Monday 8 August 2011

And MoH responds

I'd sent an OIA request on MoH's decision just to blank out the reference to Rimm and Moats 2007 and to replace it with a reference to another paper more sympathetic to their argument. Here's the result:

OIA 07-2011 Rimm and Moats MoH

They include a short document which I'd not before seen (starts at p. 12 of the attached file) outlining why NZ's Ministry of Health deems there to be no cardioprotective effect of alcohol consumption:
  1. Confounding with healthy lifestyles: moderate drinkers have more healthy lifestyles in general
    • There is no way that this is substantial. From Rimm and Moats, which you'll recall is the piece MoH had cited as proving its opposite:
      To address the issue of residual confounding by healthy lifestyle in drinkers, in a large prospective study we restricted analysis to only “healthy” men (who did not smoke, exercised, ate a good diet, and were not obese). Within this group, men who drank moderately had a relative risk for CHD of 0.38 (95% CI, 0.16–0.89) compared with abstainers, providing further evidence to support the hypothesis that the inverse association of alcohol to CHD is causal, and not confounded by healthy lifestyle behaviors.
  2. Sick quitters
    • But the whole point of Rimm and Moats is that the sick quitters hypothesis doesn't eliminate the J-curve. Again from Rimm and Moats:
      The “sick-quitter” hypothesis and the concern that moderate drinkers lead a healthier lifestyle may explain a small proportion of the benefit attributed to alcohol in some studies, but recent studies which have removed sick quitters, updated alcohol and covariate information on diet and lifestyle factors, and separately documented benefits of alcohol among healthy and unhealthy populations further add to the evidence that moderate alcohol consumption is causally related to a lower risk of CHD.
  3. Surveys giving average levels of drinking may mask heterogeneity in drinking patterns: 14 drinks per week could be two binges or a couple of glasses of wine per night.
    • Yeah, sure. But that gives us attenuation bias. If we're finding a substantial J-curve despite that some folks classed as moderate drinkers might really be folks who binge a couple times a week, doesn't that suggest that the health benefits of the couple of glasses of wine per night are understated?
What does MoH cite in support? Middleton Fillmore et al 2006, which tries to do what Castelnuovo and Donati did but with what feels like cherry-picking of which papers counted as high quality for their meta-study - all of their results on cardio hinge on which two studies they deemed high quality in evaluating the effects of alcohol on heart disease. Middleton Fillmore et al 2007 which is just a gloss on Middleton Fillmore et al 2006. Mumaki and Rimm 2001. That's a fun one. What did Mumaki and Rimm 2001 say?
This article has explored whether alcohol consumption per se is responsible for the lower risk of coronary heart disease among moderate drinkers. Based on the results of the meta-analysis of randomized trials by Rimm and colleagues (1999), the answer appears to be yes. If alcohol consumption indeed influences HDL-C, triglyceride, and fibrinogen levels to the degree documented in the meta-analysis, consumption of two standard drinks daily would be expected to lower a person's risk of coronary heart disease by nearly 25 percent, a figure that agrees well with the results of observational studies.
Sure, Mumaki and Rimm refrain from suggesting folks start drinking for their health, but MoH is here citing them on heart disease. And there's no equivocating in Mumaki and Rimm on effects on heart disease. Does MoH even bother reading the articles they cite? Or do they just assume what must be in the article based on its title? Doesn't much matter; when you call them out on it, they just delete the cite and replace it with a friendlier one. MoH isn't engaging the literature; they're playing fill-in-the-blanks looking for cites that support what they already want to say.

They then cite Middleton Fillmore et al 2007 again as showing there's no j-curve in all-source mortality. Middleton Fillmore's results there hinge on seven studies they deemed sufficiently high quality out of more than 50. I would love to hear MoH's reasons for preferring Middleton Fillmore over either di Castelnuovo or Corrao or Rimm and Moats. Is it just the conclusion? In the absence of any discussion by MoH of failings in di Castelnuovo, Rimm and Moats, or Corrao, my money's on conclusion-seeking.

While they talk about alcohol's potential carcinogenic effects, that's a sideshow. What matters is all-source mortality. That's all that can matter when evaluating the overall mortality effects of a substance that helps with some disorders and hurts with others. And that's a scrap between di Castelnuovo / Rimm & Moats and Middleton Fillmore. Rimm & Moats only address coronary heart disease, but that'll be the big one for the J-curve and they show that the J-curve in cardio is massively robust to controlling for sick quitters and for healthy lifestyles. Nowhere does MoH give me a reason to trust Middleton Fillmore over either Rimm & Moats or di Castelnuovo.

Reading through the set of documents, it looks like they read my complaint as being "you're citing the wrong thing in support of your argument" rather than as being "Even the thing you're citing in support of your argument proves the opposite; look again at the science." There's zero evidence of anyone anywhere in MoH having read Rimm & Moats; instead, they just found a reference to Middleton Fillmore to throw in instead.

I don't think I ever received the letter MoH penned for Ryall (p. 23); a lot of stuff got lost in the shuffle around the September earthquake. But Ryall's clearly not getting very good advice from his Ministry on this one.


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