If Smokers Vape, Does That Prove Vaping Causes Smoking?


FIN e-cigarette ad

A study reported today in The Journal of the American Medical Association claims to present evidence that "e-cigarette use is aggravating rather than ameliorating the tobacco epidemic among youths." The authors, Lauren Dutra and Stanton Glantz of the Center for Tobacco Research and Education at the University of California in San Francisco, claim their results "suggest that e-cigarettes are not discouraging use of conventional cigarettes." They add that their findings "call into question claims that e-cigarettes are effective as smoking cessation aids." But as Boston University public health professor Michael Siegel observes on his tobacco policy blog, Dutra and Glantz "make one of the most cardinal errors in all of epidemiology" by ignoring "the principle that 'correlation does not equal causation.'"

Dutra and Glantz's study is based on data from the National Youth Tobacco Survey, the same study the U.S. Centers for Disease Control and Prevention (CDC) cited last September in sounding the alarm about the recent increase in e-cigarette use among teenagers. The CDC neglected to mention that smoking fell as vaping rose, a trend that might have cast doubt on its warnings that e-cigarettes are a gateway to the real thing. Dutra and Glantz try to make that fear plausible by looking at associations between e-cigarette use and smoking in survey results from 2011 and 2012. They find that "use of e-cigarettes was associated with higher odds of ever or current cigarette smoking, higher odds of established smoking, higher odds of planning to quit smoking among current smokers, and, among experimenters, lower odds of abstinence from conventional cigarettes." In other words, e-cigarette users were more likely to be smokers, tended to smoke more, and were less likely to have stopped smoking, even though they were more likely to say they would like to quit.

The problem, of course, is that a cross-sectional study like this one does not tell us which came first: vaping or smoking. Dutra and Glantz concede that "the cross-sectional nature of our study does not allow us to identify whether most youths are initiating smoking with conventional cigarettes and then moving on to (usually dual use of) e-cigarettes or vice versa." If teenagers try e-cigarettes as a substitute for the conventional kind, it is hardly surprising that vapers are more likely to be smokers. In both 2011 and 2012, half of the current (past-month) e-cigarette users were also current smokers, which is consistent with the hypothesis that vaping is a strategy for cutting down or quitting. It is plausible that smokers with a strong attachment to cigarettes would be especially likely to try that strategy, which could explain why e-cigarette users smoked more and were less likely to have abstained from tobacco.

David Abrams, executive director of the Legacy Foundation's Schroeder Institute for Tobacco Research and Policy Studies, made that point in an interview with The New York Times. "I am quite certain that a survey would find that people who have used nicotine gum are much more likely to be smokers and to have trouble quitting," he said, "but that does not mean that gum is a gateway to smoking or makes it harder to quit." Thomas Glynn of the American Cancer Society likewise cautioned that "the data in this study do not allow many of the broad conclusions that it draws."

Even if we knew that some people start with vaping and move on to smoking, that would not necessarily mean that e-cigarettes made them more likely to smoke. We still would not know what would have happened in the absence of e-cigarettes. Would those same people have started smoking anyway, or did the experience of vaping somehow prime them to like a habit that otherwise would not have attracted them? The same sort of question comes up in discussions of marijuana's purported role as a "gateway" to other drugs. In both cases, symbolism and emotion seem to carry more weight than evidence and logic.

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  1. Mr. Sullum; You appear to expect members of the Anti-Smoking Crusade to make sense, use logic, and publish actual research. The fact is they went several bubbles off of true sometime in the 1980’s, and are now so far around the bend they can’t see it from where they are. Their pronouncements on smoking, vaping, and all other matters even distantly related to tobacco are irrational, hysterical, and in many cases outright deranged. Which is a pity, because smoking is a vice and is almost certainly bad for one’s health, and they are going to end up discrediting that with their antics.

    Just as the Anti-Saloon League discredited the very real ills that drinking causes for DECADES.

  2. I heard that short haired lesbians are better if you have allergies.

    1. Yes, it totally IS a weird hobby to repost things that nobody else on reason would have commented on throughout the day.

      1. Reason covered the “othering” of model train hobbyists?

        I must have missed that.

        1. That too. That Patrick Swayze newsletter thing was years ago.

        2. Model train hobbies are only not-weird if you’re either eight years old or are Mr. Rogers. And it’s still kinda weird even for him.

  3. I quite smoking real cigarettes with e-cigs and know multiple people that have done the same.

    Anecdotal, but I also don’t know a single person who got hooked on real cigarettes through e-cigs.

    Then there is the whole issue that science can’t even prove that nicotine is addictive on its own. It is used as a therapeutic treatment for Parkinson’s, and it also helps get rid of the tic due to certain drugs, and such use has not been shown to cause addiction at all. There is a theory that it is nicotine in combination with other chemicals in cigarettes are what makes them so addictive.

    1. I quite my job once.

      1. I saw it, but I didn’t give a fuck.

        *Puffs on e-cig with Kenny Loggins playing in the background.

  4. AND I, too, smoked with cigarettes.

    1. I may have laughed at that.

  5. Worst. Links after Dark. Ever.

  6. In other words, e-cigarette users were more likely to be smokers, tended to smoke more, and were less likely to have stopped smoking, even though they were more likely to say they would like to quit.

    Reminds me of a study that concluded dieting leads to being obese. Never mind people struggling with their weight are endlessly advised to use diet and exercise to control it.

  7. You all should mix vaping, heroin and glue.
    The kids call it VAGing. It’s all the rage in suburban high schools.
    [next big morale panic – where’s Time magazine when you need it]

  8. I’m shocked that Glantz found evidence of smoking. Shocked, I say.

    Stanton Glantz would be an excellent name for a new species of parasitic worms.

  9. When a smoker uses the patch, they often rip it off and smoke. They still crave a smoke, even with the patch.
    The same thing with the gum. Smokers go back and forth repeatedly, with the patch &smojes;, cold turkey & smokes, gum and smokes, … it’s quite a remarkable marketing plan for bothe companies.
    The problem with eCigs, is smokers discover they prefer the eCig over the smokes. When they crave a smoke, (super stressful situations) they can’t stand more than a few puffs. Smokes taste, smell, feel horrible after an eCig. The eCig user does not fall back onto smoking, they just buy a new mod or atty or flavor or increase their nicotine mg a bit.
    This is bad news for both big tobacco and big Pharma.
    The only eCig users still buying smokes, are those who have not yet found their flavor, nicotine strength, power volt, clearomizer, set up gear that’s right for them. The tobacco companies are selling wannabes eCigs, as are big Pharma. Both lack serious merit to the wannabe ex smoker.

    Excellent article!
    Oh, BTW, it would be great to see Glantz’s big Pharma disclosure. 🙂

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