US autism estimate rises to 1 in 68 children

The United States government's estimate of autism has moved up again, to 1 in 68 US 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 froma cultural and medical shift, with doctors diagnosingautismmore frequently, especially in childrenwithmilder problems.

"We can't dismiss the numbers. But we can't interpret it to mean more people are getting the disorder," says Marisela Huerta, a psychologist at the New York-Presbyterian Center for Autismand the Developing Brain in suburban White Plains, NewYork.

The Centers for Disease Control and Prevention released the latest estimate on March 27. The Atlanta-based agency says its calculation means autism affects roughly 1.2 million Americans under 21. Two years ago, the CDC put the estimate at 1 in88children, or about 1million.

The cause or causes of autismare still not known. Without any blood test or other medical tests for autism, diagnosis is not an exact science. It's identified bymaking judgments about a child's behavior.

Thursday's report is considered the most comprehensive on the frequency of autism. Researchers gathered data in 2010 from areas in 11 states across the country.

The report focused on 8-year-olds becausemost autismisdiagnosedby that age. The researchers checked health and school records to see which children met the criteria for autism, even if they hadn't been formallydiagnosed. Then, the researchers calculated how common autism was in each place and overall.

The CDC started using thismethod in 2007 when it came up with an estimate of 1 in 150 children. Two years later, it went to 1 in 110. In 2012, itwent to 1 in 88.

Last year, the CDC released results of a less reliable calculation-froma survey of parents-which suggestes as many as 1 in 50 childrenmay have autism.