Dramatic rise in autism prevalence parallels research explosion

"This issue of the journal features three articles on autism," she writes in her editorial. "A decade ago, the journal published about the same number of autism articles per year."

Dr. Dawson also notes that, while the funding for autism research has dramatically increased over the last decade, it hasn't kept pace with the increasing scale of the public health challenges posed by autism.

Despite an increase in research and funding, "we yet to fully describe the causes of ASD or developed effective medical treatments for it," Dr. Dawson writes. "[This issue's] articles point to an urgent need for more research on prenatal and early postnatal brain development in autism, with a focus on how genes and environmental risk factors combine to increase risk for ASD."

In one of the three articles, scientists report a three-fold increase in autism risk associated with exposure to traffic-related air pollution during pregnancy and the first year of life. The study's lead author, Heather Volk, Ph.D., M.P.H., is the recipient of an Autism Speaks research grant to study autism risk and gene-environment interactions involving air pollution. (Free full text here.)

A second report confirms an association between autism and changes in immune function. The study is the first to use new brain imaging techniques to demonstrate immune function changes in adults with autism. Specifically, it looked at microglial activation in the brain. Microglial cells are the brain's first and primary immune defense.

The third study used magnetic resonance imaging (MRI) to examine the size of the cerebral cortex (cortical volume) in ASD. It compared the cortical volume of young men on the autism spectrum with that of their unaffected peers. The study's key finding is that autism-associated differences in brain volume reflect differences in surface area, not cortical thickness. This sheds light on mechanisms that might account for early brain overgrowth in individuals with ASD.

"More research is needed to develop strategies for preventing or reducing the disabling symptoms associated with this highly prevalent and costly neurodevelopmental disorder," Dr. Dawson concludes.