1 in 50 School-Aged Children in U.S. Has Autism
Significant increase in the prevalence of the condition over the past five years, researchers say
By Steven Reinberg
WEDNESDAY, March 20 (HealthDay News) -- The number of children in the United States with autism spectrum disorder has jumped dramatically since 2007, federal health officials reported Wednesday.
As of 2012, one in 50 kids between the ages of 6 and 17 has some form of autism, compared with one in 88 only five years earlier, according to the U.S. Centers for Disease Control and Prevention.
"This estimate was a bit surprising," said report author Stephen Blumberg, a senior scientist at the CDC's National Center for Health Statistics. "There may be more children with autism spectrum disorder than previously thought."
The average school bus holds about 50 children, so there is typically one child with autism spectrum disorder on every full school bus in America, Blumberg noted.
Michael Rosanoff, associate director for Public Health Research and Scientific Review at Autism Speaks, said that "this study added to the evidence suggesting that we are underestimating the prevalence of autism in the United States."
This report, however, underestimated the real prevalence of autism, Rosanoff said. "It's probably much higher," he said.
The main reason for the increase in the prevalence of autism appears to be better diagnoses, especially in older children, Blumberg said.
In addition, boys were more than four times more likely to be diagnosed with autism than girls, which has been the historical trend, Blumberg said.
"For the most part, the increase in the prevalence is largely due to an increase in the prevalence in reported autism spectrum disorder for boys," he said.
None of the other factors, such as survey bias, could explain the increase, he added. Most of the children who were diagnosed with autism spectrum disorder were diagnosed since the last survey in 2008, Blumberg noted.
"By ruling out other explanations and noting the increase in recent diagnoses, that suggests to us that improved ascertainment -- recognizing children who were previously unrecognized as having autism spectrum disorder -- is the reason," he said.
This may be the reason most of those newly diagnosed children tend to have milder forms of autism, Blumberg said.