Tuesday, May 23, 2006

IN MY VIEW: Tobacco Control Movement is Legitimizing Junk Science Claims

For many years, tobacco companies and many other opponents of tobacco control policies have accused the tobacco control movement of engaging in junk science, especially regarding the health effects of secondhand smoke.

For example, we have been accused of cherry-picking the science on secondhand smoke, making up the science, and spreading scientific claims that are implausible, and therefore junk.

But recently, I believe that junk science has actually entered the anti-smoking movement.

The greatest example is the claim we are making that 30 minutes of secondhand smoke exposure can cause hardening of the arteries. Apparently, this claim stems from a study published in the Journal of the American Medical Association which showed that a 30-minute tobacco smoke exposure causes endothelial dysfunction (damage to the function of the cells lining the coronary arteries) in nonsmokers. Endothelial dysfunction is a marker of the earliest stage of atherosclerosis.

The significance of this study is that it demonstrates a plausible biologic mechanism by which chronic exposure to secondhand smoke can cause heart disease: repeated damage to the endothelial lining of the coronary arteries could result in a process of atherosclerosis, over a period of many years.

But instead of representing the study for what the science actually showed, we are distorting the scientific findings and using them to claim that a single 30-minute exposure to secondhand smoke is enough to cause atherosclerosis, forgetting to tell the public about the chronic (repeated) exposure part.

Moreover, a group of major anti-smoking organizations prepared a strategy document urging all of us in the movement to make this claim publicly in order to promote smoking bans. By making the damage from secondhand smoke seem immediate and severe, it was suggested, we could help break down barriers to the adoption of these smoking bans because our statements would have more of an emotional effect.

But by forgetting this key component of the scientific evidence - that it documented only a transient effect that represented the very earliest stage of atherosclerosis and did not imply that a single exposure could cause irreversible effects that would go on to result in heart disease - we turned what was otherwise good science into junk science claims.

And in doing so, we are doing everything that we had been accused of doing:

First, we are cherry-picking the evidence. For example, we are reporting the part of the study that showed that coronary blood flow under the artificial and strictly experimental conditions of hyperemia was impaired, but ignoring the part of the study which documented that there was no change in coronary blood flow in subjects exposed to secondhand smoke for 30 minutes. This is resulting in widespread claims by our organizations that 30 minutes of tobacco smoke exposure causes decreased coronary blood flow, which is a highly misleading, if not fallacious claim.

Second, we are making up the science. One of our major groups is claiming that a 30-minute exposure to secondhand smoke increased the risk of a fatal heart attack among nonsmokers to the same level as that of smokers. This is a "made up" claim, because there isn't a shred of evidence that this is the case. In fact, the claim is so preposterous that it fails, on its face, without even a need to conduct any scientific study. It simply can't be the case that a person exposed to just 30 minutes is at the same risk of a fatal heart attack as someone exposed for a lifetime to actively smoking 2-3 packs of cigarettes per day.

Third, we are making scientific claims that are completely implausible. You can't develop hardening of the arteries in just 30 minutes. It takes years.

The bottom line is that by turning otherwise good science into junk science, I believe that we as a movement are legitimizing the claims of groups (including the tobacco companies) that have wrongly (in the past) accused us of disseminating junk science claims. Now, I would have to agree with them. There is junk science in the anti-smoking movement.

The real problem is that the public cannot necessarily discriminate between good science and junk science. If some of the claims we are making are based on junk science, then what's to tell the public that all of our claims are not junk science claims. We are risking having the media, the public, and policy makers reject everything we are saying, because some of what we are saying is based on shoddy science or is completely untrue.

As I've stated before, the science is good enough. We don't need to distort it. We don't need to make it up. We don't need to cherry-pick. We don't need to make implausible claims. The truth is good enough.

By not being satisfied with letting the science speak for itself, by transforming good science into junk science in order to scare people into thinking that secondhand smoke is more severe of an acute hazard than it really is in order to support our agenda, I believe that we are in danger of losing our most prized possession - our reputation and credibility.

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