April 02, 2020
4 min read

Autism prevalence rises 10% among 8-year-olds

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The prevalence of autism spectrum disorder among 8-year-olds climbed 10% between 2014 and 2016 to 1 in 54 children, according to an analysis of data published in MMWR. For the first time, ASD prevalence in black and white children was the same.

The previous prevalence estimate was one in 59 children in 2014. The data come from the CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network.

Data from a second study published in MMWR suggested that children are being identified with ASD at younger ages. The study focused on children aged 4 years.

“Some of the increase in autism prevalence might be due to the way children are identified, diagnosed and receiving services in their communities,” Stuart Shapira, MD, PhD, associate director for science at CDC’s National Center on Birth Defects and Developmental Disabilities, said in a statement. “The increase may also reflect reductions in racial differences in identification in autism, as this is the first ADDM Network report to identify black 8-year-olds with autism having the same rates as white children.”

The ADDM Network is composed of 11 surveillance sites in Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee and Wisconsin. All children included in the study were born in 2008 and had a parent or guardian who lived in one of the surveillance sites. Each site selected a portion of its state to monitor ASD in children — other than Arkansas, which chose to include the entire state.

Data from the 11 sites showed 18.5 per 1,000 (one in 54) children had ASD, according to the researchers. Prevalence ranged from 13.1 per 1,000 children in Colorado (one in 76) to 31.4 per 1,000 children in New Jersey (one in 32).

New Jersey’s prevalence rate was higher than every other ADDM Network site. Colorado (13.1) and Missouri (13.6) had the lowest prevalence estimates and also limited or no access to education records.

ASD prevalence was higher among males than females (29.7 vs. 6.9), the researchers reported. The combined male-to-female prevalence ratio was 4.3:1. Site-specific ratios ranged from 3.4:1 to 4.7:1.

The ASD prevalence per 1,000 white or non-Hispanic black children was similar — 18.5 and 18.3.

According to the study, the prevalence rate in Asian/Pacific Island children was similar to white and black children at 17.9 per 1,000 children. Prevalence among Hispanic children was lower at 15.4 per 1,000 children.


Data included in the second study came from six of the 11 ADDM Network sites that collected surveillance data for children aged 4 years. Other than North Carolina, in which all surveillance areas were the same, surveillance among children aged 4 years was conducted in a subset of the surveillance areas that were used for children aged 8 years, the authors reported.

Children included in the study were all born in 2012 and had a parent or guardian who lived in Arizona, Colorado, Missouri, New Jersey, North Carolina and Wisconsin during 2016.

According to the study, ASD prevalence from the sites was 15.6 per 1,000 (one in 64) children. Estimates ranged from 8.8 per 1,000 children in Missouri, to 25.3 per 1,000 children in New Jersey. Prevalence was higher in male (23.9 per 1,000) than in female (6.8 per 1,000) children.

Prevalence between white and black children did not differ at any site. Overall, ASD prevalence was 13.2 per 1,000 white children compared with 14.3 per 1,000 black children.

The median age at earliest comprehensive evaluation for these children was 26 months overall. This ranged from 22 months in North Carolina to 30 months in Arizona and Missouri. Across all sites, 84% of children with ASD had a first evaluation at age 36 months or younger.

Documented ASD diagnoses were found for 71% of children aged 4 years who met the ASD surveillance case definition. The median age of the earliest diagnosis was 33 months. – by Ken Downey Jr.

Disclosures: The authors report no relevant financial disclosures.


Maenner MJ, et al. MMWR Morb Mortal Wkly Rep. 2020; doi:10.15585/mmwr.ss6904a1.

Shaw KA, et al. MMWR Morb Mortal Wkly Rep. 2020; doi:10.15585/mmwr.ss6903a1.