• What do studies say about electronic cigarettes?

    Editor’s Note: Just so you’re aware, comments conveying anecdotal stories or arguing that anecdotes matter here will not be approved.

    I got into a twitter discussion yesterday on electronic cigarettes. Evidently, Jenny McCarthy is now pitching them. Some of us were not amused. I don’t really trust Ms. McCarthy on almost any health-related issues. But people have asked me if there is any actual harm reduction with their use. That’s a question worth asking.

    I went to the medical literature. Unfortunately, there’s not much there. But here’s what I could find (with respect to clinical trials on humans):

    • A 2010 review found that lab studies show that carcinogen levels in e-cigs are much lower than traditional cigarettes. It also commented on some of the studies below.
    • A 2010 single blind randomized repeated measures cross-over trial of 40 smokers gave people (1) tobocco e-cigs, (2) placebo e-cigs, (3) nicotine inhalers, or (4) cigarettes on each of four days, three days apart, after a night of abstinence. They measured desire to smoke. The tobacco e-cigs reduced desire to smoke over the placebo, and were more well tolerated than the inhalers.
    • A 2011 prospective pilot study looked at 40 smokers who were unwilling to quit. They instead tried to get them to reduce consumption through the use of e-cigs. They found that more than half the participants reduced smoking by at least 50% at 34 weeks without significant side effects.
    • A 2012 study found that active or passive exposure to tobacco smoke increased white blood cell coulds, lymphocyte counts, and granulocyte counts for at least an hour. E-cigs did not, nor did a control situation. It’s not clear how this translates clinically, but it’s a laboratory finding in favor of e-cigs.
    • A 2012 study randomized 86 smokers to a nicotine e-cig, a placebo e-cig, or just holding the e-cig. They measured desire to smoke and withdrawal symptoms. Women had positive results with active use of either e-cig, but men did better with nicotine. There were no health outcomes.
    • An unblinded prospective 2013 study of e-cig use in 12 schizophrenic smokers for a year found that it decreased consumption without any significant side effects. Of course, this is not an RCT, and not definitive.
    • A 2013 study of 15 smokers and 15 non-smokers were exposed to nothing, tobacco smoking, and e-cig smoking (active for smokers and passive for non-smokers). Nicotine exposure, measured by cotinine levels, was similar in the two cigarette types. But lung function was impaired by traditional cigarettes, and not with e-cigs.
    • A 2013 randomized controlled trial gave 300 smokers full strength e-cigs, partial strength e-cigs, or placebo e-cigs for 12 weeks. At one year, they found that overall use and exhaled carbon monoxide declined in all three groups. But there were no differences between groups, and by a year, only 9% had quit and 10% more had a reduction. So it’s unclear if the tobacco was necessary, and how robust the results were. Here’s an article on that study.

    That’s about it. If I missed anything significant, let me know.

    My thoughts? If you’re looking for a means to help you quit, there’s a tiny bit of evidence that they might help, but that evidence favors placebo e-cigs about as much as tobacco e-cigs. There’s a bit of evidence that e-cigs are better than traditional cigarettes for lung function, although those studies are really small and transient. There’s also some tiny amount of evidence that e-cig smoke changes laboratory values less than the smoke of traditional cigarettes, although the clinical meaning of this is unclear. So it’s hard to get too excited about e-cigs.

    But tobacco smoking is terrible, full stop. If something is less terrible, I don’t see how we totally rule that out without some thought. As pediatricians, when parents or family members can’t quit smoking, we ask them not┬áto┬ásmoke around children. Why? Because we don’t want the perfect to be the enemy of the good. We’d rather have some improvement than none.

    I don’t see enough evidence to be totally psyched about e-cigs. I wish they were better regulated. But I see enough promise to warrant some larger RCTs.

    @aaronecarroll

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