One in 64 Arizona children has been identified as having autism spectrum disorder, says a new national study released Thursday.
While that rate is higher than the U.S. rate of 1 in 88, a University of Arizona researcher who worked on the report said it should not be a cause for alarm.
"I think we're identifying better. There's a lot of public awareness, and we in the medical community are identifying better. Schools have always been better at it than we are," said Dr. Sydney Rice, a developmental pediatrician at the UA.
The U.S. rate of 1 in 88 was an increase from 1 in 110 in 2009.
While better awareness, more reporting and a broader definition of the autism spectrum are at play, experts say they can't rule out other forces at work - either environmental or genetic.
The study, released Thursday by the Centers for Disease Control and Prevention, looked at health and school records on 8-year-olds in 14 states.
In Arizona, the study looked at the 2008 medical and school charts of 32,601 8-year-old boys and girls in Maricopa County.
Kim Crooks of the Tucson Alliance for Autism noted that the study area in Arizona is a major urban area, and that people with autism often congregate in larger cities where there are more services available.
A sample of children from a more rural area might show a lower prevalence, she said.
Nationally, autism spectrum disorders are almost five times more common among boys than girls, the study found.
The rate for boys in Arizona is 1 in 40, and the rate for girls is 1 in 185.
Autism is a brain disorder that affects a person's ability to communicate, to reason and to interact with others. It affects individuals differently and to varying degrees of severity, and it is often found in combination with other disabilities.
The terms "autism" and "autism spectrum disorder" are often used interchangeably. Among conditions included on the autism spectrum are Asperger's, pervasive developmental disorder and Rett syndrome.
The number of children identified with autism spectrum disorder ranged from 1 in 210 children in Alabama to 1 in 47 children in Utah.
The largest increases were among Hispanic and black children.
"Overall nationally we're identifying more children who have a higher IQ," Rice said. "This is not a bad thing. … This is better care."
Rice is part of a research team at the UA that is receiving money from the CDC as part of a national program to study autism. The Arizona Developmental Disabilities Surveillance Program is a partnership between the UA and the CDC.
"One of the challenges is that we're trying to lower the age at which it's diagnosed. It's still not as low as we'd like," Rice said.
The average age of diagnosis in Arizona is 4 years and 9 months old.
Crooks said the local alliance now offers nine programs for teens and adults, and often those people have been newly diagnosed.
Researchers know there is more than one cause of autism, Rice said.
"There are many different factors and different children may have autism for different reasons," she said. "We do recognize there is a strong genetic component. There may be an environmental component, but we haven't found it yet. It's not vaccines. But there's a lot of studies going on to see what it might be."
Crooks emphasized that many people in the autism spectrum go to universities, hold jobs, get married and have children.
"I had a woman call me yesterday who said that every one of her children has given birth to a child on the autism spectrum, and that she suspects she's on the spectrum too," Crooks said. "Back when I was in high school, there were these quirky, nerdy people who if they were here now might fall somewhere on the spectrum.
"The tools for diagnosing are just so much better. Teachers, workers in the schools, doctors and psychologists are more trained on what to look for."
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To learn more about the CDC autism study, go to www.cdc.gov/autism
Contact medical reporter Stephanie Innes at email@example.com or 573-4134.