RALEIGH, N.C. – Pre-birth exposure to a chemical widely used in plastics appears to be linked to more aggressive behavior in little girls, according to research published Tuesday by a scientist at the University of North Carolina-Chapel Hill.
The findings, which are preliminary and call for more study, are the first to connect behavior problems in humans with the chemical bisphenol A, which is a key component of plastic bottles, the liners inside canned goods and medical devices.
The chemical leaches from plastic and is detectable at some level in nearly everyone’s system. Scientists began to raise concerns about BPA because of its tendency to mimic estrogen – a hormone that plays a crucial role in establishing the sex differences in the brains of developing fetuses.
Studies in mice have shown fetal BPA exposure can abolish or reverse inherent behavioral differences between the sexes – specifically, females act more aggressive – and those studies prompted questions about what the chemical does to humans.
Joe Braun, a doctoral student in epidemiology at the UNC-CH Gillings School of Global Public Health and one of the authors of the aggression study in the journal Environmental Health Perspectives, said researchers began examining the effects of BPA two years ago with a group of pregnant women enrolled in a larger study into lead.
The researchers measured BPA levels in urine samples from 249 women at three different times during their pregnancies: At 16 weeks, 26 weeks and birth. Later, they observed the women’s children at age 2, using a standard behavioral test.
They found that women who had the highest concentrations of BPA at 16 weeks of pregnancy were inclined to have more aggressive, hyperactive 2-year-old daughters. There was no statistically significant change of behavior among the boys, although there was some evidence of heightened anxiety and depression.
“It’s an intriguing finding that suggests the need for more research in this field, especially with prenatal exposure and the timing of exposures,” Braun said.