Autism Affects 1 in 175 U.S. Children
05.04.06, 12:00 AM ET
THURSDAY, May 4 (HealthDay News) -- The first-ever national
estimate of the
prevalence of autism in the United States finds the behavioral
affects up to one in every 175 school-age children -- a total of
That finding comes from researchers at the U.S. Centers for
and Prevention in Atlanta, who presented their conclusions at a
conference on Thursday.
The agency's estimates are based on interviews conducted in 2003
with the parents of nearly 98,000 children aged 4 to 17. In two
surveys -- the National Health Interview Survey (NHIS) and the
Survey of Children's Health (NCHS) -- parents were asked: "Has a
health-care provider ever told you that [your child] has
"Estimates of diagnosed autism from these surveys were 5.7 per
school-age children from the NHIS, and 5.5 per 1,000 school-age
from the NSCH," said Laura Schieve, an epidemiologist with the
National Center on Birth Defects and Developmental Disabilities
Those ratios correspond to about one in every 181 children and
one in every
175 children, respectively, the researchers said.
"Together, these two national surveys of parents suggest that
school-age children had a diagnosis of autism in 2003-2004,"
The findings appear in this week's issue of the CDC's journal
Mortality Weekly Report.
As borne out in previous studies, "both surveys indicated that
nearly four times more likely to have been diagnosed with autism
girls," Schieve said. Hispanic parents were slightly less likely
non-Hispanic whites to report a child with autism, although the
said this may be due to cultural or other factors, including
The new national estimates echo previous surveys, most of which
on doctor and/or teacher reports and confined to specific states
Schieve said. Those studies had led experts to a slightly higher
the prevalence of autistic-spectrum disorders among U.S.
children -- about
one in every 166 children.
One autism expert said the CDC findings echo previous research.
Dr. Melissa Nishawala is clinical director of the New York
Study Center's Autism Spectrum Disorders Service and an
of Psychiatry at the NYU School of Medicine. She said a similar,
survey in England that also relied heavily on parental reports
rates there to be about 6.3 cases per every 1,000 children.
The CDC experts stressed that because these were the first such
conducted, the results say nothing about either the underlying
autism, or ongoing prevalence trends.
"These surveys are designed to provide us with a snapshot, a
picture of the
world at a given time -- in this case, the results cover the
2003-2004," said NCBDDD Director Dr. Jose Cordero.
The prevalence of diagnosed autistic spectrum disorders -- which
autism and two less severe conditions, Asperger disorder and
developmental disorder -- was found to be less among 4- to-5
year olds (4.8
cases per 1,000 children) than among children aged 6 to 8 years
of age (7.5
Schieve and Cordero attributed that statistical difference to
"Although often autism can be identified as early as 18 months,
children won't be diagnosed until they start school," Schieve
some of these 4- to-5-year-old children who might later go on to
autism diagnosis may not have been diagnosed at the time of this
Previous studies have shown that parents often miss an early
autistic disorders, only picking up on it later when youngsters
For that reason, the real prevalence of autism may slightly
numbers supplied by these surveys, the experts said.
Nishawala agreed. "Any increase in numbers is probably due to
definition and increased surveillance," the NYU expert said. "In
children on either end of the spectrum -- someone who was
to someone with an extremely high IQ --might never be
What is clear is the toll the disorder takes on parents and
"In the NHIS [survey], 83 percent of the parents who reported
child had autism also reported that their child had difficulties
emotional symptoms, conduct, hyperactivity or peer
said. "This compares to just 15 percent among children not
reported to have
Problems interacting with other children led the list of
difficulties, with the NHIS survey finding 82 percent of parents
children citing this issue. Hyperactivity was another problem,
percent of parents reporting trouble in that area.
The NSCH survey found that autistic children also required more
than non-autistic children -- nearly 94 percent of parents of
children said their child had special health-care needs lasting
one year, compared to just under 20 percent for non-autistic
nearly 93 percent of autistic children were described by their
parents as at
"high risk for developmental delay," compared to just over 9
According to Schieve and Cordero, the CDC plans to continue
type of data to track national trends and get a better
autism, the origins of which remain largely unknown.
"We share parents' frustration of not having more answers about
and cures for autism," Cordero said.
For more on autism, visit the U.S. National Institute of Mental