Young people in Britain who use e-cigarettes (vape) are nearly four times more likely to start smoking cigarettes than their non-vaping peers, our latest study has found.
When e-cigarettes first entered the market a decade ago, they were considered to be as dangerous as cigarettes. But views have changed since then, and e-cigarettes are now widely believed to be a far safer option than smoking.
In 2015, Public Health England published a detailed review of the evidence around the safety of e-cigarettes and said, at best guess, they were 95% less toxic than conventional cigarettes.
But concerns remain because e-cigarettes usually contain the addictive ingredient of cigarettes: nicotine. While recognising the harm reduction impact of e-cigarettes, it is important to ask what role, if any, e-cigarettes play in encouraging non-smoking adolescents to try their first cigarette.
For a number of years, my colleagues and I have been tracking data from several thousand schoolchildren in England to assess the impact of various anti-smoking interventions. We set about trying to identify any associations between e-cigarette use and starting to smoke within a year.
We started by looking at those children, aged 14 and 15, who had not smoked. We asked them to fill out a questionnaire at the start of the survey, and then a year later. Of those who had tried an e-cigarette, just under 34% reported having a cigarette within a year compared with just under 9% who had not. In other words, there was an almost fourfold increased chance of starting to smoke among those young people who had used an e-cigarette. This is worrying because it is known that once someone starts to smoke, the chances that they will continue to smoke are high.
Would they have started smoking anyway?
Last year, researchers in the US published their findings on smoking among a group of teenagers (average age 17) in southern California. As with our study in England, they were surveyed at the start of the study and again 16 months later. The US researchers found that e-cigarette users had six times risk of starting to smoke compared with their peers, who had not used an e-cigarette.
Perhaps these young people were going to smoke anyway, whether e-cigarettes existed or not? It is a question that gets to the heart of the risks that might be associated with e-cigarette use among the young.
We looked at those adolescents whose friends did or did not smoke, because having friends who smoke is a known risk factor for starting smoking. The data – which surprised us – suggested that e-cigarette use was a greater risk factor in starting to smoke in those without friends who smoked, compared with those with friends who smoked.
Using e-cigarettes meant they were five-and-a-half times more likely to start smoking in the group with no friends who smoked but only one-and-a-half times more likely to start smoking in the group with most or all friends who smoked.
Again, the picture in the US seems very similar to what we found in the UK. Researchers there found associations between e-cigarette use and starting to smoke among those young people who during the initial survey stated they had no intention of starting to smoke.
So what do the associations suggest is going on? The unanswered question is whether the young people who go on to smoke are simply experimenting or whether they are becoming regular smokers.
The long-term trend in the UK is for e-cigarette use to go up while smoking declines. Future research is now needed to disentangle these apparently contrary findings, and whether there is any link between the intensity of e-cigarette use among adolescents and cigarette use.