Prevalence and Early Identification of Autism Spectrum Disorder Among Children Aged 4 and 8 Years - Autism and Developmental Disabilities Monitoring Network, 16 Sites, United States, 2022

Abstract

Problem/condition: Autism spectrum disorder (ASD).

Period covered: 2022.

Description of system: The Autism and Developmental Disabilities Monitoring Network is an active surveillance program that estimates prevalence and characteristics of ASD and monitors timing of ASD identification among children aged 4 and 8 years. In 2022, a total of 16 sites (located in Arizona, Arkansas, California, Georgia, Indiana, Maryland, Minnesota, Missouri, New Jersey, Pennsylvania, Puerto Rico, Tennessee, Texas [two sites: Austin and Laredo], Utah, and Wisconsin) conducted surveillance for ASD among children aged 4 and 8 years and suspected ASD among children aged 4 years. Surveillance included children who lived in the surveillance area at any time during 2022. Children were classified as having ASD if they ever received 1) an ASD diagnostic statement in a comprehensive developmental evaluation, 2) autism special education eligibility, or 3) an ASD International Classification of Diseases, Ninth Revision (ICD-9) code in the 299 range or International Classification of Diseases, Tenth Revision (ICD-10) code of F84.0, F84.3, F84.5, F84.8, or F84.9. Children aged 4 years were classified as having suspected ASD if they did not meet the case definition for ASD but had an evaluator's suspicion of ASD documented in a comprehensive developmental evaluation.

Results: Among children aged 8 years in 2022, ASD prevalence was 32.2 per 1,000 children (one in 31) across the 16 sites, ranging from 9.7 in Texas (Laredo) to 53.1 in California. The overall observed prevalence estimate was similar to estimates calculated using Bayesian hierarchical and random effects models. ASD was 3.4 times as prevalent among boys (49.2) than girls (14.3). Overall, ASD prevalence was lower among non-Hispanic White (White) children (27.7) than among Asian or Pacific Islander (A/PI) (38.2), American Indian or Alaska Native (AI/AN) (37.5), non-Hispanic Black or African American (Black) (36.6), Hispanic or Latino (Hispanic) (33.0), and multiracial children (31.9). No association was observed between ASD prevalence and neighborhood median household income (MHI) at 11 sites; higher ASD prevalence was associated with lower neighborhood MHI at five sites.Record abstraction was completed for 15 of the 16 sites for 8,613 children aged 8 years who met the ASD case definition. Of these 8,613 children, 68.4% had a documented diagnostic statement of ASD, 67.3% had a documented autism special education eligibility, and 68.9% had a documented ASD ICD-9 or ICD-10 code. All three elements of the ASD case definition were present for 34.6% of children aged 8 years with ASD.Among 5,292 (61.4% of 8,613) children aged 8 years with ASD with information on cognitive ability, 39.6% were classified as having an intellectual disability. Intellectual disability was present among 52.8% of Black, 50.0% of AI/AN, 43.9% of A/PI, 38.8% of Hispanic, 32.7% of White, and 31.2% of multiracial children with ASD. The median age of earliest known ASD diagnosis was 47 months and ranged from 36 months in California to 69.5 months in Texas (Laredo).Cumulative incidence of ASD diagnosis or eligibility by age 48 months was higher among children born in 2018 (aged 4 years in 2022) than children born in 2014 (aged 8 years in 2022) at 13 of the 15 sites that were able to abstract records. Overall cumulative incidence of ASD diagnosis or eligibility by age 48 months was 1.7 times as high among those born in 2018 compared with those born in 2014 and ranged from 1.4 times as high in Arizona and Georgia to 3.1 times as high in Puerto Rico. Among children aged 4 years, for every 10 children meeting the case definition of ASD, one child met the definition of suspected ASD.Children with ASD who were born in 2018 had more evaluations and identification during ages 0-4 years than children with ASD who were born in 2014 during the 0-4 years age window, with an interruption in the pattern in early 2020 coinciding with onset of the COVID-19 pandemic.Overall, 66.5% of children aged 8 years with ASD had a documented autism test. Use of autism tests varied widely across sites: 24.7% (New Jersey) to 93.5% (Puerto Rico) of children aged 8 years with ASD had a documented autism test in their records. The most common tests documented for children aged 8 years were the Autism Diagnostic Observation Schedule, Autism Spectrum Rating Scales, Childhood Autism Rating Scale, Gilliam Autism Rating Scale, and Social Responsiveness Scale.

Interpretation: Prevalence of ASD among children aged 8 years was higher in 2022 than previous years. ASD prevalence was higher among A/PI, Black, and Hispanic children aged 8 years than White children aged 8 years, continuing a pattern first observed in 2020. A/PI, Black, and Hispanic children aged 8 years with ASD were also more likely than White or multiracial children with ASD to have a co-occurring intellectual disability. Identification by age 48 months was higher among children born in 2018 compared with children born in 2014, suggesting increased early identification consistent with historical patterns.

Public health action: Increased identification of autism, particularly among very young children and previously underidentified groups, underscores the increased demand and ongoing need for enhanced planning to provide equitable diagnostic, treatment, and support services for all children with ASD. The substantial variability in ASD identification across sites suggests opportunities to identify and implement successful strategies and practices in communities to ensure all children with ASD reach their potential.

FIGURE 1

Prevalence* of autism spectrum disorder among children aged 8 years, by neighborhood median household income tertile and site^† — Autism and Developmental Disabilities Monitoring Network, 16 sites, United States, 2022^§ Abbreviation: ASD = autism spectrum disorder; MHI = median household income. * Per 1,000 children aged 8 years. ^† Dots are point estimates and horizontal lines are 95% CIs. Neighborhood MHI tertiles = low ($2,499–$62,470), medium ($62,472–$97,768), high ($97,813–$250,001). Estimates for Puerto Rico medium and high MHI tertiles and Texas (Austin) and Texas (Laredo) high MHI tertiles were suppressed because relative standard error was ≥30% of the estimate. ^§ Cochran-Armitage test of trend for association between MHI tertile and ASD prevalence, by site and overall: Arizona p = 0.6; Arkansas p = 0.8; California p = 0.1; Georgia p = 0.9; Indiana p = 0.5; Maryland p = 0.1; Minnesota p = 0.4; Missouri p = 0.3; New Jersey p<0.01; Pennsylvania p = 0.7; Puerto Rico p = 0.5; Tennessee p<0.01; Texas (Austin) p = 0.2; Texas (Laredo) p = 0.04; Utah p<0.01; Wisconsin p<0.01; Total p<0.01 (not monotonic). Ns and prevalence for each MHI tertile by site are available (Supplementary Table 4, https://stacks.cdc.gov/view/cdc/177099#tabs-3).

FIGURE 2

Prevalence* of autism spectrum disorder among children aged 8 years, by identification type and site^† — Autism and Developmental Disabilities Monitoring Network, 16 sites, United States, 2022^§ Abbreviations: ASD = autism spectrum disorder; ICD = International Classification of Diseases. * Per 1,000 children aged 8 years. ^† Data from record abstraction were not available for Indiana. ^§ Horizontal line is the overall Autism and Developmental Disabilities Monitoring Network prevalence of 32.2 per 1,000 children aged 8 years. Children with documented ASD statements could also have ASD eligibility in special education or ASD ICD codes. Underlying data are available (Supplementary Table 6, https://stacks.cdc.gov/view/cdc/177099#tabs-3).

FIGURE 3

Euler diagram of different types of autism spectrum disorder identification among children aged 8 years with autism spectrum disorder* — Autism and Developmental Disabilities Monitoring Network, 15 sites, United States, 2022 Abbreviations: ASD = autism spectrum disorder; ICD = International Classification of Diseases. * N = 8,613 (the ADDM Network has 16 sites; Indiana is not included because the site did not have ASD diagnostic statement data from record abstraction available).

FIGURE 4

Cumulative incidence* of autism spectrum disorder diagnosis or autism special education eligibility among children aged 4 or 8 years, by month of age at identification and site^†,§ — Autism and Developmental Disabilities Monitoring Network, 15 sites, United States, 2022^¶ * Per 1,000 children aged 4 or 8 years. ^† The ADDM Network has 16 sites; Indiana is not included because the site did not have data from record abstraction available. ^§ Not all children aged 4 years reach age 60 months and not all children aged 8 years reach age 108 months during the surveillance year. ^¶ Data comparing cumulative incidence of autism spectrum disorder diagnosis or autism special education eligibility by age 48 months among children aged 4 or 8 years are available (Supplementary Table 10, https://stacks.cdc.gov/view/cdc/177099#tabs-3).

FIGURE 5

Difference in number of developmental evaluations and incidence* of autism spectrum disorder identification among children aged 4 years in 2022 during calendar years 2018–2022 and children aged 8 years in 2022 during calendar years 2014–2018, by month^†,§ — Autism and Developmental Disabilities Monitoring Network, 15 sites, United States * Per 1,000 children aged 4 or 8 years. ^† The ADDM Network has 16 sites; Indiana is not included because the site did not have data from record abstraction available. ^§ For children aged 4 years, year 0 to year 4 represents 2018–2022; for children aged 8 years, year 0 to year 4 represents 2014–2018. The dashed line shows the COVID-19 pandemic onset for children aged 4 years in 2022 compared with the analogous time window for children aged 8 years in 2022.

FIGURE 6

Percentage of children aged 8 years with autism spectrum disorder who have a recorded autism spectrum disorder diagnostic test, by site* — Autism and Developmental Disabilities Monitoring Network, 15 sites, United States, 2022 Abbreviations: ADI-R = Autism Diagnostic Interview-Revised; ADOS = Autism Diagnostic Observation Schedule; ASD = autism spectrum disorder; ASRS = Autism Spectrum Rating Scales; CARS = Childhood Autism Rating Scale; GARS = Gilliam Autism Rating Scale; SRS = Social Responsiveness Scale; other test category includes Asperger Syndrome Diagnostic Scale, Gilliam Asperger’s Disorder Scale, and TELE-ASD-PEDS. * N = 8,613 (the ADDM Network has 16 sites; Indiana is not included because the site did not have data from record abstraction available).