Teenagers who try e-cigarettes are more likely to go on to try smoking, research suggests. School pupils who used an e-cigarette were three times more likely to smoke cigarettes a year later, compared with those who had never used the devices. It is illegal to sell e-cigs to under-18s in the UK – but their use among teenagers is growing. Use of e-cigarettes among under-18s rose from 5 percent in 2013 to 8 percent in 2014 – and some experts are concerned that they may act as a “gateway” to smoking tobacco. Experts at the University of Hawaii surveyed 2,300 schoolchildren, 12 months apart, asking them about their experience of either smoking tobacco or ‘vaping’ with electronic devices. Some 31 percent of the pupils had used e-cigarettes when they were first questioned, aged 14 and 15, in 2013. When the researchers surveyed the children a year later, this number had gone up to 38 percent, according to the study published in the journal Tobacco Control. Overall, 15 percent had smoked at least one cigarette in 2013, rising to 21 percent by the following year. But the experts found that those who had used e-cigarettes in 2013 were three times more likely to have smoked tobacco the following year. The researchers, however, found that only those who admitted to the highest frequency of vaping in the first year were likely to become regular smokers, suggesting that many of those who tried smoking in the study were merely experimenting. The authors wrote, “We followed a sample of high school students over a one-year interval and found that among initial non-smokers, those who used e-cigarettes were more likely to initiate cigarette smoking. This suggests that e-cigarette use in adolescence has behavioural costs.” They pointed out that their study was merely statistical, so no firm conclusions could be drawn about what had caused some children to take up smoking. Critics said that the researchers had not taken into account other factors, such as parents’ smoking habits or attitudes to smoking. E-cigarettes contain a liquid form of nicotine that is heated into vapour to be inhaled, avoiding the harm caused by tobacco smoke. While most experts are agreed that vaping is far safer than smoking tobacco, many are concerned about unresolved safety concerns. Europe’s highest legal expert, Dr Juliane Kokott, the advocate general to the European Court of Justice, last month warned that e-cigarettes “possibly cause risks to human health” and said they may provide a ‘gateway’ for teenagers to go on to smoke tobacco. She dismissed an industry challenge against forthcoming EU regulations, which will including banning one in four of the strongest devices and putting health warnings on packaging telling people e-cigarettes contain a ‘highly addictive substance’. Professor Kevin Fenton, national director for health and wellbeing at Public Health England, said, “In the UK, regular use of e-cigarettes among young people is almost entirely limited to those who have already smoked. Reassuringly, while e-cigarette use has increased rapidly, rates of youth smoking have fallen to the lowest ever recorded. Unlike much of the US, in England it is an offence to sell e-cigarettes to under-18s or to buy e-cigarettes for them and already restricted advertising is set to tighten further with new EU regulations later this year.” This month the UK Medicines and Healthcare Products Regulatory Agency approved the first vaping device for medical use. The e-Voke, an e-cigarette produced by British American Tobacco, is now allowed to be marketed for smoking cessation, which means patients will be able to request the device from their GP from later this year. Professor Linda Bauld of the University of Stirling said, “This is the third published study from the USA suggesting that young people who have tried e-cigarettes at baseline are more likely to have tried tobacco smoking at follow up. However, if you look more closely at the paper any assumptions that one leads to the other are not supported, as is the case with previous studies.”