Autism Underdiagnosed Suggests South Korean Study


While previous studies have suggested autism affects about 1 in every 110 children in the United States, a new study estimates the prevalence of autism spectrum disorders in South Korea to be about 1 in 38 children. This finding suggests autism has been underdiagnosed and underreported, and may lead to an increase in the number of autism cases diagnosed.

Autism is a major worldwide concern

A collaborative team of researchers from South Korea, Canada, and the United States conducted a comprehensive of the prevalence of autism based on a total population sample of approximately 55,000 children ages 7 to 12 years. Children from both general and special education schools were included, as well as those from the disability registry.

This is the first time such a population-based study has been conducted for autism, and one reason such studies have been lacking is a lack of universal diagnostic criteria for autism spectrum disorder (ASD) as well as incomplete epidemiologic studies, according to Young Shin Kim, MD, MS, MPH, PhD, of the Yale Child Study Center. She and her team found that more than two-thirds of cases of autism spectrum disorder within the mainstream school population had gone unidentified and untreated.


Dr. Kim noted that this study allowed them “to find more children with ASD and describe the full spectrum of ASD clinical characteristics.” While other recent studies have shown that reasons for the greater prevalence of ASD may be attributed to increased awareness by the public and an expansion of diagnostic criteria, this new study “suggests that better case finding may actually account for an even larger increase.”

The study, which was funded by Autism Speaks, the world’s largest autism science and advocacy organization, was conducted in such a manner as to reduce cultural bias and so, despite the findings, does not indicate the South Korean children have more autism than other populations around the world. However, cultural factors may have an effect on diagnostic approaches and prevalence estimates.

To explore all of these factors further, Autism Speaks is supporting similar research into ASD in other countries, including India, Mexico, South Africa, and Taiwan. Geraldine Dawson, PhD, chief science officer for Autism Speaks, noted that the South Korean study “is the first comprehensive population sample-based prevalence calculation in Korea, and replication in other populations is essential.”

Dawson also pointed out that the importance of the South Korean study findings is that autism spectrum disorder “is underdiagnosed and under-reported and that rigorous screening and comprehensive populations studies may be necessary to produce accurate ASD prevalence estimates,” estimates that may well exceed previous ones.

Autism Speaks
Centers for Disease Control and Prevention