CHICAGO (AP) _ Autism and related disorders in children occur more often than previously reported, according to research from England that echoes other recent studies.
But researchers said they do not know if their results reflect a true rise in the incidence of autism or changes in diagnosis criteria and better recognition of the disorder by parents and doctors.
Rates of autism typically have been reported at 4 to 6 per 10,000 children, though these figures have increased in studies conducted over the past 15 years.
This new study of children in Staffordshire, England _ published in Wednesday's Journal of the American Medical Association _ found a rate of 16.8 per 10,000.
Other recent surveys showing a similar trend have stirred concern that the incidence of autism is on the rise.
But Drs. Suniti Chakrabarti and Eric Fombonne, authors of this latest report, said that cannot be concluded from their data. They suggested further study.
Dr. David Holmes, chairman of a panel of advisers for the Autism Society of America, said the number reflects better reporting methods and the inclusion of less severe cases. He said it provides a more accurate picture of the scope of the disorder.
``This is a far more significant health problem'' than has been acknowledged, he said. ``Children with autism are not given adequate resources and we don't have the adequate number of health professionals to work with these children.''
The researchers studied 15,500 children ages 2 1/2 to 6 1/2 in 1998 and 1999 and found a total of 97 children had a pervasive development disorder, which includes autism. That worked out to an overall rate of 62.6 per 10,000 children, roughly three times higher than previous estimates.
Autism is much more common in boys and typically shows up by age 3. Autistic children may not respond when talked to, fail to make eye contact and engage in repetitive behavior such as rocking and head-banging. They often have a severely limited range of interests and may be unusually sensitive to sounds or touch.
Experts think there are many causes but believe genetics play a role.