My original thread attracted a lot of comment, and much of what follows here is relevant to those comments. For example, one commenter who (sometimes) refers to himself as “Critical Thinker” keeps referring to a paper entitled Tobacco Science and the Thimerosal Scandal that has been posted on Kennedy’s website. Apparently this is supposed to be evidence of the dangers of thimerosal, or of a cover up or something, certainly not a dishonest, inaccurate or sensationalist article like his Salon piece, oh no.
Anyway, Autism Diva points out a rather interesting conclusion (via Michelle Dawson) from this paper. On page 40, Kennedy writes that American children received much higher doses of thimerosal than UK children, and especially, more in one day than UK children, with the conclusion that American children are at a much higher risk of autism than children from the UK (since thimerosal causes autism, you see). Okey dokey, keep that in mind and read on.
Ten pages later, Kennedy approvingly cites a paper by Marc Blaxill entitled, What's going on? The question of time trends in autism. Blaxill states that autism rates in the UK and the US rose by the same amounts, as these graphs show:
(Note: the graphs are easier to read at Autism Diva.)
The UK and the US both clearly underwent the same increase in autism at the same time, and both now have the 1 in 166 rate, despite the much lower thimerosal doses in the UK. Autism Diva summarizes:
Kennedy says that there's no comparison between the usage of thimerosal in the U.S. and the U.K., and if the Brits say they can't see thimerosal as a cause of autism it's because they have used so much less of it –
and Blaxill says that the increase of autism has been the same in the two countries.
The conclusion is: thimerosal usage has no effect on autism diagnosis rates.
That conclusion would seem to be entirely consistent with the data, although perhaps any critical thinker(s) reading could explain why this conclusion could be wrong.
(Of course, the conspiracy theorists in the UK blame autism on the MMR shot, since thimerosal is so low in the UK, but that’s another story.)
Moving on, I find that Majikthise has also read the full Simpsonwood transcript (I’m not the only one without a life, apparently). Like me, she concluded Kennedy had been dishonest about the meeting, or as she puts it:
Nothing said at Simpsonwood suggests an attempt to whitewash or cover up anything. The study got some interesting results, which later failed to withstand verification at the third HMO. Vaccine experts said some nasty things about anti-vaccine activists. That was about it.
She also makes some interesting comments on the actual data they were examining, and explains why no firm conclusions could be drawn:
Of course, there are confounds upon confounds. Care-seeking may be related to socioeconomic status, socioeconomic status to maternal mercury intake and breast feeding, and therefore to prenatal and postnatal mercury exposure, and so on. You can generate any number of alternative scenarios.
It is difficult to interpret the Simpsonwood data because the diagnoses of interest are so fuzzy. The study is trying to capture small differences in the relative risk for relatively rare conditions. As we learned from the recent JAMA obesity study, if you're studying a relatively rare phenomenon, like death at age forty (or infantile autism), small numerical differences between groups translate into huge increases in relative risk. Under these circumstances, it's especially important to be mindful of confounds that could account for small differences between the groups, e.g. local variation in diagnosis rates and diagnostic criteria in the case of relatively subtle and fluid diagnoses like "speech delay" or "attention deficit disorder."
As one of the pediatric neurologists at Simpsonwood pointed out, most of the kids in the study were too young to be diagnosed as speech delayed or attention deficit disordered with any degree of rigor. There's just too much overlap between the "normal" and the "pathological" curves at that age. Of course, once someone gets diagnosed with something, it's pretty rare for them to get undiagnosed, especially in the eyes of an administrative database. So, it's unclear how many kids with early diagnoses actually had a pathological problem to begin with.
All in all a very good write-up – worth reading the whole thing.
The Institute of Medicine
You’ll recall Kennedy accused the Institute of Medicine (IOM) of being part of the cover up. There were also some (un-sourced) IOM quotes that I had questioned. The IOM’s President replies:
Mr. Kennedy sought to buttress his misrepresentation of the purpose of the IOM studies by selectively using and fabricating quotations from the transcript of an organizational meeting held by the committee. He took words and phrases out of context, combined them and misrepresented them as direct quotes.
Hum, taking words and phrases out of context, combined them and misrepresented them as direct quotes – yep that sounds like Kennedy. The IOM president goes on to defend the IOM’s integrity, especially with reference to its studies being peer reviewed, unlike the work of many of the thimerosal activists:
Mr. Kennedy's piece does not mention that the IOM's studies on vaccines and autism -- like all IOM studies -- were peer reviewed (the equivalent of fact checking in the scientific community) by a group of outside experts before being approved for publication. The IOM, a branch of the National Academies, also follows stringent policies for reviewing the potential conflicts of interest or biases of individuals who are chosen to serve on its study committees. The members selected for the committee that reviewed vaccine safety issues had no links to the CDC, vaccine manufacturers, vaccine-related litigation or advocacy groups, and they had received no recent funding from the sponsors of the study. They received no remuneration for their work on the committee. The reputation of the National Academies for objectivity, integrity, independence and competence has been earned through numerous studies, and it is one of our most important assets.
Salon allowed Kennedy to reply. Amusingly, Kennedy pouts that the IOM President “offers no evidence of "fabricated" quotes”, as if Kennedy is all about evidence now. Of course, if Kennedy could offer evidence (with cites) of the original quotes (in context) and evidence of the “paid cover-up” that he so scandalously alleged, I might concede that the IOM President should back up his claim; but as I see it, Kennedy is the one unable to back up his claims, not the IOM President. Kennedy continues with more of the “conflict of interest” ad Hominem fallacious reasoning Orac and I have debunked before.
Finally, Michael Fumento writes in the Wall Street Journal online:
…Mr. Kennedy isn't to be relied upon for facts. He told Mr. Scarborough in a June 21 interview: "We are injecting our children with 400 times the amount of mercury that FDA or EPA considers safe." Yet four days earlier this correction to his piece appeared: "The article also misstated the level of [mercury that infants have received]." It was "40 percent, not 187 times, greater than the EPA's limit for daily exposure to methyl mercury." Mr. Kennedy not only ignored this correction on Mr. Scarborough's show; he overstated it even further.
Kennedy being loose with the facts. Wow! And Fumento comments on how Kennedy relies on people who will agree with him, rather than on people with expertise who don’t:
…Mr. Kennedy quotes from vaccine conspirators like Boyd Haley, "one of the world's authorities on mercury toxicity." Actually, Mr. Haley has co-authored, since 1993, a total of five mercury-related publications listed on the medical data base Medline--not exactly what you'd expect from a world authority. By contrast, Frank DeStefano, an epidemiologist at the CDC who does not believe that vaccines cause autism, has co-authored 49 vaccine papers.
Finally, Fumento debunks the conspiracy to hide the data:
Mr. Kennedy had claimed that "to thwart the Freedom of Information Act," the government "handed its giant database of vaccine records over to a private company, declaring it off-limits to researchers." But this practice, Dr. DeStefano noted, was required by federal regulations to protect the privacy of autistic children and their parents. It still allowed access by external researchers but not to any Joe Blow with a FOIA application.
Edited to add:
See the pretty good article in yesterday's New York Times which included this quote from David Kirby, the author of "Evidence of Harm" that premotes the link between thimerosal and autism:
Because autism is usually diagnosed sometime between a child's third and fourth birthdays and thimerosal was largely removed from childhood vaccines in 2001, the incidence of autism should fall this year
Yes it should, David, if you are right.