Monday, April 09, 2012

Autism Wars: New Autism Estimate in Perspective

1 in 88 US children have autism?

Yes according to a new study by the Centers of Disease Control and Prevention.  That's an increase from 1 in 110 in 2007 and hold on to your calculators, a whopping increase from the early 2000/2002 rate of 1 in 150 (check out the graphics). 

In other words cases of autism have nearly doubled in a decade.

What happened in the last 10 to 15 years?

Better awareness, better detection and even though Autism Speaks doesn't like to speak about it, a much larger definition of autism. 

The criteria checklist for the autistic spectrum houses over 2,000 behavioral traits.  In the early 2000s about half of kids diagnosed with autism had an intellectual disability compared to about a third today, suggesting the largest increases in diagnoses have come from the more mild end of the spectrum. See Autism Rises: More Children than Ever Have Autism, but Is the Increase Real?, Time Healthland, good article.

There's always the possibility the environment is to blame too.  Contaminated water, toxic cosmetics and baby bottles. Yet according to the CDC the "environmental" factors that have been linked to autism aren't what we typically think of as "environmental":
Children born to older parents are at slightly higher risk. 
A small percentage of children who are born prematurely or with low birth weight are at greater risk for having ASDs.
Some harmful drugs taken during pregnancy have been linked with a higher risk of ASDs; for example, the prescription drugs thalidomide and valproic acid. CDC, New Data on Autism Spectrum Disorders  
A new study suggests obese mothers are at higher risk of having a child diagnosed with autism too. 

What you don't often read is that each of these risk factors reflect a very small component of the total risk.  Most experts believe there's a multitude of triggers.  Many also contend that what we think of as autism encompasses multiple disorders.  Kids on one end of the spectrum don't resemble those at the other end, even kids in the same category, say Asperger's, can appear to have little in common. 
 
THAT 1 in 8 AUTISTIC KIDS?
 
It includes not only kids who've been diagnosed officially with autism before the start of the study but also those who the researchers deemed autistic.  After culling through the medical records of 8-year olds in 14 different locations, researchers identified kids who appeared to have autism in addition to those already diagnosed.  So they cast a wide net. It remains uncertain the extent to which these kids actually exhibited behavioral problems severe enough to warrant a diagnosis. 
 
Let's put these estimates into perspective -  1.1% of US kids have autism vs .6% in 2002.  That's nearly a 100% increase.  How does that compare to attention deficit disorder?  The figures from a decade ago range from 5.4 to 6.2 million or about 10% of kids.  A new study estimates the prevalence at 10.4 million, an increase of 66%.  Just like autism, boys are at significantly greater risk of diagnosis. Yet we rarely hear about an epidemic of ADHD anymore.  That was so last century.    
 
Pretty good piece in the New York Times - The Autism Wars.  Should we think of this as a war?

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