A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Spring, 2023 | Number 2, Volume 37

CDC findings: Prevalence of autism spectrum disorders in the United States climbs to new highs

The prevalence of autism spectrum disorders (ASD) among 8-year-olds is now higher than at any time since monitoring began in the year 2000, according to research by the Centers for Disease Control and Prevention (CDC), and a separate study indicates that the prevalence among 4-year-olds is climbing even higher. 

In the first study, Matthew Maenner and colleagues, analyzing data from 2020, found that approximately 4 percent of 8-year-old boys and 1 percent of 8-year-old girls in the United States were estimated to have autism. Among all U.S. 8-year-olds, 1 in 36 were estimated to have autism in 2020, compared to 1 in 44 two years earlier. 

Results varied from area to area, with California diagnosing 45 percent more boys with autism compared to any other state in the 11-state Autism and Developmental Disabilities Monitoring (ADDM) Network. Nearly 7 percent of all 8-year-old boys in the San Diego area were identified with ASD. The researchers say disparities between sites may be due to some regions and states making a greater effort to identify children with ASD and provide services for them.

 “The true rate may not be substantially different between California and other ADDM states, including New Jersey,” study coauthor Walter Zahorodny says. “What’s different is that California implemented some wide-ranging screening and intervention programs, which may have resulted in a higher estimated prevalence than elsewhere in the network.” 

The researchers also say, “For the first time among children aged 8 years, the prevalence of ASD was lower among white children than among other racial and ethnic groups, reversing the direction of racial and ethnic differences in ASD prevalence observed in the past.” 

In a separate study, Kelly Shaw and colleagues found that at all sites, “cumulative incidence of ASD by age 48 months among children aged 4 years was higher compared with children aged 8 years in 2020, indicating improvements in early identification of ASD.” 

However, Zahorodny says that while it is a common belief that the increasing prevalence of ASD is due solely to better awareness and the provision of more services, this alone cannot explain the rise because the increase has occurred in all subtypes of ASD and across all demographic groups. He says, “This is not just a phenomenon of becoming more sensitive to subtly impaired kids,” adding, “Once considered a rare disorder, these figures suggest that autism may be one of the most common disabilities. The trouble is we don’t understand what the primary drivers of the increase are.”


Citations

“Prevalence and characteristics of autism spectrum disorder among children aged 8 years— Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2020,” Matthew J. Maenner et al., CDC Morbidity and Mortality Weekly Report, March 24, 2023 (free online). 

—and—

 “Early identification of autism spectrum disorder among children aged 4 years — Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2020,” Kelly A Shaw et al., CDC Morbidity and Mortality Weekly Report, March 24, 2023 (free online). 

—and— 

“Rates of autism climb to new highs in the U.S., with California setting record numbers,” news release, Rutgers University, March 23, 2023. 

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“Autism now more common among Black, Hispanic kids in U.S.,” Mike Stobbe, Medical Xpress, March 23, 2023. 

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“Analysis shows shifting demographics of children identified with autism,” news release, University of Utah Health Sciences, March 24, 2023.