Secondhand smoke isn’t as bad as we thought.

Secondhand Smoke Is Not Nearly As Dangerous As We Thought. Shouldn’t That Matter?

Secondhand Smoke Is Not Nearly As Dangerous As We Thought. Shouldn’t That Matter?

Health and medicine explained.
Feb. 13 2017 5:57 AM

We Used Terrible Science to Justify Smoking Bans

Will we look at the new evidence for long enough to at least consider whether we’ve gone too far?

A young woman smoking cigarette inside.
In the early 2000s, anti-smoking advocates seized on one study to fight for expanding smoking bans to bars and restaurants in jurisdictions across the country.


Helena, Montana, does not often make global headlines, but in 2003 the small capital city became known for briefly achieving one of the most astounding public health triumphs ever recorded. In June of the previous year, Helena had implemented a comprehensive smoking ban in its workplaces, bars, restaurants, and casinos. In the first six months of the ban, the rate of heart attacks in the city plummeted by nearly 60 percent. Just as remarkably, when a judge struck down the smoking ban in November of that year, the rate of heart attacks shot right back up to its previous level.

For three anti-smoking advocates—local physicians Richard Sargent and Robert Shepard, and activist and researcher Stanton Glantz from the University of California at San Francisco—this sudden drop in heart attacks was proof that smoking bans usher in extraordinary benefits for public health. “This striking finding suggests that protecting people from the toxins in secondhand smoke not only makes life more pleasant; it immediately starts saving lives,” said Glantz in a press release sent out by UCSF.


Newspapers ran with the story, credulously assuming that the correlation had been truly caused by the smoking ban. “The bottom line of Helena’s plummeting, then soaring, heart attack rate is painfully obvious,” warned an op-ed in the New York Times. “Secondhand smoke kills.” The BBC projected that “[banning] smoking in public places could prevent hundreds of deaths from heart disease.” Wire services carried the result around the globe, and even the conservative Wall Street Journal cited the result as an important finding.

In the early 2000s, as jurisdictions across the country fought over expanding smoking bans to bars and restaurants, anti-smoking advocates seized on the Helena study and related research showing that secondhand smoke exposure can affect coronary functions to promote fear of secondhand smoke. Groups across the country stated that “even half an hour of secondhand smoke exposure causes heart damage similar to that of habitual smokers.” Not to be outdone, the Association for Nonsmokers in Minnesota wrote in a press release that just 30 seconds of exposure could “make coronary artery function of non-smokers indistinguishable from smokers.” The message to nonsmokers was clear: The briefest exposure to secondhand smoke can kill you.

A decade later, comprehensive smoking bans have proliferated globally. And now that the evidence has had time to accumulate, it’s also become clear that the extravagant promises made by anti-smoking groups—that implementing bans would bring about extraordinary improvements in cardiac health—never materialized. Newer, better studies with much larger sample sizes have found little to no correlation between smoking bans and short-term incidence of heart attacks, and certainly nothing remotely close to the 60 percent reduction that was claimed in Helena. The updated science debunks the alarmist fantasies that were used to sell smoking bans to the public, allowing for a more sober analysis suggesting that current restrictions on smoking are extreme from a risk-reduction standpoint.

By the time the Helena study was published in the British Medical Journal, the authors had lowered the observed reduction in heart attacks from 60 percent to 40 percent; still an impressive figure but a substantial drop from the claim they had prematurely publicized to press worldwide. Immediate responses to the paper from other scientists were harshly critical, noting the small size of the Helena population—about 68,000 residents at the time—and the medical implausibility of achieving such a massive effect in such a short period. It was impossible to know with certainty whether the drop was caused by the ban or was simply due to chance.


Nonetheless, the Helena paper spawned a wave of studies seeking to replicate the finding. Research observing similar reductions followed in places such as Pueblo, Colorado; Bowling Green, Ohio; and Monroe County, Indiana. One characteristic shared by these places was their low populations and correspondingly small sample sizes: The last of these studies covered only 22 heart attacks among nonsmokers over the course of nearly four years.

When studies sampling larger populations finally appeared, the reported declines in heart attacks began to shrink. A study of the Piedmont region of Italy found a much lower decline of 11 percent, though curiously only for residents under 60 years of age. England, which implemented a smoking ban nationwide, presented the first opportunity to study the matter on a national scale. Researchers there credited the ban with a heart attack reduction of just over 2 percent nationwide.

Critics noted that the rate of heart attacks in England had also been falling in the years prior to the ban and that the reason for the decline was still not clear. Regardless, the data there made it obvious that the miraculous reductions claimed in smaller studies were unrealistically high. Even so, despite acknowledging the wide variation in findings and the admitted methodological limitations of the studies, a 2009 meta-analysis conducted by the Institute of Medicine concluded that the impact of smoking bans on short-term heart attack rates was real and substantial: “Even a small amount of exposure to secondhand smoke… can cause a heart attack,” one member of the IOM panel informed the New York Times, urging that “smoking bans need to be put in place as quickly as possible.”

This report had, however, omitted one of the largest studies of secondhand smoke and heart attacks conducted to date. A 2008 study covering the entire country of New Zealand—a population smaller than England’s, but bigger than the American towns previously studied—found no significant effects on heart attacks or unstable angina in the year following implementation of a smoking ban; hospitalizations for the former had actually increased.


Contradictory research continued to come in. A clever study led by researchers at RAND Corp. in 2010 tested the possibility that the large reductions identified in small communities were due to chance. They assembled a massive data set that allowed them to essentially replicate studies like those in Helena, Pueblo, and Bowling Green, but on an unprecedented scale. Whereas those studies had compared just one small community to another, the RAND paper compared all possible pairings of communities affected by smoking bans to all possible controls, for a total of more than 15,000 pairings. They stratified results by age in case there were differential effects on the young, working age adults, or the elderly. And in an improvement on most other studies, they also controlled for existing trends in the rate of heart attacks.

The study found no statistically significant decrease in heart attacks among any age group. The data also suggested that fluctuations in heart attack rates were common, indicating that comparisons of small communities would frequently turn up dramatic reductions due purely to chance; large increases in heart attacks happened about as often. This explained the headline-grabbing dramatic results in places like Helena or Monroe County that eluded replication in larger jurisdictions. The conclusion of the study was blunt: “We find no evidence that legislated U.S. smoking bans were associated with short-term reductions in hospital admissions for acute myocardial infarction or other diseases in the elderly, children or working age adults.”

A 2012 study of six American states that had instituted smoking bans came to a similar conclusion. So did a 2014 study, which is notable for being co-authored by some of the same researchers who had previously published papers suggesting that the Colorado towns of Pueblo and Greeley had experienced reduced rates of heart attacks after implementing smoking bans. When Colorado enacted a statewide ban, the authors had an opportunity to see if their earlier results could be duplicated across the larger population of nearly 5 million people. No effect appeared. As an additional test, they re-examined the data excluding 11 jurisdictions that had already implemented comprehensive smoking bans: The statewide ban still showed no effect.

In the paper’s admirably honest commentary, the authors reflected on the reasons that earlier studies, including their own, had overstated the impact of smoking bans. The first is that small sample sizes allowed random variances in data to be mistaken for real effects. The second is that most previous studies failed to account for existing downward trends in the rate of heart attacks. And the third is publication bias: Since no one believes that smoking bans increase heart attacks, few would bother submitting or publishing studies that show a positive correlation or null effect. Thus the published record is likely unintentionally biased toward showing a larger effect than truly exists.


The medical reasoning behind why secondhand smoke would cause heart attacks posited that short-term exposure reduces blood flow, increases platelet aggregation, and causes endothelial dysfunction—all of which could increase the risk of heart attack. But looking at the most well-conducted research suggests that the actual impact is not as significant as originally feared. And where heart attacks did decline, it may not have even been because of secondhand smoke reductions: A new paper published in August 2016 considered other factors that may have been overlooked. Drawing on data from 28 states from 2001–2008, lead author Vivian Ho, an economist at Rice University, compared rates of hospitalization for heart attacks in areas with and without smoking bans.

Following the methodology of previous studies, she and her coauthors found a statistically significant reduction in hospitalizations for heart attacks and congestive heart failure following implementation of a smoking ban (though only among people older than 65). But when they went a step further, adjusting the analysis with county-by-county health data addressing variables such as access to hospitals and increases in cigarette taxes, the effect of the smoking bans disappeared. Ho and her co-authors suggest that modest improvements in cardiac health that were previously credited to smoking bans may actually be caused by differentials in access to medical care and people smoking less when cigarette taxes increase (smoking cigarettes does have a proven negative effect on cardiac health).

In the recent literature, the most notable study finding a correlation between smoking bans and rates of heart attack is a 2012 paper in Health Affairs. It is probably the strongest of the studies documenting a reduction, though it applies only to senior populations and did not make the adjustment for tobacco taxes noted above. Even those sympathetic to the claim that bans reduce heart attacks have had to concede that the larger the population studied, the smaller the alleged effect. A 2013 meta-analysis noted that “studies with smaller population in the United States usually reported larger reductions … while larger studies reported relatively modest reductions.” Or, to state things more accurately, the largest studies often report no reduction at all.

In a post on the blog he authors from the University of California San Francisco, Stanton Glantz disputes the finding in Vivian Ho’s recent paper, suggesting use of a different statistical model to make the calculation. But the reductions promised by Glantz and other smoking ban advocates were so massive that they ought to be evident under any plausible model. That in the time since the alleged Helena Miracle they have gone from claiming a 60 percent reduction in heart attacks to debating whether effects are illusory or just too small to be reliably detected says a lot about how far expectations have been lowered. As they say in the old cigarette ads, “You’ve come a long way, baby!”


* * *

Anti-smoking advocates often argue as if the existence of any effect on health, no matter how small, justifies any smoking ban no matter how extensive. If the size and certainty of alleged health risks are irrelevant, then of course the case for smoking bans is easy to make: Most nonsmokers find smoking inconvenient and have little regard for the smoking minority’s preferences. Setting such a low bar provides a convenient excuse for expanding the boundaries of the smoke-free world ever outward. The relevant question, however, should not be merely whether there are any dangers from secondhand smoke but also how big they are. If the alarmist claims made by anti-smoking groups were true, we’d be justified in avoiding secondhand smoke as if it were the plague. But we know now that those claims were exaggerated, so it’s worth asking whether contemporary bans have gone too far.

Rates of heart attack are not the only possible negative of secondhand smoke exposure, although most estimates consider improvements in coronary health to be the number one benefit of smoking bans. There are also potential impacts on respiratory health, and of course lung cancer, although the impact secondhand smoke exposure has on one’s risk of lung cancer is likely far lower than many would expect. The 2006 Surgeon General’s Report, the most definitive treatment of the topic, estimates the lung cancer risk of chronically exposed nonsmokers at just 1.12–1.43 times that of people without frequent exposure. (By comparison, smokers themselves take on a risk more than 12 times higher than that of nonsmokers.)

Now that’s not nothing, but other recent research may be even more surprising. “No clear link between passive smoking and lung cancer,” read a 2013 headline in the Journal of the National Cancer Institute, hardly a pro-tobacco publication. That was a report on a cohort study tracking 76,000 women that failed to detect a link between the disease and secondhand smoke. The finding comports with existing literature suggesting that the effect is borderline and concentrated on long-term, high levels of exposure.


Despite the mounting evidence that transient exposure to secondhand smoke is more an annoyance than a mortal threat, smoking bans have become widespread and politically entrenched. According to the latest update from Americans for Nonsmokers Rights, which publishes quarterly reports on anti-smoking laws, more than 80 percent of the American population now lives under smoking bans covering workplaces, restaurants, or bars. An additional 3,400 jurisdictions ban smoking in outdoor areas such as parks, beaches, and stadiums. More than 400 cities and counties restrict smoking while dining outdoors. More than 1,700 college campuses are completely smoke-free. Nearly 600 jurisdictions include e-cigarettes under their smoke-free laws. Some jurisdictions make limited allowance for places such as cigar bars and hookah lounges, while in others these are completely forbidden or limited to businesses grandfathered in before ordinances took effect.

The cost of these policies falls almost entirely on people who smoke, an increasingly put-upon minority of the population. Rarely are their preferences consulted. An exception is a perceptive paper published in the journal Sociology of Health and Illness evocatively titled “Every Space is Claimed.” The paper stands out for the empathy with which its authors approach smokers affected by smoking bans. They note that most tobacco research ignores the perspective of actual smokers and that the lack of interest in their experiences “speaks to the ways in which tobacco research is increasingly expected to further the goals of tobacco control.”

The paper draws on interviews with a diverse selection of smokers in Vancouver, British Columbia. One consistent theme that emerges is that smokers increasingly find their habit viewed as on a par with use of illicit drugs. Smokers also report that judgments against them cut deeper than their outward behavior, extending to their identity as human beings. “Even if you can’t articulate it you probably intuitively feel it in the same way that if you’re black or a woman and you’re being discriminated against,” one subject told his interviewers. “Like even if you can’t articulate it or you certainly can’t prove it or you’d be at the Human Rights Commission, but you kind of know it’s happening.”

To some anti-smoking advocates, that stigmatization is useful if it encourages people to quit. The authors of this paper are skeptical, noting that such stigmatization could instead lead to feelings of powerlessness. They conclude:

Participants in our study highlighted the growing restrictions on their ability to smoke and several explicitly recognised that legislative measures went well beyond the goal of protecting non-smokers from exposure to the effects of secondhand smoke and that the right to smoke altogether was being steadily eroded. Thus, while many participants expressed the view that smoking restrictions themselves were not intrinsically problematic, they emphasised that tobacco denormalisation had created an environment in which every public space was ‘claimed’ by non-smokers, making it impossible to smoke in public at all without receiving judgement. Importantly, while study participants expressed considerable felt stigma in relation to their smoking, they also recounted numerous instances of overt censure and discrimination.
Smokers’ experiences in Vancouver raise important questions about the value and ethics of denormalisation strategies. Should a liberal state ever be complicit in shaming its citizens?

Early arguments for smoking bans at least paid lip service to the idea that restrictions were necessary to protect unwilling bystanders’ health. But as bans have grown ever more intrusive even as the case for expanding them has withered, that justification has been revealed as a polite fiction by which nonsmokers shunted smokers to the fringes of society. It was never just about saving lives.

* * *

When the Helena study and its heirs were originally published, a few scientists noted that the results were wildly implausible and the methodologies deeply flawed. So did a handful of journalists, including Jacob Sullum writing for Reason (to which I am also a contributor) and Christopher Snowdon in England. Yet their criticism was generally ignored. Studies reporting miraculous declines in heart attacks made global headlines; when better studies came along contradicting those results, they barely registered a blip in the media. As Jonathan Swift said in an apt aphorism, “Falsehood flies, and truth comes limping after it.” Too late to help smokers banished from public life.

There were good reasons from the beginning to doubt that smoking bans could really deliver the promised results, but anti-smoking advocacy groups eagerly embraced alarmism to shape public perception. Today’s tobacco control movement is guided by ideology as much as it is by science, prone to hyping politically convenient studies regardless of their merit and ostracizing detractors.

This has important implications for journalism. As health journalists take on topics such as outdoor smoking bans, discrimination against smokers in employment or adoption, and the ever-evolving regulation of e-cigarettes, they should consider that however well-intentioned the aims of the tobacco control movement are, its willingness to sacrifice the means of good science to the end of restricting behavior calls for skeptical scrutiny.

As for smoking bans, few people are eager to re-litigate the battles of the previous decade. We are unlikely to return to the days of smoking on airplanes, in hospital waiting rooms, or in the aisles of supermarkets. We can acknowledge that the shift in social norms against the presumption that one may light up just about anywhere is on the whole a good thing, even if the means of bringing it about has been more coercive than some of us would prefer. But smoking bans are not an all-or-nothing affair. Policy takes place at the margins and the margins have extended far beyond the goal of protecting people from chronic exposure to high concentrations of secondhand smoke.

To cite just a few recent examples: In Washington, the city council has passed legislation restricting e-cigarettes, which emit vapor, and chewing tobacco, which doesn’t emit anything. In England, health advocates argue for restricting outdoor smoking because children should not so much as see someone lighting up. “Smokers themselves are also contaminated… smokers actually emit toxins,” one Harvard researcher mused to Scientific American in 2009, warning against exposure to invisible “thirdhand smoke” wafting off of smokers’ clothing and hair. Writers at Vox have gone so far as to advocate banning smoking even in private homes. The list could go on endlessly. Is it any wonder smokers feel stigmatized?

While science can inform, though not fully determine, the boundaries of where people are allowed to smoke, the debunking of the previous decade’s heart miracles should provide some grounds for humility. It may be neither feasible nor desirable to set back the clock and permit smoking everywhere, but laws in a liberal society can accommodate the rights and preferences of smokers and business owners far better than they do now.

So relax those outdoor bans. Let people vape. Allow there to be at least some venues in which consenting adults can gather to light up indoors. Respect for self-ownership demands it. After years of closing doors on smokers, it is time to open a few back up.

Disclosure: I worked at the Cato Institute almost a decade ago when it received some tobacco company donations. Also, as part of my career as a bartender, I made cocktails at a 2016 event sponsored by Diamond Crown; I wasn’t paid, but I was given a humidor and cigars as thanks.