South Korean study suggests many missed diagnoses in general population
A South Korean study that directly screened schoolchildren for autism spectrum disorder (ASD) revealed a prevalence of 1 in 38 children, or 2.6 percent. Two-thirds of the affected children were in mainstream classrooms, previously undiagnosed and receiving no services.
The finding, published in the American Journal of Psychiatry, raises the possibility that the current CDC estimate of autism prevalence in the United States (1 in 110 children, or about 1 percent) may be a considerable underestimate. The U.S. estimate is based on reviews of medical records, rather than the Korean study’s method of direct screening and case confirmation of children in the general community.
The South Korean study covered a wide-ranging population and used gold standard screening and diagnostic tools. Led by Young Shin Kim, M.D., Ph.D., of Yale School of Medicine, it was the first to attempt a rigorous estimate of autism prevalence in the general South Korean population and among the first such prevalence survey outside North America and Europe. It included about 55,000 schoolchildren between the ages of 7 and 12 living in a residential community near the capital city of Seoul. The researchers first screened for autism using parent and teacher questionnaires, then used standardized diagnostic methods to evaluate the children who screened positive.
The findings stress the need for improved and wider autism screening among the general population, the researchers concluded, especially among younger age groups, as early diagnosis and intervention have been shown to improve outcomes. Goyang City, where the study was conducted, now offers autism assessment and intervention services for all children entering first grade.
The study was funded in part by Autism Speaks, which is now working with the CDC to implement a study of community screening in the United States. Even at the current estimate of ASD affecting 1 in 110 US children, more children will be diagnosed with autism in the coming year than with childhood cancer, juvenile diabetes and pediatric AIDS combined.
Kim YS, Leventhal BL, Koh YJ, et al. Prevalence of autism spectrum disorders in a total population sample. Am J Psychiatry. 2011 Sep;168(9):904-12.
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