Conflating Coronary Blood Flow and Coronary Flow Velocity Reserve: The Basis for Anti-Smoking Groups’ Misleading Health Claims – ClearWay, ANR, ACS, and Tobacco-Free Kids
Leading Tobacco Control Scientist Tells Thousands of Advocates that Rest of the Story Author Has No Idea What He’s Talking About
By Michael Siegel
In an email sent to his announcement list of thousands of tobacco control advocates worldwide, a prominent tobacco control scientist tells advocates that I do not know what I am talking about and do not understand the scientific issues involved in communicating the acute cardiovascular health effects of secondhand smoke. In the message, he suggests that I am in no position to comment on the statements being made by anti-smoking groups about the acute cardiovascular effects of secondhand smoke and further, that it is irresponsible of me to do so because I have no understanding of the issues upon which I am commenting.
The message sent to an undetermined number of worldwide advocates, believed to be in at least the thousands, states:
“Michael Siegel simply does not know what he is talking about. I am attaching several peer reviewed academic reviews that show how all these things link together. Coronary flow velocity reserve is an important measure of the ability of the heart to respond to increases in demand and is closely related to endothelial and platelet function, both of which relate to both the chronic and acute risk of heart attack. It is well established that increased platelet activation causes platelets to stick to the vascular lining (the endothelium) and cause physical damage, which is important for the development of atherosclerosis. The acute effects can also trigger a heart attack in people at risk. No one is saying that one whiff of smoke causes a heart attack in everyone who breathes it. What the evidence shows is that there are substantial immediate effects that compromise the cardiovascular system and that, in some people, these changes are the same kinds of things that can trigger an acute event.The message included the text of my post, entitled “Conflating Coronary Blood Flow and Coronary Flow Velocity Reserve: The Basis for Anti-Smoking Groups’ Misleading Health Claims” which I sent out to my own email list of tobacco control groups and reporters.
Nothing that Dr. Glantz states is in any way inconsistent with my
post.So how could this be? How could it be that Dr. Glantz is basically condemning me and maligning my character (intimating that I am a complete fraud) in front of thousands of our colleagues and yet there is essentially no disagreement between us on the scientific issues?
The answer, I believe, is that Dr. Glantz is ignoring (or has not taken the time to read) my actual argument. I was not arguing in the commentary that brief exposure to secondhand smoke does not cause heart attacks in people with severe existing coronary artery disease. Nor was I criticizing any anti-smoking groups who are making such a statement to the public.
Instead, I was criticizing two specific statements made by two specific anti-smoking groups (although mirrored by similar statements made by a large number of other groups) that imply that brief secondhand smoke exposure can cause heart attacks in healthy young adults.
In fact, the statement by ClearWay Minnesota that I was criticizing stated explicitly that 30 minutes of secondhand smoke exposure decreases coronary artery blood flow in
healthy young adults.And the statement by the Association for Nonsmokers – Minnesota that I was criticizing implied that 30 seconds of secondhand smoke causes as much damage to coronary artery function as chronic active smoking. It mentioned nothing about people with existing coronary artery stenosis. It clearly represents itself as a statement about the general public exposed to secondhand smoke.
Moreover, the statement by the American Cancer Society and the Campaign for Tobacco-Free Kids stated that atherosclerosis (hardening of the arteries) is an “immediate effect” of secondhand smoke exposure. Again, this is not even remotely related to triggering of coronary events in people with high-risk heart disease; it is about whether a process that in smokers takes 20-30 years to develop can occur among nonsmokers in just minutes.
So as much as I respect Dr. Glantz and his scientific expertise, I do not believe his statement has any relevance to the discussion at hand, which is not about whether brief exposure to secondhand smoke can trigger an acute coronary event in someone who is at high risk for such an event. The discussion at hand is about: (1) whether or not it is accurate to tell the public that 30 seconds of secondhand smoke exposure is as bad as chronic active smoking in terms of damage to the coronary arteries; (2) whether or not it is accurate to tell the public that brief exposure to secondhand smoke decreases coronary artery blood flow in healthy young adults; and (3) whether or not it is accurate to tell the public that secondhand smoke can immediately result in hardening of the arteries, a process that takes 20-30 years to develop among active smokers.
It honestly appears to me that Dr. Glantz did not actually read my commentary, because it would seem that if he did, he would have understood that I was not in any way suggesting that there is no evidence that acute exposure to secondhand smoke could potentially trigger an acute coronary event in an individual with severe heart disease. If he did actually read my commentary, then it is beyond me why he would misread it so badly, but I suppose it’s always possible that I did not explain myself clearly enough.
When I stated that I was criticizing public health groups for implying that “a healthy young person exposed to secondhand smoke is at risk of death due to that exposure,” what I meant was that public health groups should not be implying that brief secondhand smoke exposure poses a risk of death from a heart attack in a healthy young person. I certainly apologize if I failed to make that clear.
I don’t exactly see how someone could misread what I wrote as criticizing these anti-smoking groups for stating that secondhand smoke exposure can precipitate an acute coronary event in people with severe existing heart disease, but if I wasn’t clear, it is my fault and I apologize for the lack of clarity in my writing.
Just to make sure that it is clear now, what I intended to say when I stated that ANR, for example, is implying that “a half hour of secondhand smoke exposure impairs the body’s ability to get life-giving blood to the heart, putting even a healthy young individual at risk of a heart attack and therefore of death,” is that I am criticizing ANR not for stating that secondhand smoke can trigger a heart attack in someone with severe narrowing of the coronary arteries and a pre-existing atherosclerotic plaque, but for implying that a half hour of secondhand smoke exposure impairs the body’s ability to get life-giving blood to the heart, putting even a healthy young individual at risk of heart attack and therefore of death.
I have so much respect for Dr. Glantz and I know that thousands of tobacco control advocates also do, so I am quite sure that there are thousands of advocates out there now who believe Dr. Glantz when he tells them that I am a complete scientific fraud who talks about things without really understanding what he is talking about. Obviously, any possibility of a career in tobacco control has been completely shot by this email announcement.
And the shame of the whole thing is that the email was completely irrelevant to the actual discussion. If I am going to be discredited and my career ruined, then I would love to be discredited and to have my career ruined based on something I actually said, rather than on something that I never said. If I had my druthers, I would choose to have a derogatory statement about me sent to thousands of colleagues address one of my many actual flaws.
While I have a lot of flaws, being a complete scientific fraud who talks out of my ear and pretends to be familiar with the science when I actually don’t have a clue what I am talking about is not one of them.
I agree that a responsible scientist should only talk about things he or she actually understands. But I think this also applies to public health groups. Tobacco control groups should only present themselves as sources of accurate scientific information if they actually understand the medical issues about which they are communicating. And I would humbly and respectfully suggest that a group which tells the public that secondhand smoke can cause, as an immediate effect, hardening of the arteries, does not truly understand the pathophysiology of heart disease.
As a physician, I not only studied the pathophysiology of heart disease in medical school, but I also treated hundreds of patients with heart disease and acute coronary events (heart attacks). I took part in surgery on blocked coronary arteries (thank goodness I wasn’t the one sewing in the bypass grafts). I followed a multitude of patients with severe coronary artery stenosis, which I measured directly by participating in the coronary angiography of those patients, and observed their progression or lack of progression to acute coronary events. I treated many patients with tissue plasminogen activator and aspirin in order to directly interfere with the platelet activation process, so as to decrease the likelihood of the triggering of an acute coronary event in these patients.
I think I know a little bit about this topic.
But frankly, I’m not sure that it even takes a physician to be able to suspect that something is fishy when an anti-smoking manual tells groups to inform the public that nonsmokers can develop atherosclerosis immediately after exposure to secondhand smoke. I don’t think it would be unreasonable for a lay person to suspect that she had been misled by a statement that it takes only minutes for secondhand smoke to cause hardening of the arteries, when that person is aware that among active smokers, the same process takes many years.
I don’t think it takes a physician to challenge the statement that 30 seconds of secondhand smoke exposure is as bad as a lifetime of chronic active smoking when it comes to coronary artery function. And I don’t think it even takes a physician to read the statement in the Otsuka et al. paper which states clearly that there was no decrease in coronary blood flow in the study subjects, and to then question why anti-smoking groups are stating that secondhand smoke reduces coronary blood flow in healthy young adults.
As my readers hopefully know, I don’t think that you have to be published in cardiovascular research to enter into this discussion intelligently. In fact, perhaps those who are furthest removed from the science and the agenda of tobacco control are in the best position to shed light on the implications of the statements being made by anti-smoking groups that I have cited and on whether or not those statements seem to be accurate and responsible communications based on even just the evidence that Dr. Glantz provides in his commentary, or based even on stipulating that everything Dr. Glantz states in his commentary is correct.
The Basis for Anti-Smoking Groups’ Misleading Health Claims – ClearWay, ANR, ACS, and Tobacco-Free Kids
Date: Fri Dec 08 2006 – 10:16:54 PST
attaching several peer reviewed academic reviews that show how all these
things link together. Coronary flow velocity reserve is an important
measure of the ability of the heart to respond to increases in demand
and is closely related to endothelial and platelet function, both of
which relate to both the chronic and acute risk of heart attack. It is
well established that increased platelet activation causes platelets to
stick to the vascular lining (the endothelium) and cause physical
damage, which is important for the development of atherosclerosis. The
acute effects can also trigger a heart attack in people at risk. No one
is saying that one whiff of smoke causes a heart attack in everyone who
breathes it. What the evidence shows is that there are substantial
immediate effects that compromise the cardiovascular system and that, in
some people, these changes are the same kinds of things that can trigger
an acute event.
fond of quoting himself (his blog), not the peer reviewed scientific
literature. In addition, while Dr. Siegel has published papers on other
topics, he is not published in cardiovascular research.
understands.
Secondhand smoke as an acute threat for the cardiovascular system: a
change in paradigm.
Eur Heart J. 2006 Feb;27(4):386-92.
Cardiovascular effects of secondhand smoke: nearly as large as smoking.
Circulation. 2005 May 24;111(20):2684-98.
How acute and reversible are the cardiovascular risks of secondhand smoke?
BMJ. 2004 Apr 24;328(7446):980-3.
Professor of Medicine (Cardiology)
Member, Cardiovascular Research Institute
University of California, San Francisco
________________________________
Sent: Friday, December 08, 2006 9:10 AM
Cc: Sylvia.Johnson@abc.com
Subject: Conflating Coronary Blood Flow and Coronary Flow Velocity
Reserve: The Basis for Anti-Smoking Groups’ Misleading Health Claims –
ClearWay, ANR, ACS, and Tobacco-Free Kids
claims being made by a large number of anti-smoking groups, such as
ClearWay Minnesota and ANR, suggesting that secondhand smoke reduces
coronary blood flow in healthy young adults, are misleading and
deceptive. It is posted today at:
http://tobaccoanalysis.blogspot.com/2006/12/conflating-coronary-blood-flow-and.html,
and excerpted below:
deception of the public that is going on regarding the acute
cardiovascular effects of brief secondhand smoke exposure, including the
deception
http://tobaccoanalysis.blogspot.com/2006/12/minnesota-anti-smoking-organizations.html
by ClearWay Minnesota which I highlighted yesterday,
and the deception
http://tobaccoanalysis.blogspot.com/2006/03/another-anti-smoking-group-makes.html>
of ANR which I highlighted back in March.
is that secondhand smoke exposure decreases coronary artery blood flow
in healthy young adults.
reduction in coronary artery blood flow implies that there is a serious
risk that not enough blood flow which reach the heart muscle. And if
that occurs, the person will suffer a heart attack. Such a heart attack
can be fatal. Therefore, what ClearWay and other anti-smoking groups
which have made similar statements are implying is that a healthy young
adult exposed to secondhand smoke is at risk of death due to that
exposure.
healthy young person exposed to secondhand smoke is at risk of death due
to that exposure.
justification for banning smoking altogether. After all, how can we take
the risk that healthy young people who are simply walking down the
street and happen to be exposed to secondhand smoke might suffer a
decrease in coronary artery blood flow and drop dead from a heart
attack?
encouraging local anti-smoking groups to make the same claim. The claim
appears in a smoking ban manual
whose
purpose is to provide direction and advice to anti-smoking groups
advocating for smoking bans. ClearWay is essentially telling these
groups that an appropriate tactic for promoting smoking bans is to
publicly state that exposure to secondhand smoke can kill healthy young
adults by decreasing the blood flow in their coronary arteries.
What’s important is that their statement inherently implies the risk of
heart attack and death. So if this implication is false, then the
statement is what I would consider to be wildly deceptive.
A similar claim http://www.no-smoke.org/pdf/SHS.pdf is being made by
Americans for Nonsmokers’ Rights (ANR), which claims
http://tobaccoanalysis.blogspot.com/2006/03/another-anti-smoking-group-makes.html
that: “Even a half hour of secondhand smoke exposure
causes heart damage similar to that of habitual smokers. Nonsmokers’
heart arteries showed a reduced ability to dilate, diminishing the
ability of the heart to get life-giving blood.”
exposure impairs the body’s ability to get life-giving blood to the
heart, putting even a healthy young individual at risk of a heart
attack, and therefore, of death.
After all, would it not be deceptive to imply that secondhand smoke
impairs the body’s ability to provide adequate blood to the heart and
therefore puts a person at risk of a heart attack and death if that is
untrue?
http://tobaccoanalysis.blogspot.com/2006/05/three-major-anti-smoking-organizations.html
is being made by the American Cancer Society and the
Campaign for Tobacco-Free Kids in a strategy document
http://www.paho.org/English/AD/SDE/RA/Guide1a_SecondhandSmoke.pdf
intended to guide anti-smoking groups nationwide in communication
tactics to promote smoking bans.
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 messages:
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.”
heart in nonsmokers. Just 30 minutes of exposure is enough to reduce
blood flow to the heart.”
that 30 minutes of secondhand smoke reduces blood flow to the heart, but
they are told to explicitly state (rather than merely imply) that this
30 minute exposure causes atherosclerosis, heart disease, heart attacks,
and stroke.
stating, then, is that just 30 minutes of secondhand smoke exposure
reduces blood flow to the heart and causes hardening of the arteries,
heart disease, heart attack, and stroke. This particular communication
leaves little to the imagination.
exposure does is to reduce not coronary artery blood flow, but coronary
flow velocity reserve. There’s a huge difference between these two, and
they should not be conflated.
coronary arteries to dilate in order to increase blood flow under
experimental conditions. What a decline in coronary flow velocity
reserve indicates is something called endothelial dysfunction – an
impairment of the ability of the coronary arteries to dilate in response
to a variety of stimuli. This ability to dilate is mediated by the
endothelial cells — the cells which line the blood vessel.
The endothelial cells respond to certain stimuli by producing nitric
oxide and other chemicals which diffuse into the smooth muscle in the
artery wall, sending a chemical message that causes the muscle to relax
and therefore causing the artery to dilate. There are a number of
exposures that impair the ability of the endothelium to accomplish this
function; among them are active smoking, secondhand smoke, high
cholesterol, consumption of trans-fats, and consumption of a high-fat
meal.
of time, it has been shown to result, ultimately, in atherosclerosis
(narrowing of the coronary arteries). When this occurs, coronary blood
flow is reduced.
observed acutely when the endothelial dysfunction is being measured from
a single experimental exposure (such as in the Otsuka et al. study). The
reduction in coronary blood flow does not occur until the process has
been sustained long enough that atherosclerosis has progressed and the
coronary artery has actually narrowed. It is the narrowing of the artery
that causes reduced coronary blood flow.
dysfunction. If you were to go to Burger King for a Whopper, fries and a
milk shake and then go to a laboratory to have your coronary flow
reserve velocity tested, you would find that it is reduced. In fact, it
will probably be reduced to the same level as in an active smoker.
eating a hamburger reduces coronary artery blood flow in healthy young
adults?
be very misleading and deceptive to the public.
Instead, what the science shows is that eating a hamburger or any
high-fat food causes endothelial dysfunction. Therefore, if you
chronically eat lots of fatty foods over a long period of time (many
years), the evidence indicates that this could cause atherosclerosis and
heart disease. If you do develop heart disease, then your coronary blood
flow will be decreased and you will be in danger of possibly suffering a
heart attack. But there is no danger of death or a heart attack after
simply eating one Whopper.
anti-smoking groups have, I think, been able to deceive people into
thinking that the effects of acute secondhand smoke exposure are much
more severe than they actually are.
health effects of secondhand smoke, implies to the lay public that a
brief exposure can be fatal for even a healthy, young person, and I
think it would scare people sufficiently that it would increase support
for smoking bans – which is the ultimate goal (and a goal I support [at
least workplace smoking bans]).
emotional public communication, have we not distorted the science and
ended up misleading and deceiving the public?
I think the answer is a definite “yes.” I see no compelling way to argue
that by using the term “coronary blood flow” rather than “coronary flow
velocity reserve,” we have not ended up deceiving anyone. In fact, I
think the difference is enormous and the difference in the implications
are even more enormous.
I don’t think it’s fair to do this to the lay public, because they are
simply not in a position to be able to understand and interpret these
communications in a critical and informed manner. When they are told
that coronary blood flow is reduced, they are naturally going to assume
(at least many of them will) that this is reducing blood flow to the
heart, which even the lay public understands is what causes a heart
attack.
statements to a large segment of the lay public is that acute and brief
secondhand smoke exposure can cause death by heart attack among healthy
young adults. Such an implication, it is important to point out, is
completely false.
groups – such as ClearWay – which have stated that brief exposure to
secondhand smoke reduces coronary blood flow in healthy young adults,
are deceiving the public.
public in their public communications, especially regarding the effects
of tobacco smoke, what possible justification can we provide for
deceiving the public ourselves in our own public communications?
wrong. It is unethical, and I think it needs to stop. I also think we
need to retract or correct our statements and apologize for having
deceived the public, whether that deception was intentional or not.
Professor
Associate Chair of Academics
Social and Behavioral Sciences Department
Boston University School of Public Health
Top Ten Junk Science Moments for 2006
December 14, 2006
By Steven Milloy
It’s time again for JunkScience.com’s review of the most notable junk science events of the year – a “top 10” list that may sometimes make you think that the year 1007, rather than 2007, is just around the corner.
