(CBS News) One out of 88 children in the U.S. has an autism spectrum disorder, according to the latest estimate by the Centers for Disease Control and Prevention.
Previously the CDC estimated autism's prevalence at about an average of 1 in 110 U.S. children. The new estimate suggests autism is more common than previously thought - about 25 percent more common - and may affect more than one million children and teens in the U.S.
"One thing the data tells us with certainty - there are many children and families who need help," CDC Director Dr. Thomas Frieden said in a written statement. "We must continue to track autism spectrum disorders because this is the information communities need to guide improvements in services to help children."
For the CDC's study, researchers looked at autism prevalence estimates from 14 areas in the country. Since every state is not included, the CDC warned the rate "should not be generalized to the United States as a whole." But the data do show that autism diagnoses continue to increase. It's published in the March 29 issue of Morbidity and Mortality Weekly Report.
Boys are still about five times more likely to be diagnosed with autism in the U.S. than girls, according to the CDC report. It estimated one in 54 boys have autism, while one in 252 girls do. The number of children identified with ASDs ranged from 1 in 210 children in Alabama to 1 in 47 children in Utah. The largest increases were among Hispanic and black children.
Some of this increase may be due to the way children are identified, diagnosed and served in their communities, although exactly how much is due to these factors is unknown, the CDC said.
Study results from the 2008 surveillance year show more than 11 out of 1,000 8-year-old kids have been identified as having an ASD, about a 23 percent increase since the last CDC report in 2009. Some of this increase is due to the way children are identified, diagnosed and served in their communities, although exactly how much is due to these factors is unknown.
"To understand more, we need to keep accelerating our research into risk factors and causes of autism spectrum disorders," said Dr. Coleen Boyle, director of CDC's National Center on Birth Defects and Developmental Disabilities.
The study also shows 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," said Boyle. "We are working hard to change that."
The CDC has a "Learn the Signs. Act Early" campaign that provides checklists for parents of developmental milestones. If a child does not reach these milestones, a parent should check with their child's doctor.
"This information paints a picture of the magnitude of the condition across our country and helps us understand how communities identify children with autism," Health and Human Services Secretary Kathleen Sebelius, said in the CDC statement. "That is why HHS and our entire administration has been working hard to improve the lives of people living with autism spectrum disorders and their families by improving research, support, and services."
For 2012, the National Institutes of Health invested $169 million in autism research to improve screening and diagnosis, develop effective services and resources for families, identify potential risk factors in the environment that may cause the disorder, and for testing potential treatments.
The CDC has more on autism.