Young people who have tried an e-cigarette may be more likely to go on to smoke cigarettes compared with those who have not, a study led by University of Stirling researchers has suggested.
The research found a link between e-cigarette use in "never smokers" - those who have never tried smoking - and their subsequent first experimentation with cigarettes in the following year.
Dr Catherine Best, Research Fellow at the University of Stirling, said: "Our findings are broadly similar to those from eight other US studies; however, this is the first study to report from the UK.
"Uniquely, we also found that e-cigarette use had a greater impact on the odds of cigarette experimentation in young never smokers who had a firm intention not to smoke and/or whose friends didn't smoke. Traditionally, this is the group of young people least likely to take up smoking."
The research, conducted by the DISPLAY Team, a collaboration between the Universities of Stirling, St Andrews and Edinburgh, and ScotCen, focused on pupils at four Scottish secondary schools. Young people aged between 11 and 18 years old were surveyed in February/March 2015 and then again 12 months later. The initial 2015 survey found that among the 2,125 never smokers, 183 (8.6%) said that they had tried an e-cigarette and 1,942 had not.
The 2016 survey found that 74 (40.4%) of those who had tried an e-cigarette in the initial 2015 survey, went on to smoke a cigarette in the following 12 months - compared to only 249 (12.8%) of young people who had not tried an e-cigarette.
The effect remained statistically significant even after adjusting for other factors that influence smoking uptake including smoking susceptibility, having friends who smoke, whether family members smoke, age, sex, family affluence, ethnic group and school.
"Young never smokers are more likely to experiment with cigarettes if they have tried an e-cigarette," the study concluded.
The research paper, Relationship between trying an electronic cigarette and subsequent cigarette experimentation in Scottish adolescents: a cohort study, has been published in the British Medical Journal's Tobacco Control journal.
Sally Haw, Professor of Public and Population Health at Stirling, added: "The greater impact of e-cigarette use on young people thought to be at lower risk of starting smoking is of particular concern.
"Further research is required to discover how experimentation with e-cigarettes might influence attitudes to smoking in young people traditionally at lower risk of becoming smokers; and importantly how many of this group who do experiment with cigarettes go on to smoke regularly."
The study was funded by the National Institute for Health Research (NIHR) Public Health Research Programme.