Brief Report: Estimated Prevalence of a Community Diagnosis of Autism Spectrum Disorder by Age 4 Years in Children from Selected Areas in the United States in 2010: Evaluation of Birth Cohort Effects.
Gnakub N Soke, M J Maenner, D Christensen and 2 others
PMID 28342162WHAT IT FOUND
The share of children with an early ASD diagnosis was similar overall between birth cohorts, but rose in sites with more complete records and not in sites with less complete records.
Key findings
01Early-diagnosed ASD was less common than later-diagnosed ASD in the earlier birth cohort.
02The overall early-diagnosed ASD prevalence was similar between birth cohorts, but some sites showed an increase.
03Later-diagnosed children were less likely to have developmental regression and, where education data were available, less likely to have low IQ.
STILL TO COME
How it was doneWhat they found
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What it does not show
The five sites are not a nationally representative sample, so these estimates may not apply to all U.S. children. Two sites had access only to health records, and the authors say this may have missed cases, so site differences may reflect record access rather than real diagnosis patterns. The analysis only included children with a documented community diagnosis of ASD, so children without such a note were not counted even if they met the ADDM case definition. The authors could not tell whether the higher early-diagnosed prevalence in some 2006 cohort sites meant better early diagnosis or simply more ASD in that birth cohort, because data on later diagnosis were not available. Data on services were not available, so the paper cannot show how many children received early intervention or special education after diagnosis.
Declared interests
All authors reported no conflicts of interest.
The easy way to misread this
Do not read the site-specific increase as proof that early diagnosis improved everywhere. The overall early-diagnosed prevalence was similar between birth cohorts, and the increase was limited to sites with more complete records.