Autism May Be More Common Than Thought
Survey Shows 1 in 91 Children May Have Autism Spectrum Disorder
Oct. 5, 2009 -- About 1% of U.S. children, or about one in 91, may have autism or an autism spectrum disorder, according to two new national surveys.
The new estimate is a dramatic increase from the previously accepted number of one in 150. But experts who discussed the findings of the two new surveys -- one released today and the other due out before year's end -- urged caution in interpreting the new information about the developmental disorders.
A new survey by the CDC found that about 1% of U.S. children are affected by an autism spectrum disorder, says Ileana Arias, PhD, deputy director of the CDC.
No further details were available on the CDC survey, due to be released in full later this year.
The same prevalence, however, was found in the survey released today, says Michael D. Kogan, PhD, of the Maternal and Child Health Bureau of the Health Resources and Services Administration. With his colleagues, Kogan drew on data from the 2007 National Survey of Children's Health, a telephone survey of parents jointly conducted by the Health Resources and Services Administration and the CDC.
The parents of more than 78,000 children ages 3 to 17 were asked if their child had ever been diagnosed with autism or other disorders on the spectrum, such as Asperger's syndrome or pervasive developmental disorder. If parents answered yes, they were then asked if their child currently had an autism spectrum disorder (ASD) and if so, how severe the condition was -- mild, moderate, or severe.
In all, 1,412 said their children had ever been diagnosed with an ASD, and 913 said their child still had the condition. Next, Kogan's team took the number of children in the survey with ASD and the total number of children surveyed and computed estimates of autism spectrum disorder prevalence based on the general population.
''We estimate that the prevalence of ASD among children 3-17 in 2007 was around 110 in 10,000,'' Kogan says. "What this translates to is about one in every 100."
The survey also showed that white non-Hispanic children were more likely than black non-Hispanic or multiracial children to have the diagnosis, he says. Boys were four times as likely as girls to have ASD.
About 38% of the parents said they had been told previously their child had an ASD but that the child did not currently have the condition. The survey results are published in the journal Pediatrics.