Do E-Cigarettes Make Teenagers More Likely to Smoke?
Thanks to decades of anti-tobacco efforts, smoking rates among children and young people have been declining: far fewer teenagers are starting to smoke than in the past. For example, in England only 3% of those aged 11 to 15 are smokers, and similar figur
Thanks to decades of anti-tobacco efforts, smoking rates among children and young people have been declining: fewer teenagers are starting to smoke than ever before.
For example, in England, only 3% of those aged 11 to 15 are smokers, with similar figures in Scotland and other parts of the UK. This is good news, as it will significantly help protect future adults from 14 types of smoking-related cancers, as well as heart disease, stroke, and other illnesses.
During the same period, we have also witnessed the arrival of nicotine replacement products that assist adults in quitting smoking. Reflecting on these products dating back to 1991, Michael Russell stated that smokers "consume nicotine but die from tar." In other words, it is many other toxic chemicals in tobacco combustion that cause disease and death, not nicotine.
The Nicotine Myth
However, there is considerable confusion among the public regarding nicotine—up to 90% of non-smokers and 75% of smokers believe it is harmful.
Encouraging smoking? Recently, we have witnessed the rapid rise of e-cigarette use, which has sparked considerable debate and controversy—especially surrounding their use and popularity among young people. This concern may partly stem from the confusion regarding the relative harmfulness of nicotine.
E-cigarettes typically contain nicotine, as well as other substances including flavorings and propylene glycol, which is a synthetic liquid used in cartridges. However, e-cigarettes do not expose users to many of the harmful chemicals found in tobacco.
They are widely available: the World Health Organization recently estimated that half of the world's population lives in countries where e-cigarettes can be purchased. Moreover, there is increasing evidence that they can help adult smokers quit tobacco.
However, health experts, policymakers, and others are concerned that the widespread availability of e-cigarettes may create a new generation of young nicotine addicts. If they start smoking, it could undermine the significant progress made in combating youth smoking. Is this concern justified?
Emerging Evidence
In early 2014, when my team at Stirling University initially reviewed studies on e-cigarette use among teenagers, we found only 9 peer-reviewed studies reporting usage rates in any country. Since then, over 30 new studies from various countries, including South Korea, France, Poland, Canada, and Iceland, have been published. Most of these studies, particularly those from major countries like the United States, focus on single regions or school districts.
The UK is an exception, as nationally representative cross-sectional data is available. So what do they show?
In 2014, four representative surveys of UK teenagers were conducted, focusing on slightly different age groups, but the findings were very consistent—a significant proportion of young people had tried e-cigarettes at least once (8% in one Great Britain survey, and 12% in the UK representative survey and national surveys in Scotland and Wales).
The same Great Britain survey was conducted previously in 2013, and the proportion of young people trying e-cigarettes increased between the two surveys. However, the proportion of those who regularly used e-cigarettes (more than once a month) remained very low in 2014 (ranging from 0.4% in Scotland to 2% in the UK) and was concentrated among youths who also smoked tobacco.
What About Non-Smokers?
Three of these surveys found no non-smokers who regularly used e-cigarettes. The fourth survey, which involved about 9,000 11 to 16-year-olds in Wales, identified only 54 participants who had never smoked but regularly used e-cigarettes.
What all this tells us is that while young people are trying e-cigarettes, and the reported proportion of those claiming to have tried them is on the rise, only a very small number of young non-smokers are regularly attracted to these products.
It is worth noting that this is during a time when youth smoking rates continue to decline, indicating—at least in the UK—there is no evidence that more young people are starting to smoke because of e-cigarettes.
But there is an important caveat. The studies in the UK—like those in other countries—are merely cross-sectional surveys that provide a snapshot. They cannot indicate any long-term trends or behavioral changes. For that, we need longitudinal studies that track the same population over time.
#p#分页标题#e#
The First Study Tracking a Cohort
A new study conducted in ten high schools in Los Angeles and published in the Journal of the American Medical Association provides the first longitudinal examination of e-cigarette and tobacco use. It involved about 3,300 participants, with an average age of 14 at the start of the study. They were followed up twice at 6 months and 12 months later.
Among all participants, 7% had used e-cigarettes at least once in the past 30 days. But when researchers examined the 2,530 subjects who had never used tobacco at the start of the study, only 222 (8.7%) reported having tried e-cigarettes.
But did these young people go on to try smoking (whether cigarettes, cigars, or hookah)? The researchers found that those who reported having tried e-cigarettes at the start of the study were more likely to have tried smoking 6 months later (30.7% vs. 8.1%) and 12 months later (25.2% vs. 9.3%).
The authors adjusted for other risks that might lead to youth smoking (such as socioeconomic background) but still found a correlation.
Some Important Caveats
How should we interpret this finding? There are a few points to note. As the authors clearly stated, this correlation does not prove that e-cigarettes cause young people to start smoking—it merely indicates a statistical association between the two. Furthermore, the way e-cigarette and tobacco use were measured was very basic, simply determining whether someone had "ever" or "recently" used them, rather than whether they were regular or persistent users.
Importantly, the age group in the study was just entering middle school—a transitional period where trying new things is common.
The number of subjects primarily focused on in the analysis was also quite small—only 222 non-smoking e-cigarette users.
Therefore, to find out more, we need longitudinal studies that track people over a longer period, providing more information on how often they use e-cigarettes and tobacco, as well as the types of products used. We also need studies that provide evidence on the safety of e-cigarettes and their role in smoking cessation.
Research also needs to assess the impact of policy changes regulating e-cigarettes in some countries, including measures to restrict youth access.
To this end, research institutions like Cancer Research UK are closely monitoring e-cigarette issues and funding some studies. If we are to influence policy and practice, ongoing monitoring and research, including studies involving the public and e-cigarette users, is crucial.
Previous research has played a very important role in helping protect young people from smoking-related diseases and deaths. The role of e-cigarettes in this remains to be seen; but it could be significant—so we need to study it.
For example, in England, only 3% of those aged 11 to 15 are smokers, with similar figures in Scotland and other parts of the UK. This is good news, as it will significantly help protect future adults from 14 types of smoking-related cancers, as well as heart disease, stroke, and other illnesses.
During the same period, we have also witnessed the arrival of nicotine replacement products that assist adults in quitting smoking. Reflecting on these products dating back to 1991, Michael Russell stated that smokers "consume nicotine but die from tar." In other words, it is many other toxic chemicals in tobacco combustion that cause disease and death, not nicotine.
The Nicotine Myth
However, there is considerable confusion among the public regarding nicotine—up to 90% of non-smokers and 75% of smokers believe it is harmful.
Encouraging smoking? Recently, we have witnessed the rapid rise of e-cigarette use, which has sparked considerable debate and controversy—especially surrounding their use and popularity among young people. This concern may partly stem from the confusion regarding the relative harmfulness of nicotine.
E-cigarettes typically contain nicotine, as well as other substances including flavorings and propylene glycol, which is a synthetic liquid used in cartridges. However, e-cigarettes do not expose users to many of the harmful chemicals found in tobacco.
They are widely available: the World Health Organization recently estimated that half of the world's population lives in countries where e-cigarettes can be purchased. Moreover, there is increasing evidence that they can help adult smokers quit tobacco.
However, health experts, policymakers, and others are concerned that the widespread availability of e-cigarettes may create a new generation of young nicotine addicts. If they start smoking, it could undermine the significant progress made in combating youth smoking. Is this concern justified?
Emerging EvidenceIn early 2014, when my team at Stirling University initially reviewed studies on e-cigarette use among teenagers, we found only 9 peer-reviewed studies reporting usage rates in any country. Since then, over 30 new studies from various countries, including South Korea, France, Poland, Canada, and Iceland, have been published. Most of these studies, particularly those from major countries like the United States, focus on single regions or school districts.
The UK is an exception, as nationally representative cross-sectional data is available. So what do they show?
In 2014, four representative surveys of UK teenagers were conducted, focusing on slightly different age groups, but the findings were very consistent—a significant proportion of young people had tried e-cigarettes at least once (8% in one Great Britain survey, and 12% in the UK representative survey and national surveys in Scotland and Wales).
The same Great Britain survey was conducted previously in 2013, and the proportion of young people trying e-cigarettes increased between the two surveys. However, the proportion of those who regularly used e-cigarettes (more than once a month) remained very low in 2014 (ranging from 0.4% in Scotland to 2% in the UK) and was concentrated among youths who also smoked tobacco.
What About Non-Smokers?
Three of these surveys found no non-smokers who regularly used e-cigarettes. The fourth survey, which involved about 9,000 11 to 16-year-olds in Wales, identified only 54 participants who had never smoked but regularly used e-cigarettes.
What all this tells us is that while young people are trying e-cigarettes, and the reported proportion of those claiming to have tried them is on the rise, only a very small number of young non-smokers are regularly attracted to these products.
It is worth noting that this is during a time when youth smoking rates continue to decline, indicating—at least in the UK—there is no evidence that more young people are starting to smoke because of e-cigarettes.
But there is an important caveat. The studies in the UK—like those in other countries—are merely cross-sectional surveys that provide a snapshot. They cannot indicate any long-term trends or behavioral changes. For that, we need longitudinal studies that track the same population over time.
#p#分页标题#e#
The First Study Tracking a CohortA new study conducted in ten high schools in Los Angeles and published in the Journal of the American Medical Association provides the first longitudinal examination of e-cigarette and tobacco use. It involved about 3,300 participants, with an average age of 14 at the start of the study. They were followed up twice at 6 months and 12 months later.
Among all participants, 7% had used e-cigarettes at least once in the past 30 days. But when researchers examined the 2,530 subjects who had never used tobacco at the start of the study, only 222 (8.7%) reported having tried e-cigarettes.
But did these young people go on to try smoking (whether cigarettes, cigars, or hookah)? The researchers found that those who reported having tried e-cigarettes at the start of the study were more likely to have tried smoking 6 months later (30.7% vs. 8.1%) and 12 months later (25.2% vs. 9.3%).
The authors adjusted for other risks that might lead to youth smoking (such as socioeconomic background) but still found a correlation.
Some Important Caveats
How should we interpret this finding? There are a few points to note. As the authors clearly stated, this correlation does not prove that e-cigarettes cause young people to start smoking—it merely indicates a statistical association between the two. Furthermore, the way e-cigarette and tobacco use were measured was very basic, simply determining whether someone had "ever" or "recently" used them, rather than whether they were regular or persistent users.
Importantly, the age group in the study was just entering middle school—a transitional period where trying new things is common.
The number of subjects primarily focused on in the analysis was also quite small—only 222 non-smoking e-cigarette users.
Therefore, to find out more, we need longitudinal studies that track people over a longer period, providing more information on how often they use e-cigarettes and tobacco, as well as the types of products used. We also need studies that provide evidence on the safety of e-cigarettes and their role in smoking cessation.
Research also needs to assess the impact of policy changes regulating e-cigarettes in some countries, including measures to restrict youth access.
To this end, research institutions like Cancer Research UK are closely monitoring e-cigarette issues and funding some studies. If we are to influence policy and practice, ongoing monitoring and research, including studies involving the public and e-cigarette users, is crucial.
Previous research has played a very important role in helping protect young people from smoking-related diseases and deaths. The role of e-cigarettes in this remains to be seen; but it could be significant—so we need to study it.
