The Minnesota-Autism and Developmental Disabilities Monitoring Network (MN-ADDM) is part of the Autism and Developmental Disabilities Monitoring (ADDM) Network, a group of programs funded through the Centers for Disease Control and Prevention (CDC) to estimate the number of children with autism spectrum disorder (ASD) and other developmental disabilities living in different areas of the United States. MN-ADDM monitors the prevalence of ASD and intellectual disability (ID) in parts of Hennepin and Ramsey counties.

Autism spectrum disorder is a developmental disability that can cause significant social, communication and behavioral challenges. There is often nothing about how people with ASD look that sets them apart from other people, but people with ASD may communicate, interact, behave, and learn in ways that are different from most other people. The learning, thinking, and problem-solving abilities of people with ASD can range from gifted to severely challenged. Some people with ASD need a lot of help in their daily lives; others need less. Intellectual disability means that a person has difficulty learning at an expected level and functioning in daily life. In this report, intellectual disability is measured by intellectual quotient (IQ) test scores of less than or equal to 70. 

The ADDM Network provides population-based estimates of ASD and other developmental disabilities across sites that can be compared over time. The combined data from the various ADDM sites can help inform us about:

  • characteristics of children with ASD,
  • whether ASD is more common in some groups of children than others and if those differences change over time, and
  • the impact of ASD and related conditions upon children, families, and communities in the United States.

This project does not examine what causes ASD. Our focus is on providing data and training that helps policymakers, educators, communities, providers, families, and individuals make informed decisions and support children with autism and their families.

Key findings from 2016 data

How many children were identified with ASD in Minnesota?

1 in 44 children were identified with ASD in Minnesota.

Using data from 2016, MN-ADDM researchers found 1 in 44 (2.3%) 8-year-old children were identified with ASD. This is higher than the national average of 8-year-old children identified with ASD (1 in 54 or 1.9%) in the United States where the CDC tracked ASD in 2014.

When were children first diagnosed with ASD in MN?

The median age of first ASD diagnosis was 4 years, 8 months.

What was the percentage of children with ID in Minnesota?

Minnesota had intelligence quotient (IQ) data available for 90% of children identified with ASD. Of those children, 25% had intellectual disability. Black, non-Somali children (36%) and Hispanic children (45%) were more likely than white children to be classified as having intellectual disability in addition to ASD. Intellectual disability is defined as an IQ score of 70 or lower.

Which children were more likely to be identified with ASD in Minnesota?

Boys were 3.9 times more likely to be identified with ASD than girls.

Prevalence of ASD in Minnesota by gender, race and ethnicity

Children with ASD identified/ Total Population

Prevalence estimate (prevalence per 1,000 children)

95% confidence interval per 1,000

Percentage of Children with ASD who also have ID

Median Age at First Clinical Diagnosis*

Overall

313 of 13,728

1 in 44

2.3%

20.4-25.4

25%

4 years, 8 months

Males

6,884

1 in 27

3.7%

32.1-41.0

22%

4 years, 8 months

Females

6,844

1 in 109

.9%

7.2-11.8

34%

4 years, 3 months

Non-Hispanic white

141 of 5,736

1 in 41

2.5%

20.8-29.0

14%

4 years, 6 months

Non-Hispanic black, non-Somali

75 of 2,994

1 in 40

2.5%

20.0-31.4

36%**

4 years, 8.5 months

Non-Hispanic, non-Hmong Asian or Pacific Islander

18 of 1,087

1 in 60

1.7%

10.4-26.3

19%

4 years, 5.5

Hispanic

36 of 2,043

1 in 57

1.9%

12.7-24.4

45%**

4 years, 8 months

Somali

20 of 682

1 in 34

2.9%

18.9-45.5

37%

4 years, 7 months

Hmong

16 of 1,003

1 in 62

1.6%

9.8-26.0

31%

NC

183 American Indian or Alaska Native children were included in the denominator but were not included in prevalence estimations due to low numbers of children with ASD

* This variable is only available for 170 children with ASD; NC=not calculated due to small number with clinical diagnosis

**p<.01

What do the prevalence rates for Somali and Hmong children tell us?

The prevalence rates of ASD were 1 in 34 for Somali children and 1 in 62 for Hmong children. Although both of these numbers look different from the overall 1 in 44 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 for these two groups. Additionally, the confidence intervals around the prevalence estimates are large (9-45.5 for Somali children and 9.8-26.0 for Hmong children), and this tells us we should use caution before drawing conclusions about any differences between these groups.

What do the differences in prevalence rates for white and black and white and Hispanic children tell us?

There were no significant statistical differences in prevalence between white and black and white and Hispanic children. Hispanic children had a lower prevalence of ASD compared to black children using a p-value of <.05.

How common is intellectual disability for children who also have ASD?

Among children identified with ASD who had IQ information available, 25% also had intellectual disability. This ranged from 14% of non-Hispanic white children to 45% of Hispanic children.

  • Intelligence quotient (IQ) scores were available for 90% of children identified with ASD by MN-ADDM. Intellectual disability is defined as IQ score ≤ 70.
  • Black, non-Somali children (36%) and Hispanic children (45%) with ASD were more likely to have intellectual disability than white children with ASD using a p-value of <.01.

Other key findings:

About 76% of children identified with ASD had concerns about their development noted in their health and/or education records by age 3.

About 39% 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 8 months.