Study Links Air Pollution to Autism and Schizophrenia

Exposure to air pollution early in life triggers harmful variations in the brain leading to autism and schizophrenia.

A study on mice model reveals that exposure to air pollution in early life causes changes in the brain including enlargement of a part of the brain as seen in humans who are diagnosed with autism and schizophrenia.  These changes mainly occur in males.  Due to the changes in the brain, these mice also fared worse on learning ability and impulsivity tests.

This study further supports the recent studies that highlight a strong correlation between air pollution and risk of autism in children. A study conducted last year showed how children residing in areas of with high levels of air pollution during the initial years of life had three-fold increased risk of 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," saidDeborah Cory-Slechta, Ph.D., professor of Environmental Medicine at the University of Rochester and lead author of the study.

In this study, the researchers conducted three experiments in which mice were exposed to various levels of air pollution that exist in U.S. cities. Just two weeks after birth the mice were exposed to pollution as this time is crucial for brain development.  They were exposed to pollution for four hours every day for two four day periods.

In the first group of mice, the researchers examined the brains for 24 hours after the final exposure to pollution. It was seen that in all the mice, inflammation was widespread throughout the brain and the lateral ventricle chambers on either side of the brain were two-three times bigger than the normal size

"When we looked closely at the ventricles, we could see that the white matter that normally surrounds them hadn't fully developed," said Cory-Slechta. "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."

The same problems were seen in the second group 40 days after being exposed to pollution and the third group 270 days after exposure. In all the three sets of mice, certain key factors were observed that are similar in humans with autism and schizophrenia like increased levels of glutamate.

"I think these findings are going to raise new questions about whether the current regulatory standards for air quality are sufficient to protect our children," said Cory-Slechta.

The finding was documented in the journal Environmental Health Perspective.