Font ResizeCHICAGO — Two new government studies indicate about 1 in 100 children have autism disorders — higher than a previous U.S. estimate of 1 in 150.
More awareness and spotting autism in younger children may explain some of the increase, federal health officials said.
"The concern is that buried in these numbers is a true increase," said Dr. Thomas Insel, head of the National Institute of Mental Health. Figuring out how many children have autism is difficult because diagnosis is based on behavior, said Dr. Susan Levy of the Children's Hospital of Philadelphia.
"There's no consistent biologic marker we can use," she said.
The new estimate would mean about 673,000 American children have autism, rather than the previous 560,000. One study, from a national survey done in 2007, was published in October's Pediatrics.
In that study, parents reported about one in 91 children, ages 3 to 17, had autism, including milder forms such as Asperger's syndrome. The other government estimate has not been formally released yet.
