Analysis finds nearly 1 percent of U.S. children diagnosed with autism

By Rob Stein
Friday, December 18, 2009; 11:12 PM

About one out of every 110 U.S. children has been diagnosed with autism, according to a new federal estimate released Friday.

An analysis of medical records from more than 307,000 8-year-olds in 2006 found that about 1 percent -- or one out of every 110 -- had been diagnosed with an "autism spectrum disorder," which includes a range of conditions including autism, the federal Centers for Disease Control and Prevention reported.

The estimate is an increase in the prevalence of the condition from a previous CDC estimate of about 1 in 150 but is consistent with another estimate the agency released in October based on a telephone survey that concluded the condition was diagnosed in about 1 out of every 100 children.

"The findings in this report are in line with other recently reported estimates," said Catherine Rice, a behavioral health scientist at the CDC's National Center on Birth Defects and Developmental Disabilities, whose report were published in the agency's Morbidity and Mortality Weekly Report.

The reason for the increase remains unclear, she said. It could be due at least in part to more children being diagnosed with one of the conditions rather than an actual increase in how many children are developing the disability, she said. But "a true increase cannot be ruled out," she said, calling the estimate "concerning."

Other factors that could be contributing to the increase include a rise in the average age that women are giving birth, and potentially air pollution, she said. But, Rice stressed "we have much to learn about the causes."

The conditions are four to five times as common among boys as girls, with one in 70 boys and one in 315 girls having the diagnosis, the report found.

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