The latest numbers from the U.S. Centers for Disease Control and Prevention now show that about one in 110 children have autism.
The numbers are a small change from the one in 100 estimate made by the CDC in October from the same study. The CDC says the latest numbers come from a more complete analysis of reports in 11 states.
Prior to the most recent report, the CDC had been saying autism occurred in one in 150 children. The new CDC estimate looks at eight-year-old children who had been diagnosed with an autism spectrum disorder in 2006.
The increase may be due in part to better diagnosis and changes in how well records of it were kept in the study sites, said Catherine Rice, a CDC behavioral scientist who worked on the new report. “At this point its impossible to say how much is a true increase and how much is identification.”
Doctors do not know what causes autism, but have been investigating possible genetic and environmental triggers. Results from the environmental research is still years away, Rice said.
In October, officials from the National Institute of Mental Health published results of a 2007 telephone survey of parents that concluded that 1 in 91 children had autism. At the same time, the CDC released to the media preliminary results of 1 in 100 from its own research.
The study is based on medical and school records of nearly 2,800 children in communities in Alabama, Arizona, Colorado, Florida, Georgia, Maryland, Missouri, North Carolina, Pennsylvania, South Carolina and Wisconsin.
