Wednesday, November 21, 2007

Absurd Claims Being Used to Defend Weak Indiana Smoking Ban/Heart Attack Study

In an article in the Indianapolis Star, an Indiana University anti-smoking researcher is quoted as saying that active and passive smoking can kill a person immediately from heart disease, without requiring years of exposure. The comment came in the context of defending the plausibility of results of a study which purported to show a 70% decline in heart attacks in nonsmokers immediately following the implementation of a smoking ban in Monroe County, Indiana. I have previously explained why the conclusions of that study are invalid (post #1; post #2).

According to the article: "When substances in smoke enter the bloodstream, they can throw off the delicate balance of chemistry in the small blood vessels, said Dr. Stephen J. Jay, a professor of medicine and public health at the Indiana University School of Medicine. That can cause a person's platelets to grow sticky and clump together, creating a blockage that can result in a heart attack or stroke. 'This is surprising to a lot of people who generally think that smoking is something that causes disease 30 or 40 years down the pike,' Jay said. 'What people don't understand is that if you look at active smoking as well as passive smoking in population studies, you can see that exposure to smoke, active or passive, is perfectly capable of killing you now.'"

The Rest of the Story

While I understand that the Indiana study is quite weak, is based on extremely small numbers of heart attack patients, and draws a conclusion that is quite implausible, I don't see how it helps the situation to defend the study's conclusion by misleading the public into believing that it does not take years of smoking to kill you.

The truth is that we do not see people dying of heart attacks in their 20's or even 30's from smoking (except in rare, exceptional situations). Clearly, it takes at least 15 to 20 years of smoking before you develop heart disease severe enough to cause a heart attack. So I'm not sure what the point is of telling the public that smoking can kill you right away.

It is highly misleading to tell the public that smoke exposure can cause a blockage that can result in a heart attack or stroke without clarifying that the person must have pre-existing coronary artery or cerebrovascular disease in order for this to occur. A healthy person is not going to have a heart attack or stroke because they are exposed briefly to tobacco smoke.

It seems to me that these absurd statements are a desperation attempt to defend a study whose conclusions we all realize are completely implausible. In fact, it would take quite absurd assumptions for the conclusions of the Indiana study to be correct. The only way we can successfully defend the plausibility of those findings is if we convince the public that healthy people do indeed drop dead instantly from brief exposure to secondhand smoke.

Even Dr. Stan Glantz himself admits that brief exposure to secondhand smoke is not going to cause a heart attack in a person who is healthy (who does not have existing coronary artery disease).

In the long run, the tobacco control movement is only going to be hurt by these absurd exaggerations. If the movement loses its scientific credibility, it can no longer be effective. And statements like this are not going to help maintain the scientific credibility of the movement.

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