Nov. 3, 2008 -- Children living in areas of high precipitation may be more likely to have autism, according to a new study, but the researchers caution that the finding of a rainfall-autism link is preliminary.

The finding may have nothing to do with the rainfall or snow itself, they say, but rather factors associated with the precipitation, such as the need to stay indoors more.

"Our results suggest there is an environmental trigger associated with precipitation," says Michael Waldman, PhD, the study's lead author and the director of the Institute for the Advancement of Economics at Cornell University in Ithaca, N.Y.

"I strongly believe it's not the precipitation itself," he tells WebMD. "My sense is, if truly there is an environmental trigger, my guess is it is one of the factors related to indoor activity." On that list: chemical exposure to indoor substances such as cleaning products, TV viewing, and vitamin D deficiency from too little sunlight.