New estimates show that 1 in 88 American children has been identified as having autism spectrum disorder, the Centers for Disease Control and Prevention said today, marking an increase of more than 20 percent since the last time such data were collected.
"Autism has now officially become an epidemic in the United States," said Mark Roithmayr, president of Autism Speaks.
But what isn't clear from the new estimates: just why the number of diagnoses are on the rise.
Study results from the 2008 surveillance year show 11.3 per 1,000 8-year-old children have been identified as having an ASD. This is a 23 percent increase since the last report in 2009, the CDC said. Some of the increase is because of the way children are identified, diagnosed, and served in their communities, although its unclear how much of the increase is because of these factors.
"We know people want answers," said Coleen Boyle, director of CDC's National Center on Birth Defects and Developmental Disabilities, during a call with reporters.
The CDC is conducting a separate study to learn more about what puts children at risk for having an autism spectrum disorder, she said. Also, a law signed last fall provided millions for further research about autism.
The estimates, based on 2008 data from 14 communities, range from 1 in 210 Alabama children having ASD to 1 in 47 children in Utah. And autism spectrum disorders are about five times more common in boys than girls: 1 in 54 boys was identified as having ASD. Previous CDC estimates found that about 1 in 80 boys and 1 in 240 girls— an overall average of 1 in 110 children—in the country had a form of autism. Other studies have found that autism is far more common than even the new CDC estimates.
The study also found that more children are being diagnosed by age 3, an increase from 12 percent for children born in 1994 to 18 percent for children born in 2000.
"Unfortunately, 40 percent of the children in this study aren't getting a diagnosis until after age 4. We are working hard to change that," Ms. Boyle said in a statement.
Research shows that an early diagnosis makes treatments and interventions more effective, she said.
So what should parents look for? If children aren't pointing at things, they aren't making eye contact, or their language development is delayed, said Dr. Susan Hyman, chairwoman of the Autism Subcommittee of the American Academy of
Pediatrics. These symptoms could mean other diagnoses, but they should give parents enough of an indication that they should start asking their doctor questions—right away.
In addition, Autism Speaks has a video glossary that shows what typical and delayed development look like in children.
Its unclear how a possible change to the definition of autism could affect future diagnoses counts.
"One thing the data tells us with certainty: There are many children and families who need help," said Dr. Thomas Frieden, director of the CDC, in a statement. "We must continue to track autism spectrum disorders because this is the information communities need to guide improvements in services to help children."