There is concern about e-cigarettes that they may cause addiction rather than cure it - California advocates are spending millions claiming Big Tobacco is marketing them to children - but like nicotine patches and chewing gum, teens may try them but unless they already smoke, they don't embrace them.

Writing in 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 sizable 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 recognized 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, but as a nicotine alternative to smoking, which has been a charge laid against smoking cessation gum and patches as well.