(Adds comments by autism experts and CDC on why rates are
rising, other background)
By Julie Steenhuysen
CHICAGO, March 27 As many as one in 68 U.S.
children have autism, a 30 percent increase in just two years,
U.S. health officials said on Thursday, but experts think the
rise may simply reflect that parents and doctors are getting
better at recognizing and diagnosing the disorder.
Experts were largely unfazed by the latest numbers, which
they say do not necessarily suggest increasing prevalence.
"It's not that surprising because as people get more aware,
the prevalence has always increased in a psychiatric disorder,"
Dr Thomas Frazier, director of Cleveland Clinic Children's
Center for Autism, said in a telephone interview.
The latest report by the U.S. Centers for Disease Control
and Prevention, which looks at data from 2010, estimates that
14.7 per 1,000 8-year-olds in 11 U.S. communities have autism.
That compares with the prior estimate of 1 in 88 children, or
11.3 of 1,000 8-year-olds, in 2008, and 1 in 150 children in
Autism encompasses a spectrum of disorders, ranging from a
profound inability to communicate and mental retardation to
relatively mild symptoms in people with very high intellectual
Coleen Boyle, director of the CDC's National Center on Birth
Defects and Developmental Disabilities, said while the report
does not explain why rates are rising, it does give some clues.
For example, almost half of children identified as having
autism in the latest report had average or above-average IQ
levels, compared with just a third of children a decade ago.
"It could be doctors are getting better at identifying these
children; it could be there is a growing number of children with
autism at higher intellectual ability, or it may be a
combination of better recognition and increased prevalence,"
Frazier said it is very likely that the current report is
still undercounting autism rates among higher-functioning black
and Hispanic children. Among black children with autism in the
report, half also had intellectual disability, a more overt sign
of problems. That compared with just 35 percent of white kids
with autism, who also had intellectual disability.
Ultimately, Frazier thinks the autism rate will settle at
around 2 percent of the population, or around 1 in 50 kids.
Part of the issue may be the way the CDC measures autism,
combing through health and school records of 8-year-olds within
fewer than a dozen communities in the United States.
The study showed significantly different autism rates by
region, ranging from 1 in 175 children in Alabama to 1 in 45
children in New Jersey, which could reflect access to healthcare
and other factors.
The CDC said the latest data continues to show that autism
is almost five times more common among boys than girls,
affecting 1 in 42 boys versus 1 in 189 girls.
White children are more likely to be identified as having
autism spectrum disorder than are black or Hispanic children.
The CDC only funded 12 tracking sites for the current study
and data from only 11 were included in the report, a drop from
14 sites in the report issued two years ago, a reflection of
tight budgets at the CDC that forced the agency to scale back.
And while the data cannot be generalized to a national
population, Boyle said it is the best estimate available.
"It's not a national probability sample, but it is a very robust
estimate and it's the best we have."
Rob Ring, chief science officer for the advocacy group
Autism Speaks, said he does not think many autism researchers
were surprised to see this increase.
He said the CDC's method relies on individuals already
flagged by the healthcare and education systems. "If you are not
in those systems, you would not be counted."
His group backed a 2011 study using a new research approach
that found one out of every 38 children in South Korea may have
The researchers used a painstaking research method that
involved screening 55,000 children aged 7 to 12 in the South
Korean city of Goyang. The team surveyed parents about their
children's behavior, then followed up with evaluations of
at-risk children to confirm their diagnosis.
The population-based approach was designed to capture cases
that might not be detected with methods that use school or
medical records to identify autistic children.
Autism Speaks is partnering with the CDC to use this same
research method in South Carolina, with results expected some
time next year.
Dr Melissa Nishawala, medical director of the Autism
Spectrum Disorders Clinical and Research Program at New York
University's School of Medicine, agrees that the new numbers
likely reflect "the way we define autism and the way we look for
cases and how good we are at finding cases."
Nishawala said reports about high rates of autism are
increasing awareness, and the latest numbers from the CDC will
likely mean even more people look for signs in their children.
(Editing by Michele Gershberg, Stephen Powell and Matthew