A comprehensive 12-year study in South Korea finds no significant increase in autism rates, casting doubt on views of an ongoing epidemic driven by environmental factors or vaccines, highlighting increased awareness and diagnostic efforts instead.
A large South Korean study has found no meaningful rise in autism prevalence over a 12-year period, adding evidence against claims that the condition is part of an “epidemic”. The findings, published in JAMA Pediatrics and reported by Healio, come as US health officials continue to suggest that autism diagnoses are being driven by vaccines, acetaminophen and environmental toxins. The researchers said the data do not support that interpretation.
The study was led by Young Shin Kim, a developmental psychopathologist at the University of Texas Dell Medical School, who told Healio that autism trends are often difficult to compare because countries and health systems collect data in very different ways. Kim said that mixing estimates produced by unlike methods is “like comparing apples to oranges”, leaving families and scientists without a clear picture of whether reported increases reflect a real change in autism occurrence or simply better identification. That concern is not new: earlier South Korean research, based on national insurance data, also recorded increases in diagnosed autism and related developmental disorders, while noting that improved awareness and diagnostic practice may help explain at least part of the rise.
Kim’s team used South Korea’s near-universal school system to screen more than 62,000 children who started school between 2005 and 2017, focusing on seven-year-olds so that milder cases would be less likely to be missed. Because elementary education is compulsory and homeschooling is uncommon, the researchers could reach almost the entire population at the point of school entry. Parents completed screening questionnaires, and children who scored in the bottom 5th percentile were referred for diagnostic assessment, alongside those flagged by parents or teachers, those in special education and those already listed on the disability registry.
Of the 62,081 children screened, just over 2,000 were referred for further evaluation, most because of questionnaire results rather than a formal referral from school staff or families. Diagnostic testing was completed in 881 children, and 447 were found to have autism spectrum disorder. The study found that cumulative incidence across birth cohorts ranged from 1.9% to 3.2%, with a median of 2.4%, while prevalence ranged from 2% to 3.4%, with a median of 2.5%. Neither measure changed significantly between children born in 1998 and those born in 2010.
The researchers did, however, find a shift in service use. More diagnosed children were receiving support services by 2010 than in 2005, while the number who had never received services fell. Among the children diagnosed with autism, most were already in clinical care, but those who were not tended to have higher IQ and adaptive functioning scores and lower rates of intellectual disability. Kim said the pattern suggests that much of the apparent increase in autism prevalence may reflect greater awareness, broader diagnostic reach and the identification of children who were previously overlooked, rather than a sudden surge in underlying cases.
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