As many as one in 68 U.S. kids may have autism: CDC

As many as one in 68 U.S. children have autism, a 30 percent increase in just two years, U.S. health officials said on Thursday, but experts think the rise may simply reflect that parents and doctors are getting better at recognizing and diagnosing the disorder.

Experts were largely unfazed by the latest numbers, which they say do not necessarily suggest increasing prevalence.

"It's not that surprising because as people get more aware, the prevalence has always increased in a psychiatric disorder," Dr Thomas Frazier, director of Cleveland Clinic Children's Center for Autism, said in a telephone interview.

The latest report by the U.S. Centers for Disease Control and Prevention, which looks at data from 2010, estimates that 14.7 per 1,000 8-year-olds in 11 U.S. communities have autism. That compares with the prior estimate of 1 in 88 children, or 11.3 of 1,000 8-year-olds, in 2008, and 1 in 150 children in 2000.

Autism encompasses a spectrum of disorders, ranging from a profound inability to communicate and mental retardation to relatively mild symptoms in people with very high intellectual ability.

Coleen Boyle, director of the CDC's National Center on Birth Defects and Developmental Disabilities, said while the report does not explain why rates are rising, it does give some clues.

For example, almost half of children identified as having autism in the latest report had average or above-average IQ levels, compared with just a third of children a decade ago.

"It could be doctors are getting better at identifying these children; it could be there is a growing number of children with autism at higher intellectual ability, or it may be a combination of better recognition and increased prevalence," Boyle said.

Frazier said it is very likely that the current report is still undercounting autism rates among higher-functioning black and Hispanic children. Among black children with autism in the report, half also had intellectual disability, a more overt sign of problems. That compared with just 35 percent of white kids with autism, who also had intellectual disability.

Ultimately, Frazier thinks the autism rate will settle at around 2 percent of the population, or around 1 in 50 kids.

Part of the issue may be the way the CDC measures autism, combing through health and school records of 8-year-olds within fewer than a dozen communities in the United States.

The study showed significantly different autism rates by region, ranging from 1 in 175 children in Alabama to 1 in 45 children in New Jersey, which could reflect access to healthcare and other factors.

The CDC said the latest data continues to show that autism is almost five times more common among boys than girls, affecting 1 in 42 boys versus 1 in 189 girls.