NEW YORK (AP) -- The government's estimate of autism has moved up again to 1 in 68 U.S. children, a 30 percent increase in two years.
But health officials say the new number may not mean autism is more common. Much of the increase is believed to be from a cultural and medical shift, with doctors diagnosing autism more frequently, especially in children with milder problems.
"We can't dismiss the numbers. But we can't interpret it to mean more people are getting the disorder," said Marisela Huerta, a psychologist at the New York-Presbyterian Center for Autism and the Developing Brain in suburban White Plains, N.Y.
The Centers for Disease Control and Prevention released the latest estimate Thursday. The Atlanta-based agency said its calculation means autism affects roughly 1.2 million Americans under 21. Two years ago, the CDC put the estimate at 1 in 88 children, or about 1 million.
The cause or causes of autism are still not known. Without any blood test or other medical tests for autism, diagnosis is not an exact science. It's identified by making judgments about a child's behavior.
The report focused on 8-year-olds because most autism is diagnosed by that age. The researchers checked health and school records to see which children met the criteria for autism.