News from the FDA/CDC

Rise in autism prevalence indicates earlier diagnosis



The prevalence of autism spectrum disorder in 4-year-olds rose from 2014 to 2016, indicating more early identification of ASD among the children born in 2012, compared with 2008, according to the Centers for Disease Control and Prevention.

Autism spectrum disorder among 4-year-olds at six sites, 2016

Data from individual surveillance sites in the CDC’s Early Autism and Developmental Disabilities Monitoring (Early ADDM) Network, however, show “wide variability in estimates [that] could reflect variable success in improving community identification,” Kelly A. Shaw, PhD, and associates wrote in MMWR Surveillance Summaries.

In 2016, the overall prevalence of ASD was 15.6 per 1,000 children aged 4 years at the six sites in the Early ADDM Network, compared with 14.1 per 1,000 in 2014, they reported.

“In addition, the cumulative incidence of ASD diagnoses at age 48 months was higher for children born in 2012 than for children born in 2008, which indicates a higher rate of diagnosis for the younger cohort,” wrote Dr. Shaw of the CDC’s National Center on Birth Defects and Developmental Disabilities, Atlanta, and associates.

A closer look at the six Early ADDM Network sites shows considerable variation in prevalence. The New Jersey site, consisting of one full county and part of another that includes metropolitan Newark, reported a rate of 25.3 per 1,000 – 38.7 for males and 11.0 for females – while the rates for Missouri – one county in metropolitan St. Louis – were 13.4 (male), 3.9 (female), and 8.8 (combined), the investigators wrote.

ASD prevalence across the six sites was 3.5 times higher among males (23.9 per 1,000) than females (6.8). “Cumulative incidence patterns also differed by sex, with a steady increase in diagnoses with age for boys but an apparent plateau for girls at approximately age 36 months,” they noted.

The median age at earliest diagnosis was 33 months for all sites, with North Carolina lowest at 29 months and Wisconsin highest at 36 months.

The overall median, Dr. Shaw and associates pointed out, is “well above the youngest age at which ASD can be identified, [so] work remains to improve early diagnosis so children can receive timely services.”

SOURCE: Shaw KA et al. MMWR Surveill Summ. 2020;69(SS-3):1-11. doi: 10.15585/mmwr.ss6903a1.

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