Prevalence and cumulative incidence of autism spectrum disorders and the patterns of co-occurring neurodevelopmental disorders in a total population sample of 5-year-old children.
Manabu Saito, Tomoya Hirota, Yui Sakamoto and 8 others
PMID 32410700WHAT IT FOUND
In a total population sample of 5-year-olds in Japan, autism prevalence was 3.22% and incidence was stable over four years.
Critically, 88.5% of diagnosed children had co-occurring neurodevelopmental disorders, and 30% had received no prior services.
Key findings
01The adjusted prevalence of autism spectrum disorders was 3.22%, with a male-to-female ratio of approximately 2.2:1.
02There was no significant linear trend in the 5-year cumulative incidence of autism across the four study years, suggesting rates were stable.
0388.5% of children diagnosed with autism had at least one co-occurring neurodevelopmental disorder, most commonly developmental coordination disorder (63.2%) and ADHD (50.6%).
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
The study relied on a statistical model to estimate prevalence for families who declined the in-person assessment, which may introduce error. ADOS (a gold-standard diagnostic tool) was not completed for all children (34 of 87 declined), so diagnoses relied on clinical judgment and other measures. The study was conducted in a single city in Japan with low ethnic diversity, so findings may not generalize to more diverse populations. The sample size for a total population epidemiological study was modest compared to other large-scale surveys.
Declared interests
The study was funded by Grants-in-Aid for Scientific Research. No specific conflicts of interest were reported in the provided text.
The easy way to misread this
Do not assume the crude prevalence of 1.73% represents the true rate in the community. The adjusted prevalence of 3.22% is the study's main estimate because it accounts for families who did not attend the in-person assessment, and the crude figure significantly underestimates the burden of disease.