Autism higher in rainy Northwest areas

WASHINGTON - Children who live in the Northwest's wettest counties are more likely to have autism, but it is unclear why, US researchers reported yesterday.

Michael Waldman of Cornell University and colleagues were searching for an environmental link with autism, a condition characterized by learning and social disabilities.

They got autism rates from state and county agencies for children born in California, Oregon, and Washington between 1987 and 1999 and plotted them against daily precipitation reports.

"Autism prevalence rates for school-aged children in California, Oregon, and Washington in 2005 were positively related to the amount of precipitation these counties received from 1987 through 2001," they wrote in the Archives of Pediatrics & Adolescent Medicine.

Dr. Michael Fitzpatrick, a London physician who wrote "Defeating Autism: A Damaging Delusion," expressed doubt, noting that autism diagnoses are on the rise in all climates.

No one knows what causes autism, which has symptoms that may include severe social avoidance, repetitive behaviors, and mental retardation.

Doctors agree that there is a genetic component to autism. They also theorize that something in the environment and possibly conditions in the womb can trigger the condition.

The researchers noted that infants and toddlers are kept indoors in front of the television more in rainy climates, and that may cause brain changes. Or perhaps they breathe in more harmful chemicals while indoors. Vitamin D deficiency caused by insufficient time in the sun might also be a trigger.

REUTERS