Key Overview

The University of Minnesota was funded by the Centers for Disease Control and Prevention (CDC) to conduct a multi-source public health project that monitors the prevalence of autism spectrum disorder (ASD) and intellectual disability in 8-year-old children within Hennepin and Ramsey counties in Minnesota.

In addition to race and ethnicity categories routinely studied by the CDC, the Minnesota-Autism and Developmental Disabilities Monitoring Network (MN-ADDM) project was interested in understanding prevalence among Somali and Hmong immigrant populations. The data was collected from health and special education records of children who were 8 years old in 2014.

Key Findings

  • Using data from 2014, MN-ADDM researchers found 1 in 42 (2.4%) 8-year-old children was identified with ASD. This percentage is higher than the average percentage identified with ASD (1.7% - 1 in 59) within all communities in the United States where the CDC tracked ASD in 2014.
  • Boys were more likely to be identified with ASD than girls.
  • There were no significant statistical differences in prevalence by racial and ethnic groups. The prevalence estimate was 1 in 26 for Somali children and 1 in 54 for Hmong children. Although both of these numbers look different from the 1 in 42 estimate, sample sizes were too small to be able to tell if these differences are real or occurred by random chance. Using a p-value of <.01, there were no statistically significant differences across race and ethnicity. Additionally, the confidence intervals around the prevalence estimates are large, and this tells us we should use extreme caution before drawing conclusions about any differences between groups.
  • There were no significant statistical differences in prevalence between white, black, and Hispanic children.
  • Among children identified with ASD who had IQ information available, less than a third (28%) also had intellectual disability.
    • Intelligence quotient (IQ) scores were available for 80% of children identified with ASD by MN-ADDM. Intellectual disability is defined as IQ score ≤ 70.
    • When we looked at ethnic groups, of the Somali children with ASD who had IQ information available, 43% also had a co-occurring intellectual disability and 18% of Hmong children with ASD also had intellectual disability.
  • About 73% of children identified with ASD had concerns about their development noted in their health and/or education records by age 3.
  • About 34% of children identified with ASD received a comprehensive developmental evaluation by age 3.
  • Even though ASD can be diagnosed as early as age 2, about half of children were not diagnosed with ASD by a community provider until 4 years and 9 months.