Autism rates may be higher than thought

In a South Korea study, the first to take a broad look at the prevalence of autism spectrum disorders, researchers find one case in every 38 children. The incidence may be similar in the U.S.

 The incidence of autism may be much higher than previously thought in the United States and elsewhere in the world, according to a rigorous, comprehensive study of the condition conducted in South Korea, researchers reported Monday.

In the first study to take a broad-population look at the prevalence of autism spectrum disorders — types of autism ranging from severe symptoms to the milder Asperger's syndrome — researchers found a rate of 2.64% among South Korean children. That's 1 in 38 children, a rate far higher than the estimate of 1 in 110 children for the U.S. by the Centers for Disease Control and Prevention.

The study, being published Monday in the American Journal of Psychiatry, suggests that, under rigorous examination, many more children may be affected than previously suspected.

The study "is different in the sense that they are screening the entire population of children" including those who have never been flagged with a potential problem, said Geraldine Dawson, chief scientific officer of the research and advocacy group Autism Speaks and an autism researcher at the University of North Carolina at Chapel Hill. "It raises a question, I think, of whether we are underestimating the prevalence in the U.S. as well as elsewhere."

The five-year study, funded partly by Autism Speaks and led by Dr. Young-Shin Kim of the Yale Child Study Center, differed significantly in methodology from earlier autism-prevalence studies. This likely accounts for the dramatically different findings, Kim said.

Previous studies assessing population-wide autism rates typically focused on high-risk populations — such as classrooms of special education students. In contrast, the study conducted in South Korea assessed more than 55,000 children, ages 7 to 12, not only from special education classrooms and mental health service organizations but also regular schools.