Exposure to high levels of air pollution during pregnancy can contribute to the development of autism spectrum disorder in children.
Autism spectrum disorder (ASD) is a development disorder that leads to significant social, communication and behavioral changes. A latest report from the Centers for Disease Control and Prevention (CDC) states that one in every 50 school children in the U.S. is affected with autism.
For the study, a team of researchers from Harvard School of Public Health (HSPH) used data from Nurses' Health Study II that included more than 116,400 participants. Of the total women, researchers selected 325 mothers who had an autistic child and 22,000 mothers who had children without the condition.
Using data from the U.S. Environmental Protection Agency, researchers measured the women's exposure to air pollution during pregnancy. Other autism-contributing factors like the habit of smoking were also taken into consideration.
Researchers found that women, who lived in areas with high levels of diesel particulates or mercury in the air, had double risks of giving birth to an autistic child than women who lived in an area with lower levels of air pollution. Additionally, exposure to lead, manganese, methylene chloride or a combination of all these metals in the air determined a 50 percent higher risk of having an autistic child.
Another interesting find of the study was the link between air pollution, autism and differences in gender of the children. Boys who were exposed to air pollutants while in their mothers' wombs were found to be at a greater risk of developing autism than girls. However, according to the researchers, the factor has to be re- examined as their study included only a few girl children.
Researchers are now worried with the findings and hope to study the subject in detail to prove the link between autism and air pollution.
"Our results suggest that new studies should begin the process of measuring metals and other pollutants in the blood of pregnant women or newborn children to provide stronger evidence that specific pollutants increase risk of autism. A better understanding of this can help to develop interventions to reduce pregnant women's exposure to these pollutants," senior author Marc Weisskopf, said in a news release.
The findings of this study were published online in the Environmental Health Perspectives. This study supports a previous research published in the Archives of General Psychiatry.
That study found that maternal exposure to traffic pollution (air) doubles the risk of developing autism. Apart from that, maternal exposure to nitrogen dioxide (NO2) and small particles also played an important role in escalating autism among children.
Previous studies have also shown that several other factors like the use of anti-epileptic drug, Valproate during pregnancy, abuse in childhood, maternal fever, maternal deficiency of vitamin D, low or high birth weight and early exposure to heavy metals like lead and mercury contributed effectively to autism.
