March 29, 2012

One In 88 U.S. Children Have Autism

According to new estimates by the Centers for Disease Control, about one in 88 children in the U.S. has autism or a related disorder.

The CDC estimate represents an increase of about 25 percent since the last analysis in 2006, and almost doubling the rate reported in 2002.

The report said that the rate of autism spectrum disorders among boys is one in 54, and among girls it is one in 252.

"One thing the data tells us with certainty - there are many children and families who need help," CDC Director Thomas Frieden said at a press conference.

The estimates come from the Autism and Developmental Disabilities Monitoring Network, which operates in 14 states.

The CDC examined the medical and school records of 337,093 eight-year-olds in the states in 2008, and conducted screenings.

The children whose records included either an explicit notation of autism-spectrum disorder or descriptions of behavior consistent with it were counted as falling on the autism spectrum.

The prevalence of autism in the states monitored by CDC varied as well, from a high of one in 47 in Utah to one in 2010 in Alabama.

Experts believe this variation could be due to the differences in awareness of the disorder among parents, teachers and even physicians.

Autism spectrum disorders are marked by a suite of symptoms, which stem from atypical brain development that creates problems with socialization, communication, and behavior.

"This is a national emergency and it's time for a national strategy," Mark Roithmayr, president of the research and advocacy group Autism Speaks, said during a conference call with reporters. "Inevitably when these statistics come out, the question is, what is driving the increase?"

There is no brain-imaging test for autism, so physicians use the American Psychiatric Association's Diagnostic and Statistical Manual (DSM) to diagnose a patient.

According to the manual, someone must fit at least eight of 16 criteria before being diagnosed with autism.  Some of those criteria include symptoms involving social interaction, communication, and repetitive or restricted behaviors and interests.

Scientists estimate that 90 percent of autism risk was genetic and 10 percent reflected environmental factors.  A 2011 twin study from Stanford University found that genes accounted for 38 percent of autism risk in twins, and environmental factors were at 62 percent.

“Only part of the increase can be explained by better and broader diagnoses,” Roithmayr during the call. “There is a great unknown. Something is going on here, and we don´t know.”

Dr. Thomas Frieden, director of the CDC, said part of the increase in autism is because doctors have gotten better at diagnosis.

"Doctors have gotten better at diagnosing the condition, and communities have gotten better at providing services for those affected by autism,” Frieden said during the conference call. “At this point, I think it´s a possibility that the increase in identification of autism is entirely the result of better detection. We don´t know whether or not that is the case, but it is a possibility.”


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