Vaping probably isn’t a gateway to smoking

Young people who try vaping are more likely to later start smoking – but a new analysis of trends in nicotine use in England suggests that the so-called gateway theory of vaping isn’t the explanation.

The real reason for the link could be that teens who start vaping are the same ones who are likely to try smoking, regardless of whether they ever have an e-cigarette.

Vaping is much less harmful for people’s health than smoking, causing about 95 per cent less damage, according to an estimate by Public Health England. UK smokers are advised to switch to e-cigarettes to help them quit, but health bodies in some other countries, such as the US and Australia, take a dimmer view of vaping.

A key argument against making it easy to buy e-cigarettes is that young people who start vaping will get addicted to nicotine, and so will end up switching to traditional cigarettes for the faster nicotine hit. Several studies have shown that teenagers who try vaping are more likely to end up smoking.

But these studies merely observe smoking rates in individuals who have vaped and those who haven’t. Such observational research can’t show that the first factor causes the second, only that the two things correlate.

“It could be the case that there’s a common vulnerability that explains this association. That could be, for instance, because there’s some genetic predisposition to try different things or there’s environmental pressures to try things,” says Lion Shahab at University College London.

Instead of looking at whether individuals were likely to start smoking, Shahab’s team looked at how the rate of smoking among 16 to 24-year-olds in England has changed over the past 11 years, as vaping caught on.

If there really was a gateway effect, then, as vaping rates changed, those for smoking also should have in a related pattern. In fact, while vaping in this age group jumped to about 5 per cent in 2013 and has hovered around there since, rates of regular smoking have fallen from about 30 per cent in 2013 to 25 per cent in 2018, the last year of the study.

The analysis can’t rule out, however, that vaping has a very small gateway effect, says Shahab.

The findings may not convince all critics of e-cigarettes. “I don’t see this study as refuting the extensive evidence that already exists for a gateway effect,” says Martin McKee at the London School of Hygiene & Tropical Medicine. “Following up individuals is the most appropriate way to answer this question.”