Poor diet and lack of exercise might not be the only factors contributing to the obesity epidemic. A new study suggests the environment may also play a role.

“Eating too much and exercising too little are important factors,” said Dr. De-Kun Li, a reproductive and perinatal epidemiologist at Kaiser Permanente in Oakland, California. “But they cannot explain the steep increase in the obesity rate the last three decades. We haven’t really changed our eating habits and exercise that much.”

The environmental culprit, according to the study published Wednesday in the journal PLOS ONE, may be bisphenol-a, a chemical commonly found in plastic and cans.

Li and colleagues studied 1,326 school-age children in Shanghai, China, and measured BPA levels in their urine. In girls ages 9 to 12, higher BPA urine levels were associated with a doubled risk of obesity. And as BPA urine levels increased, so did the girls’ obesity risk - measured using their weight in reference to weight distribution in the population. FULL POST