Vaping teens are 5 times more likely to smoke tobacco, study finds
London - Teenagers who use e-cigarettes are nearly five times more likely to go on to try tobacco, research published on Tuesday says.
The study adds considerable evidence to the theory that "vaping" can be a gateway to smoking cigarettes.
Many health experts view e-cigarettes as a crucial tool in the fight against tobacco.
But others are concerned about unresolved safety concerns and their use by young people.
Schoolchildren are now more likely to have tried e-cigarettes than traditional cigarettes. More than one in three 15-year-olds have used the devices despite the fact it has been illegal to sell them to under-18s since October 2015.
The research, led by scientists at the University of Bristol, combined the results of 17 studies to investigate whether non-smokers who tried e-cigarettes were more likely to go on to tobacco.
The data, which included under-30s in the UK, US, the Netherlands, Germany, Canada and Mexico, found that using e-cigarettes increased the odds of subsequently smoking tobacco by a factor of 4.6, when compared with those who had never vaped.
The researchers said that after years of falling tobacco use widespread uptake of e-cigarettes had created a new generation of smokers. Among the under-18s the effect was even greater, they said.
If this age group was excluded from the data, the odds of taking up cigarettes was 3.17 times higher among vapers than non-vapers.
But if under-18s were included, the multiplier rose to 4.87.
The scientists, who are funded by the research arm of the NHS, the British Heart Foundation and Cancer Research UK, stressed that the findings were not definitive.
For example, they said the link could be explained by the tendency of rebellious teenagers who try e-cigarettes to be more likely to experiment with smoking.
They wrote in the journal Tobacco Control: "In adolescence, risk-taking is common and decision making for health-risk behaviours is influenced by peers, societal influences and parental monitoring."
But they said there was some evidence of a causal link, with all the data going "consistently in the same direction".
They added: "There are plausible causal pathways (e.g. nicotine addiction, similar hand-to-mouth actions for both behaviours).
"This suggests the results provide some support for a causal relationship between e-cigarette use and later smoking.
"This is in line with the theory that e-cigarettes act as a gateway to smoking.
"E-cigarettes have historically not delivered nicotine as effectively as cigarettes, so that e-cigarettes may not be adequate to satisfy users who become more heavily addicted to nicotine."Daily Mail