Wednesday, February 03, 2010

Autism Rising in the New York Times

The New York Times has joined those who assert that rising autism rates reflect a real increase in autism and are not explained solely by changes in autism diagnosis definitions and increased awareness:

"In the United States, anti-vaccine groups have advanced other theories since then to explain why they think vaccines cause autism. For years, they blamed thimerosal, a vaccine preservative containing mercury. Because of concerns over the preservative, vaccine makers in 2001 largely eliminated thimerosal from routinely administered childhood vaccines.

But this change has had no apparent impact on childhood autism rates. "

The New York Times argument ,previously advanced by Dr. Eric Fombonne and Dr. Nancy Minshew, only makes sense if it is based on real increases in autism rates. Increases in autism rates after removal of thimerosal from vaccines solely because of diagnostic definition changes and ascertainment factors would not indicate whether thimerosal did or did not play a role in causing autism. 

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Ian MacGregor said...

In a paper published in late 2009, Epidemiology of pervasive developmental disorders. Pediatric Research, 65, 591–598.

Dr. Fombonne addresses this subject directly he does not see any secular increase in the rise of autism, but attributes it to reclassification, more awareness, earlier diagnosis, etc.

This is not to say that the rate of autism has not gone up. It definitely has. It is to say that the increase in the rate can be attributed to the above factors.

This does not rule out using the increase to rule out thimerosal. In that greatly reducing the amount of thimerosal had no impact on the rate rise.

Dr. Fombonne's paper does not rule out an environmental cause. It does state the increase is most probably artificial.

I don't know how long before awareness and expanded diagnoses become omnipresent and thus stop being factors in the increase. Dr Fombonne does not think this has yet happened.

Unknown said...

Dr. Fombonne should issue a retraction of his claim that rising autism rates after the alleged removal of thimerosal from vaccines proved that thimerosal played no part in causing autism.

As for the state of the research, perhaps you can tell Dr. Fombonne the next time you discuss it with him that Dr. Tom Insel, head of the Interagency Autism Coordinating Committee has stated in December 2009 that the diagnostic and ascertainment factors that Dr. Fombonne references when he is not trying to prove thimerosal does not cause autism only account for slightly less than HALF of the increases.

Dr. Insel has also stated that the onus is on anyone claiming these startling increases are not real to make their case.

Unknown said...

Mr. MacGregor

Please address the issue of the probative value of increases in autism rates after thimerosal removal from vaccines if the autism increases are NOT real.

Ian MacGregor said...

If the increase is artificial then it is not caused by thimerosal nor any other environmental factor. If it is real then greatly reducing the amount of thimerosal and seeing the rate increase indicates it is not thimerosal.

I suppose one could argue that the increase from thimerosal was real, but by the time the studies were done, the increase for artificial reasons hid the thimerosal caused increase. But that argument would say that thimerosal played a minor role at best. I don't think it paid any.

I'm not convinced that there is no environmental factor at play, but it is definitely not thimerosal