Thursday, June 21, 2007

TobaccoScam Says 30 Minutes of Secondhand Smoke Gives You "Smoker's Arteries"; So Why Should Any Smoker Quit?

According to the anti-smoking project TobaccoScam, if a nonsmoker is exposed to secondhand smoke for 30 minutes, he or she has "smoker's arteries" - arteries that are compromised to the same extent as those of an active smoker. This 30 minute exposure results in clogged arteries. As a result, the nonsmoker is at increased risk of suffering an immediate heart attack. Just 20 minutes of exposure to secondhand smoke is equivalent to actively smoking one pack of cigarettes per day.

Here are the specific claims being made by TobaccoScam:
Source 1: Secondhand Smoke - A Little is Dangerous
Source 2: Secondhand Smoke - A Little is Dangerous (PDF Version)

"30 minutes exposure = smoker's arteries"

"Thirty minutes of secondhand smoke compromises a non-smoker's coronary arteries to the same extent as in smokers."

"20 minutes exposure = smoking a pack a day"

"Twenty minutes of breathing secondhand smoke at levels similar to those measured in bars activates blood platelets involved in the clotting process as much as it does in pack-a-day smokers. These activated platelets increase the chances of heart attack or stroke."

"30 minutes exposure = stiffened, clogged arteries"

"All of these effects not only increase the long term risks of developing heart disease, but also increase the immediate risk of heart attack."

The Rest of the Story

These fact sheets are very deceptive for the following reasons.

"30 minutes exposure = smoker's arteries"

While it is true that 30 minutes of secondhand smoke exposure has been found to cause endothelial dysfunction in coronary arteries that is equivalent to that observed among active smokers, it is deceptive to suggest that 30 minutes of exposure is equivalent to a smoker's arteries. An active smoker may well have narrowed and clogged coronary arteries due to years of active smoking. In contrast, a nonsmoker who is just exposed to secondhand smoke for 30 minutes will not have any narrowing or clogging of the arteries due to that brief exposure. Claiming that a 30 minute exposure is equivalent to a smoker's arteries implies that a brief secondhand smoke exposure causes the kind of chronic damage that is seen among active smokers. This is not the case. Perhaps 30 years of exposure could result in smoker's arteries; but not 30 minutes.

"Thirty minutes of secondhand smoke compromises a non-smoker's coronary arteries to the same extent as in smokers."


In terms of coronary flow velocity reserve, it is true that 30 minutes of secondhand smoke compromises a nonsmoker's coronary arteries to the same extent as in smokers. However, in every other sense, it is not true. A brief exposure does not compromise the arteries in terms of the clogging, narrowing, plaque formation, thrombus formation, and atherosclerosis that is seen in smokers.

"20 minutes exposure = smoking a pack a day"

While platelet activation levels may be similar in smokers as in nonsmokers exposed to secondhand smoke for 20 minutes, it is certainly not the case that 20 minutes of secondhand smoke exposure is equivalent to smoking a pack of cigarettes per day. In an otherwise healthy person, a single 20 minute exposure to secondhand smoke causes no clinically significant damage. In contrast, smoking a pack a day can certainly cause clinically significant damage. To claim that the two are equivalent is deceptive.

"Twenty minutes of breathing secondhand smoke at levels similar to those measured in bars activates blood platelets involved in the clotting process as much as it does in pack-a-day smokers. These activated platelets increase the chances of heart attack or stroke."


While it is true that 20 minutes of secondhand smoke activates blood platelets to the same extent as in pack-a-day smokers, it is not true that this platelet activation increases the chance of a heart attack or stroke. A mere 20 minute exposure to secondhand smoke cannot possibly cause a heart attack or stroke in a nonsmoker who does not already have severe pre-existing coronary or cerebrovascular artery stenosis. It is deceptive to claim that the platelet activation observed in healthy nonsmokers who are exposed to secondhand smoke for 20 minutes increases their risk of a heart attack or stroke.

"30 minutes exposure = stiffened, clogged arteries"


It is true that 30 minutes of exposure decreases the ability of the coronary arteries to dilate (a short-term, transient effect), but it is not true that a 30 minute exposure causes clogged arteries. The arteries cannot clog that quickly. It takes more like 30 years for the arteries to clog, not 30 minutes.

"All of these effects not only increase the long term risks of developing heart disease, but also increase the immediate risk of heart attack."


A mere 20 or 30 minutes of exposure to secondhand smoke does not increase the long-term risk of developing heart disease. To develop heart disease, one would need chronic exposure - exposure for many years. It is preposterous to assert that a mere 30 minutes of exposure is enough to cause heart disease. It is equally absurd to claim that a mere 30 minutes of exposure can cause a heart attack in anyone other than an individual who already has severe, pre-existing coronary artery stenosis.

In many ways, these fact sheets are deceptive to the public. They misrepresent the science in a way that is likely to mislead people into believing things that are not true. I view it as unethical to deceive the public in this way about scientific facts.

But what is perhaps even more disturbing are the implications of the misrepresentation of the science. If a reader actually believes these assertions, then the implication is that there is really no reason to quit smoking if you are going to be exposed, even briefly, to secondhand smoke. If it is truly the case that a mere 30 minute exposure to secondhand smoke is going to give you the arteries of an active smoker, then why should a smoker bother to quit? If that smoker is exposed to tobacco smoke for 30 minutes, he is going to have the arteries of an active smoker anyway. So what reason is there for him to bother quitting?

By implying that active smoking is no worse than a brief secondhand smoke exposure, this fact sheet actually undermines the public's appreciation of the severe hazards of smoking. The message - albeit unintended - is that smoking is much less hazardous than previously thought. It is, after all, only as bad as breathing in drifting tobacco smoke for a half hour or so.

I hope that TobaccoScam will re-examine and correct these fact sheets, which have been widely copied and disseminated by many anti-smoking organizations throughout the country. It is important not only because of the principle of accurate communication of science to the public, but also because the web site is undermining years of effort by tobacco control groups to educate the public about the severe hazards of active smoking.

It wouldn't take a lot to correct these fact sheets, and frankly, I don't see what the harm would be in doing so. How could it possibly hurt to clarify the fact sheets and ensure that they are not only accurate, but also that they are not misleading?

I will be keeping on eye on these fact sheets and will report next week on whether any changes are made to them. The decision about whether or not to correct these "fact sheets" will go a long way toward shaping my impression about whether these inaccuracies are simple mistakes or oversights or whether there is an intentional effort to deceive the public by overstating the health effects of brief secondhand smoke exposure.

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