charts, researchers found.
A urine BPA concentration of 2 mcg/L or greater was tied to more than twofold increased odds (adjusted OR 2.32, 95% CI 1.15-4.65) of having weight higher than the 90th percentile for age, according to De-Kun Li, MD, PhD, of Kaiser Foundation Research Institute in Oakland, Calif., and colleagues.
The relationship between urine BPA concentration and overweight was significantly linear (P=0.006), they wrote online in PLOS ONE.
The authors noted that “the rapid increase in the prevalence of obesity/overweight in countries with differing dietary styles and patterns of physical activity suggests the possible existence of other environmental risk factors,” which they labeled “environmental obesogens.” BPA has been identified as one such environmental obesogen due to animal studies that have linked exposure with obesity, they wrote.
The study analyzed the relationship between urine BPA concentration and obesity among 1,326 school-age children as part of a larger national Chinese study of adolescent pubertal development and health.
In addition to anthropometric measures and questions about development, the researchers added questions about obesity risks and collected additional urine samples, which were used to measure BPA concentrations. The authors also gathered data on weight, height, hip circumference, waist circumference, and skinfold thickness.
Overweight was defined as 90th percentile for age- and gender-specific weight distributions, but the authors also looked at the other physiologic measures and body mass index as indicators of overweight and obesity.
Participants also answered a 24-question food questionnaire and submitted information on physical activity, parental overweight, and depression inventory status.
Data were stratified by urine BPA concentration of less than 2 mcg/L and 2 mcg/L or greater, and by sex.
Among girls ages 9 to 12 — but not among boys or other age groups — high concentrations of BPA in urine were associated with 2.32-fold increased odds of being in the 90th percentile of weight after adjustment for age, gender, schooling, residence, parental and maternal education and overweight, video game playing, unbalanced diet, depression scores, physical activity, and other dietary factors.
When urine concentrations of BPA were stratified into percentiles among girls ages 9 to 12, those with the highest concentrations had significant five-fold adjusted odds of being in the 90th percentile of weight (aOR 5.18, 95% CI 1.68-15.91, P=0.006 for trend).
In a comparison between those with and without high concentrations of BPA in urine, high BPA concentration was significantly associated with larger hip circumference, though there were no other significant associations for size measures with BPA concentration.
The authors noted that the study was limited by pregnancy confounders, sample size, and taking a single sample of urine for BPA analysis. They also cautioned that future studies should frame a clear time between BPA exposure and obesity measurement, and should include a long-term follow-up.
The study was funded by the National Science Foundation of China.
The authors declared no conflicts of interest.
From the American Heart Association:
- Approaches to the Prevention and Management of Childhood Obesity
- Heart Disease and Stroke 2013 Statistical Update
Primary source: PLOS ONE