Now that I have read the paper (thanks to Jennifer), I do have a problem with one of the conclusions made in the discussion section. They never seem to allow for early incidence not corresponding to the expected prevalence that might occur if the developmental delay was temporary. A very brief and shallow look at pubmed suggests that at least some children would no longer qualify under the diagnostic criteria if evaluated later (e.g. PMID: 17206522). Significant changes in the training of pre-k teachers in California has taken place since the last full birth cohort (1996). If nothing else it will be interesting to see if the conclusions drawn will correspond with the data as it develops over the next few years.

So, Joseph, your criticism is then mainly with the media side of this?

Obviously, it’s not mainly that. What I’m saying is that the paper should not be given a pass just because it uses some skeptical language, when the authors (and others) clearly want to communicate that this is a definitive study proving the “autism epidemic.” For reference, this is how Dr. H-P is quoted by WebMD.

“When you put it all together, this doesn’t come close to explaining the increases in the last 10 years,” Hertz-Picciotto tells WebMD. “The more you whittle away at this increase, the more you have to say that what is left over is real. Given that autism cases keep going up, and can’t be fully explained by artifacts, environmental factors deserve serious consideration.”

I took that from Autism Street, BTW, where you’ll find yet another post on the matter, primarily looking at diagnostic substitution in California, which incidentally is hard to deny once you look at an aggregate of all special education categories.

H-P:

The inclusion of milder cases has been suggested as an explanation for the increase in autism. Neither Asperger’s syndrome nor ‘pervasive developmental disorders not otherwise specified’ qualify under the category of autism in the DDS system.

CDDS (private email)

The current CDER was written in 1978 and updated in 1986, which is why the language is so out of date ( e.g., Residual Autism). California has clinicians in the field who are, of course, using modern criteria in their assessments but then they have to go backwards and try to fit those kids into the 1986 CDER. So you are going to have Aspergers kids, PDD-NOS kids in both categories 1 and 2. Categories 1 and 2 are called ‘Autism.’ But because there are so many clinicians, using lots of different techniques for evaluation, there is a lot of inconsistency and enrollment figures should not be misused as epidemiological data.

Can you see the problem with this paper yet?

But that happens to all papers all the time. No need to single this instance out as unique in this regard.

The paper is OK, a step forward in some areas, good and flawed at the same time, but not as interesting as the debate itself, in this case!

I completely disagree. I think people have been too kind to the paper, perhaps because it’s not a paper by cranks. Frankly, I would’ve expected a paper like this from the likes of the Geiers.

The only novel result from the paper is the 1.2-fold rise due to age of diagnosis. (I would caution this should not be interpreted as age of diagnosis not having changed much – that’s the change in the proportion of diagnoses by age 5).

The other results are recycled from elsewhere.

They use a single Finnish epidemiological study to come up with the figure on the impact of diagnostic criteria. It’s a complete stretch to suggest that the results of that study might be applicable to California DDS ascertainment between 1990 and 2006. Are we also to believe it’s precisely 2.2-fold and it can’t be a little higher?

It’s true that the paper uses appropriately skeptical language at times. I mean, it has to. But you should see what the primary author said to the media.

Honestly, if they wanted to raise funds for environmental research, there are probably better ways to achieve that. Calling autism an epidemic has many non-trivial moral and economic implications. False epidemics solicit false causes and waste research money.

http://www.vetmed.ucdavis.edu/cceh/Epipaper1208.pdf

The tone is completely different from that of the press releases.

You know there is a third possible explanation for the rise besides statistical or environmental. That’s that the cause of autism is genetic, but that human mating habits have changed in recent decades to promote some genetic disorders. There are recent studies that demonstrate changes in partner selection by women taking birth control over women not taking the pill. These changes certainly have implications regarding the immune system. It possible there are other effects, as well.

Before feminists jump on me, understand I’m totally with you, and I fully understand the implications of that statement. This is worth studying, and if turns out to be true, the proper response is to reevaluate how birth control is used, and to investigate non-hormonal forms of birth control for both men and women.