Photo of an ethnically diverse group of smiling six 8-year-old girls and boys.

Findings from 2020 data

How many 8-year-old children were identified with ASD in Minnesota?

3.0 percent or 1 in 34 children were identified with ASD in Minnesota. Source: MN-ADDM, ICI/U of M, 2023

Using data from 2020, MN-ADDM researchers found 1 in 34 (3.0%) 8-year-old children were identified with ASD. This is comparable to the overall ADDM Network prevalence of 8-year-old children identified with ASD (1 in 36 or 2.8%) in the United States where the CDC tracked ASD in 2020.

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

Boys were 4.3 times more likely to be identified with ASD than girls. Source MN-ADDM, ICI/U of M, 2023

Prevalence of ASD in 8-year-old children in Minnesota by sex and U.S. Census race and ethnicity

Prevalence estimate

Prevalence per 1,000 children

95% confidence interval per 1,000

Overall

1 in 34, 3.0%

29.8

27.3-32.6

Males

1 in 21, 4.7%

47.8

43.4-52.6*

Females

1 in 91, 1.1%

11.0

9.0-13.6

All Asian/Pacific Islander, incl. Hmong

1 in 41, 2.4%

24.3

19.1-30.9

All Black, Non-Hispanic, incl. Somali

1 in 30, 2.8%

27.9

23.1-33.7

Hispanic

1 in 25, 4.0%

40.4

32.2-50.7*

White, Non-Hispanic

1 in 33, 3.0%

30.0

26.2-34.4

Two or more races

1 in 32, 3.1%

31.0

22.1-43.2

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.

*Wilson score 95% CIs exclude 1.0, indicating significantly higher prevalence.

Males had a higher ASD prevalence than females.

Hispanic children had higher ASD prevalence than White, Black, and Asian/Pacific Islander children.

Prevalence of ASD in Somali and Hmong 8-year-old children in Minnesota

Prevalence estimates for Somali and Hmong children were determined by including only the children enrolled in a participating school district. This is because Somali and Hmong children were identified using data from the Minnesota Department of Education.

Prevalence estimate

Prevalence per 1,000 children

95% confidence interval per 1,000

Hmong

1 in 32, 3.1%

31.1

20.4-45.2

Somali

1 in 25, 4.0%

40.0

25.8-58.9

Somali and Hmong 8-year-old children had similar ASD prevalence as other 8-year-old children.

What do the sex and race/ethnicity differences in prevalence rates tell us?

Males aged 8 years had an ASD prevalence 4.3 times higher than females aged 8 years.

Hispanic children had higher ASD prevalence than Asian/Pacific Islander (including Hmong), Black (including Somali), and White children. Prevalence for Hispanic children was 1.7 times that of Asian/Pacific Islander children, 1.3 times that of Black children, 1.3 times that of White children. A prevalence ratio of 1.0 indicates equal prevalence rates. The confidence intervals for prevalence ratios for the above groups were all greater than 1.0, meaning these findings were very likely not due to chance.

For Hmong and Somali students attending our participating school districts, we did not find differences in ASD prevalence compared to other groups.

What was the percentage of 8-year-old children with ID in Minnesota?

Minnesota had intelligence quotient (IQ) data available for 81% of children identified with ASD. Of those children, 32% had intellectual disability. Intellectual disability is defined as an IQ score of 70 or lower. Source: MN-ADDM, ICI/U of M, 2023

Percent of 8-year-old autistic children with intellectual disability

Asian, non-Hmong and Black, non-Somali 8-year-olds had higher rates of co-occurring intellectual disability than White. There were too few Somali, Hmong, and Hispanic children with intellectual disability to include in these estimates.

How common is intellectual disability for 8-year-old children who have ASD?

Among children identified with ASD who had IQ information available, 32% also had intellectual disability.

  • Intelligence quotient (IQ) scores were available for 86% of children identified with ASD by MN-ADDM. Intellectual disability is defined as IQ score ≤ 70.

This information is based on the analysis of data collected from the health and educational records of children who were 4 and 8 years old in 2020. To compare the rate of co-occurring intellectual disability across race and ethnicity, including Hmong and Somali children, we including children attending one of our participating school districts. We did not identify enough Somali, Hmong, or Hispanic 8-year-old children with ASD and co-occurring intellectual disability to include them in these estimates. We found that Asian/Pacific Islander, non-Hmong and Black, non-Somali children had higher rates of co-occurring intellectual disability than White children.

When were children first diagnosed with ASD in Minnesota?

Age of clinical ASD diagnosis: 59 months (4 years, 11 months)

Age of ASD identification, either clinical diagnosis or special education eligibility: 56 months (4 years, 8 month)

The median age of first ASD diagnosis was 4 years, 11 months. Of the children identified with ADS, 42.2% had a recorded evaluation by 36 months of age. Source: MN-ADDM, ICI/U of M, 2023

How did COVID-19 affect Evaluation and Identification of ASD in Minnesota?

To examine the impact of COVID-19 on patterns of evaluation and identification, numbers of evaluations and ages of earliest identification were aggregated by calendar month for children aged 4 and 8 years in 2020. To compare the same age windows by calendar month, the numbers of evaluations and incidence of identification from 2012 (year 0) through 2016 (year 4) for children aged 8 years was subtracted from the same months during 2016 (year 0) through 2020 (year 4) for children aged 4 years.

From 2016 through February 2020, children aged 4 years in 2020 had more evaluations and identifications than the cohort aged 8 years in 2020 had during 2012–2016. After the COVID-19 pandemic declaration, this pattern reversed, and there were fewer evaluations and fewer identifications for children aged 4 years than children aged 8 years received 4 years earlier. Of the 11 ADDM sites, Minnesota had sustained declines in evaluation and identification through the end of 2020.

Tracking Area

The tracking area included parts of three counties (Anoka, Hennepin, Ramsey) including the large metropolitan cities of Minneapolis and Saint Paul.

8-year-old children in the tracking area included 16,150 children of the following race and ethnicity

  • American Indian or Alaska Native – 1%
  • All Asian or Pacific Islander (including Hmong) – 16%
  • Black, non-Hispanic (including Somali) – 23%
  • Hispanic –11%
  • White, non-Hispanic—42%
  • Two or more races—7%

8-year-old children attending one of our participating school districts included 13,213 children

  • Somali – 5%
  • Hmong – 6%

Implications

This is the fourth time Minnesota data has been included in findings from the ADDM Network. The 2020 overall 8-year-old prevalence rate of 1 in 34 is close to the 2018 prevalence rate of 1 in 36. However, the portions of Ramsey and Hennepin counties included in prevalence estimates differed in 2018 and 2020, which may have impacted prevalence.

In Minnesota, there are differences between the proportions of males and females identified with ASD, with more males than females. This is consistent with previous estimates. (Note: the ADDM project only collects data on male and female sex as indicated in records and does not include gender identification information.)

We found varying prevalence rates across racial and ethnic groups in Minnesota. Hispanic 8-year-olds had a higher ASD prevalence than other groups. The small number of children in some of these groups makes it difficult to determine whether the rates of children with ASD truly are different across groups. When differences are found, it is important to focus on general health disparities that may influence these differences.

In Minnesota, we identify ASD much later than when first concerns are reported. The median age of the first ASD diagnosis for 8-year-olds was 4 years and 11 months, which was the latest age across the ADDM Network. This lag is concerning due to the critical importance of early identification and intervention. Many states, including MN, have invested in early intervention to help children and families gain access to early intervention services. For example, Minnesota’s Early Intensive Developmental and Behavioral Intervention (EIDBI) Benefit provides early intensive intervention for people with ASD and related conditions. To learn more about the EIDBI benefit follow this link:

https://mn.gov/dhs/partners-and-providers/news-initiatives-reports-workgroups/long-term-services-and-supports/eidbi/eidbi.jsp

Minnesota experienced marked reductions in ASD evaluations and identifications with the onset of the COVID-19 pandemic in March 2020. These reductions persisted through the end of 2020 in Minnesota and two other states, while 8 ADDM sites showed a recovery of evaluations and identifications to close to pre-pandemic levels.

Limitations

The findings in this report reflect a small number of children concentrated in a large metropolitan area and may not reflect prevalence across the entire state.

The numbers of 8-year-old children with ASD from some racial/ethnic groups are small, and their prevalence estimates will be less precise than estimates for larger-sized populations. Confidence intervals show the range in which we are 95% confident that true prevalence lies, and a larger confidence interval means less precision (e.g., 22.1–43.2 for children with two or more races). This tells us we should use caution before drawing conclusions about differences between some groups.

MN-ADDM reviewed records from participating public school special education programs but did not review private school education records or all charter school education records in our geographic area. Similarly, if a child was identified with ASD in a clinic outside of those included in MN-ADDM’s geographic area, their health records may not have been captured. Incomplete information could lead to misclassifying children’s cognitive ability, overestimating the age when they were first evaluated or when ASD was identified, or failing to capture that the children were identified as having ASD.

Somali and Hmong children with ASD were identified based on language spoken in the home documented in health or educational records. Population denominators for Somali and Hmong children were determined from data from the Minnesota Department of Education on the percent of students in each district who spoke Hmong or Somali in the home. This method may miss Somali and Hmong children who speak English or other languages in their home.