Researchers didn’t see any differences by age groups. And, while the black children had higher levels of phthalates as a whole, the association with obesity happened at relatively low levels of exposure, Trasande said. The study used data from the U.S. Centers for Disease Control and Prevention’s 2008 nationwide testing of chemicals in people’s bodies.
It’s possible black children are simply more exposed, or they metabolize the chemicals differently, said Emily Barrett, a professor at the University of Rochester who studies exposure to environmental chemicals.
Many factors – including nutrition and stress – could alter how different children metabolize chemicals, said Jennifer Adibi, an epidemiology professor at the University of California, San Francisco.
In a study released late last year by Trasande and colleagues, another hormone disrupting chemical – bisphenol A – was linked to obesity in only white children.
Trasande controlled for diet, television watching, gender and age in the phthalate study. Pinning chemicals to weight gain is a challenge, but the study forces some new thinking about obesity, he said.
The next research step is to look at phthalate exposures from fetus to childhood to try to tease out whether the chemicals are contributing to obesity, he said.
Adibi said the findings are “interesting and scary.” While it’s not enough evidence to spur policy changes, she hopes it will reframe the conversations about risks to disadvantaged communities.
“This is another reason to increase awareness among low income, African American and Hispanic populations and let them know they’re at an increased risk of exposure to these chemicals and that we’re seeing these associations (with obesity),” Adibi said.
This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.