Air Pollutants Might Increase Risk of Autism

Children with autism spectrum disorders in the San Francisco Bay Area were 50% more likely than non-autistic children to be born in areas with higher estimated levels of toxic contaminants, a study released on Wednesday found, the Los Angeles Times reports.

The study, published online in the journal Environmental Health Perspectives, compared 284 children from six Bay Area counties who were diagnosed with autism disorders with 657 children in the counties are not autistic. All the children were born in 1994.

Researchers from the Department of Health Services reviewed data for 19 air pollutants that are known or suspected neurotoxins. The level of air pollution in the Bay Area is considered typical for urban areas.

According to the study, autistic children were 50% more likely to be born in areas with higher estimated levels of the metals mercury, cadmium and nickel and the chlorinated solvents trichloroethylene and vinyl chloride. Researchers did not find a significant link between autism and 14 other pollutants, including lead, benzene and chromium.

Researchers said the study "suggests that living in areas with higher ambient levels of hazardous air pollutants ... during pregnancy or early childhood may be associated with a moderately increased risk of autism." The authors also noted that the link found in the Bay Area is not certain and that more evidence is needed to determine whether air pollution can lead to autism.

Johns Hopkins University School of Public Health researchers are conducting a similar study in Baltimore (Cone, Los Angeles Times, 6/23).

The study is available online. Note: You must have Adobe Acrobat Reader to view the report.