Girls exposed to Bisphenol A (BPA) before birth are more likely to develop hyperactivity and have a leaner body mass, a new study finds.
BPA is a chemical found in the lining of food cans and cash register receipts. It once was in many hard plastic bottles, including baby bottles, but many companies have removed it as concerns about exposure have come to light in recent years.
These latest findings from University of Michigan School of Public Health seem to contradict previous studies on BPA that found the chemical to be a factor in obesity, the Journal of the Federation of American Societies for Experimental Biology reports.
But Dana Dolinoy, assistant professor of environmental health sciences and study co-author, says research shows that many factors impact how the body reacts to the chemical, according to a Michigan statement.
"Our hypothesis going into this study was that BPA would act as an obesogenic (obesity promoting) agent. And there is some preliminary evidence that it does," Dolinoy said.
"But there are differences in exposure, duration and when you actually measure the individual.
"Recent evidence in humans only looks at one time point. What we're really interested in is BPA exposure during early development, and how that affects health throughout life. So those are two very different questions."
Researchers exposed mothers to three different levels of BPA in the diet then followed the offspring through adulthood at three, six and nine months of age. The average lifespan of a mouse is two years, so by three months they are young adults.
"I think the most striking result we saw was the increased activity in these animals," said Olivia Anderson, doctoral student in Michigan environmental health sciences, who led the study.
As to why only females exhibited the excessive activity and lean bodies, Dolinoy said it bears more study, but because BPA is known to impact estrogen and thyroid hormone, most likely it is affecting these natural hormones in the females.