E-cigarettes are popular with teens, including those who have never smoked, but few of those who try them become regular users, while most of those who do so are also smokers, finds research published in the online journal BMJ Open.
The researchers base their findings on the results of two nationally representative surveys of primary and secondary schoolchildren (CHETS Wales 2 and the Welsh Health Behaviour in School aged Children) from more than 150 schools in Wales carried out in 2013 and 2014.
In all, 1601 children aged 10-11 and 9055 11-16 year olds were quizzed about their use of e-cigarettes.
Use of e-cigarettes at least once was more common than having smoked a conventional cigarette among all age groups, except the oldest (15-16 year olds).
Some 5.8% of 10-11 year olds had tried e-cigarettes--far more than had tried tobacco (1.6%)--while a sizeable proportion (12.3%) of 11-16 year olds said they had used e-cigarettes, irrespective of gender, ethnic background, or family affluence.
This contrasts with the patterning seen in smoking, where all these factors come into play, suggesting that e-cigarettes may have wider appeal among all sectors of the teen population, say the researchers.
Similarly, the proportion of teens who had used e-cigarettes, but who had never smoked, rose from 5.3% among 10-11 year olds, to 8% among 15-16 year olds.
But only 1.5% (125) of those aged 11-16 said they used e-cigarettes regularly--defined as at least once a month. This included 0.3% of those who claimed they had never smoked conventional cigarettes.
These figures suggest that "e-cigarettes are unlikely to make a major direct contribution to adolescent nicotine addiction at present," write the researchers, who point out that the World Health Organization has recognised that there is little evidence on whether e-cigarettes may or may not act as a gateway to conventional smoking.
The odds of regular e-cigarette use were 100 times higher among current weekly smokers than among non-smokers, and 50 times higher among those who had smoked cannabis
The strong link between current smoking and e-cigarette use suggests that teens are not using these products to help them quit smoking, say the researchers.
They admit that a lack of consensus about what constitutes 'use' of an e-cigarette presents something of a challenge for research in this area, and suggest that further much longer term studies to include the generation of young people who have grown up with e-cigarettes are needed before firmer conclusions can be drawn.