De Surgeon General (SG), een soort opperhoofd van het Amerikaanse ministerie van Volksgezondheid, bracht deze week een speciaal rapport over meeroken uit. In het meer dan 700 pagina’s tellende rapport wordt alle bekende ‘bewijsmateriaal’ over de schade van meeroken weer eens op een rijtje gezet.
Wat dat betreft niks nieuws onder de zon. Maar wat wél erg opvallend was, is dat het persbericht dat bij de verschijning van het rapport werd uitgebracht, een heel andere taal spreekt dan het rapport zelf. Het persbericht stelt dat eindelijk definitief is vastgesteld dat meeroken erg schadelijk is (er staat niets nieuws in het rapport) en dat zelfs een kortstondige blootstelling aan tabaksrook ernstige gevolgen kan hebben (staat niets van in het eigenlijke rapport!).
Deze SG staat al jaren bekend als een militant anti-roker. Hij heeft zijn positie misbruikt om, ondanks het ontbreken van enige wetenschappelijke onderbouwing van zijn beweringen, in de VS een sfeer te creëren die enige verdere twijfel aan dit soort uitspraken in de kiem moet smoren.
Dr. Michael Siegel las het hele rapport van 700 pagina’s en komt tot onthutsende conclusies over het persbericht.
The rest of the story is that the Surgeon General’s press release distorts the science presented in the report and ends up presenting misleading and inaccurate information to the public.
The press release claims that a significant finding of the Surgeon General’s report is that: “Even brief exposure to secondhand smoke has immediate adverse effects on the cardiovascular system and increases risk for heart disease and lung cancer.”
To re-phrase this for clarity, the Surgeon General is publicly claiming that brief exposure to secondhand smoke increases risk for heart disease and lung cancer.
But there is absolutely no evidence to support this claim. Certainly, no evidence is presented in the Surgeon General’s report to support this claim. And certainly, the Surgeon General’s report draws no such conclusion.
In fact, such a conclusion flies in the face of common medical sense. How could it possibly be that a brief exposure to secondhand smoke can cause heart disease? It takes many years for heart disease to develop. It takes years of exposure to tobacco smoke even for a smoker to develop heart disease. I estimate that it takes at least 25 years of exposure (based on the fact that very few smokers are diagnosed with heart disease before age 40).
So how could it possibly be that for an active smoker, heart disease takes 25 years of exposure to tobacco smoke to develop, but for a passive smoker, it only takes a single, transient, brief exposure?
It is also quite misleading to tell the public that a brief exposure to secondhand smoke increases the risk of lung cancer. There is certainly no evidence for this and the Surgeon General’s report itself draws no such conclusion. In fact, the report makes it clear that most of the studies linking secondhand smoke and lung cancer studied nonsmokers with many years of intense exposure.
The other claims made by the Surgeon General are also quite misleading, although perhaps not as absurdly inaccurate.
“Breathing secondhand smoke for even a short time can damage cells and set the cancer process in motion. Brief exposure can have immediate harmful effects on blood and blood vessels, potentially increasing the risk of a heart attack.”
This statement is misleading because it implies that a brief exposure to secondhand smoke can cause cancer (by setting the cancer process in motion). There is simply no evidence to support such a claim, and no such evidence is presented in the Surgeon General’s report. More importantly, there is no evidence that brief exposure increases the risk of a heart attack and the Surgeon General’s report offers no evidence to this effect, nor does it conclude that brief secondhand smoke exposure does increase heart attack risk. This is pure speculation, unsupported by any compelling scientific evidence.
“Breathing secondhand smoke for even a short time can have immediate adverse effects on the cardiovascular system, interfering with the normal functioning of the heart, blood, and vascular systems in ways that increase the risk of heart attack.”
Again, while there certainly is evidence presented in the report that brief secondhand smoke exposure interferes with the “normal” functioning of the heart, blood, and vascular systems, there is no evidence that these changes acutely increase the risk of a heart attack. Moreover, even if one relied on pure speculation, rather than on science, one would have to clarify one’s claim by specifying that it only referred to individuals with pre-existing severe coronary artery disease, something which the Surgeon General does not do here.
“Even a short time in a smoky room causes your blood platelets to stick together. Secondhand smoke also damages the lining of your blood vessels. In your heart, these bad changes can cause a deadly heart attack.”
Once again, this is pure speculation, not based on any scientific evidence. There is no conclusion in the Surgeon General’s report that brief exposure to secondhand smoke causes fatal heart attacks, as claimed here. There is no evidence presented in the report which documents any increased fatal heart attack risk associated with a brief exposure to secondhand smoke. And even pure speculation would require one to clarify this claim to refer only to individuals with severe existing coronary artery disease.
I need to make it clear that none of these misleading and inaccurate scientific claims are made in the Surgeon General’s report. What appears to be going on here is very similar to the “20-minute” and “30-minute” claims about which I have written extensively: the science is simply being distorted to sensationalize the findings, resulting in assertions that are misleading, inaccurate, absurd, unsupported by scientific evidence, and inconsistent with the findings of the report itself.
It appears to me that tobacco control organizations of all kinds and at every level are simply unable to accurately and honestly communicate the science of secondhand smoke to the public. For some reason, there appears to be a need to distort the science in an effort to sensationalize it and increase the emotional impact of the communication. The end result is to produce public claims that are inaccurate and which mislead the public.
Now I hope that readers can see why I wrote, even before this report and its accompanying materials were released, that the report would not matter. It turns out that I was correct. It really didn’t matter. Apparently, the Surgeon General was going to say whatever he wanted about the acute health effects of secondhand smoke and not let the actual conclusions of the report get in the way.
It didn’t matter that the report failed to conclude that there was any heart attack risk associated with brief exposure to secondhand smoke. The conclusion, widely disseminated to the public, was that a brief exposure to secondhand smoke increases heart disease risk and causes heart attacks.
The 727-page document was not necessary to make that claim. More than 80 anti-smoking groups were already making this fallacious claim and since it was and remains unsupported by scientific evidence, it really didn’t matter that the comprehensive review of the scientific evidence did not support such a conclusion. The science was simply not going to get in the way of the tobacco control movement’s ability to disseminate this sensationalized (and untruthful) claim.
It is important to understand that while the Surgeon General’s report itself underwent rigorous scientific review, and thus does not make any outlandish claims, the communications put out by the Surgeon General reporting the findings of the report did not undergo independent scientific review. And it really shows. The difference between the press release and related communications and the Surgeon General’s report itself are striking.
In fact, after reading the press release, I was fully expecting to find in the report some conclusions and supporting documentation related to an acute heart attack risk and increased lung cancer risk associated with brief secondhand smoke exposure. I was shocked to find that there was no mention of such a relationship; no conclusions, no documentation. Instead, the report appropriately presented the scientific evidence of acute effects of secondhand smoke on vascular function as supporting the biologic plausibility of the observed effects of chronic exposure on heart disease. There was no suggestion in the report that a brief exposure does or even could increase heart disease risk. Nor was there any suggestion (much less scientific evidence) that a brief exposure is enough to cause lung cancer.
Unfortunately, I’m forced to reach the conclusion that tobacco control organizations are simply unable to accurately communicate secondhand smoke science to the public. They are widely distorting the science to create a more sensational and emotional impact on the public. When this phenomenon goes all the way up to the level of the Surgeon General’s office, you know you’ve got a serious scientific integrity problem.
What has gone wrong?
I worked for two years at the Centers for Disease Control and Prevention, in the Office on Smoking and Health, which is the office that usually leads the review of the Surgeon General’s report. So I’m quite familiar with the level of scrutiny that is usually applied to any communications by the Surgeon General, but especially with regards to what is viewed as the rather “controversial” issue of secondhand smoke.
We remained highly vigilant and very careful about our public communications about the effects of tobacco smoke and those of the Department of Health and Human Services, because there was a huge perceived tobacco industry presence that would scrutinize our claims and call us to task if there were any inaccuracies, even if they were slight and not particularly meaningful.
But now, with the tobacco companies having largely abandoned this “oversight” role and playing a back-seat role (their main comment on the report was something to the effect of “We haven’t fully reviewed it yet”), there is apparently nothing to stop us from making just about any claims that we want to make.
So if we want to impress the public with the magnitude of the secondhand smoke hazard by trying to convince them that even a brief exposure can cause heart disease and lung cancer, so be it. The tobacco industry is not going to get in our way any more. Why should the science?