NEW YORK (AP) -- A new study suggests a connection between the BPA chemical used in food packaging and childhood obesity. But the researchers say their findings don't prove BPA causes obesity.

Most people have traces of the plastics chemical in their bodies. The study found that children with the highest levels in their urine were twice as likely to be obese than those with the lowest.

The researchers say there are other factors that could explain the results, and many reasons why children gain too much weight including a bad diet and lack of exercise.

The American Chemistry Council called the study speculative and noted lab animal studies that found no evidence that BPA causes obesity.

The study was published in Wednesday's issue of the Journal of the American Medical Association.