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CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network released data in 2007 that found about 1 in 150 8-year-old children in multiple areas of the United States had an ASD.

Since the ADDM sites do not represent a nationally representative sample, the prevalence estimates should not be generalized to every community in the United States. Although accurate for the areas we studied, rates may be higher or lower in other areas. However, these prevalence estimates can help communities project how many children may have autism for planning and identification purposes. They can also be used to provide for more appropriate interventions for children with ASDs.

What do the ADDM network results tell us about the prevalence of ASD in the United States?
Results from CDC’s ADDM network showed the average ASD prevalence among states participating in the project was 6.7 per 1,000 children in 2000 (6 sites) and 6.6 per 1,000 in 2002 (14 sites), or approximately 1in 150 children. Most sites identified between 5.2—7.6 per 1,000 8-year-old children with ASD in 2000 and 2002. There was some variation with ASD prevalence significantly lower in 1 site (3.3 in AL) and higher in 1 site (10.6 in NJ). Prevalence was stable from 2000 to 2002 in 4 of the 6 sites that participated in both surveillance years, but increased slightly in GA and significantly in WV, indicating the need for ongoing monitoring of prevalence over time. These data provide important information on the prevalence of ASD in areas of the United States and will be used to examine trends in the occurrence of these disabilities over time.

What did we know about the prevalence of Autism Spectrum Disorders (ASDs) before ADDM?
For decades, autism was believed to occur in 4 to 5 per 10,000 children. In 2004, CDC partnered with the American Academy of Pediatrics (AAP) to issue an Autism A.L.A.R.M. At that time, Data from several studies that used the current criteria for diagnosing ASDs (DSM-IV and ICD-10) found prevalence rates for ASDs between 2 and 6 per 1,000 children. Therefore, it was summarized that up to 1 in 166 children (6/1,000) have an ASD. While the 1in166 indicated the average upper estimate, there have been studies that have found as many as 12 in 1,000 children with an ASD in Europe and Scandinavia. Studies conducted specifically in the United States have found rates between 2 to 7 per 1,000 children in the past decade.

How do the rates of ASDs compare with other childhood disabilities?
A study conducted by the Centers for Disease Control and Prevention, the Metropolitan Atlanta Developmental Disabilities Surveillance Program, found the rate of autism for children ages 3 to 10 years to be 3.4 per 1,000 children which is lower than the rate for mental retardation (9.7 per 1,000 children); but higher then the rates for cerebral palsy (2.8 per 1,000 children), hearing loss (1.1 per 1,000 children) and vision impairment (0.9 per 1,000 children) found in the same study.

Approximately 2% of children under the age of 18 have a serious developmental disability (DD) and these include mental retardation, cerebral palsy, hearing loss and vision impairment. Of these serious DDs, mental retardation (or intellectual disability) is the most common. A genetic disorder often associated with having mental retardation (MR) or an intellectual disability (ID) that many people recognize is Down syndrome. Current information indicate that having Down syndrome occurs in 1 out of 800 births and is slightly less common than the ASDs. Approximately 17% of children have some type of developmental disability, including more mild conditions such as speech and language disorders, learning disabilities, and ADHD, which appear to be more common than the ASDs.

While developmental disabilities may affect a child’s speech or language, physical growth, psychological growth, self-care, or learning, children’s health may also be affected by diseases that impact adults as well. A common childhood disease, juvenile diabetes, is prevalent in approximately one in every 400 to 500 children and adolescents, which is in a similar range of the ASDs. However, the ASDs are more common than childhood cancer, which has a prevalence rate of 1.5 per 10,000 children (1 in 300 males and 1 in 333 females have a probability of developing cancer by age 20 according to the National Cancer Institute).

Fact Sheet
ADDM MMWR SS February 9, 2007



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About half of children with autism spectrum disorders (ASD) can be diagnosed soon after their first birthday.

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