Ever since e-cigarettes became mainstream consumer products circa 2012, there has been a steady flow of anti-vaping scare stories. In the last 12 months, it has become a flood. The stories nearly always emerge from the US, usually from California, and focus to three claims: that e-cigarettes are as dangerous as smoking, that they don’t help people quit and that non-smokers who use them are more likely to start using tobacco cigarettes.
These claims have been debunked so many times that they can fairly be described as ‘zombie arguments’. Impervious to reason, they stagger on. Only yesterday, a high-quality study funded by Cancer Research UK showed that e-cigarettes are vastly safer than smoked tobacco — but this will not stop someone in the Bay Area claiming the very opposite next week.
For every piece of evidence showing that youth smoking rates have plummeted since e-cigarettes became popular, there is a blowhard in Philadelphia who insists that vaping is a gateway not only to smoking but to crack cocaine. For every report from the Royal College of Physicians showing that e-cigarettes help people quit smoking, there are a hundred activist-researchers in San Francisco claiming that vaping makes quitting more difficult.
People who are on Facebook tell me that the most widely shared myth about e-cigarettes is that they cause ‘popcorn lung’ (they almost certainly don’t). And while I have just told you that smoking rates have dropped sharply among American youth, the Centers for Disease Control and Prevention insists that there has been ‘no decline in overall youth tobacco use since 2011.’
No wonder people are confused. Rebutting these stories has almost become a full-time job for the Science Media Centre and some of the more responsible people in the world of ‘public health’, such as Michael Siegel, Clive Bates, Carl Phillips and Linda Bauld. And today we have been told, once again, that ‘E-cigarettes act as gateway to smoking for teens, scientists warn’. This time the authors are from Michigan and their study was published in the campaigning quasi-journal Tobacco Control.
The study has not received much attention from journalists except for the Telegraph‘s Sarah Knapton, who was one of the only science correspondents to ignore Cancer Research’s study of e-cigarettes yesterday but who did find time to tell us that rice causes cancer today. So what does this new study show?
The researchers used data from a survey of 347 high school kids which included a question about whether they had tried vaping in the past 30 days or had tried smoking in the past year. They compared the surveys of 2014 and 2015 and found that those who had tried vaping in 2014 were more likely to have tried smoking by 2015. Voila! They conclude that vaping is a ‘one-way bridge to smoking’.
This can most charitably be described as an over-interpretation of the findings. As Prof Peter Hajek explains, it doesn’t tell us any more than that teenagers who like to experiment like to experiment:
This paper just shows that teenagers who try cigarettes are more likely to also try e-cigarettes (and the other way round) compared to teenagers who do not do such things. This is trivial. People who read sci-fi novels are also more likely to watch sci-fi movies than people who do not like sci-fi. There is no reason why these activities should be performed in one order only.
The findings provide no justification for the grossly misleading ‘one-way bridge’ headline. There is actually hard evidence that this is false and that the effect of vaping experimentation on smoking is more likely to be the opposite, ie smoking reduction. The increased experimentation with vaping by adolescents has been accompanied by a continuing or even accelerating decrease in youth smoking.
Moreover, as Michael Siegel points out, the sample size was ludicrously small. The number of kids who had tried smoking in 2015 after trying vaping in 2014 was four. Yes, you read that correctly: the conclusion that vaping is a ‘one-way bridge to smoking’ is based on what four teenagers in Michigan said in a survey. And we cannot fairly describe any of them as ‘vapers’ or ‘smokers’ since all we know about them is that they had at least one puff of a cigarette or e-cigarette in the recent past.
This is what passes for science in ‘public health’. Combine the post hoc ergo propter hoc fallacy with inability to understand human behaviour and this is what you get. There is nothing new about this wilful ignorance. Last year, for example, it was solemnly reported that teenagers who own alcohol merchandise are more likely to drink alcohol. Fancy that!
Teenagers experiment, and there is no doubt that they have experimented with e-cigarettes in recent years. The real question is whether they are experimenting with vaping instead of smoking or if the former leads to the latter. The drip, drip, drip of junk science from the US would have us believe that vaping is a gateway to smoking, but the empirical data strongly suggest the opposite.
The graph below shows the smoking rate among US high school students between 2004 and 2014 (data from the National Youth Tobacco Survey). The line shows how the rate would have fallen if it had continued at the same pace as it was doing before 2011.
E-cigarette use rose sharply between 2012 and 2014, from 2.8 per cent to 13.4 per cent. If teenagers who vape were four times more likely to start smoking, as today’s study claims, we might expect to see a sharp rise in the smoking rate. Instead, we see a sharp fall.
But wait a minute, Snowdon, I hear you say. Didn’t the esteemed Centers for Disease Control tell us that there has been ‘no decline in overall youth tobacco use since 2011’? Indeed they did. They have defined e-cigarettes — which contain no tobacco — as tobacco products and define anyone who has used an e-cigarette in the past 30 days as a tobacco user.
As I say, it is no wonder people are confused.