Women in the United States exposed to high levels of air pollution while pregnant were up to twice as likely to have a child with autism as women who lived in areas with low pollution, according to data from the Nurses Health Study II.
The study is described as the first large study to examine links between autism and air pollution across the United States.
“Our findings raise concerns since, depending on the pollutant, 20% to 60% of the women in our study lived in areas where risk of autism was elevated,” Andrea Roberts, the studys lead author and a research associate at the Harvard School of Public Health, said in a news release.
Exposure to diesel particulates, lead, manganese, mercury, methylene chloride and other pollutants are known to affect brain function and to affect the developing baby, according to the news release. For a study published June 18 on the website of the journal Environmental Health Perspectives, researchers examined data from the Nurses Health Study II, a long-term study based at Brigham and Womens Hospital involving 116,430 nurses that began in 1989.
Among that group, the authors studied 325 women who had a child with autism and 22,000 women who had a child without the disorder. Data showed that women who lived in the 20% of locations with the highest levels of diesel particulates or mercury in the air were twice as likely to have a child with autism as those who lived in the 20% of areas with the lowest levels.
Other types of air pollution — lead, manganese, methylene chloride, and combined metal exposure — were associated with higher autism risk as well. Women who lived in the 20% of locations with the highest levels of these pollutants were about 50% more likely to have a child with autism compared with those who lived in the 20% of areas with the lowest concentrations.
Most pollutants were associated with autism more strongly in boys than girls. However, since there were few girls with autism in the study, the authors said this finding should be examined further.
Download a PDF of the study: http://ehp.niehs.nih.gov/1206187.