New Data on Autism in 4-Year-Olds

April 15, 2019

On April 11, 2019, the CDC published a report on the prevalence and characteristics of autism spectrum disorder (ASD) among 4-year-old children. This report is based on information from the Early Autism and Developmental Disabilities Monitoring (ADDM) Network. Early ADDM is a subset of the broader ADDM Network, which has been doing ASD surveillance among 8-year-old children since 2000.

In this report, published in the Morbidity and Mortality Weekly Report (MMWR) Surveillance Summaries, scientists analyzed information from the health and/or education records of preschool-aged children. While seven sites from across the United States were included in this report, only three sites (Arizona, Missouri, and New Jersey) had data in each of the study years (2010, 2012, and 2014) that allowed for an analysis of the trends over time.

Main Findings

  • Prevalence in 4-year-olds – approximately 3% of the population, 1 in 59 nationally and 1 in 35 in NJ in 2014 (1 in 23 boys in NJ)
  • Trends – prevalence was higher in 2014 compared with 2010 in New Jersey, but was stable in Arizona and Missouri
  • First comprehensive evaluation by age 3 – no increase over time
  • Diagnosis by age 4 – no increase over time

The findings in this report do not replace the April 2018 report from the ADDM Network, which found that 1 in 59 children 8 years of age were identified with ASD nationwide, 1 in 34 in New Jersey.  Read more about our analysis of these prevalence numbers.

Explore the data

CDC has a new data visualization tool that lets users map and graph ASD data. Visit the website and explore the data!


Key Findings Reference:

Christensen, D. L., Maenner, M. J., Bilder, D. et al. (2019). Prevalence and characteristics of Autism Spectrum Disorder among 4-year-old children — Early Autism and Developmental Disabilities Monitoring Network, Seven Sites, United States, 2010-2014. MMWR Surveillance Summaries, 68 (No. SS-2), 1–19.