I have been accused of all sorts of things for doing this. One commenter (Erik) even insinuated I must be in the pockets of the CDC or Big Pharma. The same insinuation has been made about the Cornell researchers who did the TV study, and I have seen that in several blogs and mailing lists. What is the scenario here? Are we to believe that the CDC had a meeting where they decided to pay a group of economists to conduct an epidemiological study involving cable subscriptions and annual precipitation rates? Right! "Shhh... just don't tell anyone Mr. Economist." BTW, did any whistleblowers come forward yet?
This type of conspiracist paranoia is suggestive of something. It is apparent that to many the TV hypothesis is not a laughing stock, but actually very serious business. Its impact has been significant among the more anti-vaccination elements of the community. Hundreds of messages have been posted to the EOHarm mailing list about this study, many of them very angry messages. The researchers have been harassed by email, and probably even by phone. (See Kev's post on the subject).
Well, thimerosal hypothesis proponents should be worried. Here are the areas in which I believe the TV hypothesis is actually more sound and plausible than the thimerosal hypothesis:
- Time Trends.- In the last several decades, there is only one period of time when thimerosal exposure increased consistently and significantly in the US. That is the period between the birth years 1990 and 1994. At other times, thimerosal exposure has been either fairly stable or declining. In contrast, the administrative incidence of autism has been on a smooth upward trend for several decades, most notably in the 1990s. Roughly the same could be said of TV exposure.
- Regional Epidemiology.- No regional epidemiology exists involving thimerosal and autism, nor is it likely the thimerosal hypothesis could explain both a significant rise in autism incidence over time and the considerable differences in autism prevalence across states and counties. In contrast, the TV study presents a per-county analysis across several states for both cable subscription rates and precipitation rates. The cable subscription analysis even adjusts for time-independent per-county effects.
- Credibility of Researchers.- The only thimerosal epidemiology which can be found in the scientific literature has been authored by Mark and David Geier. The scientific conduct of these researchers has come under fire recently amid allegations of affiliation misrepresentation, IRB irregularities, use of dual terminology, misrepresentation and alteration of cited work, apparent plagiarism and use of salami publications, potential breaches of confidentiality, unreproducibility of results, omission of data, a suspect "order of magnitude" error, conspirationism and fear mongering, and assorted fabrications. Their conflicts of interest include having filed a patent application for their "Lupron Protocol", and, astonishingly, a connection to a pharmaceutical company. A quick search reveals nothing comparable about Waldman et al.
- Extent of Exposure.- The peak thimerosal exposure in the US from all vaccines combined was about 180 micrograms (in 1994). Each vaccine contained as much as 25 micrograms of thimerosal. A conservative estimate (by Sallie Bernard, no less) suggests an average tuna sandwich contains 12 micrograms of methylmercury. However, if we consider that 6 oz. of albacore tuna has 60 micrograms of methylmercury, a tuna sandwich could have over 30 micrograms. Either way, TV exposure appears more significant. Autistic children can watch TV for hours a time, day after day, sometimes asking to watch the same DVD over and over again.
- Strengths & Impairments.- From the very beginning autistic people were described as having areas of strength and impairment. It seems difficult to come up with a model by which brain poisoning would result in cognitive strengths. But it is not impossible to imagine how television might cause certain impairments over time while enhancing other areas of perceptual functioning.
- Removal of Thimerosal.- Thimerosal is considered to have been largely removed from vaccines in the US territory by 2001. But it has been removed in other countries too. It was removed in Sweden and Denmark in 1993. It was removed in Canada in 1996. It was removed in the UK (not sure about the year). Yet, no country has ever reported a decline in the incidence of autism, not even anecdotally. No one has ever said, "hey, wait a minute, there are less little ones with autism now" (well, actually, I know a pair of characters who have claimed just that). The TV hypothesis doesn't have something so obviously damning against it (yet).
- Anecdotal Evidence.- It's early to draw a controlled comparison, but I'll quote something from Jennifer: "By the way, my child did regress at about the same time as she became very interested in watching TV. I've wonderered for years if it wasn't a factor in her gradual social withdrawl. I was so interested that I set up a survey. I asked parents if they had found various therapies helpful (or not). One of the questions was about 'Cutting back on television/video watching'. That received 24 favorable votes, compared to 4 unfavorable, which compared quite respectably to the top therapies which were speech/language therapy which received 38 votes for and 4 votes against, and ABA which received 31 votes for and 3 votes against. Chelation was much less favored, with only 6 postive, and no negative votes."
Are there areas in which the thimerosal hypothesis looks better than the TV hypothesis? Maybe. But I'll just let readers comment on those.