Wednesday, December 30, 2009

Decline in heart attacks

Researchers almost had a heart attack recently when a study purported to show that anti-smoking bans caused a huge reduction in heart attack admissions to hospitals. As Michael Siegel explains:
In October, Dr. David Meyers and colleagues published a paper in the Journal of the American College of Cardiology in which they reported the results of a meta-analysis of published studies on the effect of smoking bans on heart attack admissions. The paper concluded that smoking bans were associated with a 17% decline in heart attack admissions in the 11 studies that were reviewed.

These results were disseminated widely in the media and heavily touted by anti-smoking groups as supporting the conclusion that smoking bans immediately and dramatically reduce heart attacks and that brief exposure to secondhand smoke in bars and restaurants causes a large number of heart attacks.
But then, like so many of these anti-smoking pronouncements, it went bust:
As it turns out, the study findings were due to a careless error. In the original study, the authors had inadvertently reported the Pueblo study has having reported a 70% reduction in heart attacks (a result that is completely implausible and clearly should have been noticed as having been in error). Instead, that study actually reported a 34% reduction in heart attacks. The meta-analysis authors published a correction in which they re-analyzed the correct data.

It turns out that the 11 studies did not find a 17% reduction in heart attacks, but only found an 8% reduction in heart attacks.
In other words, the increase was overstated by over half. That would seem to suggest that these bans might still be effective, even if not as pronounced as before. The study, however, like so many politically motivated studies, apparently did not contain a control. But you can get the rough equivalent by going outside the study to see what the total national decline is:
This level of decline in admissions for heart attacks is obviously not significantly different from the levels of decline in heart attacks that are being observed in the absence of smoking bans, which have varied between 5% and 10% per year in many communities.

For example, in the United States as a whole, heart attack admissions declined by 8.2% in 2004. The decline of 8% in communities/nations with a smoking ban is comparable to this. Therefore, the meta-analysis result fails to provide any evidence that the smoking bans resulted in a decline in heart attacks.
That's what you call the research equivalent of an exploding cigar. You would think the Science Integrity Patrol would be all over this kind of thing. But when it comes to the War on Tobacco, just one front in the Politically Correct Health Crusade, we must are all instructed to just go on as if nothing unusual had happened.

Funny how that works.


TomH said...

But don't we need to ban smoking for health reasons, so this justifies "the good lie?"

I'm playing devil's advocate.

Martin Cothran said...

Tom H:

Well, I guess as an explanation it sounds better than sheer incompetence.

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One Brow said...

The ban on second-hand smoke would primarily affect people in the service industry, and even then much less than smokers. I don't see why these effects would show up in large numbers with regard to hear attack percentages.

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