Every few weeks, a new research study makes headlines elucidating a possible link to autism. The cause du jour last Monday was air pollution.
The study, which was published online in the Archives of General Psychiatry, found that children with autism were three times as likely to have been exposed to high levels of air pollution, either prenatally or during their first year of life, compared with a control group of kids who didn't have autism.
The researchers couldn't prove that air pollution caused autism even though they controlled for other lifestyle factors that might have skewed their findings: a mother's lack of education, socioeconomics, and whether living in a city with plenty of psychologists who diagnose autism made a diagnosis more likely.
And the study authors weren't able to directly measure the levels of pollutants that the mothers were exposed to during their pregnancies or shortly afterward, instead relying on previous weather data and traffic volume to estimate emission rates in particular geographic areas where the women were living at the time.
While all of these caveats don't necessarily invalidate the findings, they do point to a larger issue: the need for better designed, better funded studies to determine what's leading to the rise in autism in American children.