That is higher than the previously, widely-quoted figure of 1 in 166 children, which was based on a study in six states of 8-year-olds born in 1992. The CDC said it focuses on 8-year-olds because most children with an autism spectrum disorder are identified by this age.
The results of this study suggest, when extrapolated nationwide, that there are 560,000 children and young adults with an autism spectrum disorder in the United States, according to a story published tonight by the Associated Press. See the story posted on The New York Times website here.
Government scientists cautioned against creating a national figure yet, because their data is new and the studies so far do not include big states such as California, Texas and Florida.
You can see a web page the CDC has set up, with links to documents, by clicking here.
There were some differences in the results in the 2002 study (children born in 1994) among the 14 states examined (Alabama, Arizona, Arkansas, Colorado, Georgia, Maryland, Missouri, New Jersey, North Carolina, Pennsylvania, South Carolina, Utah, West Virginia and Wisconsin). A media advisory fact sheet published by the CDC shows these points about this group:
- The study looked at approximately 10 percent of U.S. eight-year-old children (i.e., children born in 1994), from 14 states - Alabama, Arizona, Arkansas, Colorado, Georgia, Maryland, Missouri, New Jersey, North Carolina, Pennsylvania, South Carolina, Utah, West Virginia and Wisconsin. A total of 2,685 eight-year-olds were identified as having an ASD.
- ASD prevalence among eight-year-old children was 3.3 per 1,000 (Alabama) to 10.6 per 1,000 (New Jersey). But, 12 of the 14 sites had a closer range of 5.2 to 7.6 per 1,000 children (average across all 14 sites was 6.6 per 1,000 eight-year-old children).
- In 2002, four sites (Alabama, Missouri, Pennsylvania and Wisconsin) relied on information from health sources. On average, the prevalence was lower in those sites than in the other 10 sites that combined information from health and education sources. In both study years, many ASD cases were found through education sources alone.
- ASD prevalence was higher among boys than among girls, ranging from more than three to more than six boys for every girl with ASD.
- Boys: 5.0 per 1,000 (Alabama) to 16.8 per 1,000 (New Jersey)
- Girls: 1.4 per 1,000 (Alabama) to 4.0 per 1,000 (New Jersey)
- ASD prevalence among white non-Hispanic children ranged from 3.3 per 1,000 (Alabama) to 12.5 per 1,000 (New Jersey). For black non-Hispanic children, ASD prevalence ranged from 3.4 per 1,000 (Alabama) to 7.7 per 1,000 (New Jersey). Among Hispanic children, it ranged from 0.3 per 1,000 (Wisconsin) to 9.7 per 1,000 (New Jersey).
- The median age of earliest ASD diagnosis ranged from four years, one month (Utah) to five years, six months (Alabama). But for 51–91 percent of children with an ASD, developmental concerns had been recorded before three years of age.