Monday, July 17, 2006

At Least 18 Anti-Smoking Groups Claim that Secondhand Smoke Causes Heart Damage as Severe as that of Active Smoking

No fewer than 18 anti-smoking groups are publicly claiming that just a half hour of exposure to secondhand smoke causes damage to the heart of nonsmokers similar to the heart damage caused by active smoking.

Smoke-Free Houston: "Even half an hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."


Smoke Free Galveston: "Even half an hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

SmokeFree City: "Even half an hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

Americans for Nonsmokers' Rights
: "Even a half hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

University of Missouri Student Health Center: "Even half an hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

GottaQuit.com: "Even half an hour of ETS exposure causes heart damage similar to that of habitual smokers."

Kids Involuntarily Inhaling Secondhand Smoke: "Even half an hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

TriCounty Health Department: "A half hour of secondhand smoke exposure causes heart damage similar to that of a habitual smoker."

Virginians for a Healthy Future: "Even a half hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

Maryland Department of Health and Mental Hygiene (cached): "Even a half hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

Washington State Department of Health: "As little as half an hour of secondhand smoke exposure can cause heart damage similar to that caused by habitual smoking according to a study published in the Journal of the American Medical Association (JAMA. 2001;286:436-441)."

American Public Health Association: "Even a half hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

Illinois PIRG: "Just a half-hour of secondhand smoke exposure causes heart damage similar to that of a habitual smoker, according to the Journal of the American Medical Association."

Tobacco Technical Assistance Consortium: "Even a half hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

Coalition for a Tobacco-Free Hawaii: "even a half-hour of second-hand smoke exposure can cause heart damage similar to that of habitual smokers."

Bucks County Tobacco Control Project: "According to the Journal of the American Medical Association, even a half hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers."

Hendricks County Coalition for Tobacco Intervention and Prevention: "A half hour of secondhand smoke exposure causes heart damage similar to that of an habitual smoker."

Northwest Arkansas Radiation Institute: "Even half an hour of second hand smoke exposure causes heart damage similar to that of habitual smokers."

The Rest of the Story

The study that is being cited to back up these claims is the Otsuka et al. study published in JAMA in 2001, which reported that a 30-minute exposure to secondhand smoke impaired endothelial dysfunction, as measured by coronary artery flow reserve velocity, to the same degree in nonsmokers as observed in active smokers (see Otsuka R, Watanabe H, Hirata K, et al. Acute effects of passive smoking on the coronary circulation in healthy young adults. JAMA 2001; 286:436-441).

The problem is that endothelial dysfunction, as measured by coronary artery flow reserve velocity, is hardly a measure of what we would call heart damage. Typically, when we speak of heart damage in medicine we are talking about damage to the heart muscle, often caused by a heart attack, that decreases the ability of the heart to pump.

It is possible, for example, to have a very small heart attack that does not result in any significant heart damage. As a physician, you might tell such a patient that they did not suffer any heart damage. Obviously, on a cellular level, there was damage done. But we don't speak of that as being heart damage. When we speak of heart damage, we're really talking about clinically meaningful damage to the heart that translates into impaired function.

The decrease in coronary artery flow reserve velocity that was observed with a 30-minute secondhand smoke exposure was transient, and resulted in no clinically meaningful damage to the heart.

To claim that the study demonstrated heart damage equivalent to that seen in smokers is terribly misleading, if not an outright inaccurate use of the term heart damage as the phrase is typically used in medicine.

If you tell your physician that you have a medical history of having suffered heart damage, she will most likely assume that you've had a heart attack or some other dramatic cardiac event. She will almost assuredly not consider transient endothelial dysfunction, as might occur after a high-fat meal, to be within the realm of what you mean when you say that you have suffered heart damage.

Most importantly, I don't think that the public, upon hearing that they may suffer heart damage from an exposure, thinks that what is meant is that there may be transient physiologic changes that are of little or no consequence clinically to them. I think the public would naturally assume that the statement is talking about clinically meaningful damage to the heart.

To make matters worse, all but two of the claims imply that heart damage is automatic. The exposure causes heart damage; not can cause heart damage. So even though the results were observed in just a single study that placed subjects in an extremely smoky environment, these claims imply that any level of exposure to secondhand smoke is enough to cause the "heart damage."

I consider these claims to be irresponsible because they are misleading and wrong. But they are also irresponsible because I think they may actually cause damage. They may well undermine the public's appreciation of the cardiovascular health risks of active smoking.

You see - another way to state the same thing that these anti-smoking groups are claiming is:

"The heart damage caused by habitual smoking is no worse than that caused by just a half hour of secondhand smoke exposure."

This is, in fact, the claim that anti-smoking groups are making.

And you can see that such a claim is going to make people think that active smoking really isn't all that bad. After all, if the heart damage you'll suffer from active smoking is no worse than that which you'd suffer from breathing in a little drifting tobacco smoke for a half hour, then it really doesn't sound too bad.

Moreover, this message completely undermines the incentive to quit smoking. Why quit, when you will almost assuredly be exposed at some point to at least 30 minutes of secondhand smoke? Apparently, your risk of heart damage will be the same, so what point is there to quit smoking?

In fact, the claim makes it appear that secondhand smoke is far more hazardous than active smoking, because it takes only 30 minutes of secondhand smoke exposure to cause the same degree of heart damage as years and years of active smoking.

This is not only blatantly misleading, it is truly damaging to the very cause towards which these anti-smoking groups are supposed to be working.

The more I look, the worse and worse this problem of misleading and fallacious scientific claims by anti-smoking groups becomes. And the less and less the anti-smoking groups seem to care.

As much as I support workplace smoking bans, especially in bars and restaurants, I simply cannot go along with communicating misleading and inaccurate information to the public in order to support public policy.

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