On Friday, I explained why I think that ClearWay Minnesota's statement that secondhand smoke decreases coronary blood flow in healthy young adults is deceptive. As I explained, the group seems to be conflating coronary flow velocity reserve, which is decreased by acute secondhand smoke exposure, and coronary blood flow, which is not impaired at all.
However, the implications of the difference are immense. A decline in coronary flow velocity reserve merely indicates that physiological damage is taking place - the function of the endothelial cells has been impaired. In contrast, a decline in coronary blood flow would indicate clinical damage; reduced blood flow to the heart puts an individual at risk of a heart attack and death.
Today, I reveal that no less than 38 anti-smoking groups are making similar claims about the acute effects of secondhand smoke - claims which are deceptive because they conflate coronary blood flow and coronary flow velocity reserve.
The Rest of the Story
Here they are:
Americans for Nonsmokers' Rights: "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."
American Cancer Society and Campaign for Tobacco-Free Kids: "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."
ClearWay Minnesota: "Blood flow in the coronary arteries is decreased in healthy young adults exposed to secondhand smoke." (Note: Document has been removed from site in response to my post.)
Minnesota Smoke-Free Coalition: "Non-smokers are harmed by even brief exposures to passive smoke, according to a study published recently in the Journal of the American Medical Association. ... The study showed that after only short periods of exposure, secondhand smoke contributed to narrowing of blood vessels, restricted flow of blood and hardening of the arteries."
Asthma Initiative of Michigan: "...in as little as 30 minutes of exposure to secondhand smoke, the nonsmokers’ blood flow dropped to the same level as people who had smoked a pack of cigarettes.
American Heart Association, Heritage Affiliate: "Even 30 minutes of exposure to secondhand smoke reduces blood circulation and increases your risk for a heart attack."
SmokeFreeColorado: "Just thirty minutes of exposure to secondhand smoke can compromise the cardiovascular system of nonsmokers by reducing blood flow to the heart."
British Heart Foundation: "Just 30 minutes exposure to tobacco smoke can affect the cells lining the coronary arteries and this can contribute to the development of atheroma narrowing the coronary arteries and reducing blood flow to the heart."
Action on Smoking and Health (London): "Short term exposure to tobacco smoke also has a measurable effect on the heart in non-smokers. Just 30 minutes exposure is enough to reduce coronary blood flow."
Clearing the Air Scotland: "30 minutes exposure to second hand smoke is sufficient to reduce coronary blood flow in otherwise healthy adults."
American Lung Association of Oregon: "As few as 30 minutes of secondhand smoke exposure can impair coronary circulation in a non-smoker."
SmokeFreeOhio: "Only 30 minutes of secondhand smoke exposure can cause narrowing of blood vessels, restricting the flow of blood and contributing to hardening of the arteries." (Note: Claim was removed from fact sheet in response to my post).
Citizens Against Unhealthy Smoke-Filled Environments: "Just 30 minutes exposure to secondhand smoke can compromise the cardiovascular system of nonsmokers by reducing blood flow to the heart." (Note: Page is no longer active).
Smokefree Islington (UK): "A study published in the Journal Of The American Medical Association found that just 30 minutes' exposure is enough to reduce coronary blood flow."
Smoke-free Bristol (UK): "Short-term exposure to second-hand smoke has a measurable effect on the heart in non-smokers -– 30 minutes exposure is enough to reduce blood flow to the heart muscle."
Texas Department of State Health Services: "Just 30 minutes'’ exposure to secondhand smoke can constrict arteries and damage the body'’s ability to supply blood to the heart."
Smoke Free North West: "Short term exposure to tobacco smoke also has a measurable effect on the heart in non-smokers. Just 30 minutes exposure is enough to reduce coronary blood flow."
East Cambridgeshire and Fenland PCT: "Being exposed to 30 minutes cigarette smoke can significantly reduce the coronary blood flow in a fit healthy adult."
Smokefree Wyoming: "Within 30 minutes, your blood becomes stickier, damaging artery linings and restricting flow."
Oregon Department of Human Services: "Experts have found that just 30 minutes of secondhand smoke exposure can impair blood flow to and from the heart in non-smokers."
American Lung Association of Metropolitan Chicago: "People who spend just 30 minutes in a smoke-filled room have a measurable decrease in oxygen delivered to their heart."
Hong Kong Medical Association: "Just 30 minutes exposure is enough to reduce coronary blood flow."
Share Air: "Just 30 minutes' exposure to secondhand smoke can constrict arteries and damage the body's ability to supply blood to the heart."
Illinois Coalition Against Tobacco: "Even as little as 30 minutes of exposure to secondhand smoke has a negative effect on arteries and oxygen's flow to the heart is decreased."
Smoke Free North East: "Just 30 minutes exposure is enough to reduce coronary blood flow."
Smokefree England: "Just 30 minutes exposure is enough to reduce coronary blood flow."
Smokefree Mecklenberg: "Only 30 minutes of secondhand smoke exposure can cause narrowing of blood vessels, restricting the flow of blood and contributing to hardening of the arteries."
Smoke Free Wirral: "Short-term exposure to tobacco smoke also has a measurable effect on the heart in non-smokers. Just 30 minutes exposure is enough to reduce coronary blood flow."
Pueblo City-County Health Department: "Breathing secondhand smoke for just a few minutes increases arterial stiffness, promotes the tendency of blot to clot, reduces blood flow to the heart, and makes arteries more prone to damage."
Smoke Free Solihull: "Just 30 minutes exposure is enough to reduce coronary blood flow."
British Medical Association: "Just 30 minutes in a smoky room can reduce the flow of blood to the heart."
British Medical Association, Tobacco Control Resource Centre: "Just 30 minutes in a smoky room can reduce the flow of blood to the heart."
Smoke Free Liverpool: "Just 30 minutes exposure to other people’s tobacco smoke can be enough to reduce blood flow through the heart."
Royal College of General Practitioners: "Just 30 minutes exposure is enough to reduce coronary blood flow in a non-smoker."
Scottish Executive: "Short-term exposure to tobacco smoke also has a measurable effect on the heart of non-smokers: just 30 minutes' exposure is enough to reduce coronary blood flow."
Oregon Department of Health Services: "Experts have found that just 30 minutes of secondhand smoke exposure can impair blood flow to and from the heart in non-smokers."
British Heart Foundation: "Furthermore, exposure to cigarette smoke does not have to be particularly prolonged for it to damage your heart. One study has shown that just 30 minutes exposure is enough to reduce coronary blood flow to the heart."
State Tobacco Education & Prevention Partnership (Colorado): "Just thirty minutes of exposure to secondhand smoke can compromise the cardiovascular system of nonsmokers by reducing blood flow to the heart."
Just to make it clear, there is no evidence that acute exposure to secondhand smoke reduces coronary blood flow. It does not decrease blood flow to the heart.
What it does is decrease coronary flow velocity reserve, which is an experimental measure of reduced ability of the arteries to dilate in response to certain induced stressors. It is important to note that this is a physiological effect, not a clinical one. When it occurs in a healthy young adult, it has essentially no clinical significance. Of course, if the exposure is repeated over and over again over many years, then it could have clinical significance as atherosclerosis could develop.
What the anti-smoking groups have been doing is conflating the observed physiological change with a clinically significant effect.
To give you an idea of why this is inappropriate, consider the fact that simply eating a hamburger, fries, and milk shake at McDonalds decreases coronary flow velocity reserve. But it would obviously be misleading to put out messages to the public telling them that eating a meal at McDonalds can decrease their coronary blood flow, reducing blood flow to the heart!
The importance of today's revelation is that it demonstrates that the deception of the public about the acute cardiovascular effects of secondhand smoke, especially in relation to the effects on coronary blood flow, is not just limited to a few errant statements by a few anti-smoking groups. The deception is a widespread phenomenon that pervades the tobacco control movement.
I can't yet completely figure out how exactly this occurred. Was there simply just a very bad mistake in interpreting the clinical significance of these findings that was spread widely among the groups, or was there an intentional decision made to mislead people into thinking that the clinical significance of these findings for healthy people is more than it really is?
To me, it hardly matters, because at this point, I believe that these groups - especially the major ones and the ones with which I have communicated directly - should be aware of the mistakes and should have had plenty of time to correct them. The continued presence of these fallacious claims, in my view, does at this point represent an intentional effort to deceive, even if the original cause was simply a mistake.
At least one group - ClearWay Minnesota - has apparently responded appropriately to my pointing out its misleading statements by removing the web page containing those statements. But as today's post shows, we have a long way to go before the anti-smoking movement can regain any semblance of scientific credibility.
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