U.S. Autism Rate Rises to 1 in 36 Children

On Mar. 24, 2023, the U.S. Centers for Disease Control and Prevention (CDC) published an analysis in its epidemiological digest Morbidity and Mortality Weekly Report  (MMWR) which found the prevalence of autism spectrum disorder (ASD) among children eight years old in the United States to be 1 in 36 (2.8 percent).^{1 2 3 4 5 6}

The analysis is based on data collected in 2020 by the surveillance program known as the Autism and Developmental Disabilities Monitoring (ADDM) Network in 11 states (Arizona, Arkansas, California, Georgia, Maryland, Minnesota, Missouri, New Jersey, Tennessee, Utah and Wisconsin).²

Autism Rate in California One in 22 Children

The new estimated rate of ASD, which ranges from 1 in 44 (2.3 percent) in Maryland to one in 22 (4.5 percent) in California, represents an 18 percent increase over the 1 in 44 rate (2.3 percent), based on 2018 data, published by the CDC in November 2021. Previous ASD prevalence estimates ranged from 1 in 2,500 to 1 in 1,000 during the 1990s; 1 in 150 in 2000; 1 in 110 in 2006; 1 in 88 in 2012 and 1 in 54 in 2016.^{7 8}

Prior to the broader ASD classification of the 1990s, the rate of autism during the 1960s was 1 in 10,000 children and two in 10,000 children in the 1980s.⁷

In article for Rutgers University’s Futurity scientific research magazine, Patti Zielinski noted that the CDC analysis:

found that California set new records, diagnosing 45% more boys with autism than any other state in the network. Nearly 7% of all 8-year-old boys in the San Diego region are estimated to have autism spectrum disorder (ASD), according to the report.⁶

“For California in particular, the data are surprising and represent the highest autism prevalence estimates from a region by an epidemiologic study,”said Walter Zahorodny, PhD, director of the New Jersey Autism Study at the Rutgers University New Jersey Medical School.⁶

Autism Rate in Girls Growing Faster Than in Boys

According to the CDC analysis, for the first time in 20 years the percentage of eight-year-old girls with autism surpassed one percent. The percentage of eight-year-old boys with autism remained at four percent.²

“For every one autistic girl we identify, there are four autistic boys. We know that that ratio should be lower,” said Lauren Kenworthy, PhD, director for The Center for Autism Spectrum Disorders at Children’s National Hospital. “One reason that it’s not is because a lot of autistic girls as well as gender diverse individuals show a slightly different profile. They show autism in a slightly different way, and it can be considered sometimes to be more subtle.”³

Also, for the first time, the prevalence of autism in Black, Hispanic, Asian and Pacific Islander children was greater than the prevalence in White children—three percent versus two percent. The CDC analysis confirmed:

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.²

The latest CDC analysis for the prevalence of ASD offers one estimate for the continuing rise in the rate of autism in the U.S. Another estimate given by a study published last summer in JAMA Pediatrics found that the number of children and adolescents diagnosed with ASD in the country has grown to one in 30. That study looked at data from the annual National Health Interview Survey (NHIS) maintained by the CDC. It estimated there was a 52 percent increase in ASD diagnoses among children and adolescents in the U.S. during 2017-2020.⁹

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