Incidence of Autism Spectrum Disorders Underestimated

A total of 2.64 percent of South Korean school children found to have autism spectrum disorders

MONDAY, May 9 (HealthDay News) -- Autism spectrum disorders (ASD) may be more prevalent in children than previously estimated and are found in children in mainstream schools as well as special education schools, according to a study published online May 9 in The American Journal of Psychiatry.

Young Shin Kim, M.D., Ph.D., from the Yale University School of Medicine in New Haven, Conn., and colleagues estimated the prevalence of ASD in 55,266 children aged 7 to 12 years in a South Korean community, and described its clinical characteristics. ASD was identified using the Autism Spectrum Screening Questionnaire for systematic, multi-informant screening in a high-probability group from special education schools and a disability registry and a low-probability, general-population sample from regular schools. Comprehensive evaluations using standardized diagnostic procedures were offered to parents of children who screened positive.

The investigators estimated that the total ASD prevalence of 2.64 percent included 1.89 percent from the general-population and 0.75 percent from the high-probability group. The ASD male-to-female ratios were 2.5:1 and 5.1:1 in the general and high-probability groups, respectively. The ratios of autistic disorders to other ASD subtypes were 1:2.6 and 2.6:1 in the general population and high probability groups, respectively. Superior IQs were seen in 12 percent of children in the general-population sample and 7 percent in the high-probability group, and intellectual disability was found in 16 percent of children in the general-population sample and 59 percent in the high-probability group.

"There is a striking difference between our estimated prevalence of 2.64 percent for any ASD and previously reported estimates ranging from 0.6 to 1.8 percent," the authors write.

Several authors have served as expert witnesses for autism vaccine trials for the U.S. Departments of Health and of Justice, and for GlaxoSmithKline.

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