Thanks to decades of anti-tobacco campaigns, smoking rates among children and young people are declining: far fewer teenagers are starting to ijoy smoke.

　　 For example, in England, only 3% of 11-15 year-olds are smokers, and similar figures are also used in Scotland and other parts of the UK. This is good news, and it will play a significant role in protecting future adults from 14 types of smoking-related cancers and other diseases such as heart disease and stroke.

　　 In the same period, we also witnessed the advent of nicotine substitutes that help adults quit smoking. Looking back at these products as early as 1991, Michael Russell said that smokers “sucked nicotine and died of tar.” In other words, it is the many other toxic chemicals in the burning of tobacco that cause disease and death, not nicotine.

　　Nicotine Myth

　　 However, the public is quite confused about nicotine-up to 90% of non-smokers and 75% of smokers believe it is harmful.

　　Encourage smoking? Recently, we have witnessed the rapid rise of Vape use, and it has caused considerable debate and controversy-especially around their use and popularity among young people. This concern may be partly due to confusion about the relative harmfulness of nicotine.

　　 Vape usually contains nicotine, as well as other substances including flavoring and propylene glycol, which is a synthetic liquid substance used in cigarette cartridges. But Vape does not expose people to many harmful chemicals in tobacco.

　　 They are available everywhere: WHO recently estimated that half of the world’s population lives in countries where Vape is available. And there is growing evidence that they can help adult smokers to quit tobacco.

　　 However, health experts, policy makers and others are worried that the widespread popularity of Vape may create a new generation of young nicotine addicts. If they start smoking, it will undermine the strides made against youth smoking. Is this concern justified?

　　New evidence

　　 In early 2014, when my team at the University of Stirling first reviewed the use of Vape in adolescents, we only found 9 peer-reviewed studies that reported the use rate in any country. Since then, more than 30 new studies from different countries such as South Korea, France, Poland, Canada and Iceland have been published. Most of these studies, especially from large countries such as the United States, focus on a single region or school district.

　　 The United Kingdom is an exception. Nationally representative horizontal data are available, so what do they show?

Four representative surveys of British youth were conducted in 2014. They focused on slightly different age groups, but the results were very consistent-a significant proportion of young people had tried Vape at least once (in a British survey it was 8 %, which is 12% in the representative survey of the United Kingdom and the national survey of Scotland and Wales).

　　 The same thunderhead creations Great Britain survey was conducted before in 2013, and the proportion of young people who tried Vape increased between the two surveys. However, the frequent use of Vape (more than once a month) was still very low in 2014 (from 0.4% in Scotland to 2% in the UK) and it was concentrated among young people who also smoked tobacco.

　　How about non-smokers?

　　 Three of these surveys failed to find non-smokers who regularly use Vape. The fourth survey of about 9,000 people aged 11 to 16 in Wales determined that only 54 participants had never smoked but used Vape regularly.

　　 What all this tells us is that although young people are trying Vape, and the proportion of people who claim to have tried is on the rise, only a few young non-smokers are regularly attracted to these products.

　　 It’s worth remembering that this is a period of declining smoking rates among young people, showing that-at least in the UK-there is no evidence that more young people are starting to smoke because of adv Vape.

　　 But there is another important warning. The British study—like those in other countries—is a horizontal survey that only provides a snapshot. They cannot tell any long-term trends or changes in behavior. To do this, we need to track longitudinal surveys of the same population over time.

　　 The first study to track groups

　　 The new study conducted at ten high schools in Los Angeles and published in the Journal of the American Medical Association provides the first longitudinal study of finding Vape and tobacco use. It involved approximately 3,300 participants, with an average age of 14 years when they joined the study. After 6 months and 12 months, they were followed up twice.

　　 Among all participants, 7% have used Vape at least once in the past 30 days. But when the researchers looked at 2,530 subjects who had never used tobacco at the beginning of the study, only 222 (8.7%) of them said they had tried Vape.

　　 But are these young people more likely to try smoking later (whether it is cigarettes, cigars or hookahs)? The researchers found that those who said they had tried Vape at the beginning of the study were more likely to have tried smoking after 6 months (30.7% vs. 8.1%) and 12 months later (25.2% vs. 9.3%).

　　 The authors collected and adjusted other risks (such as socioeconomic background) that may cause adolescents to smoke, but still found relevant.

　　 some important warnings

How should treat this discovery? There are a few notes. As the authors made clear, this association does not prove that Vape caused adolescents to start smoking—it simply shows a statistical correlation between the two. On top of this, the method of measuring Vape and tobacco use is very basic, only to determine whether a person has “have” or “recently” used it, rather than whether it is used regularly or continuously.

　　The important thing is that the age group under study has just entered junior high school—a period of transition and trying new things.

　　 The main focus of this analysis is also very small-only 222 Vape users who do not smoke.

　　 So in order to find out more, it is necessary to follow people’s longitudinal studies for a longer period of time, and provide more information on how often they use Vape and tobacco, and the types of products they use. And we need research to provide evidence of Vape’s safety and role in smoant cessation.

　　Research also needs to assess the impact of policy changes to introduce Vape regulations in some countries, including measures to restrict youth.

　　 For this reason, research institutions such as Cancer Research UK are paying close attention to the Vape problem and funding some research. If we are to influence policy and practice, continuous monitoring and research, including research involving the public and Vape users, is very important.

　　 Previous research has played a very important role in helping protect young people from smoking-related diseases and deaths. The place of Vape in it remains to be seen; but it may be important-so we need to study it.