2 Addictions Department, Institute of Psychiatry, Psychology and Neurosciences, King’s College London, United Kingdom
3 Action on Smoking and Health, United Kingdom
4 Faculty of Medicine & Health Sciences, University of Nottingham, United Kingdom
5 UK Centre for Tobacco & Alcohol Studies
6 Department of Epidemiology & Public Health, University College London
80 London Road,
Total pages: 14
Abstract words: 250
Main text words: 3,045
Objectives: The recent growth in the market for electronic cigarettes (e-cigarettes) has led to concerns over their use by young people. It is therefore important to examine trends in the perception and use of e-cigarettes and conventional cigarettes in this group.
Study design:Two-wave cross-sectional survey design.
Methods: Young people aged 11-18 in Great Britain were surveyed online by YouGov in 2013 and 2014. Use of e-cigarettes, together with perceived health harms and intention to use were assessed and compared in relation to cigarette smoking history, age and gender.
Results: Ever-use of e-cigarettes increased significantly from 4.6% (95% CI 3.8-5.7) in 2013 to 8.2% (95% CI 7.0-9.6) in 2014. Monthly or more use of e-cigarettes increased from 0.9% (95% CI 0.5-1.5) to 1.7 (1.2-2.4), but remained rare in never-smokers at under 0.2%. The proportion of young people who perceived e-cigarettes to be less harmful to users than cigarettes fell from 73.4% (95% CI 71.0-75.8) to 66.9% (95% CI 64.5-69.2), while the proportion who considered e-cigarettes to cause similar levels of harm increased from 11.8% (95% CI 10.0-13.5) to 18.2% (95% CI 16.3-20.1). Of the 8.2% of e-cigarette ever-users in 2014, 69.8% (95% CI 62.2%-77.3%) had smoked a cigarette prior to using an e-cigarette, while 8.2% (95% CI 4.1%-12.2%) first smoked a cigarette after e-cigarette use.
Conclusions:A growing proportion of young people in Great Britain believe e-cigarettes are as harmful as smoking tobacco. Use of e-cigarettes by young people is increasing, but is largely confined to those who smoke.
Keywords: E-cigarettes; young people; Great Britain
Electronic devices to deliver nicotine vapour without combustion (here referred to as e-cigarettes, but also termed electronic cigarettes or e-shisha) were invented as recently as 2003, and have been available in Europe since 20061. In Great Britain, an estimated 2.6 million individuals use e-cigarettes2. The e-cigarette market has been estimated to be worth $3bn globally3, and forecast to reach $50bn by the year 20254.
This rapid rise in availability has been accompanied by controversy. Proponents1,5,6 argue that e-cigarettes could be a disruptive technology with the potential to significantly reduce the global total of six million deaths per year attributable to conventional cigarette smoking7, as well as to reduce harm to non-using bystanders8,9. A recent Cochrane review found evidence that e-cigarettes help smokers to stop smoking long-term and make substantial reductions in cigarette consumption, compared with placebo e-cigarettes (and in one randomised controlled trial, nicotine patches) although the small number of studies and other limitations indicated that further research was necessary to substantiate the findings10. Opponents, on the other hand, point out that there is relatively little research on the safety of e-cigarettes, their efficacy as cessation aids, the effects of second hand vapour, the long term health effects, quality standards in production, the adequacy and consistency of nicotine delivery, whether they introduce never smokers to nicotine or subsequent cigarette smoking or renormalize smoking 11,12.
There is a limited, albeit growing, body of research on the prevalence of e-cigarette use in young people. Although the methods used to sample the population and to define e-cigarette use vary substantially, available evidence suggests that there is a wide variation in estimated prevalence of current use of e-cigarettes, ranging from 4.7% in Korea13 to 29.9% in Poland14. In the United States the prevalence of past 30-day e-cigarette use among adolescents increased from 0.9% in 2010 to 2.3% in 201115. Use of e-cigarettes appears, however, to be largely concentrated in those already smoking conventional cigarettes. Across Europe, 1.1% of never-smokers aged 15 and above had ever tried an e-cigarette16.
This study investigates the prevalence of use, perception of harm of e-cigarettes, and intentions to use e-cigarettes and conventional cigarettes in two national samples of 11 to 18 years olds in Great Britain in 2013 and 2014. Great Britain is an important jurisdiction to study within the international context, as there are currently few restrictions on the marketing and sale of e-cigarettes. Given the rapid evolution of the e-cigarette landscape, we chose to use internet surveys rather than schools or household based surveys which take considerable time to implement and gather data. To ascertain the level of sustained use of these products we asked about both occasional and regular use.
The charity Action on Smoking and Health (ASH) commissioned YouGov PLC to conduct a national survey of 11-18 year olds in Great Britain in 2013 and again in 2014 from their panel of over 400,000 individuals aged 16 and over in Britain. Panel members have been recruited from various online and offline sources, including standard advertising and strategic partnerships with a broad range of websites. Panel members disclose sociodemographic information when initially registered and this information is periodically updated, such as the number and age of children. For national samples, YouGov uses proprietary software to draw a sub-sample of the main panel that is representative of the sample group in question. For this study, the sample was drawn to be representative of British youth in terms of age, gender and region.
The methods used in each year were identical. Recruitment in 2013 ran from March 21 to March 28. Recruitment in 2014 ran from March 21 to April 01. Individuals aged 16-18 were sampled directly from YouGov’s online panel of people who had provided consent to be contacted. They were sent an email invitation directly, informing them of the survey and inviting them to take part. Individuals aged 11-15 were recruited via an email to parents or legal guardians from the YouGov panel, which asked them to read the information about the survey, and then pass the survey over to their child if they and their child agreed to take part. Those giving consent were asked to follow a link to the survey online. Data from these samples were weighted to be representative of age, gender and region of Great Britain, which was derived from the Office for National Statistics census data.
Smoking status was assessed with the following items, which we adapted from a measure used in annual national surveys of schoolchildren17: “I have never smoked cigarettes, not even a puff or two” (categorised as never-smokers); “I have only ever tried smoking cigarettes once” and “I used to smoke sometimes but I never smoke cigarettes now” (categorised as former-smokers); “I sometimes smoke cigarettes now but less than one a week”, “I usually smoke between one and six cigarettes a week” and “I usually smoke more than six cigarettes a week” (categorised as current-smokers), and the remainder categorised as “did not want to answer”.
Individuals were then asked to respond to the following question: “An e-cigarette is a tube that looks like a normal cigarette, has a glowing tip and puffs a vapour that looks like smoke but unlike normal cigarettes, they don't burn tobacco. Have you ever heard of e-cigarettes?”
Those who had heard of e-cigarettes were then asked to describe their experience of e-cigarettes with the following responses: “I have never used them” (categorised as “never users”); “I have tried them once or twice” (categorised as “experimenters”); “I use them sometimes (more than once a month)” and “I use them often (more than once a week)” (categorised as “monthly or more users”), and the remainder categorised as “did not want to answer”. Individuals who had never heard of e-cigarettes are considered de facto “never-users”, and a logistic regression was used to assess whether any individual characteristics could differentiate between those who had never heard of e-cigarettes, and those who had heard of but never used them. Ever-use of e-cigarettes included all experimenters and monthly or more users.
Respondents who had heard of e-cigarettes were asked three questions about their perceptions of e-cigarettes. The first question was “From what you know about e-cigarettes, do they have nicotine in them?” In 2013, the responses available were as follows: “Yes, they do”, and “No, they don’t”. In 2014, the available responses were changed to the following: “Yes, they all have nicotine in them”; “Yes, some of them have nicotine in them”, and “No, none of them have nicotine in them”. The two affirmative items in 2014 were pooled to compare against 2013 positive responses. In both years, two further responses were available: “I don’t know if they have nicotine in them”, and “I don’t know what nicotine is”.
Respondents were then asked “Compared to cigarettes, do you think e-cigarettes are more or less harmful to the person using them, or is there no difference?” and “Compared to cigarettes, do you think e-cigarettes are more or less harmful to people near them when they are being used?”. They were offered a choice of four responses to each question: “More harmful”; “Less harmful”; “About the same”, and “I don’t know”.
Never-smoker respondents were asked “Do you think that you will try a cigarette soon?” and individuals who had never tried an e-cigarette were asked “Do you think that you will try an e-cigarette soon?” For both questions, the available responses were: “Yes, I do”; “No, I don’t”; “I don’t know”, and “I don’t want to say”. Individuals responding “Yes, I do” were classified as having an intention to use, while all other responses were classified as not having such an intention.
Finally, in 2014 individuals who had ever used e-cigarettes were asked the following: “You said that you have tried an e-cigarette...Which ONE of the following BEST applies to you?”, with the following responses available: “I tried smoking a real cigarette before I first tried using an e-cigarette”; “I tried using an e-cigarette before I first tried smoking a real cigarette”; “I have never smoked a real cigarette but have tried an e-cigarette”, and “I don’t remember”.
We included gender, age and region of residence within Great Britain (i.e. England, Scotland or Wales) as demographic covariates. Due to different recruitment strategies, respondents aged 11-15 were combined in one single group and respondents aged 16-18 were collapsed into a second. Three environmental covariates were extracted from the survey. Individuals who responded “Yes, they are” to the question “Are people allowed to smoke inside your home / house? (If you live between more than one house, please think about the house you spend most of your time in)” were recorded as having “smoking permitted at home”. If the respondent ever travelled in a car where smoking occurred, even if only occasionally, they were recorded as having “smoking permitted in car”. If a respondent ever noticed tobacco products for sale in a supermarket or cornershop / newsagents / off-licence, they were recorded as “tobacco seen in shops”.
All analyses were conducted by Public Health England in STATA18 using the complex survey package svy19. Descriptive statistics of demographics are presented as both weighted and unweighted percentages using procedures appropriate for weighted survey data. Other descriptive statistics reported adopt weighted percentages only. The Pearson Chi-square statistic is used to test for independence of e-cigarette awareness and use by age and smoking status. This statistic is corrected for the stratified survey design with a second-order correction20 and is converted into an F statistic19.
A series of five logistic regression models were employed to investigate potential associations between demographic and environmental covariates on ever-use of e-cigarettes, experimental use of e-cigarettes, monthly or more use of e-cigarettes, intention to smoke cigarettes and intention to use e-cigarettes. All covariates are entered simultaneously into the five multivariate models, and those individuals who did not want to disclose either their cigarette smoking or e-cigarette status were excluded from the analyses. As only never-smokers were asked about their intention to smoke cigarettes, smoking status is excluded from the model assessing intention to smoke.
A total of 2,177 11-18 year olds were recruited in 2013, and 2,068 in 2014. As 231 individuals from the 2013 sample were again sampled in 2014, half were randomly assigned to 2013 (n=115) and half randomly assigned to 2014 (n=116), resulting in a final cohort of 2,062 individuals recruited in 2013 and 1,952 individuals recruited in 2014 (Table 1). There were no significant differences in gender, age, region or smoking status between 2013 and 2014. There was, however, a significant difference in urban-rural classification with fewer individuals recruited from urban areas in 2014 and more individuals recruited from town or fringe areas in 2014. There was also a difference in e-cigarette status between 2013 and 2014.
< Table 1 about here >
Awareness of e-cigarettes increased markedly between 2013 and 2014, with the proportion of individuals who had not heard of e-cigarettes falling from 32.8% in 2013 to 16.4% in 2014 (p<0.01). The logistic regression comparing those who had never heard of e-cigarettes, and those who had heard of but never used them found no association for gender, smoking status, urban-rural classification and region covariates, but older individuals were more likely to have heard of e-cigarettes (AOR 3.07).These two categories were merged together as ‘never used’ e-cigarettes in subsequent analysis.
Ever-use of e-cigarettes increased globally from 4.6% (95% CI 3.8-5.7) in 2013 to 8.2% (95% CI 7.0-9.6) in 2014 (p<0.01), Table 2. In 2013, 0.7% of never smokers were ever-users of e-cigarettes. By contrast, 7.7% of former smokers and 36.3% of current smokers were ever-users. In 2014, the proportion of never smokers who indicated ever-use of e-cigarettes increased to 1.7%. The proportion of former smokers and current smokers indicating e-cigarette ever use increased significantly to 21.0% and 53.7% (respectively (p<0.01).
< Table 2 about here >
Table 3 presents the perceptions of nicotine content, harm to the e-cigarette user and harm to those around the e-cigarette user in 2013 and 2014. In 2013, 43.4% of individuals who had heard of e-cigarettes believed they contain nicotine; in 2014, after combining the two affirmative items, this increased to 58.9% (p<0.01). The proportion of individuals who did not know if nicotine was present in e-cigarettes fell significantly from 40.5% in 2013 to 34.3% in 2014 (p<0.01).
There was no significant change in the proportion of individuals who thought that e-cigarettes were more harmful than cigarettes to the user, with 1.5% or less in both years considering e-cigarettes more harmful (p>0.05). The proportion who considered e-cigarettes to be less harmful to the user decreased significantly, from 73.4% in 2013 to 66.9% in 2014 (p<0.01), while the proportion who considered e-cigarettes to cause about the same level of harm to the user increased from 11.8% in 2013 to 18.2% in 2014 (p<0.01).
Similarly, the proportion of individuals who considered e-cigarettes to be more harmful than cigarettes to people near users when they are being used did not change across the period (p>0.05). The proportion who thought them less harmful decreased from 78.5% in 2013 to 73.1% to in 2014 (p<0.05), and the proportion who thought they caused similar levels of harm increased from 8.0% to 12.0% (p<0.01).
< Table 3 about here >
Of the 8.2% of young people who in 2014 had ever used e-cigarettes, 69.8% (95% CI 62.2%-77.3%) had smoked a cigarette prior to using an e-cigarette, while 8.2% (95% CI 4.1%-12.2%) first smoked a cigarette after e-cigarette use. A further 18.3% (95% CI 11.7%-24.8%) had never smoked a cigarette, with the remainder stating they could not remember which came first.
The results from the multivariate regression models are given in Table 4. In these complete-case multivariate models across both survey years, ever-use of e-cigarettes was reported by 6.2% of respondents, experimental use of e-cigarettes by 5.0%, and monthly or more use of e-cigarettes was reported by 1.2%. Intentions to smoke cigarettes and to use e-cigarettes were both reported by 0.8% (0.5-1.1).
Neither region of residence, urban-rural classifications nor having smoking permitted at home were associated with any of the five outcomes. Smoking status was associated with all four outcomes it applied to (i.e. all but the intention to smoke cigarettes). Former smokers were more likely than never smokers to use e-cigarettes at any level, and more likely to intend to use e-cigarettes, and current smokers had a stronger association across these measures.
< Table 4 about here >
Whether smoking was permitted in cars was associated with both ever use and experimental use of e-cigarettes (adjusted odds ratio (AOR) 1.85 and 1.66, respectively), but was not associated with any other outcome. Whether tobacco was noticed in shops was associated with ever-use and experimental use of e-cigarettes (AOR 2.56 and 2.68, respectively), but not with any other outcome. Males were more likely than females to be monthly or more users of e-cigarettes (AOR 2.52). Being in the older age category of 16-18 was associated with an intention to smoke cigarettes (AOR 2.85).
Individuals surveyed in 2014 were more likely than those in 2013 to have ever-used e-cigarettes (AOR 2.64), to have experimented with or be monthly or more users of e-cigarettes (AOR 2.19 and 2.69, respectively), and to hold an intention to use e-cigarettes in the future (AOR 2.59).
This study demonstrates a substantial increase in awareness and use of e-cigarettes in young people in the UK between 2013 and 2014. Ever use almost doubled to 8.2% of young people, though 80% of this use comprised individuals using the product once or twice. Monthly or more e-cigarette use also doubled, to 1.7%, and the change was statistically significant in the logistic modelling. Smokers were much more likely than non-smokers to use or intend to use e-cigarettes: monthly or more use of e-cigarettes by those who have never smoked remained extremely low in both years, at less than 0.2%. The proportions of young people who thought e-cigarettes were less harmful to the user or to others both decreased between 2013 and 2014. Of those who had ever used e-cigarettes, seven in ten had previously smoked cigarettes, while just over one in twelve used e-cigarettes first and then went on to try cigarettes.
Since use of e-cigarettes is changing so rapidly and existing national surveys have not included detailed questions on e-cigarette use, we elected to use an online survey service (YouGov), which delivers data quickly from a national sample of young people. Internet-based samples may not be fully representative of the general population, but the practice of weighting the sample to be representative of age, gender and region reduces the risk of bias. It is possible that a degree of bias was introduced to the sample as participation of the 11-15 year olds was conditional on parental consent, but the presence and degree of this was not possible to estimate. The benefit of the online approach is, however, that it provides up-to-date data that are currently unavailable in this level of detail from any other source in the UK.
E-cigarettes are being used by an increasing proportion of adults2 and legitimate concerns have been voiced with regard to their attraction to young people21. Our findings indicate that experimentation with e-cigarettes is becoming more common among young people. However, the great majority of users have only tried e-cigarettes ‘once or twice’. Monthly or more use is very uncommon and is almost entirely drawn from the smoking population. Similar findings have been reported in other countries14,15 and this might reflect greater adult use or marketing and availability of e-cigarettes. It is important to note, however, that the prevalence of youth cigarette smoking has continued to decline22 as use of e-cigarettes has increased.
That an increasing proportion of young people perceive e-cigarettes to be as hazardous as tobacco cigarettes is concerning, as this perception may reduce the proportion of smokers willing to try and/or use what is evidently a much less hazardous source of nicotine1. Our findings are, however, drawn from a population that is still relatively inexperienced in the use of these products, so close surveillance is needed to establish the longitudinal relationship between e-cigarette and conventional cigarette use and the extent to which engagement in one behaviour precedes or replaces the other.
DECLARATION AND CONFLICT OF INTEREST
Brian Eastwood is employed full time at Public Health England (PHE) and has received funding from PHE to support his PhD at the Institute of Psychiatry, Psychology and Neurosciences, King’s College London. Deborah Arnott and Hazel Cheeseman are employed full time at ASH, which receives core funding from the British Heart Foundation and Cancer Research UK. ASH receives no funding from commercial organisations. Martin Dockrell, John Britton, Ann McNeill and Martin Jarvis have no interests to declare.
All authors contributed to the analysis plan, which was implemented by B.E. All authors contributed to the drafting of the paper, and all have approved the final version for submission to Public Health.
Action on Smoking and Health commission and fund the annual youth survey, which is conducted by YouGov. Public Health England provided the analytical resources for this study.
The body responsible for collecting the data (YouGov) adhere to the code of conduct set out by the Market Research Society (https://www.mrs.org.uk/pdf/mrs%20code%20of%20conduct%202014.pdf). Informed consent to take part in the online survey was provided either by the parents of those aged 11-15, or by those individuals aged 16-18.
1. Hajek P, Etter J-F, Benowitz N, Eissenberg T, McRobbie H. Electronic cigarettes: review of use, content, safety, effects on smokers and potential for harm and benefit. Addiction. 2014 Nov 1;109(11):1801–10.
2. Use of electronic cigarettes in Great Britain [Internet]. Action on Smoking and Health (ASH); 2015 May [cited 2015 May 28]. Available from: http://www.ash.org.uk/files/documents/ASH_891.pdf
3. Smithers R. Whether they’re called “e-cigarettes” or “vaporisers” the market is heating up [Internet]. the Guardian. 2014 [cited 2015 May 28]. Available from: http://www.theguardian.com/business/2014/jun/26/e-cigarettes-market-vaporisers
4. Electronic Cigarette & E Vapor (Vaporizer) Market Research Reports [Internet]. BIS Research; 2014 [cited 2015 May 28]. Available from: http://bisresearch.com/electronic-cigarette-market-size-forecast.html
5. Palazzolo DL. Electronic Cigarettes and Vaping: A New Challenge in Clinical Medicine and Public Health. A Literature Review. Front Public Health [Internet]. 2013 Nov 18 [cited 2015 May 28];1. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3859972/
6. Gray NJ. Nicotine Yesterday, Today, and Tomorrow: A Global Review. Nicotine Tob Res. 2013 Nov 5;ntt171.
7. WHO | Tobacco [Internet]. WHO. [cited 2015 May 28]. Available from: http://www.who.int/mediacentre/factsheets/fs339/en/
8. Goniewicz ML, Knysak J, Gawron M, Kosmider L, Sobczak A, Kurek J, et al. Levels of selected carcinogens and toxicants in vapour from electronic cigarettes. Tob Control. 2013 Mar 6;tobaccocontrol – 2012–050859.
9. Harrell PT, Simmons VN, Correa JB, Padhya TA, Brandon TH. Electronic Nicotine Delivery Systems (“E-cigarettes”) Review of Safety and Smoking Cessation Efficacy. Otolaryngol -- Head Neck Surg. 2014 Sep 1;151(3):381–93.
10. McRobbie H, Bullen C, Hartmann-Boyce J, Hajek P. Electronic cigarettes for smoking cessation and reduction. Cochrane Database of Systematic Reviews [Internet]. John Wiley & Sons, Ltd; 1996 [cited 2015 Jun 1]. Available from: http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD010216.pub2/abstract
11. Cobb NK, Abrams DB. E-cigarette or drug-delivery device? Regulating novel nicotine products. N Engl J Med. 2011 Jul 21;365(3):193–5.
12. Chapman S. E-cigarettes: the best and the worst case scenarios for public health—an essay by Simon Chapman. BMJ. 2014 Sep 9;349:g5512.
13. Lee S, Grana RA, Glantz SA. Electronic Cigarette Use Among Korean Adolescents: A Cross-Sectional Study of Market Penetration, Dual Use, and Relationship to Quit Attempts and Former Smoking. J Adolesc Health. 2014 Jun;54(6):684–90.
14. Goniewicz ML, Gawron M, Nadolska J, Balwicki L, Sobczak A. Rise in Electronic Cigarette Use Among Adolescents in Poland. J Adolesc Health. 2014 Nov 1;55(5):713–5.
15. Camenga DR, Delmerico J, Kong G, Cavallo D, Hyland A, Cummings KM, et al. Trends in use of electronic nicotine delivery systems by adolescents. Addict Behav. 2014 Jan;39(1):338–40.
16. Vardavas CI, Filippidis FT, Agaku IT. Determinants and prevalence of e-cigarette use throughout the European Union: a secondary analysis of 26 566 youth and adults from 27 Countries. Tob Control. 2014 Jun 16;tobaccocontrol – 2013–051394.
17. Smoking, drinking and drug use among young people in England in 2012 [Internet]. Health & Social Care Information Centre; 2013 [cited 2015 May 28]. Available from: http://www.hscic.gov.uk/catalogue/PUB11334/smok-drin-drug-youn-peop-eng-2012-repo.pdf
18. STATA Statistical Software: Release 13. College Station, TX: StataCorp LP; 2013.
19. StataCorp. STATA Survey Data Reference Manual, Release 13. College Station, TX: StataCorp LP; 2013.
20. Rao JNK, Scott AJ. On Chi-Squared Tests for Multiway Contingency Tables with Cell Proportions Estimated from Survey Data. Ann Stat. 1984 Mar;12(1):46–60.
21. Electronic nicotine delivery systems [Internet]. World Health Organisation (WHO); 2014 [cited 2015 May 28]. Available from: http://apps.who.int/gb/fctc/PDF/cop6/FCTC_COP6_10Rev1-en.pdf
22. Smoking, drinking and drug use among young people in England in 2013 [Internet]. Health & Social Care Information Centre; 2014 [cited 2015 May 28]. Available from: http://www.hscic.gov.uk/catalogue/PUB14579/smok-drin-drug-youn-peop-eng-2013-rep.pdf