By Dr. Geoffrey Modest
This is the second of the smoking-related emails, a provocative perspective appeared in the journal Addiction arguing for easier access to vaporized nicotine products (VNPs) as a means of harm reduction for smoking (see doi:10.1111/add.13394 ). Their lines of argument (which does include some mathematical modeling to assess the potential long-term outcomes of these pretty new devices):
- A multi-criteria decision analysis estimated that exclusive VNP use would be associated with about 5% of smoking’s mortality risk (and is similar to low-nitrosamine smokeless tobacco).
- Studies looking at cancer biomarkers suggest an even lower risk for cancer, 9-450 times lower than cigarette smoking
- So, the crux of the decision analysis of benefits of VNPsreally relies on whether VNPs do lead to cigarette smoking in those not having smoked before, whether their use is helpful in smoking cessation, and if their use as least leads to a reduction of the much more toxic cigarettes.
- Here are the fragments of evidence so far:
- Transitions of never smokers to cigarette smokers
- Studies have shown in general that adolescents/young adults are far more likely to have smoked cigarettes before using VNPs than to start with VNPs
- 2014 study in UK: past month use of VNPs was 0.2% among never smokers but 13.5% among current smokers; 8.2% of those who ever used a VNP subsequently smoked a cigarette vs 68.2% who smoked a cigarette before a VNP
- Several studies in the US and other countries (they cite 7) in youths/young adults find current smokers >15 times more likely to use VNPs than never smokers
- As a perspective quantifying the VNP use, though 13.4% of US high school kids reported using a VNP in the prior 30 days, only 15.5% had used them >=20 days (i.e., 2% of high school students)
- It is important to remember that those who try VNPs are at higher risk group to smoke than those who never did: more likely to engage in other high risk behaviors or have executive function deficits as found in smokers. (This suggests that the model may be one of common liabilities as opposed to VNPs being a “gateway” drug)
- Studies looking at transition from current smoking to VNPs
- 2 RCTs found that VNPs lead to smoking cessation, at a rate roughly equivalent to nicotine replacement therapy. Uncontrolled prospective studies have repeatedly found higher rates of smoking abstinence with VNPs; a 2015 UK public health review suggested using VNPs to help stop smoking when other methods fail.
- Of note, of those who are long-term ex-smokers, very few (0.8%) used VNPs (in contrast to recent quitter, where 13% have)
- And, there is concern that ex-smokers might relapse more often if they use VNPs. at this point long-term data suggest that about 6% of former smokers who used daily VNPs relapsed to cigarettes after 1 month and 6% at 1 year (similar to rates in non VNPs users)
- Studies have shown in general that adolescents/young adults are far more likely to have smoked cigarettes before using VNPs than to start with VNPs
- Decreases in amount of cigarette smoking if also using VNPs
- For patients who continue to smoke, a recent meta-analysis (see http://journals.plos.org/plosone/article/asset?id=10.1371%2Fjournal.pone.0122544.PDF ) found a decrease in the use of cigarettes in patients who continue to smoke cigarettes along with VNPs. In all of the studies they reviewed there was a decrease, and in 3 of them it was >50%.
- One background issue is that though these VNPshave some reasonable arguments to decrease the only-too-well-known harms of cigarettes, 55 of 123 countries surveyed have bans or laws that prohibit or restrict their sales, and 71 have laws to regulate the minimum purchase age, marketing or taxation (increased cost leading to decreased use). The FDA may well get a law passed to regulate them (though the really huge available carcinogens, tobacco and alcohol, are not regulated…). More restrictive VNP regulations may ironically result in more people smoking cigarettes and perhaps making it longer/harder for them to quit or cut down
- Concerns include the ever-ingenious companies increasing the likability of VNPs (newer, more seductive flavors), their targeted advertising (perhaps including comments about how safe they are compared to cigarettes). And with this, not only alluring young people into using VNPs but making it increasingly attractive to continue to do so for a really long time (so, this is different from nicotine replacement therapy, where most of my patients are disgusted by the taste of the gum/lozenges and do not like the patches so much, leading to pretty short-term usage). And, I think a real issue (somewhat downplayed in this article) is that encouraging VNPs does undercut the pretty successful public health message that “tobacco is bad for you” (witness the 50% drop in smoking in the past 50 years), in effect “normalizing” or at least de-demonizing tobacco use.
- Over the past couple of years I personally have encouraged many patients to try VNPs if they have not been successful with the usual meds to quit smoking, with the following results: a few have been able to quit entirely with VNPs, and more have been able to cut down significantly in their cigarette usage for a sustained period. And, though they use VNPs, they really don’t like them and they wean themselves off them within a few months. Also, interestingly, even the pretty heavy smokers using VNPs often just use a few puffs a day (and get much less nicotine than if they had smoked many full cigarettes), though they may have 1-2 cigarettes as well (and I continue to work with them on that)
- One positive issue is that the VNPs industry is pretty separate from the traditional tobacco companies. So, there is no profit in this industry promoting simultaneous cigarette smoking (those tobacco companies producing smokeless tobacco do encourage dual use with cigarettes)
- The mathematical assumptions in terms of long-term risk are likely to be reasonable, since VNPs have many fewer toxic chemicals added (see https://stg-blogs.bmj.com/bmjebmspotlight/2016/02/11/primary-care-corner-with-geoffrey-modest-md-e-cigarettes-and-smoking-cessation-are-they-useful/ , which analyzes a pretty deeply flawed article suggesting that VNPs do not help with smoking cessations, but I argue that VNPs are much less toxic than cigarettes, which have on the order of 3000 chemical additives. There are certainly additives in e-cigarettes, including propylene glycol, as an emulsifier; several flavors such as vanilla, menthol; several chemicals to improve the smell such as 2-acetylpyridine and others; and none of these are regulated by the FDA since e-cigarettes are not a “drug”, but are likely less toxic than the multitude of chemicals in cigarettes, including known carcinogens).
- So, the real issue is that about 40% of smokers make a quit attempt every year (i.e., a large % really do want to quit!!). Perhaps availability of VNPs could help some of these actually quit. Clearly it is in the public health interest to help them, but also to discourage never smokers from using VNPs, since their use is not benign. But my experience has really been consistent with the conclusions of this paper: VNPs seem to have a role in helping people quit or cut back on cigarettes, and I think should be on the list of harm reduction tools we have for cigarette smokers. But there should be a vigorous public health campaign to try to limit their use in kids who have not smoked (even perhaps limiting the array of fanciful flavors???)
- And, by coincidence, this am the NY Times had a report that the Royal College of Physicians in UK came out with an endorsement of using VNPs to help people quit smoking. See http://www.nytimes.com/2016/04/28/health/e-cigarettes-vaping-quitting-smoking-royal-college-of-physicians.html?smprod=nytcore-iphone&smid=nytcore-iphone-share&_r=0
- Transitions of never smokers to cigarette smokers
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