Researchers from the University of Southern California have released the results of a study that may strengthen the link between air pollution and autism but has prompted immediate calls for caution in embracing the connection.
Children with autism were exposed to car exhaust, smog and other air pollution two to three times more than other children during pregnancy and the first year of life. However, researchers emphasized that this does not prove that air pollution causes autism.
The study analyzed a group of 524 Californian children, 279 with autism and 245 with typical development. Each mother supplied her address for each home in which she lived during the 21 months of pregnancy and first-year life of the child.
The researchers calculated the traffic volume, vehicle emissions, wind patterns and amount of pollutants such as particulate matter, nitrogen oxide and ozone to reach each child’s likely exposure. Kids with autism were far more likely to be in the top 25% of pollution exposure than those in the bottom 25%.
Lead author Dr. Heather Volk, Assistant Professor of Preventive Medicine, released a study on this topic back in 2010.
Critics of the study were swift to point out several shortcomings, including the lack of any data related to the mothers’s work locations, amount of time spent outdoors and the fact that air pollution is at a ten-year low.
The findings were published online in the Archives of General Psychiatry.