US survey shows autism more common than believed
WASHINGTON, Feb 9 (Reuters) Autism is more common in the United States than anyone had estimated, affecting about one in every 150 children, the US Centers for Disease Control and Prevention reported.
Two surveys by the agency encompassed 22 states and represented the largest and most comprehensive studies of how many children have autism. It showed a wide variation among the states, ranging from 4.5 per 1,000 children having an autism-related disorder in West Virginia to 9.9 per 1,000 in New Jersey.
''There's been a lot of concern about what the prevalence of autism is in the United States and we haven't really had the data systems to answer that completely,'' said Catherine Rice of the CDC's birth-defects division, who helped lead the study.
The surveys look at 8-year-olds, the first in eight states and the second looks at 8-year-olds in 14 states. On average, they found that about one in 150 children born in 1992 and 1994, or 6.7 per thousand, have autism.
Previous estimates had put the incidence at somewhere between one in 166 children and one in 175.
The reports are the first from the government-funded Autism and Developmental Disabilities Monitoring Network.
''We really do think that these data are important because they represent the most complete and accurate picture of autism spectrum disorders in the United States to date,'' Rice said in a telephone interview.
Types of ''autism spectrum disorder'' range from autism, which can severely disable a child by interfering with speech and behavior, to Asperger's syndrome, a much milder behavioral problem.
The researchers hope to eventually use the surveys to help figure out what causes autism. They also want to be able to verify suspicions autism may be growing more common in the United States.
BUILDING AWARENESS ''We hope these findings will build awareness,'' Rice said.
Activists have said for years that autism was becoming more common.
Some experts discount claims of skyrocketing rates, saying the definition of autism has changed over the years, but reliable survey figures have been scarce.
''A lot of professionals were asking what had changed, had we seen more children than in the past?'' said Dr Marshalyn Yeargin-Allsopp, who helped lead the study.
The CDC surveys, published in yesterday's weekly report on death and disease, use a variety of sources such as schools, physician reports and other data. Rice said it took years to get required approvals to see the data.
The autism rates remained fairly stable over the two years in which the surveys were taken, Rice said, except for in West Virginia, where the prevalence rose greatly. Rice said it is not clear yet why.
The studies also showed far fewer of the autistic children had mental retardation than in previous estimates.
''The
older
statistics
always
estimated
70
to
75
per
cent
of
kids
with
autism
had
cognitive
impairment,''
Rice
said.
''We
found
33
to
62
per
cent.''
REUTERS
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