Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 8 Years - Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2018.
Level 4 - case-series / case-control
Cross-sectional active surveillance study (population-based prevalence survey)
PubMed 34855725 · doi:10.15585/mmwr.ss7011a1
What was done
The CDC Autism and Developmental Disabilities Monitoring (ADDM) Network conducted active surveillance of autism spectrum disorder (ASD) among children aged 8 years in 2018 across 11 US sites (Arizona, Arkansas, California, Georgia, Maryland, Minnesota, Missouri, New Jersey, Tennessee, Utah, and Wisconsin). Surveillance staff reviewed and abstracted medical and special education records. Cases were defined by a documented ASD diagnostic statement, ASD special education eligibility, or an ASD ICD code.
What was found
Across the 11 sites, 5,058 children met the ASD case definition. Overall ASD prevalence was 23.0 per 1,000 (one in 44) 8-year-olds, ranging from 16.5 per 1,000 in Missouri to 38.9 per 1,000 in California. ASD was 4.2 times more prevalent in boys than in girls. Overall prevalence was similar across most racial/ethnic groups, though American Indian/Alaska Native children had higher prevalence than White children (29.0 vs. 21.2 per 1,000), and Hispanic children had lower prevalence than White or Black children at several individual sites. Of identified cases, 75.8% had a formal diagnostic statement, 18.8% had special education eligibility only, and 5.4% had an ICD code only. Median age at earliest known diagnosis ranged from 36 months (California) to 63 months (Minnesota). Among 3,007 children with cognitive data, 35.2% had an IQ ≤70 (49.8% in Black, 33.1% in Hispanic, and 29.7% in White children). Children with IQ ≤70 were diagnosed earlier than those with IQ >70 (median 44 vs. 53 months).
Why it matters
This report provides updated 2018 US benchmark surveillance estimates of pediatric ASD prevalence, documenting wide geographic variations and persistent racial disparities in intellectual disability classification and identification rates.
Limits
Data are derived from retrospective record reviews rather than direct clinical evaluations, making ascertainment dependent on local record access and documentation quality. The 11 surveillance sites are not nationally representative. Cognitive data were unavailable for 40.5% (2,051 of 5,058) of identified children.
Cited by
- supports More than 1 in 100 children in the United States are diagnosed with autism.