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
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
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
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.
Interpreting the New Autism Data
Experts are not certain what to make of the findings but urged caution in
interpreting them. "In ASD, we don't know if the change in the numbers over
time is a change in the actual condition," Arias says, or to other factors.