The number of U.S. children diagnosed with autism continues to rise, with new data announced today by the U.S. Centers for Disease Control and Prevention showing that about 1 in 88 children have the disorder -- a 23 percent increase in just two years, and a 78 percent increase since 2000.
The rate among boys is alarmingly high: According to CDC, 1 in 54 boys were identified as having an autism spectrum disorder, while just 1 in 252 girls were diagnosed with it.
[Related: 5 ways to support a friend whose child has autism]
"One thing the data tells us with certainty - there are more children and families that need help," CDC Dr. Director Thomas Frieden said 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."
Since 2000, the CDC has used surveillance reports from its Autism and Developmental Disabilities Monitoring Network to track the autism rate for kids in the United States. Every two years, researchers count the number of 8-year-olds with autism in anywhere from six to 14 communities (depending on funds available for research). This year's numbers come from data collected in 2008 from 14 communities.
The autism rates in Alabama were the lowest, just 1 in 210 children. In Utah, where the community with the highest rate was located, 1 in 47 children had autism, according to the CDC report. The largest increases were among Hispanic and African-American children.
The study looked at the number of children who showed behaviors consistent with autism, Asperger's Syndrome, and the catch-all spectrum diagnosis Pervasive Developmental Disorder-Not Otherwise Specified (PPD-NOS). Researchers pored over school and medical records to decide what data to include. Typical characteristics of autism spectrum disorders include verbal delays, repetitive behaviors, and problems involving socialization, though the symptoms can vary wildly from child to child.
In 2000, the CDC determined that the autism rate was 1 in 150 children. That rate jumped to 1 in 110 in 2006, and to 1 in 88 now -- an increase of 78 percent since 2000.
There are several possible reasons why the autism rate continues to rise. The study showed that more children are being diagnosed by age 3 -- an important change, given that early intervention can vastly improve treatment.
"Doctors are getting better at diagnosing autism; communities are getting much better at [providing] services to children with autism, and CDC scientists are getting much better at tracking which kids in the communities we're studying have autism," Frieden told CNN.com.
"How much of that increase is a result of better tracking and how much of it is a result of an actual increase, we still don't know," he added. "We know more about autism today than we have ever known, but there is still so much we don't know and wish that we knew."
The criteria for diagnosing a child with autism can be found in American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DMS). According to the current (fourth edition) version of the manual, a person qualifies if they show at least any six out of 12 specialized behaviors.
But in January, experts started working on the fifth edition of the DSM, and have proposed changing the way autism is diagnosed. The changes include eliminating Asperger's Syndrome and PDD-NOS from the manual, instead consolidating them under a single "Autism Spectrum Disorder" category. The criteria for qualification in that category would also change: Instead of having to show six out of 12 behaviors, a person would have to show three specific problems with social interaction and communication and at least two repetitive behaviors. The change would mostly affect people who are on the "high-functioning" side of the autism spectrum.
The proposed change has many parents worrying that their children might not be eligible for services they need, but some experts say that current definition of autism has resulted in high rates that aren't necessarily accurate.
"It was an artificial inflation," Jennifer Pinto-Martin, director of the Center for Autism and Developmental Disabilities at the University of Pennsylvania, told Time magazine in January. "If you have a larger umbrella, more kids will fit under that umbrella." A study published in January edition of the journal "Pediatrics" seems to underscore the idea, indicating that some children who are on the autism spectrum may be there because other conditions -- like anxiety, developmental delays, or behavioral issues -- led to a false diagnosis.
No one knows what causes autism, though many different studies point to everything from environmental pollution to genetic triggers to the possibility of an immune-system overload. Dr. Andrew Wakefield's link between autism and the MMR vaccine has been proven false and was found to have been based on fraudulent data.
Scientists are still searching for an answer. "To understand more, we need to keep accelerating our research into risk factors and causes of autism spectrum disorders," said Coleen Boyle, Ph.D., M.S.Hyg., director of CDC's National Center on Birth Defects and Developmental Disabilities.
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