Autism and highways

by Russ Roberts on January 20, 2011

in Health

Love the scientism of this article:

There are many reasons why living near a highway is undesirable — the noise, the poor air quality, the endless stream of lost tourists using your driveway to turn around. But a new study published in Environmental Health Perspectives offers another: children who lived near highways at birth had twice the risk of autism as those who live farther way.

Researchers interviewed and examined 304 children with autism and, as a control, 259 typically developing children in the Los Angeles, San Francisco and Sacramento metropolitan areas. Researchers found that children whose families lived within 1,000 feet from a freeway at birth — about 10% of the children in the study — were twice as likely to have autism as those who lived farther from a highway.

The link held up after controlling for other variables such as maternal age, parental education and smoking. Interestingly, however, the same effect did not apply to kids who lived near other heavily trafficked streets. The researchers theorized that the type and sheer quantity of chemicals distributed on highways are different from those on even the busiest city roadways.

“This study isn’t saying exposure to air pollution or exposure to traffic causes autism,” lead author Heather Volk, researcher at the Saban Research Institute of Children’s Hospital Los Angeles, told the Los Angeles Times. “But it could be one of the factors that are contributing to its increase.”

Or it could not be. Very hard to tell from this article or the study, which is here. To say that the link “held up” after controlling for a few variables is not much holding up. My favorite line from this story is this one:

The researchers theorized that the type and sheer quantity of chemicals distributed on highways are different from those on even the busiest city roadways.

Don’t you love that word “theorized?” That is not the right word. There is no theory. In fact, the finding that living near busy city roads is uncorrelated with autism shows that the central claim of the study has been refuted. This is how the paragraph should have been written:

The researchers could only hope in desperation that the type and sheer quantity of chemicals distributed on highways are different from those on even the busiest city roadways. Otherwise, their finding is meaningless.

Be Sociable, Share!

Comments

comments

36 comments    Share Share    Print    Email

Previous post:

Next post: