Vaping: safer smoking, or a gateway to teen addiction?

14 February 2017

Interview with

Lion Shahab, University College London; Richard Miech, University of Michigan

The number of people using electronic or e-cigarettes has doubled in the last 5 years and now stands at about 15% of adults. Because e-cigarettes work by evaporating a nicotine-rich liquid to produce the vapour, rather than by burning tobacco, some people regard them as a much safer alternative to conventional smoking. But are they safer, and might the perception of safety encourage non-smokers to embrace the habit? This week two papers have been published examining these possibilities, one by Richard Miech from the University Michigan, and the other by Lion Shahab from University College London. Chris Smith spoke to Lion first...

Lion - In our study, we are interested to have a look at the relative risk of using e-cigarettes compared with standard conventional cigarettes. We looked at long term users of these products so these are people who have been using e-cigarettes for at least one and a half years and we compared their exposure to various cancer causing chemicals with people who smoke cigarettes. We also had another control groups which were people who were using nicotine replacement therapy for those who had stopped smoking. Nicotine replacement therapy are things such as patches and nicotine gum. Compared with cigarette smokers, those people who completely switched over the e-cigarettes dramatically reduced their exposure to these cancer causing chemicals to between 50 to 97 percent reduction of the levels of cigarette smokers, and the levels were very similar to people who use conventional forms of nicotine replacement therapy.

Chris - Therefore, on the basis of what you have seen from your study, what conclusion do you draw?

Lion - I think the main conclusion I draw from this study is that some of the literature out there on the risks and dangers of e-cigarettes probably overstates the harm that they can cause. Certainly, compared with the use of conventional cigarettes as those people who did switch over to using e-cigarettes dramatically reduced their exposure to cancer causing chemicals meaning that it’s likely that it reduces their risk of subsequent diseases, including cancer, greatly.

Chris - Well that sounds very encouraging but, on the other hand, Richard Miech, you’re coming at this from a different direction. What’s your perspective?

Richard - We looked at it slightly different research question. So, as you pointed out in the introduction, there’s a lot of debate right now about whether e-cigarettes and their use among teens is leading them to become smokers or whether, alternatively, kids are vaping instead of smoking. What we did is we interviewed a group of 17 year olds and then we followed them up a year later. So among kids who had never smoked at the baseline, those who were vaping as compared to those who weren’t vaping are about four times more likely to have smoked a cigarette in the following year. And among kids who had smoked in the past but weren't current smokers at the baseline, we’ve found that those who were vaping were also more likely to come back to smoking and there were about twice as likely to have smoked a cigarette in the past year.

Chris - I suppose you can’t really tell though whether those individuals who vaped and then smoked, or carried on vaping were just going to become smokers anyway?

Richard - We actually looked at that. We had a question at the baseline: how dangerous do you think smoking is? And we had a sizeable group who said that smoking was the most dangerous thing you could do. So we just looked at those kids who wouldn't seem to be likely to go onto smoking and, even among them, we found that those who vaped were more likely to smoke. We also found that among the kids who were vaping, those who thought that smoking cigarettes was highly dangerous at baseline were more likely to move away from that view. They’re more likely to reduce their perceived risk of smoking as they vaped.

Chris - What reasons did they give for taking up this habit in the first place?

Richard - The predominant reason for their vaping among those who vaped was they wanted to experiment to see what it was like and also that they liked the flavours. Because vaping comes in a wide variety of vapours, some which really appeal to teens like chocolate, or cherry, or bubblegum.

Chris - Lion, it seems that there’s a bit of tension here because, on the one hand, we have this tool that you're saying appears to really help on the basis of your data. On the other hand, we’ve got Richard here saying well actually, it’s pretty attractive to teens.

Lion - Well, yes. I have to say I’m not entirely convinced that it’s actually possible to prove a gateway hypothesis. We’ve looked at this in the UK, which has quite a relaxed attitude towards e-cigarettes, we have seen an increase in the use of e-cigarettes among youth as well. Although the use of e-cigarettes among non-smoking kids is very, very low indeed. And we can compare this with a country where e-cigarettes are not really widely available, such as New Zealand, and what you see when you compare the trajectory is that the decline is very comparable. So the proof is in the pudding, in a sense, that indeed, if there is a gateway effect from using e-cigarettes to using cigarettes, then you would expect, in the long term, that the decrease in cigarette consumption, in cigarette prevalence in youth should stop. But this is not the case, and neither is it the case in the US where I think the latest data shows that levels in cigarette consumption is the lowest since recording has started.

Chris - Richard…

Richard - Yes, that is true in fact that there’s a historical low in the level of cigarette smoking among teens in the US. There are studies, one that actually was the first to report this. But actually, that’s a long decline that started more than two decades ago and I’d like to point out that the decline started well before e-cigarettes even existed.

Chris - Do you think then, Richard, that these are an evil thing and we shouldn’t use them? On the basis of this, you’re only seeing a negative, it’s encouraging more people who have previously been extremely diligent and giving up, or not taking up smoking in the first place to embrace this habit?

Richard - My main message would be that many teenagers believe that vaping is completely innocuous and it has no negative consequences at all. But I think if word got out that kids who vape are significantly more likely to start smoking, I think many teens would think twice before vaping and, maybe stay clear of vaping devices.

Chris - Do you not think that’s a risk, Lion, that it’s not just kids, it could be some of the adults we are seeing who are not smokers but might be tempted to toy with the idea of vaping because it does taste nice perhaps, or it’s not regarded as so bad for you?

Lion - Yes, it is a theoretical risk but the data in the UK just do not bear this out. There’s no evidence that I can see currently that non-smokers are taking up vaping.

Chris - So in your view it’s a good thing, it’s going to help people to minimise the harms that cigarettes do?

Lion - Yeah. Just to reiterate, the vast majority of people who use e-cigarettes are either current smokers or ex smokers. And it is a sad truth that only 50 percent of smokers ever manage to stop smoking their lifetime which means that, in the UK for instance, still nearly 100,000 people die because of smoking and e-cigarettes are, potentially, a way of  helping some people who have failed to stop smoking with other conventional forms of support to stop smoking, and they appear to be significantly safer than continued smoking.

Chris - Richard, last word from you.

Richard - Yeah, I’ll point out that among 13 and 15 year olds, vaping is more than twice as prevalent than cigarette smoking. Amongst teens, vaping has really taken off to the extent that it is a bridge to smoking; I think that’s a message that teens need to hear.

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