Autism rose in 14 communities, including St. Louis and several Missouri counties, in 2008, the Centers for Disease Control and Prevention reported Thursday. It said the prevalence of autism spectrum disorders among 8-year-olds in in Missouri communities was 13.9 for every 1,000 children — or 1 for every 72 children in that age group.

The national rate, based on data from all 14 sites, was 11.3 for every 1,000 children, or 1 in 88.  Utah had the highest rate at 21.2 and Alabama the lowest at 4.8, CDC officials said.

Autism spectrum disorders are described as a group of developmental disabilities involving impaired social interaction and communication as well as restricted or repetitive patterns of behavior. The CDC says symptoms typically become apparent before age 3. Absence of biologic markers for a diagnosis and changes in clinical defintions over the years have made it difficult to monitor the prevalence of the disease.

Washington University is one of 14 institutions or agencies that have been tracking the rise of autism spectrum disorders as part of the CDC study. The local study involves St. Louis city, along with the counties of St. Louis, St. Charles, Jefferson and Franklin.

Researchers have yet to determine what's driving the increase, says Robert Fitzgerald, coordinator of the local project in the Department of Psychiatry at Washington University.

"In terms of data reported Thursday, Missouri is above the average, a little bit higher than the average," he says. "If you look at the prevalence between the 2002 surveillance report and the 2008 report, there has been a 78 percent increase across the network and a 23 percent increase from 2006 to 2008."

He says parents concerned about the disorders should take note of children showing "deficits in social interaction, communications and repetitive or unusual behaviors." He adds that some believe that the rise in the number of cases is due partly to better reporting, a view echoed by the CDC and other officials during a conference call with reporters.

"One of the things the data tell us with certainty: There are more children and families that need help," says Dr. Thomas Frieden, director of the CDC. "In recent years, we've learned more about autism than ever before and we know now that autism is nearly five times more common among boys than among girls, with one in 54 boys identified compared with one in 252 girls."

In Missouri, the rate for boys in the latest data was 21.6 for every 1,000 or 1 in 46, compared to 5.9 per 1,000 for girls, or 1 in 169. For white youngsters, the rate was 14.6 per 1,000, compared to 9.3 for black children, 9.0 for Hispanics and 9.8 for Asian or Pacific Islanders.

Coleen Boyle, head of the National Center on Birth Defects and Developmental Disabilities at CDC, said during the conference call Thursday that the tracking was providing "a more complete picture of autism, helping us to understand how communities identify children with autism. Tracking also helps identify potential risk factors. We know more about how advanced parental age and premature birth contribute to a child's risk of having autism."

In addition, Boyle said the tracking can help determine that many autistic children are not being diagnosed as early as they could be.

Boyle and Fitzgerald at Washington University stressed that parents need to be take action whenever a child doesn't appear to be developing normally.

"Don't wait," Boyle said. "The most important thing for parents to know is that it's critical to act quickly if there is a concern about your child's development. Talk to your child's doctor about your concerns. Call your local early intervention program or school system for free assessment and remember, you don't need a diagnosis to get services."

Missouri has passed a law requiring insurers to cover autism, but Mark Roithmayr, president of the advocacy group Autism Speaks, said at the conference sesson that many insurance companies "discriminate against families with autism denying reimbursement for the basic evidence-based services that often dramatically improve the quality of life of children with autism."

He took issue with those suggesting that the jump in numbers is explained mainly by more diagnosis, detection and awareness.  "A large portion of the increase, some of the 50 percent, remains unexplained," he said. "That is why we need to fund research aggressively including critical study of potential environmental factors. We need answers."

He added: "At one in 88, the United States is experiencing an autism epidemic. This is a national emergency in need of a national plan."

Still, the CDC's Frieden said, "Doctors have gotten better at diagnosing the condition. Communities have gotten better at providing services, so at this point, I think there is a possibility that the increase in identification is entirely the result of better detection."

He added that "we need to continue to increase the number of kids who are detected, detected early and enrolled in services early."

Although the data are based on research involving a relatively small number of communities in 14 states, the officials said the numbers probably reflected the prevalence of autism nationwide.

The Obama administration used the findings to call attention to its health reforms. It noted, among other things, that the Affordable Care Act, which is before the Supreme Court, prohibits the denial, limitation or exclusion of coverage to any child under age 19 based on a pre-existing condition.

The administration added that new health insurance plans or insurance policies must cover preventive services without cost-sharing, including autism screening for children at 18 and 24 months. It also noted that, starting in 2014, children with autism and developmental disorders and their families will have expanded access to affordable insurance options through proposed  insurance exchanges and improvements in Medicaid.

In a background paper, the administration called autism "a critical public health issue that deeply impacts the lives of millions of Americans." In the current fiscal year, it said the National Institutes of Health was spending about $169 million in research on autism and related conditions.

Other programs, it said, included the CDC's "Learn the Signs. Act Early" campaign to increase awareness of the disease.

NOTE: An earlier version of this story contained an error in reported statistics.