Thursday, April 12, 2007

Evidence based woo

The National Center for Complementary and Alternative Medicine, which I will henceforth refer to as the National Center for the Promotion of Pseudoscience (NCPP), has just released a study claiming that Tai Chi boosts immunity against HVZ (Shingles) virus. There’s something in this paper to make all the alties happy. The anti vaccination crowd will be excited to learn that Tai Chi worked as well as vaccination. For the integrative medicine enthusiasts there was the finding that Tai Chi combined with vaccination worked better than either treatment alone.

If you ignore the obvious problem of biologic implausibility (the “mechanism” of Tai Chi is said to be the unblocking of the flow of the vital energy Qi along the body’s meridians) the paper appears sound at first glance. With its prospective randomized design, p values and prestigious institutional representation (UCLA and UCSD) it has all the trappings of science. But the ever diligent Orac, in contrast to the sound bite style of the popular media and much of the blogosphere, looked beyond the abstract and, digging deep into the methods section of the paper, discovered that this study proved nothing whatsoever about the effect of Tai Chi on the immune system. Because the control subjects merely “sat on their behinds in a class” the study suggests only that exercise might boost immunity. As Orac points out, to prove any unique effect of Tai Chi a comparison group treated with conventional exercise at a comparable aerobic level, or Tai Chi exercises with the “wrong moves” (a valid Tai Chi placebo for most subjects unschooled in the ways of woo) would have been necessary.

That is a patently obvious, huge, huge design flaw! Why was this study conceived in this way and why was it accepted for publication? Orac suggests a significant conflict of interest: woo is sexy these days, it sells, and it gets funded.

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