Poor diets and sedentary lifestyles are known to contribute to the nation’s childhood obesity problem. But a new study has found a surprising new contributing factor: Prenatal exposure to air pollution.
The study, published in the American Journal of Epidemiology, is based on an analysis of pregnant women and their children in New York City. Researchers from Columbia University's Mailman School of Public Health found the women who were exposed to higher concentrations of chemicals called polycyclic aromatic hydrocarbons were more than twice as likely to have children who were obese by age 7 than unexposed women.
The chemicals are a common urban pollutant, caused by the burning of oil, fuel, gas, coal and even tobacco.
"Obesity is a complex disease with multiple risk factors. It isn't just the result of individual choices like diet and exercise," said lead researcher Dr. Andrew G. Rundle. "For many people who don't have the resources to buy healthy food or don't have the time to exercise, prenatal exposure to air pollution may tip the scales, making them even more susceptible to obesity."
For the study, researchers tracked 702 non-smoking pregnant women through prenatal clinics at NewYork-Presbyterian Hospital and Harlem Hospital. Children of women exposed to high levels of pollution during pregnancy were nearly twice as likely to be obese at age 5 and 2.26 times more likely to be obese at age 7, as those whose moms had lower levels of exposure.
Prior studies in animals have found pollutants cause gains in fat mass and may block the processes by which fat cells shed shrink in size.
Previous Columbia research found that prenatal exposure to pollutants can affect childhood IQs and is linked to anxiety, depression and attention problems in young children.