Today I am revealing an important new finding in my investigation of the source of the widespread claim being made by anti-smoking groups (the count is now up to 68) that a single, acute exposure to secondhand smoke causes hardening of the arteries and heart attacks in nonsmokers.
It turns out that three major anti-smoking organizations - the American Cancer Society, the International Union Against Cancer, and the Campaign for Tobacco-Free Kids - urged 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 Campaign for Tobacco-Free Kids appears to also have been a part of this strategy guide, although it is not listed as a primary author but instead, referred to in the document's introduction:
"On behalf of the American Cancer Society, The International Union Against Cancer, the Campaign for Tobacco-Free Kids, and the many wise and experienced colleagues who contributed to this lengthy project, we are deeply pleased to offer this series of guides, Tobacco Control Strategy Planning to the global tobacco control community."
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 strategy guide reiterates the message that advocates should communicate to the public that a single acute exposure to secondhand smoke causes heart attacks and strokes: "There are immediate and substantial effects from secondhand smoke. For example, 30 minutes of breathing secondhand smoke makes blood platelets get as activated as in habitual pack-a-day smokers. These activated platelets damage the lining of arteries, which leads to heart disease. If they form a blood clot that lodges in a coronary artery, we call that a heart attack. If it
lodges in the brain, we call it a stroke."”
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.
The claim that 30 minutes of secondhand smoke exposure activates platelets and causes endothelial damage "which leads to heart disease" and results in clot formation that results in heart attacks and strokes is also false, or at least misleading. While it is true that 30 minutes of secondhand smoke exposure causes platelet activation and endothelial dysfunction, these changes cannot result in heart disease from just a single exposure. Chronic exposure over long periods of time is necessary.
Remember that eating a single high-fat meal can also cause significant endothelial dysfunction, damaging the lining of the coronary arteries. Plotnick et al., writing in JAMA, reported that: "A single high-fat meal transiently reduces endothelial function for up to 4 hours in healthy, normocholesterolemic subjects, probably through the accumulation of triglyceride-rich lipoproteins." It would not be accurate to interpret this study as indicating that a high-fat meal could cause a heart attack; instead, it does provide plausibility for an association between a high-fat diet and the development of atherosclerosis. The same is true with the Otsuka study. It provides evidence that chronic exposure to secondhand smoke could promote atherosclerosis by inducing changes in endothelial function; however, one cannot extrapolate from that and claim that a single acute exposure increases the risk of a heart attack in someone without severe pre-existing coronary artery stenosis.
This story has a number of important implications.
First, it lets some of the 65+ organizations that are making fallacious scientific claims off the hook slightly. It suggests that there is perhaps a more centralized source for these untruthful claims, and that perhaps many anti-smoking groups were just blindly following the advice of the anti-smoking leadership. That still doesn't justify, in my mind, misleading the public, but it at least lessens the degree of responsibility because it suggests that some of these groups may simply have been following a strategy issued from above.
Second, it makes it more difficult to rationalize this fiasco by arguing that it was simply a series of innocent mistakes made by anti-smoking groups. Instead, it argues for an impression that there was an intentional, centralized effort to make the hazards of secondhand smoke seem more emotionally stimulating by over-stating the acute cardiovascular effects of exposure in order to garner greater support for smoking bans.
This appears not to be simply an innocent misinterpretation of scientific evidence. Instead, it appears to be an intentional manipulation of people's emotions through the manipulation of scientific findings in order to make public claims that are more startling than they would otherwise be, in an effort to promote a desired public policy outcome.
Finally, the rest of the story suggests that the anti-smoking movement is in quite a crisis. Because there are really only two possibilities I can think of to explain what is happening.
One possibility is that anti-smoking groups are lying to the public about the science in order to promote smoking bans. If this is the case, then we face an ethical crisis. Such misconduct would represent a serious violation of accepted ethical standards of public health practice.
The second possibility is that anti-smoking groups are not lying, but that they actually believe that hardening of the arteries can occur in 30 minutes. If this is the case, then we face a crisis of scientific credibility. Because if we do believe that the process which leads to heart disease can happen in just 30 minutes, then I don't see any reason why the public should trust us in the future to provide scientific judgment on health issues.
If we're off by a factor of 500,000 in scientific claims that we're disseminating widely to the public, then why should the public place any trust in us to convey accurate health information?
Either way, the situation is ugly. It is embarrassing to me as a tobacco control practitioner. Yet I myself bear some of the blame and responsibility for this problem. Perhaps I could have been more aware and more attentive to the claims that were being made back in 2001 and 2002 and perhaps I could have done something to point out the errors in interpretation of the scientific evidence before the situation got completely out of hand. And perhaps less damage would have been done. I don't know what I was doing when all of this was first occurring, but I didn't follow it closely enough and it all has come upon me suddenly during the past few months.
By the way - I don't think this is necessarily a fatal problem. I think the anti-smoking movement can recover from it. But it is going to take a rather massive job of acknowledging the mistakes, apologizing to the public, and correcting the inaccurate and misleading communications.
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