Toffins writes: A leading pediatrics journal has published a peer-reviewed paper on autism by Michael Waldman (lay summary) showing a link between mean annual precipitation and the prevalence of autism, and a further link showing proportionality between the amount of precipitation children under 3 years old are exposed to and subsequent rates of autism prevalence. The results from the cohort study suggest there is an environmental trigger for autism — that something linked with high rainfall, e.g. more time spent indoors, reduced vitamin D levels, increased exposure to household chemicals and fungal spores, or reduced social interaction, is partly responsible for autism in children who are genetically vulnerable to the disease. One of the co-authors, Dr. John Williams of the Department of Child and Adolescent Psychiatry at the Children's Hospital of Pennsylvania, said, 'These are provocative data that will generate a lot of discussion in the clinician and patient communities. Clearly, further study is required, especially given that many of the possible environmental triggers discussed may be avoidable or correctable.'.