1 in 150 children has autism, U.S. study says
The survey offers no clues as to the cause of autism disorders.
WASHINGTON -- Approximately one in every 150 children in the United States has autism or a closely related disorder -- a figure higher than most recent estimates -- according to a federal survey released Thursday, the most thorough ever conducted.
The new data do not mean that autism is on the rise, because the criteria and definitions used were not the same as those used in the past.
But the sheer number of children apparently affected -- 560,000 nationwide if the new statistics are extrapolated to all 50 states -- makes autism an "urgent public health issue" and a "major public health concern," said Marshalyn Yeargin-Allsopp, chief of the developmental disabilities branch of the Centers for Disease Control and Prevention, which conducted the survey.
The prevalence of autism, a poorly understood behavioral syndrome that interferes with a child's ability to relate to or interact with others, varies mysteriously from state to state in the survey, with New Jersey standing out as a hot spot and Alabama and West Virginia having low rates. West Virginia, however, appeared to tally a significant increase from 2000 to 2002, the two years for which data have been compiled so far.
No answers on cause
The survey, which is to be updated regularly, offers no clues about what causes autism or the range of related disorders that together cost the nation tens of billions of dollars a year and take an immeasurable emotional toll on families.
In particular, it sheds no light on the controversial claim that trace amounts of mercury in childhood vaccines are behind the growing number of diagnoses in recent decades. The survey data may help settle that question in future years, since most vaccines have recently eliminated the ingredient.
The survey does provide an unequaled, standardized baseline measure of the prevalence and distribution of autistic behaviors around the country, CDC officials said. In the short term, that can help state and federal officials budget their special education and mental health services needs. Over the longer term, it may tell at last whether autism is becoming more common and, if so, why.
"We need to do our best to get a better understanding of how many children are affected," said Catherine Rice, a CDC behavioral scientist and a senior author of the new report, published in today's issue of the agency's Morbidity and Mortality Weekly Report.
The results are the first to come out of CDC's Autism and Developmental Disabilities Monitoring Network, launched in 2000. That program aims to get the most accurate statistics possible on the prevalence of autistic behaviors by collecting information on thousands of children from schools, medical clinics and social service providers.
Past estimates have varied because there is no simple test to provide a definitive diagnosis and because the behavioral measures used to define the syndrome have changed over time.
Today, the definition encompasses a wide range of children, some "fully disabled" and others who "have something that is much more mild and can attend school but may have some social disability," said Thomas Insel, director of the National Institute of Mental Health.
He emphasized that the new numbers may not reflect the true incidence of the syndrome since they are derived not from clinical exams but from descriptive reports provided by teachers and others, which were reviewed by experts for key words that suggested a diagnosis of autism, Asperger's syndrome or any of several related disorders.
Medical exam data
The CDC is comparing selected survey cases with data collected from medical exams to test the accuracy and validity of the survey's impressions.
The survey looks at records of 8-year-olds, the age by which the vast majority of autistic children are diagnosed. Alison Singer, senior vice president of New York-based Autism Speaks, an advocacy group that funds about 30 million in research, said the survey pulls back the veil on the huge toll autism is taking in America.
"We need to remember that behind every one of these 1 in 150 is a family," said Singer, the mother of a 9-year-old autistic girl. She said Congress should take heed and fund the Combating Autism Act it passed in December, which authorized 925 million in research and other funds over five years.