Air Pollution May Double the Risk of Autism

Pregnant women who are exposed to relatively higher levels of the fine particulate matter in air pollution can have twice the risk of having a child with autism, according to a study from Harvard School of Public Health published in Environmental Health Perspectives. The researchers reported a direct link between increasing exposure to air pollution and increasing risk.

Although previous, smaller studies have found similar links, according to a Harvard School of Public Health press release this is the first U.S.-wide study to explore the link between airborne particulate matter and autism. “The study population included offspring of participants living in all 50 states in Nurses’ Health Study II, a cohort of more than 116,000 female U.S. nurses begun in 1989,” stated the press release. “The researchers collected data on where participants lived during their pregnancies as well as data from the U.S. Environmental Protection Agency and other sources on levels of fine particulate matter air pollution… The researchers identified 245 children who were diagnosed with autism spectrum disorder (ASD) and a control group of 1,522 children without ASD during the time period studied.”

“Our data add additional important support to the hypothesis that maternal exposure to air pollution contributes to the risk of autism spectrum disorders,” study co-author Marc Weisskopf said in the press release. “The specificity of our findings for the pregnancy period, and third trimester in particular, rules out many other possible explanations for these findings.”

Reuters reported that, “U.S. diagnoses of autism soared to one in 68 children in 2010 (the most recent data) from one in 150 in 2000… Experts are divided on how much of the increase reflects greater awareness and how much truly greater incidence. It is not clear how tiny particles might cause autism, but they are covered with myriad contaminants and penetrate cells, which can disrupt brain development.”

“Last year the Environmental Protection Agency, citing the link to asthma, lung cancer and cardiovascular disease, tightened air quality standards for fine particulate pollution,” reported Reuters. “States have until 2020 to meet the new standards.”

Fine particulate air pollution linked with increased autism risk (Harvard School of Public Health press release, December 18, 2014)

Autism risk linked to particulate air pollution (Reuters, December 18, 2014)

(Abstract) (Full text) Autism Spectrum Disorder and Particulate Matter Air Pollution before, during, and after Pregnancy: A Nested Case–Control Analysis within the Nurses’ Health Study II Cohort (Raz, Raanan et al. Environmental Health Perspectives. December 2014. DOI:10.1289/ehp.1408133)