While experts largely chalk up the higher number to better recognition and diagnosis of autism spectrum disorders (ASDs), they say the sheer number of cases is an urgent public health problem. In Utah alone, the study revealed, 1 in 133 children have an ASD - the third highest rate among the 14 U.S. sites that gathered data.
"This is a wake up call," said Ed Clark, medical director at Primary Children's Medical Center, "because it really should stimulate our community and other communities across the nation to address this up front."
Clark said the data confirms anecdotal evidence that the number of children with autism has swelled over the last decade, which he attributes to both improvements in diagnoses and an increase in the number of children being born with the disease.
"It meets the spirit of the definition [of an epidemic] in that it is occurring so much more frequently now and it is having such a devastating effect on the children," he said.
In 2003, the Utah Registry of Autism and Developmental Disabilities (URADD), in collaboration with the Centers for Disease Control and Prevention (CDC), began reviewing health and education records of 26,108 children - all age 8 - in Davis, Salt Lake and Utah counties.
The purpose of the study was to find out how many children have an autism spectrum disorder, identify their characteristics and create a benchmark for future research.
Of those Utah children whose records were reviewed, researchers identified 196 who had been diagnosed with, or were likely to have, an ASD. While the overall mean prevalence of ASD at the 14 U.S. sites was 6.6 per 1,000 children, Utah's rate was higher: 7.5 per 1,000 children.
Boys in Utah, the study revealed, are six-and-a-half times more likely to have autism than girls. About 1 in 79 boys have it, compared to 1 in 500 girls. Girls, however, are more likely to have cognitive impairment - an IQ less than 70 - than boys.
Most of the 196 children, researchers found, had a documented history of concerns about their development before age 3. The median age when they were diagnosed with an autism spectrum disorder, however, was around age 4. By age 8, most children were receiving special education services.
The data confirms that "a significant lag exists between early concerns and actual identification of an ASD in all areas of the country, contributing to potentially significant delays in intervention," the study said.
Utah ranked the highest among the 14 sites for the percentage of children who lost social, communication, play or motor skills. About a third of Utah's children with ASDs showed such a regression.
But Utah also had the highest percentage - at 12.8 percent - of children who did not regress but stopped developing new skills.
The disorder, the study found, occurs more often in Utah's Caucasian children - at 8 cases per 1,000 children - than in the state's Latino children, whose prevalence rate is 4.4 per 1,000.
The number of children from other minority groups was too small to determine reliable prevalence rates.
Not since the UCLA-University of Utah Autism Epidemiology study in the mid-1980s has the state gotten such a glimpse of the problem, said William McMahon, a professor of psychiatry at the University of Utah and URADD's director.
The earlier statewide study, he said, identified 243 people, ages 3 to 21, with autism. The prevalence rate at the time was 4 per 10,000.
"You could look at that and say, 'Why is it [the prevalence rate] almost 20 times greater?' And there is no good answer to that," McMahon said.
One possibility, he said, is that recognition of mild autism is much better. While the earlier Utah research identified only persons with autism, the new study identified children with autism spectrum disorders, which include Asperger's Syndrome and Pervasive Developmental Disorder, Not Otherwise Specified (PDD-NOS.)
"Once the condition is understood, the definition gets broader and the recognition of mild cases gets so much better," McMahon said. "So, I would say that is likely what's happening, but I can't rule out something else."
Catherine Johnson, program manager of the Giant Steps pre-school program for autistic children in Orem, said diagnosis methods haven't changed much in the last decade. Yet the number of children entering her program has grown, and "that's what's scary to me," she said.
Ten years ago, the Giant Steps program - which treats 37 children - admitted children with autism and other disabilities. Now it treats autistic children exclusively and has a 100-person waiting list. Many of those children will age out before they're ever admitted.
"It wasn't anywhere near the numbers we see now," Johnson said.
The study's findings, McMahon said, underscore the need for earlier diagnosis and treatment of a developmental disorder that has long puzzled researchers. It is generally believed that ASDs result from some combination of genes, along with exposure to environmental factors in the mother's womb.
"I would compare our knowledge of autism and ASDs now as analogous to medical knowledge of fever at the end of the 18th century," he said. "We recognize phenomena - the social and language behaviors - but we're not smart enough to understand the subtypes and causes."
Judith Zimmerman, an assistant professor of psychiatry at the U. who, along with McMahon, was a principal investigator on the new Utah study, said she hopes the data will raise awareness of autism and the challenges Utah families and schools face.
"I hope the data can be used to show the scope of the issue and how many kids there are and the difficulty families have in getting services," she said.
More children will be diagnosed with autism this year than with AIDS, diabetes and cancer combined, she pointed out, yet autism receives less than 5 percent of the research funding of many less prevalent childhood diseases.
Nationally, 67 children are diagnosed with autism every day. The disorder now costs the country more than $90 billion a year - a figure expected to double in the next decade, according to URADD.
In Utah, where an estimated 6,339 children have an autism spectrum disorder, the costs are also spiraling upward. Based on economic studies, the costs for these children is estimated at well above $20 billion across their lifetimes, Zimmerman said.
McMahon and Zimmerman are now working with the Utah Department of Health to find money to continue their research and expand it statewide.
The $350,00 CDC grant that funded the new study ended six months ago, but the state's health department and the U.'s School of Medicine's Department of Psychiatry have continued with temporary funding.
The National Children's Study, said Clark of Primary Children's Medical Center, is also a pivotal next step, to help researchers understand autism's causes.
The study, approved by Congress and awaiting President Bush's signature, would examine environmental influences on the health of more than 100,000 children across the U.S., following them from before birth until age 21.
"I think we have to come to grasp with this severe and devastating disease and provide resources to families to improve the outcome for their children," he said. "That means insurers, that means the community, that means the system has to address this."