A new method to estimate autism prevalence worked out that 2.6% of South Korea’s population has an autism spectrum disorder, much higher than previous estimates, researchers from the USA and South Korea revealed in the American Journal of Psychiatry. That is 1 in every 38 children.
Scientists from Yale University and George Washington University said that autism globally may be considerably more common than experts realize. They carried out an autism prevalence study in South Korea on 55,000 kids aged 7 to 12 years – it included children in general education schools, as well as those in a disability registry and special education services.
The authors stressed that it is not South Korea that appears to have a higher-than-average autism prevalence rate, but rather that calculations so far have underestimated the total numbers all over the world.
Research study member, Professor of of anthropology, Roy Richard Grinker, said:
“While this study does not suggest that Korean children have more autism than other populations or that a more accurate rate for the U.S. is closer to 2.64 percent, it does suggest that autism may be more common than previously thought. This research powerfully demonstrates that the methods one uses to study prevalence will profoundly influence the estimate.”
The researchers screened all the children using comprehensive diagnostic assessments, as well as questioning teachers and parents.
This study differed from others in that it did not just rely on records and registries, but attempted to physically look at every child in each school, including those with no record of any special educational requirement. The researchers tried to make sure that no cases had slipped through the net, as may have happened, for example, with CDC studies which rely totally on records.
Put simply – other studies have only examined kids known to have a neurological disorder, or those at higher-than-average risk of developing one. This one saw each and every child.
Autism Speaks Chief Science Officer Geraldine Dawson, said:
“This study is further evidence that autism transcends cultural, geographic and ethnic boundaries and that autism is a major global public health concern, not limited to the Western world. Notwithstanding the need for replication, this study also provides important evidence that the application of validated, reliable and commonly accepted screening procedures and diagnostic criteria applied to a total population has the potential to yield an ASD prevalence exceeding previous estimates.”
ASD (autism spectrum disorder) does not appear to be expressed differently in different countries, researchers say. However, estimates of ASD rates may be influenced by diagnostic methods and cultural factors.
In order to address potential cultural bias, the authors explain that this study took a wide-ranging and anthropological approach. They conducted parent and teacher focus groups to identify local factors that may impact on the reporting of symptoms and other misunderstandings.
The diagnostic tools were translated and then translated back and validated for Korean kids. They only reported best-estimate clinical diagnoses. The diagnostic teams consisted of Korean experts whose extensive experience was gained in Korea and the USA. North American experts examined random samples of diagnoses.
Because of the way its education system is set up, mainstream Korean education settings may have more children with autism spectrum disorders than other settings. The highly-structured Korean school day and week, sometimes over 12 hours per day, five to six days of school per week, and extra lessons at other academic institutes, are ideal settings for many children with ASD. Hence, a significant number of Korean children with ASD most likely do not receive special education services.
Autism is not just a Western world problem, the authors stressed. It has no borders and exists in every country, culture and ethnic environment – it is a worldwide public health concern. Standard diagnostic methods used in the USA, UK, Ireland, Canada and Australia can diagnose autism just as effectively in other cultures and languages.
“Prevalence of Autism Spectrum Disorders in a Total Population Sample”
Young Shin Kim, M.D., Ph.D., Bennett L. Leventhal, M.D., Yun-Joo Koh, Ph.D., Eric Fombonne, M.D., Eugene Laska, Ph.D., Eun-Chung Lim, M.A., Keun-Ah Cheon, M.D., Ph.D., Soo-Jeong Kim, M.D., Young-Key Kim, M.D., HyunKyung Lee, M.A., Dong-Ho Song, M.D., and Roy Richard Grinker, Ph.D.
Am J Psychiatry. Published May 9, 2011. doi: 10.1176/appi.ajp.2011.10101532
Written by Christian Nordqvist