Prevalence of Autism Spectrum Disorders Autism &  Developmental Disabilities Monitoring Network, 14 Sites, United States, 2002

The Centers for Disease Control and Prevention reviewed the 2002-2003 medical and educational records for 407,578 eight-year old children in 14 surveillance areas in the United States. Of the group, based on medical and educational records, 2,685 children were identified as having autism spectrum disorder (ASD). The prevalence differed between areas and is possibly due to different access to records. The rate in New Jersey was 10.6 children with ASD per 1,000; in northern Alabama 3.3 children per 1,000 were identified with ASD. The key difference between these rates is that researchers had full access to New Jersey children's education records. In Alabama, access to education records was restricted. Overall, states that limited access to education records had an average ASD rate of 5.1 children per 1,000; states that provided full access had an average ASD rate of 7.2 children per 1,000.

Overall, the rate of males with ASD ranged from 6.6 to 14.8 per 1,000 boys. The ASD rate for females was between 2.0 to 4.3 per 1,000 girls. Females with an ASD were more likely than males to also have a cognitive disorder.

The study results will be used in a longitudinal study to determine if ASD prevalence rates are increasing and if so, among what populations. In six sites for which prevalence data were available from both 2000 and 2002, ASD prevalence was stable in four sites and increased in two sites (17% in Georgia and 39% in West Virginia).