By Julie Steenhuysen
CHICAGO, March 27 (Reuters) - As many as one in 68 U.S. children may have autism, U.S. health officials said on Thursday, a sharp increase over an estimate of 1 in 88 children just two years ago that raises questions about why the number has risen so dramatically.
Researchers at the U.S. Centers for Disease Control and Prevention noted in their report that the data, gleaned from a study of children in 11 communities, could not be generalized to the national population. They also did not study why the rates were so much higher.
But the study found that almost half of children identified as having autism also had average or above-average IQ levels, compared with just a third of children a decade ago.
That suggests doctors may be getting better at identifying higher-functioning children with autism, or it could be that there is a growing number of children with autism, Coleen Boyle, director of the CDC's National Center on Birth Defects and Developmental Disabilities, said in a conference call.
"To better understand the why, there is an urgent need to do more research," Boyle said.
Some experts believe the higher rates reflect a heightened focus on autism by parents, doctors and teachers that may be resulting in more children being diagnosed with the disorder.
In its latest report, the CDC studied medical, school and other records on 8-year-olds within 11 U.S. communities to determine whether a child had autism.
There were significant differences 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. (Reporting by Julie Steenhuysen; Editing by Michele Gershberg and Leslie Adler)