More Evidence that Prenatal Exposure to Air Pollution Ups Autism Risk

Date: June 18, 2013
Nurses Health study supports earlier findings that exposure to air pollution during pregnancy increases baby’s risk of autism

Harvard researchers are reporting strong evidence that prenatal exposure to high air pollution can up to double the chance that a child will develop autism. The results – drawn from the large, nationwide U.S. Nurses Health Study – back those of previous studies suggesting this link. The report appears online today in Environmental Health Perspectives.

The researchers mined data from the Nurses’ Health Study II, which has tracked the health of 116,430 nurses since 1989. Within this group, they studied 325 women who had children with autism. For comparison, they tracked another 22,000 women whose children did not have the disorder.

The researchers used Environmental Protection Agency pollution tracking to estimate each mother’s exposure during pregnancy. They adjusted for the influence of factors such as income, education and smoking during pregnancy.

In particular, the researchers looked at pollutants known to affect brain development and function. These included air particulates, lead, manganese, mercury and methylene chloride.

The increased risk varied from 20 to 100 percent depending on the pollutant.

The women who lived in locations with the highest levels of air pollution particulates were twice as likely to have a child with autism as those who lived in areas with the lowest levels. Women exposed to the highest levels of other air pollutants were about 50 percent more likely to have a child with autism than those exposed to the lowest concentrations.
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