Public Health

CDC-Commissioned Report Says More Evidence Is Needed to Decide Whether Smoking Bans Are Good

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Just kidding. The report, which an Institute of Medicine committee issued yesterday, concludes, per the press release, that "smoking bans reduce the risk of heart attacks associated with secondhand smoke." The committee's chairwoman, Lynn Goldman, a professor of environmental health sciences at Johns Hopkins, sums up the report's findings this way:

It's clear that smoking bans work. Bans reduce the risks of heart attack in nonsmokers as well as smokers. Further research could explain in greater detail how great the effect is for each of these groups and how secondhand smoke produces its toxic effects. However, there is no question that smoking bans have a positive health effect.

As with the 2006 surgeon general's report on secondhand smoke, the press release goes farther than the report itself, which in turn draws conclusions that are not justified by the evidence it presents. The judgment about the effectiveness of smoking bans is based on 11 studies that looked at heart attack rates in eight jurisdictions after smoking bans took effect. "None was designed to test the hypothesis that secondhand-smoke exposure causes cardiovascular disease or acute coronary events," the report concedes. Furthermore, "only two of the studies distinguished between reductions in heart attacks suffered by smokers versus nonsmokers." Even so, the report concludes that smoking bans reduce heart attacks, at least partly by reducing nonsmokers' exposure to secondhand smoke.

To accomplish that impressive feat, the report underplays two major problems with attempts to measure the impact of smoking bans through observational studies. First, in recent decades there has been a general decline in heart attack rates, driven mainly by improvements in preventive medication and treatment. A decrease in heart attacks seen after a smoking ban takes effect could be part of this pre-existing trend. One way to address that possibility is to use comparison jurisdictions that do not have smoking bans but are otherwise similar, a precaution most of these studies did not take. 

Second, random variation means that some jurisdictions with smoking bans are bound to see significant drops in heart attacks purely by chance, while others will see no real change or significant increases. The largest study of the issue, which used nationwide data instead of looking at cherry-picked communities, found that smoking bans "are not associated with statistically significant short-term declines in mortality or hospital admissions for myocardial infarction or other diseases." Furthermore, "An analysis simulating smaller studies using subsamples reveals that large short-term increases in myocardial infarction incidence following a workplace ban are as common as the large decreases reported in the published literature."

That study, published by the National Bureau of Economic Research in March, suggests that publication bias can explain what the IOM panel describes as the "consistent" results of the studies it considered (meaning that they all found drops in heart attacks, although the magnitude of these decreases varied widely, from 6 percent in Italy to an astonishing 47 percent in Pueblo, Colorado). If a researcher runs the numbers for a particular jurisdiction and finds no impact from a smoking ban, he is not likely to write up that result, especially if he supports smoking bans as part of the effort to reduce tobacco-related disease. Even if he does submit an article describing his findings, it is not likely to be published, not just because of an anti-smoking bias but because negative results are perceived as boring. 

The NBER paper was mysteriously excluded from the IOM report, even though the authors say they bent over backward to compensate for publication bias by looking for relevant data that did not appear in medical journals. They also ignored analyses that found no declines in heart attacks following smoking bans in California, Florida, New York, Oregon, England, Wales, and Scotland. The omission of the Scottish data is especially striking because they contradict one of the 11 studies included in the IOM report, showing that a decrease in heart attacks during the first year was exaggerated and in any case disappeared the following year.

The report is slippery in addressing the biological plausibility of attributing immediate, dramatic reductions in heart attacks to smoking bans.  For example, the study of Helena, Montana (the one that started it all) found a 40 percent drop in heart attacks within the first six months of the city's smoking ban. As I've said before, it is simply not possible that the smoking ban caused that big a drop so quickly, unless the CDC and the American Heart Association are wildly off in their estimates of the heart disease caused by smoking and secondhand smoke, respectively. If smoking and secondhand smoke together account for about 25 percent of all heart disease deaths, a smoking ban could not cause a 40 percent reduction in heart attacks even if everyone in the city immediately stopped smoking. 

For some reason (a convenient error, I assume), the IOM report describes the utterly implausible 40 percent reduction in Helena as a 16 percent reduction, as part of an attempt to show that bigger declines were found in the studies with longer follow-up periods. (Most of the studies had follow-up periods of a year or less.) What the comparison of studies actually shows is that the most dramatic results were found in the studies with the tiniest samples (e.g., Helena , Pueblo, and Monroe County, Indiana), where random variation would be expected to have the biggest impact.

Although the authors work hard to make patently ridiculous claims seem plausible, they never settle on an explanation of how, exactly, these reductions in heart attacks are accomplished. When people stop smoking, their heart attack risk declines gradually over several years, and it's hard to see why the heart attack risk in people exposed to secondhand smoke would fall any faster. Given a lack of information about individual exposure patterns in studies of secondhand smoke and heart attacks, the report says, "the committee could not determine whether acute exposures were triggering acute coronary events, chronic exposures were causing chronic damage that eventually resulted in acute coronary events, or a combination of chronic damage and an acute-exposure trigger led to the increased risk of acute coronary events." But if the impact of a smoking ban is seen within six months (or two, as in one of the Italian studies), the only possible explanation, since heart disease takes years to develop, is that the ban prevents heart attacks in people who would otherwise keel over from acute exposure.

Who are these people? The report acknowledges that people with severe heart disease are most vulnerable, but it also intimates that perfectly healthy people might drop dead from a heart attack after spending a half-hour in a smoky bar. "The risk of acute coronary events is likely to be increased if a person has preexisting heart disease," it says, implying that even people without pre-existing heart disease take their lives in their hands by grabbing a drink in a bar where smoking is allowed. At the same time, the report concedes "there is no direct evidence [as opposed to suggestive laboratory results] that a relatively brief exposure to secondhand smoke can precipitate an acute coronary event." No kidding. Not to put too fine a point on it, but where are the bodies? The sort of immediate effect they are talking about should be readily apparent. Yet the committee cites no reports of people, whether sick or healthy, having heart attacks after brief exposures to secondhand smoke.

Assuming that smoking bans do reduce heart attacks, that result could be due to declines in smoking, declines in secondhand smoke exposure, or some combination of the two. The report settles on that last explanation, even though only two of the 11 studies bothered to distinguish between smokers and nonsmokers. The authors do concede that, given the paucity of the data, "it is not possible to determine the magnitude of the effect that is attributable to changes in nonsmokers compared with smokers."

Likewise, because of the limitations of the studies and the wide variations between them, the report says, "the committee has little confidence in the magnitude of the effects and, therefore, thought it inappropriate to attempt to estimate an effect size." Michael Siegel, a Boston University public health professor who was one of the report's reviewers, notes that "if you can't even estimate the magnitude of an effect—if you have no confidence in even providing an estimate—you are hardly in a position to conclude that there is a significant effect of smoking bans on heart attacks, an effect which exceeds random variation combined with the known secular decline in heart attack rates." Siegel faults the authors for a "sensationalistic" approach, especially as reflected in their attempt to "scare people into thinking that they could drop dead from a heart attack from a brief tobacco smoke exposure."

The main goal of this project, which was commissioned by the CDC, seems  to have been producing a document that could be waved around at city council meetings and state legislative hearings. If so, the authors have succeeded. "The evidence is clear," says CDC Director Thomas Frieden. "Smoke-free laws…prevent heart attacks in nonsmokers." Although the IOM panel said it would be reckless to estimate the impact of smoking bans on heart attacks, Frieden (an avid smoking ban advocate when he was New York City's health commissioner) is willing to go there. "These findings suggest that tens of thousands of heart attacks could be prevented each year," he claims. "States and communities that do not have comprehensive smoke-free laws could have significant cardiovascular health benefits by doing so." Neal Benowitz, a member of the IOM panel, insists that "smoking bans need to be put in place as quickly as possible," because "the longer we wait, the more disease we are accepting."

My own view is that the scientific findings are not relevant to the policy question, which is a matter of property rights. Regardless of the hazards posed by secondhand smoke, business owners should be free to set the smoking rules on their own property, which no one is forced to enter. At the same time, I recognize that reports like this provide ammunition to advocates of smoking bans, so I am more inclined to be skeptical of claims about the impact of such laws than someone who has no problem with them would be. (I do agree that smoking bans, to the extent that they encourage smokers to quit, can be expected to gradually reduce heart disease over the long term, as opposed to dramatically reducing it immediately.) Yet the people conducting these reviews are not neutral observers either; as reflected by Benowitz's comments, they are committed partisans in the push to extend strict smoking bans across the country.

NEXT: I'd Call That a Bargain / The Best I Ever Had

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  1. Damn you Sullum! You pulled a Balko on me with that headline.

  2. Just kidding.

    You are an evil little man.

  3. Nice article, but a bit long for a blog post. The “Read More” functionality would’ve been useful.

  4. We’re in the middle of the Make Shit Up Era. If facts stubbornly contradict your ideology, and you just know you’re right (because you feel it), you lie, and you enlist your buddies in the media as accomplices in the scam. Lying in the media has become so common, it’s dangerously close to becoming an accepted practice.

  5. OT: It is now after 3:00 PM here and stalker chick has not looked for herself on my blog today! Am declaring victory and hoping her next person does not have a bunny in the home.

      1. Didn’t need that advertised that much.

  6. And people wonder how folks like the creationists can persist in their beliefs in the face of being soundly contradicted by science? Maybe it’s because too many scientists have been caught with their hands in the ideological cookie jar too many times to be trusted?

    Scientific methods might be helpful in ascertaining the truth – but that doesn’t necessarily mean scientists can be relied upon to report the results truthfully. I’ll never be a creationist, but given how many times the scientists have caught flat-out lying, I can’t really blame them for flipping off conventional wisdom. “Because the scientists say so” has ceased to be a reliable endorsement of fact.

    1. “‘Because the scientists say so’ has ceased to be a reliable endorsement of fact.”

      Nor should it ever be. It makes no difference how many scientists claim a ‘fact,’ it doesn’t make it so. Newton, (absolutely one of the most intelligent humans in history) as Einstein showed, was ultimately wrong. All a scientist can do is look at the evidence they can observe and claim it fits (or doesn’t fit) a particular hypothesis. At this point, the evidence for the dangers of second-hand smoke seems about as strong as the arguments for an Earth-centered universe.

  7. For small cities like Helena and Pueblo, I would wonder if smoking bans didn’t lead to a population drop as smokers moved to adjacent smaller towns without such bans, but with a similar culture. With big cities, disaffected smokers would have fewer and more distant options of exit with similar cultures. My underlying assumption being that smokers would be more likely to have heart attacks.

    In other words, while heart attacks went down in Pueblo, maybe they went up in Colorado Springs or Trinidad after many Pueblo smokers moved out of town. Smokers in New York just stayed put and had their heart attacks in New York after then ban.

  8. Who are these people?

    That’s why this statistical and methodological b.s. isn’t even arguable-about. It’s a theology. The leap into madness is that denied-but-assumed premise: Smoking sections cause motherfucking heart attacks.

    Whose? How? “Acute exposure?” To what? Smokers don’t exhale the same stuff they inhale, and even they don’t keel over from any single exposure to it.

    “The policy question” of “property rights” is outside the Sacred Text, too, so there’s nothing to talk about with the banners and their excuse-makers.

    They’re just crazy people, with gunmen. Hide.

  9. So, a smoker should have the right to light up wherever they want, but a non-smoker shouldn’t have the right to breath in (relatively) clean air?

    I think this is a property rights question and a civil liberties question. By what measure is the right of a smoker inherently more worthy of protection than the right of a non-smoker? At the end of the day, any individual can choose whether or not to light up at home, but we all have to make use of the public domain (walking down the street, working as a waitress, and remember the days of smoking in hospitals?).

    Perhaps I’m biased because I’m not so personally fond of the cancer sticks (though you may inhale toxic chemicals to your heart’s extent in the privacy of your home/car etc). Key difference:

    A smoker can choose where they light up, whereas breathing is somewhat involuntary.

    Why can’t the nonsmoker be FREE from the imposition of the smoker’s poor choices?Aren’t you a libertarian?

    1. a smoker should have the right to light up wherever they want [?]

      I don’t think anyone is saying that. What we DO say is that owners of private property should be able to allow or disallow smoking on their property, as they wish. Non-smokers are free to choose non-smoking property to hang out in.

      1. Roger that.

        Libertarian? gives a sarcastic nod to the rights of the property owner then leaps into Big Brother territory.

        As far as public property goes, first there should be precious little of it, second that is fully within the rights of the “collective” to regulate as the consitituency sees fit.

  10. For those of you who do not know, the author Jacob Sullum, ALWAYS claims the tobacco industry is correct on anything. It is people like him who make lots of normal people be disgusted by the libertarians.

    I don’t have time to go through a point by point rebuttal, but I’ll go through the three most glaring errors.

    1) Sullum tries to attribute the sharp fall in heart attack rates in places instituting smoking bans to the long term national decline. But this is quantitatively absurd. If you see an annual drop of less than one percent over decades, and then one month after a city bans smoking in public places you see a 30 percent drop, the 30 percent drop is not explainable as merely the long term decline

    2) Sullum claims the effects could be due to random fluctuations. In reality, the studies were put through the mathematical test for “statistical significance”, and this showed there is no reasonable possibility of them being random fluctuations

    3) Sullum claims that the best study was a nationwide study. While that sounds good, it makes no sense. Smoking bans are done locally. If Rhode Island bans smoking then what one needs to do is look at the heart attack in RHODE ISLAND, not nationally. Any effects nationally would be drowned out by statistical noise.

    I don’t have time to go through a point by point rebuttal, but Il go through the three most glaring errors.

    1) Sullum tries to attribute the sharp fall in heart attack rates in places institutting smoking bans to the long term national decline. but this is quantitatively absurd. if you see an annual drop of less than one percent over decades, and then one month after a city bans smoking in public places you see a 30 percent drop, the 30 percent drop is not explainable as merely the long term decline

    2) Sullum claims the efffects could be due to random fluctuations. In reality the studies were put through the mathematical test for “statistical significance”, and this showed theere is no reasonable possibbility of them being random fluctuations

    3) Sullum claims that the best study was a nationwide study. while that sounds good, it makes no sense. Smoking bans are done locally. If Rhode island bans smoking then what one needs to do is look att he heart attack in RHODE ISLAND, not nationally. Any effects nationally would be drowned out by statistical noise. His claim that it should be done nationwide for a local ban makes no sense at all.

    1. But they are, so you wasted many electrons.

  11. Jacob Sullum’s analysis is, as usual, well done. Paul L’s criticisms do not hold water but it’s rather late on a Friday night so I’m not going to have at them myself. Hopefully someone will pick up my slack on that! 🙂

    Here is what I’ve been posting variations of in relation to this “Big New Study” ”

    ===

    This report is basically the same as the Meyers one from August and the Glantz one from a few weeks ago. Taken together they’re like the Three Stooges. All three get the same basic conclusion and share the same fatal defect: all three take about a dozen small “garbage studies,” studies that have been heavily discredited for various weaknesses, flaws, misinterpretations and false claims, and piled them up into what is essentially one BIG pile of garbage, and then tried to pass it off as a Crystal Castle of new knowledge.
    .
    It’s not. It’s essentially just a continuation of efforts to frighten people with exaggerated propaganda claims that are only very weakly supported, if at all, by legitimate science.
    .
    Let me take one quote from one of the articles about this study as an example: “While heavier exposure to secondhand smoke is worse, there’s no safe level.” There’s actually never been a single study that has shown this to be true. It’s just like saying “While heavier exposure to the sun causes malignant melanoma, there’s no safe level.” and then using that statement to ban patio dining “to protect the workers” while declaring that awnings and sunscreen “only provide partial protection.”
    .
    Sure, they could hide behind the idea that at *some* level they’re telling the truth, but no one in their right mind is going to worry about reaching out the front door in the morning to grab the newspaper off the porch because of “the deadly carcinogenic rays” of sunshine that might peek through the clouds.
    .
    Additionally, when you look at the official summary/release of this latest report, you find in the small print that they carefully note that they cannot actually relate anything in their findings to exposure to secondary smoke. They’re willing to ASSUME that such exposure played a part in their numbers, but they’re careful not to say so officially – when they mouth off to the media it’s a totally different story of course. The findings indicate that BANS correlated in these cherry picked areas to heart attack reductions, but there’s very little data (only gathered at all in 2 out of the 11 studies!) on nonsmokers’ exposures to smoke.
    .
    Want to see how these studies juggle statistics to get the “right” sort of results that they promise their antismoking funding organizations and WHY they do it? Read the AfterComments to Jacob Grier’s article at:
    .
    http://www.jacobgrier.com/blog/archives/2210.html
    .
    and you’ll get an eyeful.
    .
    Michael J. McFadden
    Author of “Dissecting Antismokers’ Brains”

  12. Michael Mcfaddon writes

    Well, it is no longer late on Friday night, and so if you really have found something incorrect in what I wrote, why not tell us?

    1. Ooops, the message did not post correctly, so let me try again

      Michael McFaddon wrote that he could demonstrate that I was incorrect, but that because it was late on Friday night he would not have time. (Thanks for stopping in anyway, Mike!)

      Well, it is no longer late on Friday night, and so if you really have found something incorrect in what I wrote Michael, why not tell us?

      1. OK Paul! 🙂 Thanks for giving me a few days… it was a GOOD Friday night! :> {and I’ve had *severe* posting problems getting this up: fifth attempt in 24 hours here…}

        You numbered 3 things, so let me take them one by one, but I first wanted to comment on your comment on Sullum. I don’t know him other than through his columns and books, but my guess is that the Antismokers got him royally teed off when they took his acceptance of a $5,000 reprint fee for a column he’d already written an published and tried to play it up as “Sullum is a paid hack for Big Tobacco.” Heh… he’s gotten back at them in spades! :>

        OK…

        #1&2) The long term decline in terms of recent years is a lot more than 1% per year. I think it’s more in the area of 3 to 7% depending on the period and the population. When you take something like Scotland’s Pell claim of a 17% drop, then correct it for the actual hospital records to a real drop of just 9%, and then realize that you’d be EXPECTING a drop of 5 to 7%, and then go back over the last five or ten years and I believe you’ll see that there were one or two with LARGER drops with NO smoking ban… then the argument becomes much stronger. For some much better information on this I’d recommend reading Dr. Michael Siegel’s blog posts of the last week or so (Oct 15 to 20) at:

        http://tobaccoanalysis.blogspot.com/

        While reading his criticisms, also check out the comment threads below them. There are some good insights there as well.

        3) Your criticism of local vs national studies is the opposite from what is usually claimed. Whenever the small studies have been criticized the antismoking researchers have generally claimed the effects would be even larger with statewide or national bans since smokers wouldn’t be traveling out of town to avoid the bans. Dave Kuneman and I showed this wasn’t the case with our own unpublished study done back in 2005. See:

        http://www.acsh.org/factsfears…..detail.asp

        for the full story on that and a look at its publication problems. The RAND/NBER study used a similarly large sampling and arrived at the same conclusions we did four years ago. Hopefully they’ll have enough clout to get it published… although for the purposes of the current Blitz it will be just like ours: A study delayed, a study denied.

        Sorry for the long delay in getting back to you Paul! Looking forward to seeing what you think of the above as well as being interested in hearing your comments/criticisms of my own posting from 10/17 at 2am.

        Michael J. McFadden
        Author of “Dissecting Antismokers’ Brains”

  13. For me the biggest surprise was how the Wall Street Journal presented this story. I had had a higher impression of them.

  14. There are no published reports on California, Florida, Oregon, England, or Wales… And the published reports on NY and Scotland show a 9% and 17% drop in AMI respectively.

  15. Actually, the report, if you read the entire 200+ pages does support the conclusions that 1) secondhand smoke can trigger a heart attack and 2) communities that go smoke-free have a drop in AMI. They IOM does say that they don’t know if #2 is due to reduced exposure among non-smokers, quits by smokers or a combo of these and other factors, but inthe end does it matter? If communities on average are seeing a drop of 17% in heart attacks (per reviews this month in Circulation and Journal American College of Cardiology), this seams like evidence on why all public places should be smoke-free.

  16. There are no published reports on California, Florida, Oregon, England, or Wales… And the published reports on NY and Scotland show a 9% and 17% drop in AMI respectively.

  17. I see Paul Lasr, despite asking me to get back to him in the comments, never bothered to respond to my assent to his request.

    Meanwhile, it also appears that the IOM Report Sullum talks about here not only didn’t prove its case, but has now been forced to recant its main finding: Due to an “mistake” of some sort they’d used a figure of 70% instead of 40% or something regarding one of their main studies and their overall 17% drop claim seems to have now been reduced to about 8% – equal to the national average!

    See: http://tobaccoanalysis.blogspo…..is-of.html for further analysis/confirmation.

    Given general national trends the NY Times et al *SHOULD* have blared headlines of “CDC Study Now Finds That Smoking Bans Do NOT Reduce Heart Attacks At All!”

    Anyone here remember seeing such headlines? Of course not: they wouldn’t fit in with the politically correct propaganda campaign now would they?

    Michael J. McFadden
    Author of “Dissecting Antismokers’ Brains”

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