(November 3, 2008 - Insidermedicine) A tentative link has been made between autism rates and the amount of precipitation that occurs annually in a particular region in research published in the Archives of Pediatrics & Adolescent Medicine.

Here is some information about autism:

•    It is a developmental disorder characterized by impaired social interaction, problems with verbal and nonverbal communication, and unusual, repetitive, or severely limited activities and interests.

•    Males are four times more likely to have autism than females.

•    No one knows the exact cause, but it is believed to be associated with a genetic susceptibility combined with unknown environmental triggers.

Researchers from Cornell University compared annual rates of autism in the states of Oregon, California, and Washington between 1987 and 1999 with precipitation rates in these same regions between 1987 and 2001.

In all three states, rates of autism in the year 2005 were higher in regions that received more precipitation between 1987 and 2001. In California and Oregon, children who were under three during years with relatively high amounts of precipitation had higher rates of autism. Autism is usually diagnosed in the first three years of life.

We had a chance to speak to Dr. Sean Nicholson, Cornell University, Department of Policy Analysis and Management, who offered some further insight.

Today’s research suggests there may be a link between autism and precipitation rates, possibly due to more time spent indoors or more direct environmental effects of precipitation. This link is far from certain but deserves further study.