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Two New CDC Autism Prevalence Studies Confirm Upper End of Prevalence Range

August 20, 2007

The Centers for Disease Control in Atlanta released the results of two new autism prevalence studies on May 4, 2006. The first, the National Health Interview Survey (NHIS) reports the prevalence of autism as 5.7 per thousand among children aged 4-17. The second, the National Survey of Children's Health (NSCH) pegs prevalence at 5.5 per thousand among children 4-17. The data were collected from parental surveys in 2003-2004. CDC reports a range of prevalence (2-6 per thousand) based on data from approximately 20 studies. Today's data are not expected to result in any immediate change in that reported range.

The data are based on parental reports. In both surveys autism was ascertained from the question “Has a doctor or health-care provider ever told you that your child has autism?” For both surveys, children who were aged 4-17 at the time of the survey were selected. The final samples included 18,885 in the NHIS and 79,590 in the NSCH.

Results from the two surveys suggest that as of 2004, autism had been diagnosed in at least 300,000 children aged 4-17. Parents who reported their children had autism also reported that these children experienced moderate or high levels of social, behavioral and emotional difficulties and needed special health care and educational services.

The findings in this report are subject to several limitations. Parental report of autism is dependent on access to appropriate health services for diagnosis and communication of that diagnosis to parents. Also, because the survey only asked about autism, parents whose children had been diagnosed with other autism spectrum disorders (Aspergers Syndrome, PDD-NOS) may not have responded affirmatively.

The data were released in the May 5, 2006 issue of the “Morbidity and Mortality Weekly Report”. To read the full report, click here.