Girls ages 9 to 12 with higher-than-average levels of bisphenol-A in their urine had double the risk of being obese compared with girls with lower levels of BPA, according to a Chinese study.
“This study provides evidence from a human population that confirms the findings from animal studies that high BPA exposure levels could increase the risk of overweight or obesity,” De-Kun Li, MD, PhD, principal investigator of the study and a reproductive and perinatal epidemiologist at the Kaiser Permanente Division of Research in Oakland, Calif., said in a news release.
BPA, used to make plastics and other materials, is a known endocrine disruptor with estrogenic properties. In children and adolescents, BPA is likely to enter the body primarily through the ingestion of foods and liquids that have come into contact with BPA-containing materials, Li said.
“Girls in the midst of puberty may be more sensitive to the impacts of BPA on their energy balance and fat metabolism,” Li said. Although BPA continues to be examined, he said it has been shown to interfere with a body’s process of relating fat content and distribution.
The study published June 12 in the open-access journal PLOS One and described as the first study specifically designed to examine the relationship between BPA and obesity in school-age children was conducted in Shanghai as part of a larger national study of puberty and adolescent health.
Li and colleagues studied 1,326 male and female children in the fourth through 12th grades at three Shanghai schools (one elementary, one middle and one high school). In addition to urine samples collected (using BPA-free materials), they obtained information on other risk factors for childhood obesity, such as dietary patterns, physical activity, mental health and family history.
The researchers found that in girls ages 9 to 12, a higher-than-average level of BPA in urine (2 micrograms per liter or greater) was associated with twice the risk of having a body weight in the top 10th percentile for girls of their age in the same population.
The impact was particularly pronounced among 9- to 12-year-old girls with extremely high levels of BPA in their urine (more than 10 micrograms per liter): Their risk of being overweight in the top 10th percentile was five times greater.
The researchers did not identify significant BPA effects in any other groups studied, including girls older than 12 and boys.
Among all the 9- to 12-year-old girls studied, 36% of those with a higher-than-average level of BPA in their urine were overweight or obese, compared with 21% of those with a lower-than-average level of BPA.
“Our study suggests that BPA could be a potential new environmental obesogen, a chemical compound that can disrupt the normal development and balance of lipid metabolism, which can lead to obesity,” the authors wrote. “Worldwide exposure to BPA in the human population may be contributing to the worldwide obesity epidemic.”
Read the study: www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0065399.