Researchers at Pitt took a look at births in southwest Pennsylvania and found a link between exposure to chromium and styrene and autism.
The study is here. We’re going to do our best to summarize it below.
Who did the study?
The study leader is Evelyn Talbot. She’s an epidemiologist in the public health school at Pitt. Epidemiologists try to establish cause and effect for disease, but often, they are also looking for correlations – things that have a relationship to each other, but aren’t necessarily cause and effect. A correlation is what they say they have found in this paper.
Who was in the study?
Talbot’s team took a look at the medical history and talked to the moms of 217 children born between 2005 and 2009 who have a diagnosis on the autism spectrum. These kids live in Allegheny, Armstrong, Beaver, Butler, Washington or Westmoreland Counties. The researchers also looked at a similar number of children who weren’t on the autism spectrum and interviewed their moms. They also compared their findings to thousands of births in the area, but there were no interviews.
Um, 217 kids doesn’t seem like a lot. Is it?
Is 217 enough to do a study? The authors said that based on predictions of the number of children born in these counties in those years, they wanted to enroll about half the number predicted to have ASD (autism spectrum disorder). That would be 250 children. Pretty close!
How do you know the kids were exposed to anything?
The team used computer models based on pollution data collected by U.S. Environmental Protection Agency to predict the actual exposure of each kid in the study based on addresses during the study period. They looked at 30 different air toxics that are found in southwestern PA that have been known to effect development, our nervous systems or our hormone systems.
And they found what?
Of the 30 different air toxics they looked at (things like benzene, arsenic and lead), they found a pretty strong correlation between developing autism and exposure to styrene, an oily chemical that ends up in plastics and chromium, a metal that is sometimes used in steel production.
The study is just the beginning, but since we already know that exposure to pollution can impact children and adults, the authors think that following up with monitoring the levels of styrene and chromium in the air can give us more data to better understand individual outcomes. One surprising thing is that we have no autism registry in PA. Given the number of people studying the disorders, and the list of potential causes, the researchers are calling on the state, if not the nation, to start a registry.