Autism Background

1. What is autism?

Autism spectrum disorder (ASD) is a developmental disability that results from differences in how the brain functions. People with ASD may communicate, interact, behave, and learn in different ways. Signs of ASD begin during the early childhood years and usually last throughout a person’s life.

The term “spectrum” in ASD means that each person can be affected in different ways, and symptoms of ASD can range from mild to severe. People with ASD share some similar symptoms, such as difficulties with social interaction, difficulties with communication, and highly focused interests and/or repetitive activities. How the symptoms affect a person’s functioning depends on the severity and combination of those symptoms.

CDC 2016 Community Report retrieved on 3/27/18 from: PDF

2. Why do we need to know how many children have ASD?

Findings from the MN-ADDM help us understand more about the number of children with ASD, the characteristics of those children and the age at which they are first evaluated and diagnosed.

MN-ADDM’s findings can be used to promote early identification of ASD, plan for ASD services/supports, identify training needs, guide future ASD research and inform policies promoting improved outcomes in health care and education for individuals with ASD.

Study Findings

3. What are the prevalence estimates for ASD in MN?

Using data from 2014, MN-ADDM researchers found 1 in 42 (2.4%) 8-year-old children was identified with ASD in Hennepin and Ramsey counties. This percentage is higher than the average percentage identified with ASD (1.7% - or 1 in 59 children) in all communities in the United States where the CDC tracked ASD in 2014.

4. How do these MN prevalence estimates relate to the national average?

The estimated prevalence of autism in the MN-ADDM surveillance area is higher than the overall prevalence estimated for the communities in the United States where CDC tracked ASD in 2014. This is the first time Minnesota has been a part of the ADDM network and we are working on expanding our geographic area. The findings in this report reflect 9,767 children concentrated in a large metropolitan area (i.e., portions of Hennepin and Ramsey counties). Higher prevalence rates in the Minnesota data as compared to the national estimate may be due in part to a concentration of services and supports in the Minneapolis-Saint Paul area and the availability of both education and clinic source records for review.

5. When is ASD first being diagnosed?

In the reported area in Minnesota, we identified autism much later than when first concerns were reported. Although 73% of children had developmental concerns documented in their records before the age of 3, the average age of first diagnosis in our study was 4 years and 9 months of age. This lag between noted developmental concerns and age of first diagnosis is concerning due to what we know about the importance of early intervention.  

Based on the findings, Minnesota must find ways to lower the age of first evaluation by community providers. With over 2% of the population of 8-year-old children having autism, it is important to continue efforts to support diagnostic, educational and treatment options for children with autism. Minnesota currently has a workforce and provider shortage in the area of autism diagnosis and treatment, and continued efforts are needed to train, recruit and retain professionals and support workers in the field of autism, particularly individuals from racially, culturally and linguistically diverse backgrounds.

6. Does this data show that Minnesota has the second highest rate of ASD in the United States?

The data shows that within the states and geographic areas included in the ADDM Network, MN-ADDM data shows the second highest rate. MN-ADDM data reflects ASD prevalence estimates in the two largest counties in Minnesota. It does show that within these two counties there is a very high rate of ASD among 8-year old children in 2014. MN-ADDM does not know the estimated ASD prevalence rate across the entire state of Minnesota. To estimate the rate for the entire state of Minnesota, researchers would need to expand the geographic region in which data is collected.

7. Does this data show that the prevalence rate of autism in Minnesota is 1 in 42?

We do not know the estimated autism prevalence rate across the entire state of MN. In order to estimate this rate, we’d need to expand the geographic region in which we are gathering data. This data tells us that the estimated prevalence rate of autism for 8-year olds in parts of Hennepin and Ramsey county is 1 in 42.

8. Do these results tell us anything about the reasons for a higher prevalence of ASD in two Minnesota counties?

Tracking prevalence is important to help us understand more about children with ASD; however, this data does not tell us anything about the reasons ASD prevalence is higher in Minnesota. We anticipated a higher prevalence rate compared to the national estimate due to a concentration of services and supports in the Minneapolis-Saint Paul area where this prevalence study took place.

9. How do these findings about prevalence of ASD compare to previous studies about autism in MN?

This project builds on earlier ICI work that estimated the prevalence of ASD among Somali and non-Somali children in Minneapolis, which was the largest project to date to look at the number and characteristics of Somali children with ASD in any U.S. community. The findings of that project, released in 2014, showed notable differences in ASD prevalence and co-occurring conditions, such as intellectual disability, between children from different ethnic groups.

The MN-ADDM project looks more closely at some of those differences among children in the broader two-county area. It is important not to compare the findings from the Minneapolis Somali Autism Prevalence Project because the geographic area was different, the age of the children included in the project was different and it was in a different year. Moving forward we will be able to compare MNADDM data year to year.

There have been two other studies conducted in Minnesota that specifically look at ASD prevalence and the Somali community. It is important to know that these two previous studies used different methods and focused on different groups of children. Thus, making comparisons is likely not wise. You can learn more about these two previous studies by clicking on the links provided here. 

A Qualitative Study of Families of Children with Autism in the Somali Community: Comparing the Experiences of Immigrant Groups. Minnesota Department of Health Report to the Minnesota Legislature 2014 PDF 

Autism Spectrum Disorders Among Preschool Children Participating in Minneapolis Public Schools Early Childhood Special Education Programs PDF. This report provided information on the rates of preschool special education program participation in MPS only.

Study Approach

10. What data was gathered to determine the results?

The information was gathered from health and special education records of children who lived in Hennepin or Ramsey counties and who were 8 years old in 2014.

11. Why is the data from 2014 and not more recent?

ADDM is a rigorous and labor-intensive data collection process. It takes a lot of time to gain access to the data and to conduct the detailed review and analyses for the entire ADDM network. ADDM data is retrospective and relatively time consuming to collect, but if offers a level of detail, insight, and precision that a simple count (e.g. administrative prevalence) cannot provide.

12. How and where was this information collected?  

The ADDM Network estimates the number of children with ASD using a systematic record review method. Trained abstractors reviewed records at sources in the community that educate, diagnose, treat, and/or provide services to children with developmental disabilities. It is important to note that this review did not only rely on a child having an ASD diagnosis, but also included a review of records for children with documented behaviors that are consistent with a diagnosis of ASD. Abstracted information from all sources for a child was then reviewed by highly trained clinicians who determined if the child met the definition of ASD using the DSM-IV-TR and now also DSM-5 criteria.

CDC 2016 Community Report retrieved on 3/27/18 from: PDF]

13. Why was the data not collected statewide?

MN-ADDM was funded to estimate the prevalence of 8-year-olds with ASD and with intellectual disabilities in Hennepin and Ramsey counties. This project also identified disparities in prevalence, characteristics and age of diagnosis across demographic groups, including two large racial/ethnic groups unique to the area – Somali and Hmong children.

Many other ADDM sites supplement their funds with state dollars. The MN-ADDM project is only funded by the CDC, and our geographic area is limited by availability of resources. Having access to a larger geographic area would increase the MN-ADDM population size included in the identification of prevalence. This would provide more information about the geographic variation among regions and likely identify sufficient numbers of children in diverse racial, ethnic and linguistic populations to draw conclusions about differences in prevalence estimates and disparities.

MN-ADDM is a valuable resource for the state of Minnesota, but it will need more funds to support expansion into more communities in the state.

14. In the future, how could the number of children included in MN-ADDM be increased?

The population is based on access to records in school districts and clinics within Hennepin and Ramsey counties. To increase the geographic scope, any additional counties would need to border Hennepin or Ramsey counties to be analyzed per CDC methodology. Additional funding would also need to be secured to expand the geographic area of MN-ADDM. As MN-ADDM continues its work in Hennepin and Ramsey counties, researchers anticipate partnering with additional school districts. MN-ADDM has secured at least two new school districts for the 2016 review of data as of April 2018.  

15. Why study 8-year-olds instead of adults?

The CDC's ADDM Network methodology is standardized across all data years and has estimated the prevalence of autism for 8-year-olds since its first data cycle and continues to do so. By age 8, a child with autism should have been identified either clinically or through the education system. Some ADDM sites receive additional funding to look for prevalence of autism in 4-year-olds. The MN-ADDM is not one of those sites at this time; but would be interested in expanding to 4-year-olds in the future.

16. Are the diagnostic criteria different for the presentation of ASD in girls?

Diagnostic criteria used to identify ASD are the same across all genders, and racial and ethnic groups. In Minnesota, more boys than girls were identified with ASD. This is consistent with previous national estimates on ASD and gender.            

17. How have quality and accuracy of results been ensured?

Established protocols have been followed in the planning, gathering and analysis of all data. Specifically, the standard criteria used as part of the ADDM Network method ensures that all records are evaluated and reviewed in the same way and that all children are defined as having ASD using the same definition. The CDC monitors the project to ensure adherence to CDC methods.

18. What were the criteria used in the MN-ADDM data to confirm whether a child had autism or not? DSM-IV or DSM-5?

In 2013, the American Psychiatric Association changed the criteria for making a diagnosis of ASD. Beginning in 2014, the ADDM Network incorporated a new ASD surveillance case definition based on these revised criteria. Clinicians reviewed the abstracted records to determine ASD case status using two coding processes, one based on DSM-IV criteria and another on DSM-5. Each case was reviewed separately once using DSM IV criteria and once using DSM-5. This was important, because researchers wanted to see if the change to DSM-5 would have an impact on overall prevalence. The ADDM project will continue to provide valuable information on the impact of the full implementation of the DSM-5 and how it in influences prevalence rates in ASD.

19. Were there differences in the prevalence estimates in children based on DSM-IV or DSM-5 criteria?

Recent changes in the diagnostic criteria for autism had little impact on the percentage of school-aged children identified as having ASD by ADDM Network surveillance. In 2013, the American Psychiatric Association changed the criteria for making a diagnosis of ASD. Beginning in 2014, the ADDM Network incorporated a new ASD surveillance case definition based on these revised criteria. Estimates of the percentage of children identified with ASD based on the old and new surveillance case definitions were similar, especially among children with an existing ASD diagnosis or eligibility for autism special education services. It may be too soon to determine the long-term impact of the changes in the diagnostic criteria on ASD prevalence and characteristics. CDC will continue to monitor this in the next ADDM Network report.

Overall, comparisons of DSM-IV-TR and DSM-5 were similar, even when stratified by sex, race/ethnicity, DSM-5 diagnostic subtype, or level of intellectual disability. Further, prevalence estimates based on the new DSM-5 case definition were very similar in magnitude, but slightly lower than those based on the historical DSM-IV-TR case definition.  The ADDM project will continue to provide valuable information on the impact of the full implementation of the DSM-5 and how it in influences prevalence rates in ASD.

20. What role has the community had in the project?

MN-ADDM collaborates with a wide variety of community ASD organizations and several Minnesota state agencies including the Minnesota Departments of Education (MDE), Human Services (DHS), and Health (MDH). School districts and clinics are important community partners. MN-ADDM uses an active community advisory board consisting of parents/family members, advocates, researchers, service providers, administrators, faith leaders, educators, clinicians, and community organizers to inform, guide and support the work of MN-ADDM.

Racial and Ethnic Group Analysis

21. Why does MN-ADDM focus on the Somali and Hmong populations in its project?

This project builds on earlier ICI work entitled the Minneapolis Somali ASD Prevalence Project that estimated the prevalence of ASD among Somali and non-Somali children in Minneapolis. That project is the largest project to date to look at the number and characteristics of Somali children with ASD in any community within the United States. The findings of that 2014 project, showed notable differences in ASD prevalence and co-occurring conditions, such as intellectual disability, between children from different ethnic groups in Minneapolis. Other studies conducted in the United States have identified disparities among children with autism from racially and ethnically diverse backgrounds in terms of age of diagnosis and access to and utilization of services.

The MN-ADDM project looks more closely at possible differences among children across a variety of racial and ethnic groups in the broader two-county area so that we can expand the number of children in sub-populations and better understand if there are estimated prevalence differences and disparities.

22. How have quality and accuracy of results been ensured?

The ADDM Network method is a rigorous and standardized process. We maintain a high level of staff training, ongoing quality assurance monitoring, and precision by collecting and reviewing information on all children the same way using the same criteria. These steps help ensure that ADDM Network results are accurate and unbiased.

23. How did the study approach estimation of prevalence of ASD for the different racial/ethnic groups?

MN-ADDM collected racial and ethnic data per CDC methodology, but it also looked at autism and intellectual disability prevalence in two racial/ethnic groups with high populations in Minnesota: Somali and Hmong. To do this, data is gathered on language spoken in the home.

24. How does the Somali prevalence data compare to other racial and ethnic communities?

While MN-ADDM found varying prevalence estimates across racial and ethnic groups in Minnesota, there were no significant differences in prevalence by racial and ethnic group (using a p-value of <.01). 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. Additionally, the confidence intervals around the prevalence estimates are large, and researchers urge caution before drawing conclusions about any differences between groups. As the geographic area for MN-ADDM grows and includes more children, MN-ADDM will be better able to judge whether there are true differences in prevalence estimates. If differences are found, it will be important to focus on general health disparities that may influence these differences.   

MN-ADDM found that of the children with ASD who had IQ tests in their records, overall 28% also had an intellectual disability. When we looked at ethnic groups, we found that 43% of Somali children with ASD also have an intellectual disability and 18% of Hmong children with ASD also had an intellectual disability. While the percentages appear different, sample sizes were too small to be able to tell whether this difference was real or whether it occurred by random chance.

25. Does this data show that Somali children have the highest rates of ASD in Minnesota?

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. Additionally, the confidence intervals around the prevalence estimates are large, and therefore, researchers urge caution before drawing conclusions about any differences between groups.

Critical Issues and Next Steps

26. Is this an epidemic or crisis? Why are more children being identified with ASD?  

A large number of children are identified as having ASD and the prevalence rates have certainly increased over time. We do not know whether more children are truly developing ASD than in the past or whether we are doing a better job at identifying it. Tracking prevalence is important to help us understand more about children with ASD; however, this data does not tell us anything about the reasons why ASD prevalence is high within the United States and higher in Minnesota. The higher prevalence estimate compared to national estimates is not unanticipated in a large metropolitan area and given we have both education and clinic site records to review. 

27. What is the cause of autism? What is being done to find a cause(s)?

MN-ADDM was designed to identify the prevalence of autism in 8-year-olds in Hennepin and Ramsey counties. Its purpose was not to figure out the causes of autism. It can help MN-ADDM understand who lives with autism so it can advocate for resources and policies that support families and individuals with ASD.

ASD is a complex condition, and most scientists who study ASD believe that there is no single cause. There is strong evidence that ASD is genetic and involves multiple genes. There may also be environmental and other factors which make a child more likely to have ASD. We do not yet know enough about environmental factors that might be linked to autism to make definitive statements. Understanding more about these factors will help us learn about the causes of ASD. It is important to remember that no single risk factor leads to ASD, and many of these risk factors are outside of an individual’s control.

There are many researchers interested in understanding causes of autism, including some at the University of Minnesota who are looking at the genetics of autism and at early brain development in children at risk for autism. MN-ADDM is happy to connect you with specific research studies if you are interested.

28. What is the CDC doing to study the causes of ASD?

For more information on CDC autism research, please visit

29. Do immunizations cause ASD?

Research has not found evidence that vaccines cause autism. The only study that suggested a link was later found to be untrue, because the researcher misrepresented his findings and used unethical methods. MDH has a link to more information about this topic, but we also recommend you talk with your child's pediatrician about your concerns.

30. Immunizations rates for Somali children have gone down over time, so why did ASD rates go up?

This tells us that avoiding vaccines does not prevent autism in children. We understand that parents are fearful their child may develop autism and want answers for what causes autism. We know it's not vaccines, but we don't yet know what all of the causes of autism are and finding those answers would help put to rest fears about vaccines. We hope that resources can be dedicated to understanding what really does cause autism and, even more importantly, what treatments, supports, and services work to improve the lives of people with autism and their families. It is important to talk with your doctor at your well child visits about your child's development and also about any concerns you might have about vaccinations.

31. Why are we still looking at prevalence when we know a high percentage of children in Minnesota have ASD?

Documenting prevalence is a necessary step towards establishing the need for developing more services and supports to meet the demand in Minnesota and also for identifying the need for more research. While many children have been diagnosed with ASD, MN-ADDM data helps to better understand differences in prevalence related to geographic location, race, ethnicity and linguistic background. Continuing to expand our knowledge about prevalence to a larger geographic area helps us move closer to being able to answer these types of questions with confidence.

32. What are possible next research steps?

ADDM data has played an important role in documenting the number of children identified with ASD in the United States. This data has laid the groundwork for ongoing ASD research such as who is likely to develop ASD, when children are identified with ASD, and how to best support children with ASD and their families. MN-ADDM will allow for the same work to happen in the state of Minnesota, including the ability to study the differences between racial and ethnic communities in Minnesota.

More About MN-ADDM and ASD Resources

33. What other community work and resources does MN-ADDM provide?

MN-ADDM actively engages culturally and linguistically appropriate dissemination, educational and outreach activities designed to target hard-to reach communities. MN-ADDM partnered with the CDC funded "Learn the Signs. Act Early" (LTSAE) project and Help Me Grow MN to conduct outreach and educational activities on early developmental screening and early identification in under-identified communities such as Latino, Hmong, and Somali communities. MN-ADDM together with MN Act Early has translated and customized ASD and LTSAE outreach materials and resources for our local diverse communities. 

A short film series was developed in partnership with MN Department of Human Services to raise awareness of Autism Spectrum Disorder (ASD) for local diverse communities (e.g. Somali, Hispanic, Hmong, African American, and American Indian). They are designed to help families access evaluation resources, early intervention services, and ASD support resources.

34. What are state agencies in MN doing to address the issue of high prevalence rates of autism in our children?

Representatives from the Minnesota Departments of Education, Health, Human Services, and Employment and Economic Development, in partnership with other stakeholders including providers, parents and caregivers, clinicians, researchers, self-advocates and advocates  continue to work towards coordination across the range of services available.

People with ASD or related conditions often need a variety of supports and services over the course of their lifetime. To meet each individual person and family’s needs, the state of Minnesota offers many programs, including those for health care, education, home and community-based supports and mental health services.

Even before a child receives a formal diagnosis, local school districts serve as a resource for referrals and services. For children birth to age 5, families can contact Minnesota Help Me Grow. For children over the age of 5, contact local school districts can be contacted for special education services.

County public health, social services or tribal offices can provide local information and referrals, including advocacy, child care, community resources, county services, education and medical specialists. For information and referrals, contact the child’s local county agency or tribe.

If you have concerns or have recently received a referral from a child’s school or child care provider, and a diagnosis of ASD or a related condition is suspected, contact your doctor or locate a provider to complete an assessment at or contact the Disability Hub at 1-866-333-2466 or

35. When the rate of autism is growing and so many more children are being diagnosed, how will we be able to provide services to all children with ASD? How much more will it cost to serve children, youth and adults given this new prevalence estimate?

The rates of autism are high and it is critical for children to get assessed and diagnosed early so that they can get early intensive intervention services. These services and supports do cost money and most people with ASD will require some time of support throughout their lives. As a community we will need to come together to ensure our elected officials understand the importance of access to affordable services and supports. A critical component of the service system is having enough qualified and trained professional staff with the skills to deliver the interventions. This too will need to be addressed.

36. Many treatments and supports for children with ASD are expensive, how can families afford them?

In Minnesota both private and public health insurers are required to offer services.

37. What is the Minnesota Department of Health doing to address autism prevalence in MN?

MDH actions are focused on four important things – prevention, intervention, research, and outreach.

PREVENTION: We know the mother’s nutrition and health during pregnancy is crucial to the future health of the baby.

  • Some research indicates a lack of folic acid can contribute to autism and thus our Birth Defects Program provides education and outreach to many audiences.
  • Continuing to stay current on new research for key risk factors is critical so we can educate mothers regarding healthy pregnancy’s.
  • MDH has many programs including WIC and the family home visiting to help women have healthy pregnancies.

INTERVENTION: When a child has autism, one the most important things is to identify the condition as early as possible so they can start getting intervention.

  • MDH works with the Minnesota Department of Education and Department of Human Services to help identify children with autism as early as possible.
  • State agencies are working to improve referral and access systems to decrease time from parental concerns to accessing resources. 
  • MDH has been encouraging clinics, through the Health Care Homes program, Follow Along Program, and the Child and Teen Check-Ups program, to do a better job screening for developmental delays, including autism.
  • MDH builds capacity and expands the provider networks for families to access medical, Human Services and Education treatment options.

RESEARCH: MDH is in trying to learn what is happening in communities and that is where MDH has focused their research efforts. 

OUTREACH: MDH is working on getting information out to families so they understand more about autism and the services available to help their children with autism. Our efforts are especially focused in underserved communities and in communities most impacted by autism and other developmental delays.