(Reuters) - About one in 88 children in the United States has autism or a related disorder, the highest estimate to date and one that is sure to revive a national argument over how the condition is diagnosed and treated.
The estimate released on Thursday by the Centers for Disease Control and Prevention represents an overall increase of 25 percent since the last analysis in 2006 and a near-doubling of the reported rate in 2002.
Among boys, the rate of autism spectrum disorders is one in 54, almost five times that of girls, in whom the rate is one in 252.
"One thing the data tells us with certainty - there are many children and families who need help," said CDC Director Thomas Frieden. "We must continue to track autism spectrum disorders because this is the information communities need to guide improvements in services to help children."
Advocates for people with autism seized on the apparent spike in the prevalence of the disease to call for more research to identify its causes and more services for those affected by it.
"This is a national emergency and it's time for a national strategy," said Mark Roithmayr, president of the research and advocacy group Autism Speaks. He called for a "national training service corps" of therapists, caregivers, teachers and others who are trained to help children with autism.
Some researchers have questioned whether the increases over the last decade are real or reflects greater awareness that has led parents and teachers to see symptoms of autism in children who would not have received the diagnosis a generation ago.
Changes in how the disease is diagnosed explains a large fraction of the reported increase in prevalence, even advocates acknowledged.
"Inevitably when these statistics come out, the question is, what is driving the increase?" said Roithmayr. Better diagnoses, broader diagnostic criteria and higher awareness, he said, account for about half the reported increase.
The new estimate from the CDC comes from the Autism and Developmental Disabilities Monitoring Network, which operated in 14 states.
To determine whether a child has autism or a related disorder, what CDC calls "clinician reviewers" examined the medical and school records of 8-year-olds in the 14 states and also conducted screening. Children whose records included either an explicit notation of autism-spectrum disorder or merely descriptions of behavior consistent with the disorder were counted as falling on the autism spectrum.
CDC investigators warned, however, that the 14 sites are not "nationally representative." As a result, the rate of autism being reported on Thursday in CDC's Morbidity and Mortality Weekly Report, "should not be generalized to the United States as a whole."
Autism spectrum disorders are marked by a suite of symptoms, all arising from atypical brain development that results in problems with socialization, communication, and behavior.
Although the disorder can be mild or severe, in general children with autism have difficulty communicating and making friends. Many find it painful to look other people in the eyes, which impairs their ability to understand what others are thinking and feeling.
(Reporting by Sharon Begley; Editing by Michele Gershberg and Philip Barbara)