Wednesday, October 08, 2008

Who Wrote this Commentary on the Helena Study, Arguing that Using it to Conclude that Smoking Bans Reduce Heart Attacks is Wishful Thinking?

Today I offer a puzzle for Rest of the Story readers. Below is a commentary (unpublished) written by a scientist regarding the famous Helena study. The Helena study concluded that the smoking ban in that city immediately and dramatically reduced heart attack admissions (by 40%). That study has been widely cited throughout the world as demonstrating that smoking bans quickly and dramatically reduce heart attack rates.

The question is this: who wrote this commentary?

Writing to the Centers for Disease Control and Prevention (CDC) about a draft of its commentary that accompanied the Helena study, the scientist in question wrote:

"I would be very cautious with this and I think the first couple of paragraphs are far too strong for the data presented in the paper. I have seen earlier drafts of this paper with more complete descriptions of the data that were far less compelling. In your discussion of the limitations you seem to believe that the numbers presented are per month. That is not true, they are for the 6 month interval (i.e., 3-4 cases per month), and the difference is largely in the first couple of months in the earlier drafts. Small numbers or no, it would be useful to know the distribution of current, former, and never smokers for the different years (would you feel differently if 70% of the 24 AMI [acute myocardial infarctions] in Helena during 2002 were current smokers for example). The reluctance to produce these breakouts is concerning.

To validate this article with a CDC editorial ("the answer is yes") runs the risk of the writers of the editorial being associated with the over interpretation of the data presented in the article and you should think carefully about it. At best this is a provocative observation, but to suggest that it demonstrates that smoke free ordinances can lower AMI rates is wishful thinking."

The Rest of the Story

It was very interesting for me to read this commentary on the Helena study and its accompanying editorial, because it expresses exactly my scientific opinion regarding that study. At very best, the results of the Helena study are provocative. But the sample size is so small that the study cannot possibly conclude that the observed change in heart attacks is attributable to the smoking ban. To suggest that the Helena study demonstrates that smoke free ordinances can lower acute myocardial infarction rates is wishful thinking.

In addition, the commentary is interesting because it warns the CDC scientists not to put their own scientific integrity into question by blindly jumping on the Helena bandwagon. To argue that the Helena study supports the conclusion that smoke-free ordinances immediately decrease heart attacks or that the study demonstrates the positive benefits of a smoke-free ordinance would amount to over-interpretation of the data presented in the article.

While the CDC did tone down the article and included some limitations of the Helena study, it unfortunately did not alter its underlying conclusion that brief secondhand smoke exposure precipitates heart attacks among nonsmokers, and the headlines derived from the CDC commentary were wildly exaggerated and misleading.

Who do you think wrote this commentary, which expresses a scientific opinion which is virtually identical to that which I have expressed for many months on this blog?

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