Thursday, March 02, 2006

Invalid Studies Being Used to Promote Smoking Bans

According to an article in the Loveland Daily Reporter-Herald, two authors of the Helena and Pueblo studies (which purported to show that smoking bans in these cities reduced heart attack admissions by 40% and 27%, respectively) are using the conclusions from these studies to promote smoking bans throughout Colorado.

According to the article: "Controversial studies in Pueblo and Helena, Mont., link smoking ordinances to a decrease in heart attacks. Doctors involved with both studies spoke Wednesday afternoon at McKee Medical Center to kick off presentations around the state to promote smoking bans, whether on a local or state level. 'We'’ve been invited to a number of states to talk about the study. With the increased interest in Colorado, we decided to pair off the studies,' said Dr. Robert Shepard, medical director of New West Health Services in Helena, who oversaw the Helena study. ... Dr. Carl Bartecchi, a professor of clinical medicine at the University of Colorado School of Medicine ... used that study to promote a citywide indoor smoking ban in Pueblo, which took effect July 2003. ... 'The chances of this happening by chance are extremely thin,' Bartecchi said. ... Shepard added that most criticism comes from 'naysayers who just don'’t want to believe it.'"”

The Rest of the Story

Well I'm not a naysayer and I do want to believe it because it would be wonderful if smoking bans could decrease heart attacks by more than a complete ban on smoking would.

Unfortunately, an analysis of the plausibility of the Helena and Pueblo claims demonstrates that it is simply mathematically impossible for a smoking ban to result in a 40% decline in heart attacks when a complete ban on smoking would not likely result in that great a decline in heart attacks. Thus, in order to explain the Helena conclusion, the smoking ban would have had to cause every smoker in the city to quit smoking, and even then it's not clear there would have been a 40% decline in heart attacks. The purported effect of the smoking ban in Pueblo is equally implausible.

The Pueblo study is particularly unconvincing, and in my opinion, weak scientifically, because it compares two data points - one from the 18 months after the smoking ban and one from the 18 months prior to the smoking ban. There is simply not a long enough baseline period to establish what the baseline variability in heart attack admissions in Pueblo is and what the secular trend was in order to determine whether the observed 27% decline in hospital admissions was due to the smoking ban or to random variation in the underlying data.

It seems particularly unfortunate that the Pueblo study is being disseminated and used to promote smoking bans in Colorado, especially the fact that it is apparently being disseminated by the author himself, because the study is unpublished and is apparently under review by a scientific journal. Most journals frown upon the results of studies being disseminated while they are being peer reviewed and prior to publication.

And I find it unfortunate that the results and conclusions of this scientific study are apparently being disseminated and being used to promote policy prior to being published. In fact, it's not clear exactly what the point of seeking publication of these findings is, if they are going to be disseminated and used to promote policy prior to publication.

Usually, we wait until a scientific study is peer-reviewed and then published before disseminating the findings to the public and the media. There are of course some exceptions, but here it appears that the Pueblo findings are basically on tour.

I guess we can call this Winter Tour '06.

And it's really a shame because the Pueblo and Helena studies are not a reason to ban smoking in restaurants. In my opinion, there are other data to support smoke-free workplace policies. Therefore, I think it is a shame that the implausible and scientifically weak results from Pueblo and Helena are being used to promote these policies.

(In honor of smoking bans and Colorado: Here's the setlist from the Grateful Dead August 12, 1979 concert at Red Rocks)

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