Jane Galt, of Asymetrical Information, points out that yet another study, once again using faulty methodology and carried out by the foxes guarding the henhouse (vaccine researchers), is being touted as the evidence of no provable link between the mercury-based vaccine preservative, Thimerosal, and the increase in autism.
While I know other qualified medical pundits have more indepth critiques of the study (particularly a shift in methodology in the middle of the research) I have to admit that I've only glanced briefly over the study, having mentally discredited it after reading that Thimerosal was discontinued in vaccines in Denmark after 1992. See, the main argument emanating from most US research is that it was the massive increase in the amount of ethylmercury children were exposed to, and at an extremely young age (merely days after birth in some instances) which may be responsible for the association between Thimerosal and autism. Children have been exposed to small amounts of ethylmercury in vaccines for decades, particularly in the DTaP/DTP jabs. It wasn't until the early 1990s however, with the inclusion of both the HepB and HIB vaccines, both containing between 12.5-25up of mercury in each dose, that children under the age of 6 months were getting many times safe levels of mercury injected directly into their bloodstreams. Danish researchers were studying children subjected to much lower levels of ethylmercury exposure, namely the 25ug/visit in the DTP, versus 62.5ug in children immunized with the DTP, HepB and HIB, all in one visit.
Thus, if Denmark banned Thimerosal before these vaccines were even in widespread use, then the study is frankly useless. Well, medically speaking, it's useless. Of course, for the apologists for corporate and governmental irresponsibility, it's quite valuable, as what percentage of the public is familiar with the intricasies of the Thimerosal debate? As Ms. Galt herself said, "It doesn't help anyone to get so attached to a possible problem that you reflexively attack anyone who suggests that it doesn't exist."
Posted by MB Williams at September 5, 2003 01:11 PM | TrackBackThe abstract of the study is here. The full article is behind a $ wall.
According to the abstract, the design of the study looked at "Analysis of data from the Danish Psychiatric Central Research Register recording all psychiatric admissions since 1971, and all outpatient contacts in psychiatric departments in Denmark since 1995."
Why do they thinks that hospital admissions or outpatient psychiatric visits are an appropriate method of determining the incidence of autism? My son has had neither at any time since he left the hospital after birth.
Secondly, does anyone know what the vaccine regimen was in Denmark at the various times? How much mercury was being given to kids before the thimerosal ban in 1992?
I also note that the incident ststistics in the popular reporting of the study are odd. They suggest that Denmark's autism incidence has risen from less than 1 in 10,000 to less than 4 in 10,000. During the same period, the incidence in the US has risen from about 4 in 10,000 to about 50+ in 10,000.
Is there supposed to be some reason why Denmark has autism rates less than 10% of the US?
There is something very odd about that study. If anyone gets a copy of the full article, could you please send it to me or post it somewhere?
I know someone who can get you a copy, Dwight (Emily, remind me to ask Ambre if I get overwhelmed the next few days with school starting.)
I'm fairly positive that the amounts of mercury kids were exposed to in Denmark prior to 1992 was at or lower than 25ug/visit, as neither HepB or HIB were in widespread use until the early 1990s. Neither polio or MMR contain mercury. I tend to agree with you that perhaps researchers should be investigating information such as this in order to determine WHY there's such a disparity between autism rates in the US/UK and Denmark.
Posted by: MB at September 5, 2003 01:57 PMDwight -- the reason they used psychiatric outpatient records is that, as the New York Times article makes clear, in Denmark a psychiatrist is required to sign off on a diagnosis of autism. If you spend any time at all looking at transnational medical research, you realize just how difficult it is to compare studies between countries. Just to take one example: our infant mortality statistics are awful compared to other industrialized nations, even Cuba. . . because we perform heroic interventions on premature babies that are declared stillborn, and thus left out of the statistics, in other countries. We save more babies, but our stats suffer. Random digression, but it goes to show that you can never assume that your experience is comparable to people with the same problem in another country. The fact that psychiatric diagnosis might be a bad proxy here doesn't mean it is in Denmark's national health system.
Posted by: Jane Galt at September 5, 2003 02:19 PM