The cumulative incidence of autism spectrum disorder (ASD) has remained stable across 12 consecutive birth cohorts, according to a report in JAMA Pediatrics. This suggests that the well-publicized increase in reported ASD prevalence is due to better detection, not a true epidemic.Why It’s Relevant
Since 1970, ASD prevalence estimates have risen sharply, from 0.07% to more than 3%, prompting public concern about an autism epidemic. Existing studies have been limited in their ability to determine if these observed prevalence increases reflect a true increase in incidence.
To get at the underlying truth, researchers comprehensively screened incoming first graders across Goyang, South Korea (a satellite city of Seoul), each year between 2005 and 2017 (excluding 2011). Potential undiagnosed ASD cases were then invited to be examined by clinicians using standardized diagnostic assessments.
By the Numbers
- In total, more than 62,000 children were screened; 2,077 screened positive for potential ASD and were invited for detailed evaluation, of whom 881 completed diagnostic assessments.
- Across birth cohorts, both the cumulative incidence (diagnoses among all children born in Goyang) and prevalence (diagnoses among all children regardless of birthplace) of ASD at age 7 remained stable; ASD incidence ranged from 1.9% to 3.2%, while prevalence ranged from 2.0% to 3.4%.
- In the final assessment year (2017), ASD incidence and prevalence were 2.6% and 2.7%, respectively.
- Female children with ASD were disproportionately represented among previously undiagnosed cases identified in school settings.
The Other Side
Participation in screening was high overall (85%) but varied from 60% to 93% across birth cohorts. Limited information was available for children who did not participate in initial screening, which may have skewed results.
Takeaway Message
Using consistent methods across consecutive birth cohorts, this study showed stable incidence and prevalence rates, strongly suggesting that improved detection rather than increased occurrence or an epidemic is responsible for increasing rates of ASD diagnosis.
Related Information
Source
Young Shin Kim, et. al. Cumulative incidence and prevalence of autism spectrum disorder. JAMA Pediatrics. Published September 14, 2026. doi:10.1001/jamapediatrics.2026.4066
(Image: Getty Images/iStock/Vladimir Vladimirov)
