One in five teenagers in a large survey has accessed e-cigarettes, and of these, 16% have never otherwise smoked, according to research published in the open access journal BMC Public Health. The highest numbers though were regular smokers - of whom over two thirds had accessed them.

E-cigarettes have been marketed as an alternative nicotine delivery system that is healthier than tobacco. There has been debate around the safety and efficacy of these devices, and whether they reduce the harm caused by smoking, or if they detract from healthy anti-smoking messages. A concern with clinicians, policymakers and parents alike is whether these devices act as a potential gateway to smoking, and discussion has ensued about the sale and marketing of these products to minors.

Researchers from Liverpool John Moores University surveyed 16,193 secondary school students in the north west of England aged from 14 to 17 years. They were asked about their alcohol and tobacco-related behaviors. This was part of a biennial survey conducted in partnership with Trading Standards whose remit includes enforcing regulations on the sale of age-restricted products in the UK.

In response to growing concerns about their use this was the first time students were asked about the purchase and use of e-cigarettes. One question posed to students was: "Have you ever bought or tried electronic cigarettes?" This was to identify all those who had accessed e-cigarettes. The researchers believe it is reasonable to assume those who had bought an e-cigarette would then also try it. If the students were smokers and drinkers they were also asked about their behavior during this type of activity.

One in five teenagers who responded to the survey said they had accessed e-cigarettes, this figure was higher in males -- increasing with age and if living in a deprived area. Of the teenagers that had accessed e-cigarettes, 15.8% had never smoked, 23.3% had tried smoking but didn't like it, 35.8% were regular smokers, 11.6% only smoked when drinking, and 13.6% were ex-smokers.

The team found that there was also an association between alcohol and e-cigarette access. Students who drank alcohol were significantly more likely to have accessed e-cigarettes than non-drinkers. Among those who had never smoked, it was found that those who regularly binge drank were four times more likely to access e-cigarettes than those who didn't drink.

In all of those that drank, regardless of smoking status, e-cigarette access was associated with binge drinking and involvement with violence after drinking. The researchers say that these findings suggest that teenagers who access e-cigarettes are those that are most susceptible to other forms of substance use and risk-taking behaviors.

One of the study's authors, Karen Hughes, says: "We found that e-cigarette access is strongly related to alcohol use in teenagers (14-17 year olds). Those who drink are more likely to have accessed e-cigarettes than non-drinkers regardless of whether they smoke normal cigarettes or not, and those who drink frequently, binge drink, drink to get drunk, drink strong alcohol products and show signs of unsupervised alcohol consumption are most likely to have accessed e-cigarettes. This suggests that e-cigarettes have rapidly become part of at-risk teenagers' substance using repertoires."

The researchers note that as these data are self-reported there could be under or over-reporting of the figures due to various factors such as poor recall or lack of knowledge. As there are little data on e-cigarette use in children or adults, these findings are not representative of all teenagers in England or the North West region.

Another author on the study, Mark Bellis says: "Our research suggests that we should be very concerned about teenagers accessing e-cigarettes. While debate on e-cigarettes has focused largely on whether or not they act as a gateway to tobacco cigarette use, e-cigarettes themselves contain a highly addictive drug that may have more serious and longer lasting impacts on children because their brains are still developing.

"Despite being practically unheard of just a decade ago, e-cigarettes are now widely available, heavily promoted yet weakly regulated and our study found that one in five 14-17 year old school children in the North West has accessed them. Such rapid penetration into teenage culture of what is essentially a new drug use option is without precedent. Of particular concern is our finding that teenage ex-smokers who accessed e-cigarettes were outnumbered by those who had never smoked but simply decided to experiment with what might be packaged to look like a safe attractive product but actually contains a highly addictive drug."

At the same time as the article publishes a guest blog from Wilson M. Compton, deputy director of the National Institute on Drug Abuse of the US National Institutes of Health will also go live on the BioMed Central website. In this guest blog he discusses the implications of these results.