Autism Rising : Its Groundhog Day

I read the latest CDC report on autism prevalence for 2006 and 2004 and I am beginning to feel that I am trapped in that movie Groundhog Day.  You know the one, where Bill Murray is doomed to repeat the same day over and over and over again until he gets it right.  This report from the CDC is like that - these same lines have been repeated over and over again for over a decade.

In 2006, on average, approximately 1% or one child in every 110 in the 11 ADDM sites was classified as having an ASD (approximate range: 1:80--1:240 children [males: 1:70; females: 1:315]). The average prevalence of ASDs identified among children aged 8 years increased 57% in 10 sites from the 2002 to the 2006 ADDM surveillance year. Although improved ascertainment accounts for some of the prevalence increases documented in the ADDM sites, a true increase in the risk for children to develop ASD symptoms cannot be ruled out.

Looks strangely like the lines that we have been hearing for years now.  Yes, autism is once again more common than thought, but no, we don't know why that is.  We think it is because we are getting better at finding it but we cannot rule out a true increase.

I love that phrase - "cannot rule out".  That phrasing makes you believe that there is strong evidence that shows that autism is not rising but, to be overly cautious, they will still admit that it might be possible that it is more common than it used to be.

Like the movie Groundhog Day, I think we will be seeing these lines again when we hear about the next revision in two years.  I am going to go out on a limb here, but I expect the number that we will hear next is 1 in 80.

But enough of me rambling on about this, I think I have made my opinion clear before.  Instead, I am going to use some pretty pictures to demonstrate my point.  The numbers on the following charts are from the CDC's data for 2000, 2002, 2004, 2006 and the National Survey of Children's Health (NSCH).

First up is the prevalence of autism in 8 year olds from the CDC and NSCH from 2000 to 2007.  The last point is from the 8 year olds from the 2007 NSCH survey and is likely a little high.

The next chart is the approximate year over year change in the autism prevalence from the above chart.  If you look at the average percent change, you will see that the number of 8 year olds with autism is growing about 10% per year.

The next series of charts are from the CDC's data for 2000,2002, 2004, and 2006.  For each of the states that had data for at least 2 years I charted the prevalence per 10,000.

Anyone see a pattern?