An ambitious six-year effort to gauge the rate of childhood autism in a middle-class South Korean city has yielded a figure that stunned experts and is likely to influence the way the disorder’s prevalence is measured around the world, scientists reported on Monday.
But experts said the findings did not mean that the actual numbers of children with autism were rising, simply that the study was more comprehensive than previous ones.
“This is a very impressive study,” said Lisa Croen, director of the autism research program at Kaiser-Permanente Northern California, who was not connected with the new report. “They did a careful job and in a part of the world where autism has not been well documented in the past.”
For the study, which is being published in The American Journal of Psychiatry, researchers from the Yale Child Study Center, George Washington University and other leading institutions sought to screen every child aged 7 to 12 in Ilsan, a community of 488,590, about the size of Staten Island.
“From the get-go we had the feeling that we would find a higher prevalence than other studies because we were looking at an understudied population: children in regular schools,” said the lead researcher, Dr. Young-Shin Kim, a child psychiatrist and epidemiologist at the Yale Child Study Center.
South Korea was chosen not only because autism prevalence had not been measured there, but also because its national health care system, universal education and homogeneous population made it a promising region for a planned series of studies that will also look at genetic and environmental factors in autism.
The study, which was largely financed by the research and advocacy group Autism Speaks, raises the question of whether a similarly high prevalence would be found in the United States if all children were screened.
A study in South Korea suggests about 1 in 38 children have traits of autism, higher than a previous U.S. estimate of 1 in 100. By casting a wider net and looking closely at mainstream children, the researchers expected to find a higher rate of autism characteristics. But they were surprised at how high the rate was. They don't think South Korea has more children with autism than the United States, but instead that autism often goes undiagnosed in many nations. U.S. estimates are based on education and medical records, not the more time-consuming survey conducted in South Korea.
Two-thirds of the children with autism traits in the study were in the mainstream school population, hadn't been diagnosed before and weren't getting any special services. Many of those undiagnosed children likely have mild social impairments, rather than more severe autism.
Sunday, May 8, 2011
Korea: One in 38
Previous posts have dealt with the question of prevalence: just how much autism is there? The New York Times reports: