One in 64 Arizona children has been identified as having an autism spectrum disorder, says new national study released today.

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 UA developmental pediatrician Dr. Sydney Rice.   “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.”

The average age of autism spectrum disorder diagnosis in Arizona is 4 years and 9 months old.

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.

The study released today and published in the CDC’s Morbidity and Mortality Weekly Report looked at data from 14 communities, including Arizona.  Autism spectrum disorders are almost five times more common among boys than girls, the report says.

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.”

The study looked at the 2008 medical and school records of 32,601 Maricopa County 8-year-olds.

Kim Crooks  of the Tucson Alliance for Autism  noted that Maricopa County, where the Arizona study group of 8-year-olds lives, is a large city and people with autism often congregate in larger cities where there are more services available.

Like Rice, Crooks stressed that there’s been a dramatic increase in the diagnosis of autism spectrum disorders in recent years. She said the local alliance now offers nine programs for teens and adults and often those people have been newly diagnosed, for example.

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.

Researchers say the reasons for the increase likely include more awareness of autism, better reporting and broader criteria of what defines autism-spectrum disorder.

But the jump in cases over the last two decades also can't rule out other forces at work — either environmental or genetic, they say.

“There are many different factors and different children may have autism for different reasons,” Rice 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.”