Friday, August 21, 2009

Autism Rising?

One of the burning questions about autism is whether it is more common today than in the past. This question is more than idle curiosity and the answer has the potential to reshape how we think about autism.

Over the past twenty years we have been treated to an ever rising statistic for how common autism is. Twenty years ago it was something like 4 in 10,000, ten years ago it was 1 in 500, and in 2002 it was 1 in 150. How common is it today? Good question, the CDC is supposed to tell us any day now....

No one will dispute the fact that we seem to be able to find more children with autism than we could in the past and that an ever increasing number of children are being diagnosed each year. Yet there is no agreement of what these rising numbers mean.

So, are we in the midst of an autism epidemic or has the medical community finally put on their collective glasses and seen what has been staring them in the face these past several thousand years of human existence (Gee, the kid can't talk, won't look me in the eye and keeps doing funny things with their hands, maybe something isn't right there) ?

As Harold Doherty recently pointed out researchers have been noodling over this ever increasing figure for a number of years. However, to date, the response has been something along the lines of - "Huh, that's strange, I wonder what is causing that. Maybe we should look at that closer". I am sure that they will get around to looking closely at the issue any day now.

Earlier this month we were handled another tidbit of information in the form of the second National Survey of Children's Health (NSCH). This is a nationwide survey of children's health issues that was first done in 2003 and then again in 2007. The results of the 2007 survey were released earlier this month and they had something interesting to say about autism -

The rate of autism now seems to be at 1 in 100.

That rate does keep moving up, maybe looking at why would be a good idea?

Since the data for 2003 and 2007 are publicly available I thought I would make a pretty picture of the differences in rates between the years. Just as a note, this comparison is not perfect because the wording of the question changed between the years.

In 2003 the question was whether the child ever had autism while in 2007 it was whether the child currently has autism or another asd.

I think the ever vs current would over estimate the 2003 numbers and the autism vs "autism or another asd" has the potential to inflate the 2007 numbers. Although in all honesty, I don't think the exact wording of autism vs "autism or another asd" would make a huge difference because most parents whose child had pdd-nos or aspergers would have said "yes" to the autism alone question in 2003.

But, without further ado, here is a pretty picture of the rates between 2003 and 2007.

Those number are definitely going up, I just have to wonder what it means.

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