ATLANTA (AP) -- The rate for autism in five metropolitan Atlanta counties is vastly greater -- by a rate of about nine times more -- than studies on the neurological disorder previously have documented, federal researchers said Tuesday.

In the largest study of its kind in the country, the Centers for Disease Control and Prevention studied 289,456 children in Clayton, Cobb, DeKalb, Fulton and Gwinnett counties and found autism at a rate of 3.4 per 1,000 children, according to a study in the Journal of the American Medical Association. About 1,000 children had autism or related disorders.

Previous studies, conducted in the 1980s and 1990s, said that autism was much more rare, only afflicting children at a rate of .04 per 1,000 children. The Atlanta study is much closer to a CDC-sponsored study released in 2001 of New Jersey children that found an autism rate of 4 per 1,000 kids.

"Autism is more common today was previously reported," said Dr. Marshalyn Yeargin-Allsopp, a medical epidemiologist with the CDC. "From the standpoint of a physician or a teacher or a professional, ... you will see more children with autism and should recognize the criteria for (autism) behavior with children."

But the CDC stopped short of saying that autism was on the rise in metro Atlanta, primarily because there is no national data available and there have only been four autism studies conducted in the United States. Autism is caused by a neurological disorder that can severely impair social and behavioral skills.

The CDC study looked at information from schools and treatment centers on children with developmental disorders. The data is from 1996 and it will be used as a baseline that will be compared against a second, upcoming, study that will use data from Atlanta students in 2000.

Researchers in the metro Atlanta area also plan to examine how autism is caused. The CDC is providing funding for a dozen other states to determine autism rates in their areas.

Angela Collins, president of the Autism Society of America's Greater Georgia chapter, said she hopes the research will help raise awareness about autism.

Her 10-year-old son has autism and Collins said she's received strange looks from other adults after they've seen her son's behavioral disorders.

"Maybe now we won't be looked at as parents with 'bad parenting' skills," Collins said. "Most individuals with autism ... have unusual behaviors and they can behave in such a way that's 'not acceptable"' to mainstream parents.

"I was looked at as I had 'horns on my head,"' she added. "That's very hurtful."

In the Atlanta study, researchers found the autism rate was no different among black and white kids. But the rate varied by age, from 1.9 per 1,000 children for 3-year-olds to 4.7 per 1,000 for 8-year-olds.

"Younger children have lower prevalence rates than older children since many young children may not yet have come to the attention of professionals," the CDC said.

The CDC said the Atlanta study's higher autism rate compared to previous studies may only be a reflection of better awareness of the neurological disorder that can severely impair social and developmental skills.

Media coverage, classification of autism for special education services and even research that suggests some children with autism respond well to early educational intervention may have contributed to the rise in the case rate.

"It remains unclear whether specific environmental, immunologic, genetic or unidentified factors also have contributed to these higher reported prevalence rates," the CDC said.

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