Traffic Air Pollution may Increase Autism Risk

Exposure to air pollution while in the mother's womb or during the early stages after birth can increase the risk of developing autism, a new study says.

Autism spectrum disorder (ASD) is a developmental disorder that leads to significant social, communication and behavioral changes.

Researchers from University of Southern California (USC) and Children's Hospital Los Angeles found maternal exposure to traffic air pollution or exposure in infancy carrying a twofold risk of developing autism. Apart from that, maternal exposure to nitrogen dioxide (NO2) and small particles were also found playing an important role in escalating autism risks.

"This work has broad potential public health implications," Dr. Heather Volk, the study's principal investigator, said in a news release. "We've known for a long time that air pollution is bad for our lungs, and especially for children. We're now beginning to understand how air pollution may affect the brain."

For the study, researchers looked at nearly 280 autistic children and 245 children without the disorder. Adopting various methods, the researchers measured and recorded exposure to traffic air pollution and nitrogen dioxide of the participants, before and after birth.

"We took into account how far away people lived from roads, meteorology such as which way the wind was blowing, how busy the road was, and other factors to study traffic-related pollution," she said. "We also examined data from air quality monitors, which measure pollution over a larger region that could come from traffic, industry, rail yards, or many other sources."

Results of the study have been published in the Archives of General Psychiatry.

Previous studies have shown many health risks associated with exposure to traffic pollution. According to a study published in Endocrine Society's Journal of Clinical Endocrinology and Metabolism (JCEM), exposure to air pollution during pregnancy can increase the risks of giving birth to a baby with vitamin D deficiency. Vitamin D is essential for bone growth and a deficiency can lead to many diseases including rickets, a bone-softening disease found in young children.

Another study published in the Journal of Epidemiology & Community Health found traffic pollution during pregnancy leading to maternal pre-eclampsia. Pre-eclampsia is a condition that triggers hypertension and will have a negative impact on both expecting mothers and their babies.