December 16, 2006
By Michael Siegel
In their zeal to scare people about acute cardiovascular effects of secondhand smoke that do not exist in order to promote public support for smoking bans, anti-smoking groups have engaged in what essentially amounts to a strategy of misrepresenting the science: taking evidence of minor, transient, physiologic effects and telling the public that this translates into major, permanent, clinically significant damage to healthy nonsmokers.
The claims have ranged from severe exaggerations to complete absurdity, but they all have one thing in common: they are distorting and misrepresenting the science.
The groups involved range from the smallest of anti-smoking organizations to the largest and most prominent figure in tobacco control - the Surgeon General himself.
Anti-smoking groups have told the public that 30 minutes of secondhand smoke is enough to cause hardening of the arteries. They have told the public that 30 minutes of exposure reduces coronary blood flow and deprives the heart of life-giving blood. They have told the public that brief secondhand smoke exposure causes reduced oxygen delivery that is comparable to that observed in cyanotic heart disease. They have even told the public that just 30 seconds of secondhand smoke is enough to make coronary artery function in nonsmokers indistinguishable from that in chronic active smokers.
The net effect of all of these deceptive and inaccurate claims is to undermine the true scientific basis for tobacco control policy, especially for the regulation of smoking in public places and workplaces. By virtually making up the science as they go along, these anti-smoking groups (or at least those feeding them the misleading information) are not only destroying the scientific credibility and integrity of the tobacco control movement, but they are also rendering as meaningless the years of research into the effects of secondhand smoke that scientists like myself have conducted.
What good is all the research that I've conducted on the actual hazards of secondhand smoke when anti-smoking groups are going to tell the public that a few whiffs of tobacco smoke can cause atherosclerosis? What value is there in my research when these groups are going to tell the public that brief exposure to secondhand smoke causes as much damage to the heart as years of active smoking?
What exactly is the purpose of conducting careful scientific research on the effects of secondhand smoke if anti-smoking groups are essentially just going to make things up, making whatever claims they want to the public in order to embellish the emotional appeal of the message?
Why am I needed anymore? If the groups are going to say that 30 minutes of tobacco smoke causes hardening of the arteries, then who needs to know exactly what the actual risk of chronic secondhand smoke exposure on heart disease is? If the groups are going to say that even a minor dose of secondhand smoke causes as much damage as a lifetime of active smoking, then why do we need to know what the actual levels of secondhand smoke exposure are for workers in different occupational settings?
In many ways, I feel that the nonsense that is going on in the tobacco control movement has made a mockery of my own career in tobacco control. Had I known 15 years ago that we were going to send a widespread message to the public that brief exposure to secondhand smoke can cause heart disease, then I would never have devoted the past 15 years of my career to researching the actual health effects of secondhand smoke.
What importance is there to knowing the actual health effects of secondhand smoke if we are going to deceive the public about what those health effects are?
One of the reasons that the events of the past several months sadden me so much is that it renders my research meaningless. What value did I add to the movement by carefully documenting the levels of exposure of restaurant workers and the health effects of chronic secondhand smoke exposure if these groups are simply going to tell people that 30 seconds of exposure is enough to kill anyone?
It makes me feel like all of my efforts were a waste, or at least, that my research is virtually worthless (at least irrelevant) at this point.
I remember being disturbed at a tobacco trial once when the tobacco industry attorneys kept standing up and objecting to my testimony on the grounds that it was "irrelevant and immaterial."
Well right now I feel as though my testimony about the health effects of secondhand smoke and what the evidence actually shows is "irrelevant and immaterial" because the anti-smoking groups are going to push their pre-ordained agenda regardless of what the evidence actually shows. They are going to make whatever claims they feel they need to in order to garner support for their increasingly draconian proposals, even if those claims defy the research, the science, and common sense.
So the tobacco company lawyers were right - my testimony, knowledge, and expertise in this area truly is irrelevant at this point. Once anti-smoking groups are telling the public that 30 minutes of exposure is enough to cause atherosclerosis, I don't really feel like I'm needed anymore.
And I think that's the truth: I'm not needed anymore.
More than that, I'm not wanted any more. When I was generating evidence that could be used to support the agenda, I was very much wanted in the movement. But now that I'm questioning the tactics and statements being used to promote the agenda (which I largely support) and questioning aspects of the agenda itself, I'm no longer wanted. There really isn't any room for someone like me in the tobacco control movement.
In fact, I'm a grave danger to the movement, because my parents instilled a value in me which I refuse to reqlinquish: something called the truth.
There really is not any room in the movement for someone who speaks the truth and refuses to shade the truth in order to follow the party line. There is simply no place for a person like me in this movement. When you speak the truth, you're forced out of the movement because you become a threat to it.
So now I join the tobacco company attorneys in standing to voice objection to the value of my own research and testimony: "Irrelevant and immaterial," I say.
Read
By Michael Siegel
In their zeal to scare people about acute cardiovascular effects of secondhand smoke that do not exist in order to promote public support for smoking bans, anti-smoking groups have engaged in what essentially amounts to a strategy of misrepresenting the science: taking evidence of minor, transient, physiologic effects and telling the public that this translates into major, permanent, clinically significant damage to healthy nonsmokers.
The claims have ranged from severe exaggerations to complete absurdity, but they all have one thing in common: they are distorting and misrepresenting the science.
The groups involved range from the smallest of anti-smoking organizations to the largest and most prominent figure in tobacco control - the Surgeon General himself.
Anti-smoking groups have told the public that 30 minutes of secondhand smoke is enough to cause hardening of the arteries. They have told the public that 30 minutes of exposure reduces coronary blood flow and deprives the heart of life-giving blood. They have told the public that brief secondhand smoke exposure causes reduced oxygen delivery that is comparable to that observed in cyanotic heart disease. They have even told the public that just 30 seconds of secondhand smoke is enough to make coronary artery function in nonsmokers indistinguishable from that in chronic active smokers.
The net effect of all of these deceptive and inaccurate claims is to undermine the true scientific basis for tobacco control policy, especially for the regulation of smoking in public places and workplaces. By virtually making up the science as they go along, these anti-smoking groups (or at least those feeding them the misleading information) are not only destroying the scientific credibility and integrity of the tobacco control movement, but they are also rendering as meaningless the years of research into the effects of secondhand smoke that scientists like myself have conducted.
What good is all the research that I've conducted on the actual hazards of secondhand smoke when anti-smoking groups are going to tell the public that a few whiffs of tobacco smoke can cause atherosclerosis? What value is there in my research when these groups are going to tell the public that brief exposure to secondhand smoke causes as much damage to the heart as years of active smoking?
What exactly is the purpose of conducting careful scientific research on the effects of secondhand smoke if anti-smoking groups are essentially just going to make things up, making whatever claims they want to the public in order to embellish the emotional appeal of the message?
Why am I needed anymore? If the groups are going to say that 30 minutes of tobacco smoke causes hardening of the arteries, then who needs to know exactly what the actual risk of chronic secondhand smoke exposure on heart disease is? If the groups are going to say that even a minor dose of secondhand smoke causes as much damage as a lifetime of active smoking, then why do we need to know what the actual levels of secondhand smoke exposure are for workers in different occupational settings?
In many ways, I feel that the nonsense that is going on in the tobacco control movement has made a mockery of my own career in tobacco control. Had I known 15 years ago that we were going to send a widespread message to the public that brief exposure to secondhand smoke can cause heart disease, then I would never have devoted the past 15 years of my career to researching the actual health effects of secondhand smoke.
What importance is there to knowing the actual health effects of secondhand smoke if we are going to deceive the public about what those health effects are?
One of the reasons that the events of the past several months sadden me so much is that it renders my research meaningless. What value did I add to the movement by carefully documenting the levels of exposure of restaurant workers and the health effects of chronic secondhand smoke exposure if these groups are simply going to tell people that 30 seconds of exposure is enough to kill anyone?
It makes me feel like all of my efforts were a waste, or at least, that my research is virtually worthless (at least irrelevant) at this point.
I remember being disturbed at a tobacco trial once when the tobacco industry attorneys kept standing up and objecting to my testimony on the grounds that it was "irrelevant and immaterial."
Well right now I feel as though my testimony about the health effects of secondhand smoke and what the evidence actually shows is "irrelevant and immaterial" because the anti-smoking groups are going to push their pre-ordained agenda regardless of what the evidence actually shows. They are going to make whatever claims they feel they need to in order to garner support for their increasingly draconian proposals, even if those claims defy the research, the science, and common sense.
So the tobacco company lawyers were right - my testimony, knowledge, and expertise in this area truly is irrelevant at this point. Once anti-smoking groups are telling the public that 30 minutes of exposure is enough to cause atherosclerosis, I don't really feel like I'm needed anymore.
And I think that's the truth: I'm not needed anymore.
More than that, I'm not wanted any more. When I was generating evidence that could be used to support the agenda, I was very much wanted in the movement. But now that I'm questioning the tactics and statements being used to promote the agenda (which I largely support) and questioning aspects of the agenda itself, I'm no longer wanted. There really isn't any room for someone like me in the tobacco control movement.
In fact, I'm a grave danger to the movement, because my parents instilled a value in me which I refuse to reqlinquish: something called the truth.
There really is not any room in the movement for someone who speaks the truth and refuses to shade the truth in order to follow the party line. There is simply no place for a person like me in this movement. When you speak the truth, you're forced out of the movement because you become a threat to it.
So now I join the tobacco company attorneys in standing to voice objection to the value of my own research and testimony: "Irrelevant and immaterial," I say.
Read
Biased Science in Tobacco Control: A Re-Evaluation of a 1997 Study on Secondhand Smoke and Heart Disease
November 22, 2006
By Michael Siegel
I recently re-examined an article that is widely cited by tobacco control groups as supporting the contention that chronic exposure to secondhand smoke causes heart disease -- a claim that, right off the bat, I acknowledge I think is scientifically sound. However, in re-evaluating the article, I noticed something disturbing. The study showed evidence of a severe investigator bias -- one that raises serious questions about the scientific objectivity of the tobacco control movement.
The paper, published in 1997 in the British Medical Journal (BMJ), is entitled "Environmental tobacco smoke exposure and ischaemic heart disease: An evaluation of the evidence" (see Law MR, Morris RK, Wald NJ. BMJ 1997; 315:973-980).
The article presents a meta-analysis of 19 "acceptable" published studies of the risk of heart disease among nonsmokers living with smokers versus nonsmokers, and reports a pooled relative risk of 1.30 (95% confidence interval, 1.22-1.38).
The Rest of the Story
I was curious as to what represented an "acceptable" study. It turns out that there were 21 studies identified that met the inclusion criteria for the meta-analysis. However, the authors deemed that two studies (references 35 and 36 in the paper) were not acceptable and excluded these studies from the meta-analysis.
Nowhere in the methods section of this article does it state the reasons why these two studies were excluded. Nor are there any objective criteria offered by which the inclusion or exclusion decision was to be made.
Instead, in the discussion section of the paper, the following explanation for the decision to excluded these two studies is offered:
"A separate analysis of one of the studies of environmental tobacco smoke exposure and ischaemic heart disease in the set of 19 studies (fig 1), and of two data sets not published elsewhere (from the US National Center for Health Statistics and the American Cancer Society) has been published by Layard and LeVois, consultants to the tobacco industry. They reported a combined relative risk estimate from the three studies of 1.00, with a narrow 95% confidence interval (0.97 to 1.04). This negative result is statistically inconsistent with the estimate of 1.30 (1.22 to 1.38) from the above analysis of 19 studies (P
To be completely honest, this reasoning was quite shocking to me. Essentially, what the paper is saying is that an "acceptable" paper is one that contributes to finding an effect of secondhand smoke on heart disease, while an "unacceptable" paper is one which finds no such effect.
In other words, what the paper is explaining is that these two studies were excluded specifically because they failed to find a significant increase in heart disease risk associated with secondhand smoke exposure!
This paper has committed perhaps the most egregious possible cardinal sin of a meta-analysis: making a decision about what studies to include or exclude after the fact and based on the results, rather than on the methodologic aspects of the study. If you conduct your meta-analysis first among studies you know to support your pre-determined conclusion and then you exclude from the meta-analysis any specific studies that you know not to support that conclusion, then you are automatically guaranteed of concluding your pre-determined conclusion!
I don't know how something like this passed peer review. However, mistakes like this are sometimes made. The point is not how the mistake was made but the fact that the article would use this type of reasoning in the first place.
Think about it this way: you have a collection of studies, most of which support your hypothesis, but several of which do not. You have two choices. First, you can combine all the studies together. If you do that, there is a risk that the negative studies will wash out (negate) or dilute the positive ones. Second, you can combine the positive ones to derive an estimate of the effect and then show that the negative studies are inconsistent with that finding. Then, you argue against including the negative studies because they are inconsistent. This is precisely the reasoning that was used in this paper.
Before discussing the implications, let me first make several points to dispel comments that I know some will make:
1. I am not arguing here that secondhand smoke does not cause heart disease. I think that even including the two studies that were excluded, if you look at Figure 1 in the paper you'll see that there is still an overall finding of a small increased heart disease risk among those exposed to secondhand smoke.
2. I am not arguing here that the two studies that were excluded should not necessarily have been excluded. There may be valid methodologic reasons to exclude these papers. However, any such methodologic flaws are not the reason provided for why these papers were excluded.
3. That the studies in question were published by authors with tobacco industry ties is not the reason given by the paper for excluding them. Even if it were, the nature of the funding is probably not sufficient reason to exclude the studies. But the point is moot, because the article makes it clear that the two studies were excluded not because they were commissioned by the industry, but because they failed to find positive results.
This paper represents a revelation to me. It really is a revelation for me, because it is something that I previously failed to look closely at - I assumed that a paper of this nature, published in a journal like BMJ, would naturally have used reasonable criteria for study inclusion and exclusion. It would never have occurred to me that the paper would have made the decision about excluding studies after the positive studies were combined and that the decision would be based on whether or not a study found an effect or not.
There are several important implications of this revelation.
First, it suggests that there is a serious bias inherent in the tobacco control movement, one which raises serious concerns about the scientific objectivity of the movement.
I have already expressed similar concerns based on the fallacious claims being made by a large number of anti-smoking groups about the acute cardiovascular effects of secondhand smoke. But this is the first instance in which I have found blatant scientific bias in the literature on the chronic effects of secondhand smoke.
Second, it suggests that the tobacco control movement has a crisis of scientific integrity on its hands. We need to respond to this crisis immediately and definitively in order to reclaim our scientific integrity and to prevent any loss of scientific credibility.
Third, it suggests that the loss of objectivity in tobacco control is something that is not restricted to the past eighteen months - a time period during which I have been documenting numerous examples of misrepresentation of the science by anti-smoking groups, including by the Surgeon General. This particular story would have made my blog headlines in 1997, if I had a blog at that time (or even knew what a blog was).
Finally, it reminds us that the peer review process, while an essential and usually an effective one, is not perfect. As I teach my students, one must always take the time to critically evaluate any published study, no matter how prestigious the journal. There is no substitute for careful evaluation of the published literature. The scientific review process must not end when the journal's peer review process ends.
Read
IN MY VIEW: Anti-Smoking Movement Has Lost High Ground in Public Debate
By Michael Siegel
I recently re-examined an article that is widely cited by tobacco control groups as supporting the contention that chronic exposure to secondhand smoke causes heart disease -- a claim that, right off the bat, I acknowledge I think is scientifically sound. However, in re-evaluating the article, I noticed something disturbing. The study showed evidence of a severe investigator bias -- one that raises serious questions about the scientific objectivity of the tobacco control movement.
The paper, published in 1997 in the British Medical Journal (BMJ), is entitled "Environmental tobacco smoke exposure and ischaemic heart disease: An evaluation of the evidence" (see Law MR, Morris RK, Wald NJ. BMJ 1997; 315:973-980).
The article presents a meta-analysis of 19 "acceptable" published studies of the risk of heart disease among nonsmokers living with smokers versus nonsmokers, and reports a pooled relative risk of 1.30 (95% confidence interval, 1.22-1.38).
The Rest of the Story
I was curious as to what represented an "acceptable" study. It turns out that there were 21 studies identified that met the inclusion criteria for the meta-analysis. However, the authors deemed that two studies (references 35 and 36 in the paper) were not acceptable and excluded these studies from the meta-analysis.
Nowhere in the methods section of this article does it state the reasons why these two studies were excluded. Nor are there any objective criteria offered by which the inclusion or exclusion decision was to be made.
Instead, in the discussion section of the paper, the following explanation for the decision to excluded these two studies is offered:
"A separate analysis of one of the studies of environmental tobacco smoke exposure and ischaemic heart disease in the set of 19 studies (fig 1), and of two data sets not published elsewhere (from the US National Center for Health Statistics and the American Cancer Society) has been published by Layard and LeVois, consultants to the tobacco industry. They reported a combined relative risk estimate from the three studies of 1.00, with a narrow 95% confidence interval (0.97 to 1.04). This negative result is statistically inconsistent with the estimate of 1.30 (1.22 to 1.38) from the above analysis of 19 studies (P
To be completely honest, this reasoning was quite shocking to me. Essentially, what the paper is saying is that an "acceptable" paper is one that contributes to finding an effect of secondhand smoke on heart disease, while an "unacceptable" paper is one which finds no such effect.
In other words, what the paper is explaining is that these two studies were excluded specifically because they failed to find a significant increase in heart disease risk associated with secondhand smoke exposure!
This paper has committed perhaps the most egregious possible cardinal sin of a meta-analysis: making a decision about what studies to include or exclude after the fact and based on the results, rather than on the methodologic aspects of the study. If you conduct your meta-analysis first among studies you know to support your pre-determined conclusion and then you exclude from the meta-analysis any specific studies that you know not to support that conclusion, then you are automatically guaranteed of concluding your pre-determined conclusion!
I don't know how something like this passed peer review. However, mistakes like this are sometimes made. The point is not how the mistake was made but the fact that the article would use this type of reasoning in the first place.
Think about it this way: you have a collection of studies, most of which support your hypothesis, but several of which do not. You have two choices. First, you can combine all the studies together. If you do that, there is a risk that the negative studies will wash out (negate) or dilute the positive ones. Second, you can combine the positive ones to derive an estimate of the effect and then show that the negative studies are inconsistent with that finding. Then, you argue against including the negative studies because they are inconsistent. This is precisely the reasoning that was used in this paper.
Before discussing the implications, let me first make several points to dispel comments that I know some will make:
1. I am not arguing here that secondhand smoke does not cause heart disease. I think that even including the two studies that were excluded, if you look at Figure 1 in the paper you'll see that there is still an overall finding of a small increased heart disease risk among those exposed to secondhand smoke.
2. I am not arguing here that the two studies that were excluded should not necessarily have been excluded. There may be valid methodologic reasons to exclude these papers. However, any such methodologic flaws are not the reason provided for why these papers were excluded.
3. That the studies in question were published by authors with tobacco industry ties is not the reason given by the paper for excluding them. Even if it were, the nature of the funding is probably not sufficient reason to exclude the studies. But the point is moot, because the article makes it clear that the two studies were excluded not because they were commissioned by the industry, but because they failed to find positive results.
This paper represents a revelation to me. It really is a revelation for me, because it is something that I previously failed to look closely at - I assumed that a paper of this nature, published in a journal like BMJ, would naturally have used reasonable criteria for study inclusion and exclusion. It would never have occurred to me that the paper would have made the decision about excluding studies after the positive studies were combined and that the decision would be based on whether or not a study found an effect or not.
There are several important implications of this revelation.
First, it suggests that there is a serious bias inherent in the tobacco control movement, one which raises serious concerns about the scientific objectivity of the movement.
I have already expressed similar concerns based on the fallacious claims being made by a large number of anti-smoking groups about the acute cardiovascular effects of secondhand smoke. But this is the first instance in which I have found blatant scientific bias in the literature on the chronic effects of secondhand smoke.
Second, it suggests that the tobacco control movement has a crisis of scientific integrity on its hands. We need to respond to this crisis immediately and definitively in order to reclaim our scientific integrity and to prevent any loss of scientific credibility.
Third, it suggests that the loss of objectivity in tobacco control is something that is not restricted to the past eighteen months - a time period during which I have been documenting numerous examples of misrepresentation of the science by anti-smoking groups, including by the Surgeon General. This particular story would have made my blog headlines in 1997, if I had a blog at that time (or even knew what a blog was).
Finally, it reminds us that the peer review process, while an essential and usually an effective one, is not perfect. As I teach my students, one must always take the time to critically evaluate any published study, no matter how prestigious the journal. There is no substitute for careful evaluation of the published literature. The scientific review process must not end when the journal's peer review process ends.
Read
IN MY VIEW: Anti-Smoking Movement Has Lost High Ground in Public Debate
