Exposure to traffic-related air pollution during pregnancy and in infancy can double the risk of autism, according to a new study conducted by the University of Southern California and Children’s Hospital of Los Angeles. In addition, the researchers found that the increase in autism occurred even when the mother did not live near a busy road but was exposed to PM2.5 and PM10 on a regional level.
Heather Volk, lead author of the study and an assistant professor of preventive medicine at USC, said the study focuses attention on an area of growing concern for air quality researchers.
“We’ve known for a long time that air pollution is bad for our lungs, and especially for children,” Volk said in a press release. “We’re now beginning to understand how air pollution may affect the brain.”
The link between poor air quality and cognitive decline is a growing area of concern for those who study health and the environment. “Cognitive impairment is often a prelude to dementia,” says the Alzheimer Research Foundation.
The authors of the new research were careful to point out that the study does not prove that air pollution causes autism, but rather that it’s one important risk factor among many. “Autism is a complex disorder and it’s likely that there are many factors contributing,” Volk told a leading news magazine.
The USC/Children’s Hospital team is now shifting its focus toward genetic factors and risks that might make autistic children most susceptible to environmental influences. Autism occurs in one out of every 88 children, and was unheard of more than two generations ago. In the past six years, the rate of occurrence of autism has increased 78%.