Besides causing respiratory diseases, air pollution also increases the risk of autism and schizophrenia, according to a University of Rochester study.
Researchers say that air pollution exposure during early stages of life leads to inflammation of a region of the brain that is normally seen in patients suffering from autism and schizophrenia. The harmful changes in the brain predominantly occurr in males.
For the study, the researchers conducted three experiments on mice, where they were exposed to air pollution levels similar to the levels emitted during rush hour in mid-sized U.S. cities. The experiments were conducted during the first two weeks after birth, a crucial time in the brain's development, for four hours each day for two four-day periods.
In one group of mice, the brains were analyzed 24 hours after the pollution exposure. The researchers observed inflammation throughout the brain with lateral ventricles bloating up two-to-three times more than their normal size.
"When we looked closely at the ventricles, we could see that the white matter that normally surrounds them hadn't fully developed," Deborah Cory-Slechta, Ph.D., professor of Environmental Medicine and lead author of the study, said in a press release. "It appears that inflammation had damaged those brain cells and prevented that region of the brain from developing, and the ventricles simply expanded to fill the space."
Permanent brain damage was also observed in the second and third groups of mice that were examined 40 and 270 days after exposure to air pollution.
Mice from all the three groups showed heightened levels of glutamate, which is also noticed in humans with autism and schizophrenia. The rodents were associated with poor performances in tests related to short-term memory, learning ability and impulsivity.
The findings support the conclusions of previous studies that showed a link between air pollution and autism in children. A 2013 study in JAMA Psychiatry found that children exposed to high levels of traffic-related air pollution during their first year of life were three times more likely to develop autism.
"Our findings add to the growing body of evidence that air pollution may play a role in autism, as well as in other neurodevelopmental disorders," said Cory-Slechta.
The findings are published in the journal Environmental Health Perspectives.
