Monday, August 06, 2007

American Cancer Society Continues to Urge Anti-Smoking Groups to Tell the Public that Brief Secondhand Smoke Exposure Causes Hardening of the Arteries

In spite of my pleadings to correct the fallacious claims in its smoking ban strategy guide, the American Cancer Society continues to urge anti-smoking groups to sensationalize the secondhand smoke health hazard message by telling the public that brief exposure immediately causes hardening of the arteries and heart disease.

It turns out that two major anti-smoking organizations - the American Cancer Society and the International Union Against Cancer - are urging anti-smoking groups to increase the emotional appeal of the secondhand smoke health hazard message by communicating to the public that secondhand smoke can virtually instantly cause hardening of the arteries and heart disease (a point which is clinically impossible - since it takes years for atherosclerosis and heart disease to develop).

In an internal strategy document entitled "Building Public Awareness About Passive Smoking Hazards," the American Cancer Society and International Union Against Cancer offer suggestions to anti-smoking advocates about how to increase the emotional appeal of secondhand smoke health hazard claims. The guide was designed "to help advocates develop practical strategies to overcome specific barriers to effective tobacco control policies."

One strategy put forward to help advocates overcome barriers to the adoption of smoking bans is to convey to the public that some of the effects of secondhand smoke are "virtually instant" because "these messages convey the issue's urgency." Specifically, the strategy urges advocates to emphasize the following two messages:

1. "Immediate effects of secondhand smoke include cardiovascular problems such as damage to cell walls in the circulatory system, thickening of the blood and arteries, and arteriosclerosis (hardening of the arteries) or heart disease, increasing the chance of heart attack or stroke."

2. "Short-term exposure to tobacco smoke has a measurable effect on the heart in nonsmokers. Just 30 minutes of exposure is enough to reduce blood flow to the heart."

According to the document, these messages which convey the instant harm of secondhand smoke are effective because they provoke "an emotional response in almost any listener." The guide goes on to say that an effective message:

a) "conveys the fact that even short periods of exposure are harmful;"

b) "evokes an emotional reaction from the use of scientific terms;"

c) "utilizes startling and memorable imagery;" and

d) "clearly states the risk of grave health conditions such as heart attacks and strokes."

The document describes these communication tactics as "effective advocacy strategies to enact and enforce laws mandating smoke-free public environments."

The Rest of the Story

The message that the immediate effects of secondhand smoke exposure include "arteriosclerosis (hardening of the arteries) or heart disease" is blatantly false on its face. Such an effect is clinically impossible, since it takes years for atherosclerosis and heart disease to develop. You simply cannot develop atherosclerosis as an "immediate" effect of secondhand smoke exposure.

I have been quite clear about my opinion that chronic exposure to secondhand smoke does cause hardening of the arteries and heart disease. But it takes years of exposure. It certainly does not happen immediately.

Even if you look at heavy active smokers, you don't see them developing heart disease or suffering heart attacks within minutes of their first cigarettes. It takes a minimum of 15-20 years before these effects occur. Since most smokers begin smoking in their teens and it is quite unusual to observe heart disease and heart attacks in smokers before they reach 30 years old, it is clear that the atherosclerotic process takes no less than 15 years or so to occur. And this is in extreme cases and under conditions of heavy, repeated, active smoking.

In most cases, we start to observe heart disease in smokers in their 40s - about 25-30 years after the initiation of smoking.

So the claim that secondhand smoke causes heart disease in just 30 minutes is off by a factor of 525,600, or half a million!

The claim that 30 minutes of exposure to secondhand smoke "is enough to reduce blood flow to the heart" is also false, or at least misleading.

It's not accurate to claim that a 30 minute exposure to secondhand smoke reduces the blood flow to the heart because what the Otsuka study actually showed is that there was no reduction in coronary blood flow (see Otsuka R, Watanabe H, Hirata K, et al. Acute effects of passive smoking on the coronary circulation in healthy young adults. JAMA 2001). In other words, 30 minutes of secondhand smoke exposure was documented not to reduce blood flow to the heart.

The truth is that the Otsuka study, which is being used to back up the strategy document's claim that 30 minutes of exposure reduces blood flow to the heart, actually provides documentation that this brief exposure does not reduce coronary blood flow and therefore poses no acute risk of clogged coronary arteries and an acute myocardial infarction (heart attack) in someone without severe pre-existing coronary artery stenosis.

On the contrary, the study reported that: "Passive smoking exposure had no effect on basal coronary flow velocity in either group." In other words, this study documents that a 30-minute exposure to secondhand smoke does not present a threat of reducing coronary blood flow in patients without severe coronary disease.

So the very study that the document relies upon to make its scientific claim actually refutes the very claim that these groups are making.

What makes these false claims particularly troublesome are the following two factors:

1) It is not just an isolated statement by the American Cancer Society. It comes in the context of a strategy guide which is making specific recommendations about exactly what statements anti-smoking groups throughout the world should make about the health effects of secondhand smoke. So the ACS is not just claiming that secondhand smoke exposure immediately causes hardening of the arteries and heart disease, they are instructing anti-smoking groups worldwide to make this statement to the public.

2) It comes in the context of instructing anti-smoking groups how to sensationalize their messages about the health effects of secondhand smoke.

Apparently, the fact that secondhand smoke does not immediately cause the grave health conditions of heart attacks and strokes is no deterrent to the ACS to publicly make such a statement and to encourage all anti-smoking groups to do the same.

But the worst part of the story is that the American Cancer Society has apparently decided to retain these false claims on its web site even after having been informed by an expert on the issue (who they rely upon for other claims that they make - see reference 21, for example) that their claims are wrong.

No matter how many times I email the ACS about this, and no matter how many people at the national and state levels of ACS that I email, I never get so much as a response, I never get an explanation or defense of the claims, and I certainly never get a thank you for pointing out the errors so that the ACS can fix them before misleading anyone else or suffering further embarrassment or further risk of undermining its credibility and scientific reputation.

I would have thought that my May 2006 commentary would have been enough to get the ACS to take this issue seriously. Then, despite no response, I thought that my December 2006 commentary would have caused the Cancer Society to review and correct the document. Then, despite still no response, I thought my March 2007 commentary would have finally served to interest the ACS in defending and preserving its own scientific integrity.

Apparently not.

Nevertheless, it is never too late. A timely and definitive response by the ACS would go a long way towards letting us know that the Cancer Society is sincerely interested in its scientific integrity, and not merely in using the tobacco industry's age-old tactics of dishonesty and deception in order to support its policy agenda.

No comments: