View source for Usage of electronic cigarettes

{{short description|Overview about the usage of electronic cigarettes}}
The '''usage of electronic cigarettes''' has risen rapidly<ref name=Rom2014/> since their introduction to the market in 2002.<ref name=Bhatnagar2014/> The global number of adult [[electronic cigarette|e-cigarettes]] users rose from about 7 million in 2011 to between 68 million<ref>{{cite journal | vauthors = Jerzyński T, Stimson GV, Shapiro H, Król G | title = Estimation of the global number of e-cigarette users in 2020 | journal = Harm Reduction Journal | volume = 18 | issue = 1 | pages = 109 | date = October 2021 | pmid = 34688284 | pmc = 8541798 | doi = 10.1186/s12954-021-00556-7 }}</ref> and 82 million<ref>{{cite web |date=February 2022 |title=82 million vapers worldwide in 2021: the GSTHR estimate |url=https://gsthr.org/briefing-papers/82-million-vapers-worldwide-in-2021-the-gsthr-estimate/ |work=Global State of Tobacco Harm Reduction |publisher=Knowledge-Action-Change}}</ref> in 2021. Awareness and use of e-cigarettes greatly increased over the few years leading up to 2014, particularly among young people and women in some parts of the world.<ref name=Schraufnage2014/> Since their introduction vaping has increased in the majority of high-income countries.<ref name=BourkeBauld2017/> E-cigarette use in the US and Europe is higher than in other countries,<ref name=Rahman2014/> except for China which has the greatest number of e-cigarette users.<ref name=CaiWang2017>{{cite journal | vauthors = Cai H, Wang C | title = Graphical review: The redox dark side of e-cigarettes; exposure to oxidants and public health concerns | journal = Redox Biology | volume = 13 | pages = 402–406 | date = October 2017 | pmid = 28667909 | pmc = 5493817 | doi = 10.1016/j.redox.2017.05.013 }}</ref> Growth in the UK {{asof|January 2018|lc=y}} had reportedly slowed since 2013.<ref name=West2018/> The growing frequency of e-cigarette use may be due to heavy promotion in youth-driven media channels, their low cost, and the belief that e-cigarettes are safer than traditional cigarettes, according to a 2016 review.<ref name=CamengaKlein2016>{{cite journal | vauthors = Camenga DR, Klein JD | title = Tobacco Use Disorders | journal = Child and Adolescent Psychiatric Clinics of North America | volume = 25 | issue = 3 | pages = 445–460 | date = July 2016 | pmid = 27338966 | pmc = 4920978 | doi = 10.1016/j.chc.2016.02.003 }}</ref> E-cigarette use may also be increasing due to the consensus among several scientific organizations that e-cigarettes are safer (although not without risk) compared to combustible tobacco products.<ref name="Public Health Consequences of E-Cigarettes">{{cite report|title=Public Health Consequences of E-Cigarettes |url=https://www.nap.edu/resource/24952/012318ecigaretteHighlights.pdf |website=The National Academies of Science Engineering and Medicine}}</ref> E-cigarette use also appears to be increasing at the same time as a rapid decrease in cigarette use in many countries,<ref name="Etter Jean-François, 2018">{{cite journal | vauthors = Etter JF | title = Gateway effects and electronic cigarettes | journal = Addiction | volume = 113 | issue = 10 | pages = 1776–1783 | date = October 2018 | pmid = 28786147 | doi = 10.1111/add.13924 | hdl-access = free | hdl = 2027.42/143795 | url = https://archive-ouverte.unige.ch/unige:99686 }}</ref> suggesting that e-cigarettes may be displacing traditional cigarettes.

The prevalence of vaping among adolescents is increasing worldwide.<ref name=SchneiderDiehl2016/> There is substantial variability in vaping in youth worldwide across countries.<ref name=YoongStockings2018/> Over the years leading up to 2017, vaping among adolescents has grown every year since these devices were first introduced to the market.<ref name=BiyaniDerkay2017/> There appears to be an increase of one-time e-cigarette use among young people worldwide.{{sfn|McNeill|2015|p=87}} Most e-cigarette users among youth have never smoked.<ref name=ZhongCao2016/> Many youths who use e-cigarettes also smoke traditional cigarettes.<ref name=Grana2014/> While some studies find associations between the use of e-cigarettes and traditional cigarettes,<ref>{{cite journal | vauthors = Grana R, Benowitz N, Glantz SA | title = E-cigarettes: a scientific review | journal = Circulation | volume = 129 | issue = 19 | pages = 1972–1986 | date = May 2014 | pmid = 24821826 | pmc = 4018182 | doi = 10.1161/CIRCULATIONAHA.114.007667 }}</ref><ref name="PetersonHecht2017"/><ref name="ChatterjeeAlzghoul2016"/> studies that estimate this relationship using causal methods from health economics have concluded the opposite.<ref name="Etter Jean-François, 2018" /><ref name = "Pesko_2022">{{cite web | vauthors = Pesko M | date = March 2022 |title= Mike Pesko's E-cigarette Policy Evaluation Research |url=https://drive.google.com/file/d/1T2-svdWPVuNXXzA1nnYsVYaqkVK7Skhk/view |website=Google Docs }}</ref> In general, those studies tend to use robust quasi-experimental econometrics methods along with policy variation to predict e-cigarette use rather than relying on individual selection. Using policy variation is critical as it avoids the methodological challenge that many e-cigarette users are high-risk individuals that would have otherwise smoked cigarettes and may now use e-cigarettes first to “test the waters” before transitioning to their a-priori preferred choice of cigarettes. Therefore, using policy variation is an improvement over much of the current e-cigarette research to date that fails to separate the causal effect of e-cigarette use from preferences to gradually increase the riskiness of tobacco product use over time. These studies using policy variation generally conclude that e-cigarettes are displacing smoking, which aligns with cigarette use rates falling while e-cigarette use rates are rising.<ref>{{cite journal | vauthors = Bauld L, MacKintosh AM, Eastwood B, Ford A, Moore G, Dockrell M, Arnott D, Cheeseman H, McNeill A | display-authors = 6 | title = Young People's Use of E-Cigarettes across the United Kingdom: Findings from Five Surveys 2015-2017 | journal = International Journal of Environmental Research and Public Health | volume = 14 | issue = 9 | pages = 973 | date = August 2017 | pmid = 28850065 | pmc = 5615510 | doi = 10.3390/ijerph14090973 | doi-access = free }}</ref><ref>{{cite web |title=E-cigarette use triples among middle and high school students in just one year. |url=https://www.cdc.gov/media/releases/2015/p0416-E-cigarette-use.html. |website=Centre for Disease Control and Prevention Newsroom (2015)}}</ref><ref>{{cite journal | vauthors = Levy DT, Warner KE, Cummings KM, Hammond D, Kuo C, Fong GT, Thrasher JF, Goniewicz ML, Borland R | display-authors = 6 | title = Examining the relationship of vaping to smoking initiation among US youth and young adults: a reality check | journal = Tobacco Control | volume = 28 | issue = 6 | pages = 629–635 | date = November 2019 | pmid = 30459182 | pmc = 6860409 | doi = 10.1136/tobaccocontrol-2018-054446 }}</ref><ref>{{cite journal | vauthors = Hallingberg B, Maynard OM, Bauld L, Brown R, Gray L, Lowthian E, MacKintosh AM, Moore L, Munafo MR, Moore G | display-authors = 6 | title = Have e-cigarettes renormalised or displaced youth smoking? Results of a segmented regression analysis of repeated cross sectional survey data in England, Scotland and Wales | journal = Tobacco Control | volume = 29 | issue = 2 | pages = 207–216 | date = March 2020 | pmid = 30936390 | pmc = 7036293 | doi = 10.1136/tobaccocontrol-2018-054584 }}</ref> This contrasts with much of the literature not using policy variation and spuriously concluding that e-cigarettes are gateways to subsequent cigarette use, which does not align with observed patterns of tobacco use.<ref name = "Pesko_2022" />

There are varied reasons for e-cigarette use.<ref name=Rahman2014/> Most users' motivation is related to trying to quit smoking, but a large proportion of use is recreational.<ref name=Rahman2014/> Adults cite predominantly three reasons for trying and using e-cigarettes: as an aid to smoking cessation, as a safer alternative to traditional cigarettes, and as a way to conveniently get around [[smoking ban|smoke-free laws]].<ref name=GlantzBareham2018/> Many users vape because they believe it is healthier than smoking for themselves or bystanders.<ref name=Pepper2013/> Usually, only a small proportion of users are concerned about the potential adverse [[health effect]]s.<ref name=Pepper2013/> Seniors seem to vape to quit smoking or to get around smoke‐free policies.<ref name=QasimKarim2017/> There appears to be a hereditary component to tobacco use, which probably plays a part in transitioning of e-cigarette use from experimentation to routine use.<ref name=Weaver2014>{{cite journal | vauthors = Weaver M, Breland A, Spindle T, Eissenberg T | title = Electronic cigarettes: a review of safety and clinical issues | journal = Journal of Addiction Medicine | volume = 8 | issue = 4 | pages = 234–240 | year = 2014 | pmid = 25089953 | pmc = 4123220 | doi = 10.1097/ADM.0000000000000043 }}</ref> The introduction of e-cigarettes has given [[cannabis (drug)|cannabis]] smokers a different way of inhaling [[cannabinoid]]s.<ref name=Giroudde2015/> Recreational cannabis users can individually "vape" deodorized or flavored cannabis extracts with minimal annoyance to the people around them and less chance of detection, known as "stealth vaping".<ref name=Giroudde2015/>

[[File:Various types of e-cigarettes.jpg|thumb|right|upright=1.25|Various types of e-cigarettes.|alt=Various types of e-cigarettes.]]

== Use ==

=== Frequency ===

[[File:Naomi 214.2 (12883884613).jpg|thumb|right|upright|[[Aerosol]] ([[vapor]]) exhaled by an e-cigarette user using a nicotine-free e-cigarette.|alt=Aerosol (vapor) exhaled by an e-cigarette user using a nicotine-free e-cigarette.]]

Since their introduction to the market in 2003,<ref name=Bhatnagar2014>{{cite journal | vauthors = Bhatnagar A, Whitsel LP, Ribisl KM, Bullen C, Chaloupka F, Piano MR, Robertson RM, McAuley T, Goff D, Benowitz N | display-authors = 6 | title = Electronic cigarettes: a policy statement from the American Heart Association | journal = Circulation | volume = 130 | issue = 16 | pages = 1418–1436 | date = October 2014 | pmid = 25156991 | pmc = 7643636 | doi = 10.1161/CIR.0000000000000107 | doi-access = free }}</ref> global usage of [[electronic cigarette|e-cigarettes]] has risen [[exponential growth|exponentially]].<ref name=Rom2014>{{cite journal | vauthors = Rom O, Pecorelli A, Valacchi G, Reznick AZ | title = Are E-cigarettes a safe and good alternative to cigarette smoking? | journal = Annals of the New York Academy of Sciences | volume = 1340 | issue = 1 | pages = 65–74 | date = March 2015 | pmid = 25557889 | doi = 10.1111/nyas.12609 | bibcode = 2015NYASA1340...65R | s2cid = 26187171 }}</ref> By 2013, there were several million users globally.<ref name=Felberbaum2013>{{cite news|url=http://www.huffingtonpost.com/2013/06/11/marlboro-electronic-cigarette_n_3420938.html|title=Marlboro Maker To Launch New Electronic Cigarette| vauthors = Felberbaum M |work=HuffPost|date=11 June 2013}}</ref> In 2011 there were approximately seven million adult e-cigarette users globally in 2011 to 41 million of them in 2018.<ref name=Janes2019>{{cite news|url=https://www.bbc.com/news/business-44295336|title=Vaping: How popular are e-cigarettes? - Spending on e-cigarettes is growing| vauthors = Jones L |work=BBC News|date=15 September 2019}}</ref> Awareness and use of e-cigarettes greatly increased over the few years leading up to 2014, particularly among young people and women in some parts of the world.<ref name=Schraufnage2014>{{cite journal | vauthors = Schraufnagel DE, Blasi F, Drummond MB, Lam DC, Latif E, Rosen MJ, Sansores R, Van Zyl-Smit R | display-authors = 6 | title = Electronic cigarettes. A position statement of the forum of international respiratory societies | journal = American Journal of Respiratory and Critical Care Medicine | volume = 190 | issue = 6 | pages = 611–618 | date = September 2014 | pmid = 25006874 | doi = 10.1164/rccm.201407-1198PP | s2cid = 43763340 | url = https://figshare.com/articles/journal_contribution/Electronic_Cigarettes_A_Position_Statement_of_the_Forum_of_International_Respiratory_Societies/10758143 }}</ref> A 2013 four-country survey found there was generally greater awareness among white adult smokers compared with non-white ones.<ref name=HartwellThomas2017>{{cite journal | vauthors = Hartwell G, Thomas S, Egan M, Gilmore A, Petticrew M | title = E-cigarettes and equity: a systematic review of differences in awareness and use between sociodemographic groups | journal = Tobacco Control | volume = 26 | issue = e2 | pages = e85–e91 | date = December 2017 | pmid = 28003324 | pmc = 5739861 | doi = 10.1136/tobaccocontrol-2016-053222 }}</ref> Vaping is increasing in the majority of high-income countries.<ref name=BourkeBauld2017>{{cite journal | vauthors = Bourke L, Bauld L, Bullen C, Cumberbatch M, Giovannucci E, Islami F, McRobbie H, Silverman DT, Catto JW | display-authors = 6 | title = E-cigarettes and Urologic Health: A Collaborative Review of Toxicology, Epidemiology, and Potential Risks | journal = European Urology | volume = 71 | issue = 6 | pages = 915–923 | date = June 2017 | pmid = 28073600 | doi = 10.1016/j.eururo.2016.12.022 | hdl-access = free | hdl = 1893/24937 | url = http://shura.shu.ac.uk/15010/1/Bourke%20E-cigarettes%20and%20urologic%20health.pdf }}</ref> E-cigarette use in the US and Europe is higher than in other countries,<ref name=Rahman2014/> except for China which has the greatest number of e-cigarette users.<ref name=CaiWang2017/> Growth in the US had reportedly slowed in 2015, lowering market forecasts for 2016.<ref name=Mickle2015>{{cite news|url=https://www.wsj.com/articles/e-cig-sales-rapidly-lose-steam-1447798921|title=E-Cigarette Sales Rapidly Lose Steam| vauthors = Mickle T |publisher=[[Wall Street Journal]]|date=17 November 2015}}</ref> Growth in the UK {{asof|January 2018|lc=y}} had reportedly slowed since 2013.<ref name=West2018>{{cite web|url=http://www.smokinginengland.info/latest-statistics/|title=Electronic cigarettes in England - latest trends (STS140122)| vauthors = West R, Beard E, Brown J |publisher=Smoking in England|page=28|date=9 January 2018}}</ref> The growing frequency of e-cigarette use may be due to heavy promotion in youth-driven media channels, their low cost, and the belief that e-cigarettes are safer than traditional cigarettes, according to a 2016 review.<ref name=CamengaKlein2016/> In 2018, it was estimated that there were 35 million e-cigarette users globally (including [[heat-not-burn product|heat-not-burn tobacco products]]), with this rapid growth predicted to continue.<ref name=McCauslandMaycock2019>{{cite journal | vauthors = McCausland K, Maycock B, Leaver T, Jancey J | title = The Messages Presented in Electronic Cigarette-Related Social Media Promotions and Discussion: Scoping Review | journal = Journal of Medical Internet Research | volume = 21 | issue = 2 | pages = e11953 | date = February 2019 | pmid = 30720440 | pmc = 6379814 | doi = 10.2196/11953 }}{{CC-notice|cc=by4|url=https://www.jmir.org/2019/2/e11953/|author(s)=Kahlia McCausland, Bruce Maycock, Tama Leaver, and Jonine Jancey}}</ref>

Surveys in 2010 and 2011 suggested that adults with higher incomes were more likely to have heard of e-cigarettes, but those with lower incomes may have been more likely to try them.<ref name=Chapman2014/> Most users had a history of smoking regular cigarettes, while results by race were mixed.<ref name=Chapman2014/> At least 52% of smokers or ex-smokers have used an e-cigarette.<ref name=Alaws2015>{{cite journal | vauthors = Alawsi F, Nour R, Prabhu S | title = Are e-cigarettes a gateway to smoking or a pathway to quitting? | journal = British Dental Journal | volume = 219 | issue = 3 | pages = 111–115 | date = August 2015 | pmid = 26271862 | doi = 10.1038/sj.bdj.2015.591 | s2cid = 24120636 }}</ref> Of smokers who have, less than 15% become everyday e-cigarette users.<ref name=McRobbieBullen2014>{{cite journal | vauthors = McRobbie H, Bullen C, Hartmann-Boyce J, Hajek P | editor1-first = Hayden | editor1-last = McRobbie | title = Electronic cigarettes for smoking cessation and reduction | journal = The Cochrane Database of Systematic Reviews | volume = 12 | issue = 12 | pages = CD010216 | year = 2014 | pmid = 25515689 | doi = 10.1002/14651858.CD010216.pub2 }}</ref> Though e-cigarette use among those who have never smoked is very low, it continues to rise.<ref name=Bullen2014>{{cite journal | vauthors = Bullen C | title = Electronic cigarettes for smoking cessation | journal = Current Cardiology Reports | volume = 16 | issue = 11 | pages = 538 | date = November 2014 | pmid = 25303892 | doi = 10.1007/s11886-014-0538-8 | s2cid = 2550483 }}</ref> Daily vapers are typically recent former smokers.<ref name=GlasserCollins2017>{{cite journal | vauthors = Glasser AM, Collins L, Pearson JL, Abudayyeh H, Niaura RS, Abrams DB, Villanti AC | title = Overview of Electronic Nicotine Delivery Systems: A Systematic Review | journal = American Journal of Preventive Medicine | volume = 52 | issue = 2 | pages = e33–e66 | date = February 2017 | pmid = 27914771 | pmc = 5253272 | doi = 10.1016/j.amepre.2016.10.036 }}</ref> E-cigarettes are commonly used among non-smokers.<ref name=DeVitoKrishnan-Sarin2017/> This includes young adult non-smokers.<ref name=DeVitoKrishnan-Sarin2017>{{cite journal | vauthors = DeVito EE, Krishnan-Sarin S | title = E-cigarettes: Impact of E-Liquid Components and Device Characteristics on Nicotine Exposure | journal = Current Neuropharmacology | volume = 16 | issue = 4 | pages = 438–459 | year = 2017 | pmid = 29046158 | pmc = 6018193 | doi = 10.2174/1570159X15666171016164430 }}</ref> Vaping is the largest among adults between 18 and 24 years of age, and use is the largest among adults who do not have a high school diploma.<ref name=Chaffee-Couch2016>{{cite journal | vauthors = Couch ET, Chaffee BW, Gansky SA, Walsh MM | title = The changing tobacco landscape: What dental professionals need to know | journal = Journal of the American Dental Association | volume = 147 | issue = 7 | pages = 561–569 | date = July 2016 | pmid = 26988178 | pmc = 4925234 | doi = 10.1016/j.adaj.2016.01.008 }}</ref> Young adults who vape but do not smoke are more than twice as likely to intend to try smoking than their peers who do not vape.<ref name=ZhongCao2016/> A worldwide survey of e-cigarette users conducted in 2014 found that only 3.5% of respondents used liquid without [[nicotine]].<ref name=Tomashefski2016/>

Greater than 10 million people vape daily, {{asof|2018|lc=y}}.<ref name=SerrorChaouat2018/> Everyday use is common among e-cigarette users.<ref name=Pepper2013/> E-cigarette users mostly keep smoking traditional cigarettes.<ref name=Grana2014/> Adults often vape to replace tobacco.<ref name=Chapman2014/> Most vapers still use nicotine liquids after stopping smoking for several months.<ref name=Farsalinos2014>{{cite journal | vauthors = Farsalinos KE, Spyrou A, Tsimopoulou K, Stefopoulos C, Romagna G, Voudris V | title = Nicotine absorption from electronic cigarette use: comparison between first and new-generation devices | journal = Scientific Reports | volume = 4 | pages = 4133 | date = February 2014 | pmid = 24569565 | pmc = 3935206 | doi = 10.1038/srep04133 | bibcode = 2014NatSR...4E4133F }}</ref> Most e-cigarette users are middle-aged men who also smoke traditional cigarettes, either to help them quit or for [[recreational drug use|recreational use]].<ref name=Rahman2014/> Older people are more likely to vape for quitting smoking than younger people.<ref name=Vogel2016>{{cite journal | vauthors = Vogel WH | title = E-Cigarettes: Are They as Safe as the Public Thinks? | journal = Journal of the Advanced Practitioner in Oncology | volume = 7 | issue = 2 | pages = 235–240 | date = March 2016 | pmid = 28090372 | pmc = 5226315 | doi = 10.6004/jadpro.2016.7.2.9 }}</ref> Men were found to use higher nicotine doses, compared with women who were vaping.<ref name=Cormet-BoyakaZare2018/> Among young adults e-cigarette use is not regularly associated with trying to quit smoking.<ref name=Chapman2014/> The research indicates that the most common way people try to quit smoking in the UK is with e-cigarettes.{{sfn|McNeill|2018|p=106}}

Dual use of e-cigarettes and traditional tobacco is common.<ref name=EbbertAgunwamba2015>{{cite journal | vauthors = Ebbert JO, Agunwamba AA, Rutten LJ | title = Counseling patients on the use of electronic cigarettes | journal = Mayo Clinic Proceedings | volume = 90 | issue = 1 | pages = 128–134 | date = January 2015 | pmid = 25572196 | doi = 10.1016/j.mayocp.2014.11.004 | doi-access = free }}</ref> Dual use of e-cigarettes with cigarettes is the most frequent pattern.<ref name=RinkooKaur2017>{{cite journal | vauthors = Kaur J, Rinkoo AV | title = Getting real with the upcoming challenge of electronic nicotine delivery systems: The way forward for the South-East Asia region | journal = Indian Journal of Public Health | volume = 61 | issue = Suppl 1 | pages = S7–S11 | date = September 2017 | pmid = 28928312 | doi = 10.4103/ijph.IJPH_240_17 | doi-access = free }}</ref> One-time e-cigarette use seems to be higher in people with greater levels of educational achievement.<ref name=HartwellThomas2016>{{cite journal | vauthors = Hartwell G, Thomas S, Egan M, Gilmore A, Petticrew M | title = E-cigarettes and equity: a systematic review of differences in awareness and use between sociodemographic groups | journal = Tobacco Control | volume = 26 | issue = e2 | pages = e85–e91 | date = December 2017 | pmid = 28003324 | pmc = 5739861 | doi = 10.1136/tobaccocontrol-2016-053222 | doi-access = free }}</ref> Women smokers who are poorer and did not finish high school are more likely to have tried vaping at least once.<ref name=Sanford2014/> Vaping is increasing among people with cancer who are frequent smokers.<ref name=Zborovskaya2017>{{cite journal | vauthors = Zborovskaya Y | title = E-Cigarettes and Smoking Cessation: A Primer for Oncology Clinicians | journal = Clinical Journal of Oncology Nursing | volume = 21 | issue = 1 | pages = 54–63 | date = February 2017 | pmid = 28107337 | doi = 10.1188/17.CJON.54-63 | s2cid = 206992720 }}</ref>

=== Gateway or Displacement theory ===

In the context of drugs, the [[gateway drug theory|gateway hypothesis]] predicts that the use of less deleterious drugs can lead to a future risk of using more dangerous hard drugs or crime.<ref name=Lee2015>{{cite journal | vauthors = Lee PN | title = Appropriate and inappropriate methods for investigating the "gateway" hypothesis, with a review of the evidence linking prior snus use to later cigarette smoking | journal = Harm Reduction Journal | volume = 12 | issue = 1 | pages = 8 | date = March 2015 | pmid = 25889396 | pmc = 4369866 | doi = 10.1186/s12954-015-0040-7 }}{{CC-notice|cc=by4|url=https://harmreductionjournal.biomedcentral.com/articles/10.1186/s12954-015-0040-7?optIn=false| vauthors = Lee PN }}</ref> Some research provides suggestive evidence that vaping is a "gateway" to smoking by examining how e-cigarette use in one period predicts cigarette use in another period.<ref name=Franck2014>{{cite journal | vauthors = Franck C, Budlovsky T, Windle SB, Filion KB, Eisenberg MJ | title = Electronic cigarettes in North America: history, use, and implications for smoking cessation | journal = Circulation | volume = 129 | issue = 19 | pages = 1945–1952 | date = May 2014 | pmid = 24821825 | doi = 10.1161/CIRCULATIONAHA.113.006416 | doi-access = free }}</ref> However, under the common liability model, some have suggested that any favorable relation between vaping and starting smoking is a result of common [[risk factor]]s.{{sfn|Stratton|2018|loc=Conceptual Framework: Patterns of Use Among Youth and Young Adults; p. 497}} Health economics research using e-cigarette policy variation to examine use of cigarettes independent of common sources of confounding factors such as personal risk preferences generally finds that vaping is an "exit ramp" from, or displacing, smoking.<ref>{{cite journal | vauthors = Walker N, Parag V, Wong SF, Youdan B, Broughton B, Bullen C, Beaglehole R | title = Use of e-cigarettes and smoked tobacco in youth aged 14-15 years in New Zealand: findings from repeated cross-sectional studies (2014-19) | journal = The Lancet. Public Health | volume = 5 | issue = 4 | pages = e204–e212 | date = April 2020 | pmid = 31981489 | doi = 10.1016/S2468-2667(19)30241-5 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Hajek P, Phillips-Waller A, Przulj D, Pesola F, Myers Smith K, Bisal N, Li J, Parrott S, Sasieni P, Dawkins L, Ross L, Goniewicz M, Wu Q, McRobbie HJ | display-authors = 6 | title = A Randomized Trial of E-Cigarettes versus Nicotine-Replacement Therapy | journal = The New England Journal of Medicine | volume = 380 | issue = 7 | pages = 629–637 | date = February 2019 | pmid = 30699054 | doi = 10.1056/NEJMoa1808779 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Jackson SE, Kotz D, West R, Brown J | title = Moderators of real-world effectiveness of smoking cessation aids: a population study | journal = Addiction | volume = 114 | issue = 9 | pages = 1627–1638 | date = September 2019 | pmid = 31117151 | pmc = 6684357 | doi = 10.1111/add.14656 }}</ref><ref>{{cite journal | vauthors = Zhu SH, Zhuang YL, Wong S, Cummins SE, Tedeschi GJ | title = E-cigarette use and associated changes in population smoking cessation: evidence from US current population surveys | journal = BMJ | volume = 358 | pages = j3262 | date = July 2017 | pmid = 28747333 | pmc = 5526046 | doi = 10.1136/bmj.j3262 }}</ref><ref>{{cite web |title=Nicotine science and policy Q & A |url=https://www.clivebates.com/vaping-tobacco-harm-reduction-nicotine-science-and-policy-q-a/ |website=The counterfactual |date=17 February 2020}}</ref>

Additionally, descriptive evidence of e-cigarette and cigarette use patterns in the United States suggests that e-cigarettes are displacing cigarettes. The rise in e-cigarette use has coincided with a sharp decline in cigarette use for both teenagers and adults. For example, youth current cigarette smoking, at 5.8% in 2019, has declined by 63.3%<ref>{{cite web | author = Office of the Commissioner|title=Trump Administration Combating Epidemic of Youth E-Cigarette Use with Plan to Clear Market of Unauthorized, Non-Tobacco-Flavored E-Cigarette Products |url=https://www.fda.gov/news-events/press-announcements/trump-administration-combating-epidemic-youth-e-cigarette-use-plan-clear-market-unauthorized-non |website=FDA |language=en |date=24 March 2020}}</ref> from 2011 to 2019 (compared to only a 17.4% decline<ref>{{cite web |title=Youth Online: High School YRBS - 2017 Results {{!}} DASH {{!}} CDC |url=https://nccd.cdc.gov/youthonline/App/Results.aspx?TT=B&OUT=0&SID=HS&QID=H32&LID=LL&YID=RY&LID2=&YID2=&COL=&ROW1=&ROW2=&HT=&LCT=&FS=&FR=&FG=&FA=&FI=&FP=&FSL=&FRL=&FGL=&FAL=&FIL=&FPL=&PV=&TST=&C1=&C2=&QP=G&DP=&VA=CI&CS=Y&SYID=&EYID=&SC=&SO= |website=nccd.cdc.gov}}</ref> from 2003 to 2011 when e-cigarettes were not widely used). Over the same time period youth current e-cigarette use rose from 1.5% in 2011 to 27.5% in 2019. E-cigarettes are not as regularly used among adults, with adult current use<ref>{{cite journal | vauthors = Wang TW, Asman K, Gentzke AS, Cullen KA, Holder-Hayes E, Reyes-Guzman C, Jamal A, Neff L, King BA | display-authors = 6 | title = Tobacco Product Use Among Adults - United States, 2017 | language = en-us | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 67 | issue = 44 | pages = 1225–1232 | date = November 2018 | pmid = 30408019 | pmc = 6223953 | doi = 10.15585/mmwr.mm6744a2 }}</ref> at 2.8% in 2017.  The adult current smoking rate, at 13.7% in 2018, has declined by a more modest 27.9% between 2011<ref>{{cite web |title=Current Cigarette Smoking Among Adults — United States, 2011 |url=https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6144a2.htm |website=www.cdc.gov}}</ref> to 2018<ref>{{cite web |title=Current Cigarette Smoking Among Adults in the United States |url=https://www.cdc.gov/tobacco/data_statistics/fact_sheets/adult_data/cig_smoking/index.htm#anchor_1549902047693 |website=Centers for Disease Control and Prevention |language=en-us |date=18 November 2019}}</ref> compared to the more rapid 63.3% decline for youth current cigarette use.

[[File:Teens Using E-cigarettes More Likely to Start Smoking Tobacco.ogv|thumb|left|[[National Institute on Drug Abuse]] director [[Nora Volkow]] discussing a study that shows teens using e-cigarettes are more likely to start smoking tobacco.<ref>{{cite web|url=http://www.drugabuse.gov/videos/teens-using-e-cigarettes-more-likely-to-start-smoking-tobacco|title=Teens Using E-cigarettes More Likely to Start Smoking Tobacco| vauthors = Volkow N |author-link=Nora Volkow|publisher=[[National Institute on Drug Abuse]]|date=August 2015}}</ref>|alt=National Institute on Drug Abuse director Nora Volkow discussing a study showing teens using e-cigarettes are more likely to start smoking tobacco.]]
There is evidence for young adults and youth that e-cigarette use  is correlated with an increased change of one-time traditional cigarette use.<ref name="Public Health Consequences of E-Cigarettes"/> The evidence indicates that the e-cigarettes such as [[Juul]] that can provide greater levels of nicotine could increase the chance for users to transition from vaping to smoking cigarettes.<ref name="sciencedirect.com">{{cite journal | vauthors = Fadus MC, Smith TT, Squeglia LM | title = The rise of e-cigarettes, pod mod devices, and JUUL among youth: Factors influencing use, health implications, and downstream effects | journal = Drug and Alcohol Dependence | volume = 201 | pages = 85–93 | date = August 2019 | pmid = 31200279 | pmc = 7183384 | doi = 10.1016/j.drugalcdep.2019.04.011 }}</ref> Ethical concerns have been raised about minors' e-cigarette use and the potential to weaken cigarette smoking reduction efforts.<ref name="Franck2014"/> Protective factors from using e-cigarettes were better ability to read and write, exercising, being female, and not smoking.<ref>{{cite journal | vauthors = Naskar S, Jakati PK | title = "Vaping:" Emergence of a New Paraphernalia | journal = Indian Journal of Psychological Medicine | volume = 39 | issue = 5 | pages = 566–572 | date = 2017 | pmid = 29200550 | pmc = 5688881 | doi = 10.4103/IJPSYM.IJPSYM_142_17 }}</ref> Studies indicate vaping is correlated with traditional cigarettes and [[cannabis]] use.<ref name="sciencedirect.com"/> This includes impulsive and [[sensation seeking]] [[trait theory|personality types]] or exposure to people who are sympathetic with smoking and relatives.{{sfn|Stratton|2018|loc=Conceptual Framework: Patterns of Use Among Youth and Young Adults; p. 497}} A 2014 review using animal models found that nicotine exposure may increase the likelihood to using [[tobacco and other drugs|other drugs]], independent of factors associated with a common liability.{{#tag:ref|A 2012 review found "Whereas the "gateway" hypothesis does not specify mechanistic connections between "stages", and does not extend to the risks for ''addictions'', the concept of common liability to addictions incorporates sequencing of drug use initiation as well as extends to related addictions and their severity, provides a parsimonious explanation of substance use and addiction co-occurrence, and establishes a theoretical and empirical foundation to research in etiology, quantitative risk and severity measurement, as well as targeted non-drug-specific prevention and early intervention."<ref name=VanyukovTarter2012>{{cite journal | vauthors = Vanyukov MM, Tarter RE, Kirillova GP, Kirisci L, Reynolds MD, Kreek MJ, Conway KP, Maher BS, Iacono WG, Bierut L, Neale MC, Clark DB, Ridenour TA | display-authors = 6 | title = Common liability to addiction and "gateway hypothesis": theoretical, empirical and evolutionary perspective | journal = Drug and Alcohol Dependence | volume = 123 | issue = Suppl 1 | pages = S3-17 | date = June 2012 | pmid = 22261179 | pmc = 3600369 | doi = 10.1016/j.drugalcdep.2011.12.018 }}</ref>|group=notes}}{{sfn|Wilder|2016|p=123}} The gateway theory, in relation to using nicotine, has also been used as a way to propose that using tobacco-free nicotine is probably going to lead to using nicotine via tobacco smoking, and therefore that vaping by non-smokers, and especially by children, may result in smoking independent of other factors associated with starting smoking.{{sfn|Wilder|2016|p=123}} Some see the gateway model as a way to illustrate the potential risk-heightening effect of vaping and going on to use combusted tobacco products.{{sfn|Stratton|2018|loc=Conceptual Framework: Patterns of Use Among Youth and Young Adults; p. 496}}

There is concern regarding that the accessibility of e-liquid [[Flavoring#Flavorants or flavorings|flavors]] could lead to using additional [[tobacco products]] among non-smokers.<ref name=ShieldsBerman2017/> It is argued to implement the [[precautionary principle]] because vaping by non-smokers may lead to smoking.<ref name=FarsalinosLeHouezec2015>{{cite journal | vauthors = Farsalinos KE, Le Houezec J | title = Regulation in the face of uncertainty: the evidence on electronic nicotine delivery systems (e-cigarettes) | journal = Risk Management and Healthcare Policy | volume = 8 | pages = 157–167 | year = 2015 | pmid = 26457058 | pmc = 4598199 | doi = 10.2147/RMHP.S62116 }}</ref> There is a concern with the possibility that non-smokers as well as children may start nicotine use with e-cigarettes at a rate higher than anticipated than if they were never created.{{sfn|WHO|2014|p=6}} In certain cases, e-cigarettes might increase the likelihood of being exposed to nicotine itself, especially for never-nicotine users who start using nicotine products only as a result of these devices.<ref name=DropeCahn2017/> A 2015 review concluded that "Nicotine acts as a gateway drug on the brain, and this effect is likely to occur whether the exposure is from smoking tobacco, passive tobacco smoke or e-cigarettes."<ref name=KandelKandel2015>{{cite journal | vauthors = Kandel D, Kandel E | title = The Gateway Hypothesis of substance abuse: developmental, biological and societal perspectives | journal = Acta Paediatrica | volume = 104 | issue = 2 | pages = 130–137 | date = February 2015 | pmid = 25377988 | doi = 10.1111/apa.12851 | s2cid = 33575141 }}</ref> Because those with mental illness are highly predisposed to nicotine addiction, those who try e-cigarettes may be more likely to become dependent, raising concerns about facilitating a transition to combustible tobacco use.<ref name=HefnerValentine2017/> Even if an e-cigarette contains no nicotine, the user mimics the actions of smoking.<ref name=DautzenbergAdler2017/> This may renormalize tobacco use in the general public.<ref name=DautzenbergAdler2017/> Normalization of e-cigarette use may lead former cigarette smokers to begin using them, thereby reinstating their [[nicotine dependence]] and fostering a return to tobacco use.<ref name=NansseuBigna2016>{{cite journal | vauthors = Nansseu JR, Bigna JJ | title = Electronic Cigarettes for Curbing the Tobacco-Induced Burden of Noncommunicable Diseases: Evidence Revisited with Emphasis on Challenges in Sub-Saharan Africa | journal = Pulmonary Medicine | volume = 2016 | pages = 4894352 | year = 2016 | pmid = 28116156 | pmc = 5220510 | doi = 10.1155/2016/4894352 | doi-access = free }}{{CC-notice|cc=by4|url=https://www.hindawi.com/journals/pm/2016/4894352/|author(s)=Jobert Richie N. Nansseu and Jean Joel R. Bigna}}</ref> There is a possible risk of re-normalizing of tobacco use in areas where smoking is banned.<ref name=DautzenbergAdler2017/> Government intervention is recommended to keep children safe from the re-normalizing of tobacco, according to a 2017 review.<ref name=BiyaniDerkay2017/>

The "catalyst model" suggests that vaping may proliferate smoking in minors by sensitizing minors to nicotine with the use of a type of nicotine that is more pleasing and without the negative attributes of regular cigarettes.{{sfn|Stratton|2018|loc=Conceptual Framework: Patterns of Use Among Youth and Young Adults; p. 531}} A 2016 review, based on the catalyst model, "indicate that the perceived health risks, specific product characteristics (such as taste, price and inconspicuous use), and higher levels of acceptance among peers and others potentially make e-cigarettes initially more attractive to adolescents than tobacco cigarettes. Later, increasing familiarity with nicotine could lead to the reevaluation of both electronic and tobacco cigarettes and subsequently to a potential transition to tobacco smoking."<ref name=SchneiderDiehl2016/>

A 2016 UK [[Royal College of Physicians]] report stated that the concerns regarding vaping leading to smoking in young people are unfounded.{{sfn|Wilder|2016|p=128}} They stated that it more likely occurs from a common liability to using both products.{{sfn|Wilder|2016|p=128}} They went on to state, "Renormalisation concerns, based on the premise that e-cigarette use encourages tobacco smoking among others, also have no basis in experience to date."{{sfn|Wilder|2016|pp=186-187}} A 2015 [[Public Health England]] (PHE) report found no evidence e-cigarettes increase adult or [[youth smoking]].{{sfn|McNeill|2015|p=38}} They stated that it is possible e-cigarettes has contributed to the drop in [[smoking]].{{sfn|McNeill|2015|p=38}} In 2018, other scientific organizations, such as the Forum of International Respiratory Societies, disagrees.<ref>{{cite journal | vauthors = Ferkol TW, Farber HJ, La Grutta S, Leone FT, Marshall HM, Neptune E, Pisinger C, Vanker A, Wisotzky M, Zabert GE, Schraufnagel DE | display-authors = 6 | title = Electronic cigarette use in youths: a position statement of the Forum of International Respiratory Societies | journal = The European Respiratory Journal | volume = 51 | issue = 5 | pages = 1800278 | date = May 2018 | pmid = 29848575 | doi = 10.1183/13993003.00278-2018 | doi-access = free }}</ref>

=== Pregnancy ===

E-cigarette use was also rising among women, including women of childbearing age {{asof|2014|lc=y}},<ref name=Suter2015>{{cite journal | vauthors = Suter MA, Mastrobattista J, Sachs M, Aagaard K | title = Is there evidence for potential harm of electronic cigarette use in pregnancy? | journal = Birth Defects Research. Part A, Clinical and Molecular Teratology | volume = 103 | issue = 3 | pages = 186–195 | date = March 2015 | pmid = 25366492 | pmc = 4830434 | doi = 10.1002/bdra.23333 }}</ref> but the rate of use during pregnancy is unknown.<ref name=England2015>{{cite journal | vauthors = England LJ, Bunnell RE, Pechacek TF, Tong VT, McAfee TA | title = Nicotine and the Developing Human: A Neglected Element in the Electronic Cigarette Debate | journal = American Journal of Preventive Medicine | volume = 49 | issue = 2 | pages = 286–293 | date = August 2015 | pmid = 25794473 | pmc = 4594223 | doi = 10.1016/j.amepre.2015.01.015 }}</ref> Many woman still vape during pregnancy because of their perceived safety in comparison with tobacco.<ref name=QasimKarim2017/> In one of the few studies identified, a 2015 survey of 316 pregnant women in a Maryland clinic found that the majority had heard of e-cigarettes, 13% had ever used them, and 0.6% were current daily users.<ref name=SGUSReport2016/> These findings are of concern because the dose of nicotine delivered by e-cigarettes can be as high or higher than that delivered by traditional cigarettes.<ref name=SGUSReport2016/> The rate of e-cigarette use among pregnant adolescents is unknown.<ref name=SGUSReport2016/>

Descriptive evidence on vaping prevalence among pregnant women provides additional confirmation of such women's potential interest in e-cigarettes.  Data from two states in the Pregnancy Risk Assessment System (PRAMS) show that in 2015—roughly the mid-point of the study period—10.8% of the sample used e-cigarettes in the three months prior to the pregnancy while 7.0%, 5.8%, and 1.4% used these products respectively at the time of the pregnancy, in the first trimester, and at birth.<ref>{{cite journal | vauthors = Kapaya M, D'Angelo DV, Tong VT, England L, Ruffo N, Cox S, Warner L, Bombard J, Guthrie T, Lampkins A, King BA | display-authors = 6 | title = Use of Electronic Vapor Products Before, During, and After Pregnancy Among Women with a Recent Live Birth - Oklahoma and Texas, 2015 | language = en-us | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 68 | issue = 8 | pages = 189–194 | date = March 2019 | pmid = 30817748 | pmc = 6394383 | doi = 10.15585/mmwr.mm6808a1 }}</ref> According to National Health Interview Survey (NHIS) data from 2014 to 2017, 38.9% of pregnant smokers used e-cigarettes compared to only 13.5% of non-pregnant, reproductive age women smokers.<ref>{{cite journal | vauthors = Liu B, Xu G, Rong S, Santillan DA, Santillan MK, Snetselaar LG, Bao W | title = National Estimates of e-Cigarette Use Among Pregnant and Nonpregnant Women of Reproductive Age in the United States, 2014-2017 | journal = JAMA Pediatrics | volume = 173 | issue = 6 | pages = 600–602 | date = June 2019 | pmid = 31034001 | pmc = 6547070 | doi = 10.1001/jamapediatrics.2019.0658 }}</ref> A health economic study found that passing an e-cigarette minimum legal sale age laws in the United States increased teenage prenatal smoking by 0.6 percentage points and had no effect on birth outcomes.<ref>{{cite journal | vauthors = Pesko MF, Currie JM | title = E-cigarette minimum legal sale age laws and traditional cigarette use among rural pregnant teenagers | journal = Journal of Health Economics | volume = 66 | pages = 71–90 | date = July 2019 | pmid = 31121389 | pmc = 7051858 | doi = 10.1016/j.jhealeco.2019.05.003 }}</ref>

=== International ===

Among current and former smokers who have vaped at least once were reported in Canada, the UK, France, Belgium, Austria, Germany, the Netherlands, Luxemburg, Greece (22.4% in 2012), Malta (16.7% in 2012), Portugal (17.0% in 2012), Slovenia (20.3% in 2012), Spain (10.9% in 2012), Cyprus (23.6% in 2012), Denmark (36.3% in 2012), Slovakia (7.9% in 2012), the Czech Republic (34.3% in 2012), Ireland (12.1% in 2012), Latvia (23.9% in 2012), Lithuania (11.8% in 2012), Finland (20.5% in 2012), Sweden (12.4% in 2012), Estonia (22.3% in 2012), Hungary (22.3% in 2012), Bulgaria (31.1% in 2012), Romania (22.2% in 2012), Australia (2.0–20.0% in 2010–2013), Italy (5.6% in 2013), Poland (31.0% in 2012), Malaysia (19% in 2011), Brazil (8% in 2013), Mexico (4% in 2011), South Korea (11% in 2010), Brazil (8% in 2013), and China (2% in 2009).<ref name=BrelandSoule2017>{{cite journal | vauthors = Breland A, Soule E, Lopez A, Ramôa C, El-Hellani A, Eissenberg T | title = Electronic cigarettes: what are they and what do they do? | journal = Annals of the New York Academy of Sciences | volume = 1394 | issue = 1 | pages = 5–30 | date = April 2017 | pmid = 26774031 | pmc = 4947026 | doi = 10.1111/nyas.12977 | bibcode = 2017NYASA1394....5B }}</ref> In countries where there is not [[regulation of electronic cigarettes|regulation on e-cigarettes]], vaping is common in areas where smoking is not permitted.<ref name=ZainolAbidinZainalAbidin2017>{{cite journal | vauthors = Zainol Abidin N, Zainal Abidin E, Zulkifli A, Karuppiah K, Syed Ismail SN, Amer Nordin AS | title = Electronic cigarettes and indoor air quality: a review of studies using human volunteers | journal = Reviews on Environmental Health | volume = 32 | issue = 3 | pages = 235–244 | date = September 2017 | pmid = 28107173 | doi = 10.1515/reveh-2016-0059 | s2cid = 6885414 | url = http://psasir.upm.edu.my/id/eprint/61699/1/Electronic%20cigarettes%20and%20indoor%20air%20quality.pdf }}</ref> Of the participants 15 and higher in Taiwan in 2015, 2.7% stated to have ever tried an e-cigarette.{{sfn|McNeill|2018|p=99}} Of the participants 15 to 65 in Hong Kong in 2014, 2.3% stated to have ever tried an e-cigarette.{{sfn|McNeill|2018|p=99}} Of the adult participants in the Republic of Korea in 2013, 6.6% stated to have ever tried an e-cigarette while 1.1% were current e-cigarette users.{{sfn|McNeill|2018|p=99}} Of the participants 15 and higher in New Zealand in 2014, 13.1% stated to have ever tried an e-cigarette while 0.8% were current e-cigarette users.{{sfn|McNeill|2018|p=100}}

=== United States ===

In the US, vaping is normally the highest among young adults and adolescents.<ref name=JenssenWalley2019/> In 2016 in the US, there were greater than 2.5 million e-cigarette users.<ref name=SerrorChaouat2018/> In 2016, 3.2% of US adults were current e-cigarette users.<ref name=CDC2017/> Among current e-cigarette users aged 45 years and older in 2015, most were either current or former regular cigarette smokers, and 1.3% had never been cigarette smokers.<ref name=CDC2017/> In contrast, among current e-cigarette users aged 18–24 years, 40.0% had never been regular cigarette smokers.<ref name=CDC2017>{{cite web|url=https://www.cdc.gov/tobacco/basic_information/e-cigarettes/index.htm|title=Electronic Cigarettes|publisher=Centers for Disease Control and Prevention|date=7 September 2017}}{{PD-notice}}</ref> A 2018 review suggested that e-cigarettes are contributing to the [[prevalence of tobacco consumption|tobacco epidemic]] by attracting smokers who are interested in quitting but reducing the likelihood of those smokers to quit successfully.<ref name=GlantzBareham2018/> This effect maybe reflected in the fact that in 2015 the number of cigarettes consumed in the US was higher than in 2014, the ﬁrst time cigarette consumption increased since 1973.<ref name=GlantzBareham2018/> In the US, {{asof|2014|lc=y}}, 12.6% of adults had used an e-cigarette at least once and about 3.7% were still using them.<ref name=CDC2015>{{cite web|url=https://www.cdc.gov/nchs/data/databriefs/db217.pdf|title=Electronic Cigarette Use Among Adults: United States, 2014|pages=1–8| vauthors = Schoenborn CA, Gindi RM |publisher=Centers for Disease Control and Prevention|date=October 2015}}</ref> In 2014, about 3.8% employed adults were e-cigarette users.<ref name=SyamlalJamal2016>{{cite journal | vauthors = Syamlal G, Jamal A, King BA, Mazurek JM | title = Electronic Cigarette Use Among Working Adults - United States, 2014 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 65 | issue = 22 | pages = 557–561 | date = June 2016 | pmid = 27281058 | doi = 10.15585/mmwr.mm6522a1 | doi-access = free }}</ref> As of mid-2015 around 10% of American adults are current users of e-cigarettes.<ref name=Mincer2015>{{cite news|url=https://www.reuters.com/article/us-usa-ecigarette-poll-analysis-idUSKBN0OQ0CA20150610|title=E-cigarette usage surges in past year: Reuters/Ipsos poll| vauthors = Mincer J |work=[[Reuters]]|date=10 June 2015}}</ref> In 2014, 1.1% of adults were daily users.<ref name=Delnevo2015>{{cite journal | vauthors = Delnevo CD, Giovenco DP, Steinberg MB, Villanti AC, Pearson JL, Niaura RS, Abrams DB | title = Patterns of Electronic Cigarette Use Among Adults in the United States | journal = Nicotine & Tobacco Research | volume = 18 | issue = 5 | pages = 715–719 | date = May 2016 | pmid = 26525063 | pmc = 5896829 | doi = 10.1093/ntr/ntv237 }}</ref> In 2014 in the US, 93% of e-cigarette users continued to smoke cigarettes.<ref name=GlantzBareham2018/> Non-smokers and former smokers who had quit more than four years earlier were extremely unlikely to be current users.<ref name=Delnevo2015/> Former smokers who had recently quit were more than four times as likely to be daily users as current smokers.<ref name=Delnevo2015/> Experimentation was more common among younger adults, but daily users were more likely to be older adults.<ref name=Delnevo2015/> Cigarettes and e-cigarettes are most frequently used together for adults and youth utilizing more than one tobacco product.<ref name=ShieldsBerman2017>{{cite journal | vauthors = Shields PG, Berman M, Brasky TM, Freudenheim JL, Mathe E, McElroy JP, Song MA, Wewers MD | display-authors = 6 | title = A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation | journal = Cancer Epidemiology, Biomarkers & Prevention | volume = 26 | issue = 8 | pages = 1175–1191 | date = August 2017 | pmid = 28642230 | pmc = 5614602 | doi = 10.1158/1055-9965.EPI-17-0358 }}</ref> More generally, there is supportive evidence that e-cigarettes and traditional cigarettes are economic substitutes, and that e-cigarettes are displacing smoking rather than causing more smoking through a gateway effect.

<ref>{{cite journal | vauthors = Pesko M, Warman C |title=The Effect of Prices and Taxes on Youth Cigarette and E-cigarette Use: Economic Substitutes or Complements? | journal = Health Economics |publisher=Social Science Research Network |language=en |date=5 September 2017|ssrn=3077468 }}</ref><ref>{{cite journal | vauthors = Saffer H, Dench D, Grossman M, Dave D | title = E-Cigarettes and Adult Smoking: Evidence from Minnesota | journal = Journal of Risk and Uncertainty | volume = 60 | issue = 3 | pages = 207–228 | date = June 2020 | pmid = 32943812 | doi = 10.3386/w26589 | publisher = National Bureau of Economic Research | pmc = 7491748 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Pesko MF, Courtemanche CJ, Catherine Maclean J | title = The effects of traditional cigarette and e-cigarette tax rates on adult tobacco product use | journal = Journal of Risk and Uncertainty | volume = 60 | issue = 3 | pages = 229–258 | date = June 2020 | pmid = 33584006 | doi = 10.3386/w26017 | publisher = National Bureau of Economic Research | pmc = 7880200 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Abouk R, Adams S, Feng B, Maclean JC, Pesko MF |title=The Effect of E-Cigarette Taxes on Pre-Pregnancy and Prenatal Smoking, and Birth Outcomes | journal =  National Bureau of Economic Research |date=July 2019 |url=https://www.nber.org/papers/w26126 |doi=10.3386/w26126 |doi-access=free }}</ref><ref>{{cite report | vauthors = Cotti CD, Courtemanche CJ, Maclean JC, Nesson ET, Pesko MF, Tefft N |title=The Effects of E-Cigarette Taxes on E-Cigarette Prices and Tobacco Product Sales: Evidence from Retail Panel Data |date=January 2020 |url=https://www.nber.org/papers/w26724 |publisher=National Bureau of Economic Research|doi=10.3386/w26724 |doi-access=free }}</ref> Also, it is interesting to note that 15% of individuals with mental illness have tried vaping.<ref name=DasProchaska2017>{{cite journal | vauthors = Das S, Prochaska JJ | title = Innovative approaches to support smoking cessation for individuals with mental illness and co-occurring substance use disorders | journal = Expert Review of Respiratory Medicine | volume = 11 | issue = 10 | pages = 841–850 | date = October 2017 | pmid = 28756728 | pmc = 5790168 | doi = 10.1080/17476348.2017.1361823 }}</ref>

==== United States youth ====

The recent decline in smoking has accompanied a rapid growth in the use of alternative nicotine products among youth and young adults.<ref name=Lauterstein2014/> E-cigarettes are the most frequently used tobacco product among US youths.<ref name=SinghKennedy2016>{{cite journal | vauthors = Singh T, Kennedy S, Marynak K, Persoskie A, Melstrom P, King BA | title = Characteristics of Electronic Cigarette Use Among Middle and High School Students - United States, 2015 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 65 | issue = 50–51 | pages = 1425–1429 | date = December 2016 | pmid = 28033310 | doi = 10.15585/mmwr.mm655051a2 | doi-access = free }}{{PD-notice}}</ref> In the US, youth are more likely than adults to use e-cigarettes.<ref name=CDC2017/> In the US among youth, vaping is the most in boys, non-Hispanic white youth and Hispanic youth.<ref name=JenssenWalley2019>{{cite journal | vauthors = Jenssen BP, Walley SC | title = E-Cigarettes and Similar Devices | journal = Pediatrics | volume = 143 | issue = 2 | pages = e20183652 | date = February 2019 | pmid = 30835247 | pmc = 6644065 | doi = 10.1542/peds.2018-3652 }}</ref> A considerable increase in e-cigarette use among US youths, coupled with no change in use of other tobacco products during 2017–2018, has erased recent progress in reducing overall tobacco product use among youths.<ref name=GentzkeCreamer2019/> Among both US high school and middle school students, current use of e-cigarettes increased considerably between 2017 and 2018, reaching epidemic proportions, according to the [[Surgeon General of the United States|US Surgeon General]]; approximately 1.5 million more youths currently used e-cigarettes in 2018 (3.6 million) compared with 2017 (2.1 million).<ref name=GentzkeCreamer2019/> However, no significant change in current use of combustible tobacco products, such as cigarettes and cigars, was observed in recent years or during 2017–2018.<ref name=GentzkeCreamer2019/> This recent increase in e-cigarette use among youths is consistent with observed increases in sales of the e-cigarette Juul, a USB-shaped e-cigarette device with a high nicotine content that can be used discreetly and is available in flavors that can appeal to youths.<ref name=GentzkeCreamer2019/> This indicates that e-cigarettes were the driver of the observed increase in any tobacco product use.<ref name=GentzkeCreamer2019>{{cite journal | vauthors = Gentzke AS, Creamer M, Cullen KA, Ambrose BK, Willis G, Jamal A, King BA | title = Vital Signs: Tobacco Product Use Among Middle and High School Students - United States, 2011-2018 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 68 | issue = 6 | pages = 157–164 | date = February 2019 | pmid = 30763302 | pmc = 6375658 | doi = 10.15585/mmwr.mm6806e1 }}{{PD-notice}}</ref>

Among American youth who had tried a vaporizer at least once, 65-66% most recently tried flavoring in 12th, in 10th, and in 8th grade in 2017.<ref name=MiechPatrick2017/> Vaping with nicotine was approximately 20% in 12th and 10th grade and for 8th graders 13%, according to data from the [[Monitoring the Future]] in 2017.<ref name=MiechPatrick2017>{{cite journal | vauthors = Miech R, Patrick ME, O'Malley PM, Johnston LD | title = What are kids vaping? Results from a national survey of US adolescents | journal = Tobacco Control | volume = 26 | issue = 4 | pages = 386–391 | date = July 2017 | pmid = 27562412 | pmc = 5326604 | doi = 10.1136/tobaccocontrol-2016-053014 }}</ref> E-cigarettes were the most commonly used tobacco product among US middle school and high school students in 2016.<ref name=TsaiWalton2018/> In 2016, more than 2 million US middle and high school students used e-cigarettes in the past 30 days, including 4.3% of middle school students and 11.3% of high school students.<ref name=CDC2017/> In 2015, 58.8% of high school students who were current users of combustible tobacco products were also current users of e-cigarettes.<ref name=CDC2016>{{cite web|url=https://www.cdc.gov/tobacco/data_statistics/sgr/e-cigarettes/pdfs/2016_SGR_Chap_2_508.pdf|title=2016 Surgeon General's Report: E-Cigarette Use Among Youth and Young Adults - Chapter 2 - Patterns of E-Cigarette Use Among U.S. Youth and Young Adults|publisher=Centers for Disease Control and Prevention|year=2016}}{{PD-notice}}</ref> 1 in 6 high school students used an e-cigarette in the past 30 days in 2015.<ref name=HHS2016>{{cite web|url=https://www.hhs.gov/about/news/2016/12/08/surgeon-general-reports-youth-and-young-adult-e-cigarette-use-poses-public-health-threat.html|archive-url=http://wayback.archive-it.org/3926/20170128144427/https://www.hhs.gov/about/news/2016/12/08/surgeon-general-reports-youth-and-young-adult-e-cigarette-use-poses-public-health-threat.html|url-status=dead|archive-date=28 January 2017|title=Surgeon General Reports Youth and Young Adult E-Cigarette Use Poses a Public Health Threat|publisher=United States Department of Health and Human Services|date=8 December 2016}}{{PD-notice}}</ref> Between 2011 and 2015, vaping among minors increased 900 percent.<ref name=Mays2016>{{cite news| vauthors = Mays L |title=U.S. Surgeon General calls for crackdown on e-cig use|url=http://abc3340.com/news/local/us-surgeon-general-calls-for-crackdown-on-e-cig-use|publisher=[[WBMA-LD]]|agency=[[Sinclair Broadcast Group]]|date=8 December 2016}}</ref> In the US, vaping among youth exceeded smoking in 2014.<ref name=Hildick-SmithPesko2015>{{cite journal | vauthors = Hildick-Smith GJ, Pesko MF, Shearer L, Hughes JM, Chang J, Loughlin GM, Ipp LS | title = A Practitioner's Guide to Electronic Cigarettes in the Adolescent Population | journal = The Journal of Adolescent Health | volume = 57 | issue = 6 | pages = 574–579 | date = December 2015 | pmid = 26422289 | doi = 10.1016/j.jadohealth.2015.07.020 | doi-access = free }}</ref> {{Asof|2014}}, up to 13% of American high school students had used them at least once in the last month.<ref name=CDCUSE2015>{{cite web|url=https://www.cdc.gov/media/releases/2015/p0416-e-cigarette-use.html|title=E-cigarette use triples among middle and high school students in just one year|publisher=Centers for Disease Control and Prevention|date=16 April 2015}}</ref>

Youth are attracted by e-cigarettes’ novelty, the perception that they are harmless or less harmful than cigarettes, and the thousands of flavors (e.g., fruit, chocolate, peanut butter, bubble gum, gummy bear, among others).<ref name=GlantzBareham2018/> As a result, youth e-cigarette use in the US doubled or tripled every year between 2011 and 2014.<ref name=GlantzBareham2018/> At the same time that e-cigarette use was increasing, cigarette smoking among youth declined, leading some to suggest that e-cigarettes were replacing traditional cigarettes among youth and are contributing to declines in youth smoking.<ref name=GlantzBareham2018/> At least through 2014, however, e-cigarettes had no detectable effect on the decline in cigarette smoking among US adolescent.<ref name=GlantzBareham2018/> Between 2013 and 2014, vaping among students tripled.<ref name=KambojSpiller2016>{{cite journal | vauthors = Kamboj A, Spiller HA, Casavant MJ, Chounthirath T, Smith GA | title = Pediatric Exposure to E-Cigarettes, Nicotine, and Tobacco Products in the United States | journal = Pediatrics | volume = 137 | issue = 6 | pages = e20160041 | date = June 2016 | pmid = 27244861 | doi = 10.1542/peds.2016-0041 | doi-access = free }}</ref> In 2013 the [[Centers for Disease Control and Prevention]] (CDC) estimated that around 160,000 students between 2011 and 2012 who had tried vaping had never smoked cigarettes.<ref name=Lauterstein2014>{{cite journal | vauthors = Lauterstein D, Hoshino R, Gordon T, Watkins BX, Weitzman M, Zelikoff J | title = The changing face of tobacco use among United States youth | journal = Current Drug Abuse Reviews | volume = 7 | issue = 1 | pages = 29–43 | year = 2014 | pmid = 25323124 | pmc = 4469045 | doi = 10.2174/1874473707666141015220110 }}</ref> E-cigarette use among never-smoking youth in the US correlates with elevated desires to use traditional cigarettes.<ref name=EbbertAgunwamba2015/> Teenagers who had used an e-cigarette were more inclined to become smokers than those who had not.<ref name=Schraufnagel2015/> In the 2015 Monitoring the Future survey, a majority of students who used e-cigarettes reported using liquid without nicotine the last time they vaped.<ref name=MTF2015>{{cite web|url=https://www.drugabuse.gov/related-topics/trends-statistics/monitoring-future/monitoring-future-survey-overview-findings-2015|title=Monitoring the Future Survey, Overview of Findings 2015|publisher=National Institute on Drug Abuse|date=December 2015}}</ref> The majority of youth who vape also smoke.<ref name=CDCNYTS2013>{{cite journal | vauthors = Chatham-Stephens K, Law R, Taylor E, Melstrom P, Bunnell R, Wang B, Apelberg B, Schier JG | display-authors = 6 | title = Notes from the field: calls to poison centers for exposures to electronic cigarettes--United States, September 2010-February 2014 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 63 | issue = 13 | pages = 292–293 | date = April 2014 | pmid = 24699766 | pmc = 5779356 | url = https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6345a2.htm?s_cid=mm6345a2_w }}</ref> A long-term survey of high school students in Hawaii reported that shifting from never-use to smoking was associated with vaping.<ref name=EchevarriaSinha2016>{{cite journal | vauthors = Echevarria C, Sinha IP | title = Heterogeneity in the measurement and reporting of outcomes in studies of electronic cigarette use in adolescents: a systematic analysis of observational studies | journal = Tobacco Control | volume = 26 | issue = 3 | pages = 247–253 | date = May 2017 | pmid = 27129981 | doi = 10.1136/tobaccocontrol-2015-052881 | s2cid = 3355614 }}</ref> A 2010–2011 survey of students at two US high schools found that vapers were more likely to use [[hookah]] and [[Blunt (cigar)|blunts]] than smokers.<ref name=Cooke2015/> Among grade 6 to 12 students in the US, the proportion who have tried them rose from 3.3% in 2011 to 6.8% in 2012.<ref name=Chapman2014>{{cite journal | vauthors = Carroll Chapman SL, Wu LT | title = E-cigarette prevalence and correlates of use among adolescents versus adults: a review and comparison | journal = Journal of Psychiatric Research | volume = 54 | pages = 43–54 | date = July 2014 | pmid = 24680203 | pmc = 4055566 | doi = 10.1016/j.jpsychires.2014.03.005 }}</ref> Those still vaping over the last month rose from 1.1% to 2.1% and dual use rose from 0.8% to 1.6%.<ref name=Chapman2014/> Over the same period, the proportion of grade-6-to-12 students who regularly smoke tobacco fell from 7.5% to 6.7%.<ref name=MMWR-2013>{{cite journal | title = Tobacco product use among middle and high school students--United States, 2011 and 2012 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 62 | issue = 45 | pages = 893–897 | date = November 2013 | pmid = 24226625 | pmc = 4585347 | url = https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6245a2.htm?s_cid=mm6245a2_e | author1 = Centers for Disease Control Prevention (CDC) }}</ref> The evidence indicates that vaping may promote, instead of impede, the use of traditional cigarettes among US adolescents.<ref name=Siqueira2016>{{cite journal | vauthors = Siqueira LM | title = Nicotine and Tobacco as Substances of Abuse in Children and Adolescents | journal = Pediatrics | volume = 139 | issue = 1 | pages = e20163436 | date = January 2017 | pmid = 27994114 | doi = 10.1542/peds.2016-3436 | doi-access = free }}</ref>

=== European Union & UK ===

In 2016 in Europe, there were 7.5 million e-cigarette users.<ref name=SerrorChaouat2018>{{cite journal | vauthors = Serror K, Chaouat M, Legrand MM, Depret F, Haddad J, Malca N, Mimoun M, Boccara D | display-authors = 6 | title = Burns caused by electronic vaping devices (e-cigarettes): A new classification proposal based on mechanisms | journal = Burns | volume = 44 | issue = 3 | pages = 544–548 | date = May 2018 | pmid = 29056367 | doi = 10.1016/j.burns.2017.09.005 }}</ref> There were an estimated 3.6 million adult users in the UK in 2019.<ref name=ASH2019>{{cite web|url=https://ash.org.uk/wp-content/uploads/2019/09/Use-of-e-cigarettes-among-adults-2019.pdf|title=Use of e-cigarettes (vaporisers) among adults in Great Britain|publisher=[[Action on Smoking and Health#ASH (United Kingdom)|ASH UK]]|date=September 2019}}</ref> In 2018, regular e-cigarette use in the UK was greater than in other countries in the EU.{{sfn|McNeill|2018|p=15}} Regular e-cigarette use in the UK in 2018 was about 2%.{{sfn|McNeill|2018|p=15}} In the UK in 2018, e-cigarette use among adults was about 6%.{{sfn|McNeill|2018|p=14}} In the UK in 2017, around 2.9 million adults use e-cigarettes.<ref name=ASH2017>{{cite web|url=http://ash.org.uk/media-and-news/press-releases-media-and-news/large-national-survey-finds-2-9-million-people-now-vape-in-britain-for-the-first-time-over-half-no-longer-smoke/|title=Large national survey finds 2.9 million people now vape in Britain: For the first time over half don't smoke|publisher=ASH UK|date=8 May 2017}}</ref> In the UK, user numbers increased from 700,000 in 2012 to 2.6 million in 2015, but use by current smokers remained flat at 17.6% from 2014 into 2015 (in 2010, it was 2.7%).<ref name=ASH2016/> About one in 20 adults in the UK uses e-cigarettes.{{sfn|McNeill|2015|p=8}} In the UK in 2015, 18% of regular smokers said they used e-cigarettes and 59% said they had used them in the past.<ref name=ASH2016/> Among those who had never smoked, 1.1% said they had tried them and 0.2% still use them.<ref name=ASH2016>{{cite web|url=http://www.ash.org.uk/files/documents/ASH_891.pdf|title=Use of electronic cigarettes (vaporisers) among adults in Great Britain|publisher=ASH UK|date=May 2016}}</ref> In 2014 in the UK, 60% e-cigarette users continued to smoke cigarettes.<ref name=GlantzBareham2018/> About 60% of all users are smokers and most of the rest are ex-smokers, with negligible numbers of never-smokers.<ref name=ASH-2014>{{cite web|url=http://www.ash.org.uk/media-room/press-releases/:over-2-million-britons-now-regularly-use-electronic-cigarettes|title=Over 2 million Britons now regularly use electronic cigarettes|publisher=ASH UK|date=28 April 2014}}</ref> In 2015 figures showed around 2% monthly EC-usage among under-18s, and 0.5% weekly, and despite experimentation, "nearly all those using EC regularly were cigarette smokers".{{sfn|McNeill|2015|p=31}} Non-smokers in the UK who vaped are more likely to have smoked later on than people who did not vape.{{sfn|McNeill|2018|p=13}}

==== European Union youth ====

Public Health England reported that 1.7% of those aged 11–18 years in England had regularly used e-cigarettes in 2018.<ref name=PH2018/> Regular use was low among those who had never smoked.<ref name=PH2018>{{cite news |title=Regular e-cigarette use remains low in young people and stable in adults, PHE report finds|url=https://www.pharmaceutical-journal.com/20206230.article|publisher=Pharmaceutical Journal|date=28 February 2019}}</ref> Those from 11 to 16, one-time e-cigarette use varied from 7-18% of the respondents among the 2015-2016 EU surveys.{{sfn|McNeill|2018|p=65}} Regular vaping in young people who have not tried smoking, varied from 0.1% to 0.5% in all EU surveys.{{sfn|McNeill|2018|p=65}} In 2016 in the UK, those between 11 and 18 in the UK, 10% reported they have used e-cigarettes at least once or twice.<ref name=ASH-2016/> In 2016 in the UK, 2% reported they have vaped more than once a month, including 1% stated they used them every week.<ref name=ASH-2016>{{cite web|url=http://ash.org.uk/download/use-of-electronic-cigarettes-among-children-in-great-britain/|title=Use of electronic cigarettes among children in Great Britain|publisher=ASH UK|date=October 2016}}</ref> A 2016 study found 11–16-year-olds English children exposed to e-cigarette advertisements highlighting flavored, in contrast to flavor-free products, did bring about more appeal to e-cigarettes.<ref name=PetersonHecht2017/> In Fife, Scotland in 2013, 19% of 15-year-olds and 10% of 13-year-olds reported they tried e-cigarettes.<ref name=de-AndradeAngus2015>{{cite journal | vauthors = de Andrade M, Angus K, Hastings G | title = Teenage perceptions of electronic cigarettes in Scottish tobacco-education school interventions: co-production and innovative engagement through a pop-up radio project | journal = Perspectives in Public Health | volume = 136 | issue = 5 | pages = 288–293 | date = September 2016 | pmid = 26543156 | doi = 10.1177/1757913915612109 | s2cid = 3792825 }}</ref> Both were 3% above that of the typical figures in Scottish for this age group.<ref name=de-AndradeAngus2015/> 10–11-year-olds Welsh never-smokers are more likely to use e-cigarettes if a parent used e-cigarettes.<ref>{{cite journal | vauthors = Moore GF, Littlecott HJ, Moore L, Ahmed N, Holliday J | title = E-cigarette use and intentions to smoke among 10-11-year-old never-smokers in Wales | journal = Tobacco Control | volume = 25 | issue = 2 | pages = 147–152 | date = March 2016 | pmid = 25535293 | pmc = 4789807 | doi = 10.1136/tobaccocontrol-2014-052011 }}</ref> The popularity of vaping is greater among the youth from Central and Eastern Europe than other places in Europe.<ref name=JankowskiBrożek2017/>

=== France ===

In France, a 2014 survey estimated between 7.7 and 9.2 million people had tried e-cigarettes and 1.1 to 1.9 million use them on a daily basis.<ref name=FODDA2014/> The same survey also found 67% of smokers used e-cigarettes to reduce or quit smoking.<ref name=FODDA2014/> Of respondents who indicated they tried e-cigarettes, 9% said they had never smoked tobacco.<ref name=FODDA2014/> Of the 1.2% who had recently stopped tobacco smoking at the time of the survey, 84% (or 1% of the population surveyed) credited e-cigarettes as essential in quitting.<ref name=FODDA2014>{{cite web|url=http://www.ofdt.fr/BDD/publications/docs/eisxalu2.pdf|publisher=Observatoire Français des Drogues et des Toxicomanies|title=Prévalence, comportements d'achat et d'usage, motivations des utilisateurs de la cigarette électronique|trans-title=Prevalence, buying and use behaviour, motivations of users of electronic cigarette|language=fr|date=12 February 2014}}</ref> Approximately greater than 90% of French smokers have vaped.<ref name=DautzenbergAdler2017>{{cite journal | vauthors = Dautzenberg B, Adler M, Garelik D, Loubrieu JF, Mathern G, Peiffer G, Perriot J, Rouquet RM, Schmitt A, Underner M, Urban T | display-authors = 6 | title = Practical guidelines on e-cigarettes for practitioners and others health professionals. A French 2016 expert's statement | journal = Revue des Maladies Respiratoires | volume = 34 | issue = 2 | pages = 155–164 | date = February 2017 | pmid = 28189437 | doi = 10.1016/j.rmr.2017.01.001 }}</ref> In 2014 in France, 83% e-cigarette users continued to smoke cigarettes.<ref name=GlantzBareham2018/>

=== Australia ===

Vaping in Australia has risen quickly even with legal barriers to trade of nicotine for non-therapeutic uses.<ref name=FraserWeier2015>{{cite journal | vauthors = Fraser D, Weier M, Keane H, Gartner C | title = Vapers' perspectives on electronic cigarette regulation in Australia | journal = The International Journal on Drug Policy | volume = 26 | issue = 6 | pages = 589–594 | date = June 2015 | pmid = 25724266 | doi = 10.1016/j.drugpo.2015.01.019 | doi-access = free }}</ref> It is unclear whether comparable rises in e-cigarette use as seen in the US are to be anticipated in Australia.<ref name=HessLachireddy2016>{{cite journal | vauthors = Hess IM, Lachireddy K, Capon A | title = A systematic review of the health risks from passive exposure to electronic cigarette vapour | journal = Public Health Research & Practice | volume = 26 | issue = 2 | date = April 2016 | pmid = 27734060 | doi = 10.17061/phrp2621617 | doi-access = free }}</ref> In New South Wales in 2014, the frequency of regular e-cigarettes users was 1.3%, with 8.4% had tried them.<ref name=HessLachireddy2016/> Around 78,000 people were regular e-cigarettes users in New South Wales; this is generally low than in some other countries, such as the US and the UK.<ref name=HessLachireddy2016/> A 2015 online survey found that 97% of participants stated they were daily smokers before trying an e-cigarette.<ref name=FraserWeier2015/> Data on daily vaping in Australia is not available.<ref name=Chapman-2015/> A 2013 national Australian survey showed that 15.4% of smokers that were 14 years old or higher had vaped at least one time in the prior 12 months, even though selling nicotine liquid is not legal their.<ref name=Chapman-2015>{{cite journal | vauthors = Chapman S | title = The future of electronic cigarette growth depends on youth uptake | journal = The Medical Journal of Australia | volume = 202 | issue = 9 | pages = 467–468 | date = May 2015 | pmid = 25971560 | doi = 10.5694/mja15.00304 | doi-access = free }}</ref>

=== Youth ===
[[File:Home-page-chart-infographic.png|thumb|upright=1.5|Today, more high school students use e-cigarettes than regular cigarettes.<ref name=SGUS2016/> The use of e-cigarettes is higher among high school students than adults.<ref name=SGUS2016>{{cite web|url=https://e-cigarettes.surgeongeneral.gov/|title=THE FACTS on e-cigarette use among youth and young adults|publisher=Surgeon General of the United States|year=2016}}{{PD-notice}}</ref>|alt=Today, more high school students use e-cigarettes than regular cigarettes. The use of e-cigarettes is higher among high school students than adults.]]
The prevalence of vaping among adolescents is increasing worldwide.<ref name=SchneiderDiehl2016>{{cite journal | vauthors = Schneider S, Diehl K | title = Vaping as a Catalyst for Smoking? An Initial Model on the Initiation of Electronic Cigarette Use and the Transition to Tobacco Smoking Among Adolescents | journal = Nicotine & Tobacco Research | volume = 18 | issue = 5 | pages = 647–653 | date = May 2016 | pmid = 26386472 | doi = 10.1093/ntr/ntv193 }}</ref> There is substantial variability in vaping in youth worldwide across countries.<ref name=YoongStockings2018>{{cite journal | vauthors = Yoong SL, Stockings E, Chai LK, Tzelepis F, Wiggers J, Oldmeadow C, Paul C, Peruga A, Kingsland M, Attia J, Wolfenden L | display-authors = 6 | title = Prevalence of electronic nicotine delivery systems (ENDS) use among youth globally: a systematic review and meta-analysis of country level data | journal = Australian and New Zealand Journal of Public Health | volume = 42 | issue = 3 | pages = 303–308 | date = June 2018 | pmid = 29528527 | doi = 10.1111/1753-6405.12777 | doi-access = free }}</ref> Over the years leading up to 2017 vaping among adolescents has grown every year since theses devices were first introduced to the market.<ref name=BiyaniDerkay2017/> There appears to be an increase of one-time e-cigarette use among young people worldwide.{{sfn|McNeill|2015|p=87}} The frequency of vaping in youth is low.<ref name=Brandon2015/> The result of youth e-cigarette use leading to smoking is unclear.<ref name=ZhongCao2016/> Most e-cigarette users among youth have never smoked.<ref name=ZhongCao2016>{{cite journal | vauthors = Zhong J, Cao S, Gong W, Fei F, Wang M | title = Electronic Cigarettes Use and Intention to Cigarette Smoking among Never-Smoking Adolescents and Young Adults: A Meta-Analysis | journal = International Journal of Environmental Research and Public Health | volume = 13 | issue = 5 | pages = 465 | date = May 2016 | pmid = 27153077 | pmc = 4881090 | doi = 10.3390/ijerph13050465 | doi-access = free }}</ref> Many youth who use e-cigarettes also smoke traditional cigarettes.<ref name=Grana2014/> Some youths who have tried an e-cigarette have never used a traditional cigarette; indicating e-cigarettes may be a starting point for nicotine use.<ref name=Grana2014/> Adolescents who would have not been using nicotine products to begin with are vaping.<ref name=Modesto-LoweAlvarado2017>{{cite journal | vauthors = Modesto-Lowe V, Alvarado C | title = E-cigs . . . Are They Cool? Talking to Teens About E-Cigarettes | journal = Clinical Pediatrics | volume = 56 | issue = 10 | pages = 947–952 | date = September 2017 | pmid = 28443340 | doi = 10.1177/0009922817705188 | s2cid = 44423931 }}</ref> Twice as many youth vaped in 2014 than also used traditional cigarettes.<ref name=EnglandAagaard2017>{{cite journal | vauthors = England LJ, Aagaard K, Bloch M, Conway K, Cosgrove K, Grana R, Gould TJ, Hatsukami D, Jensen F, Kandel D, Lanphear B, Leslie F, Pauly JR, Neiderhiser J, Rubinstein M, Slotkin TA, Spindel E, Stroud L, Wakschlag L | display-authors = 6 | title = Developmental toxicity of nicotine: A transdisciplinary synthesis and implications for emerging tobacco products | journal = Neuroscience and Biobehavioral Reviews | volume = 72 | pages = 176–189 | date = January 2017 | pmid = 27890689 | pmc = 5965681 | doi = 10.1016/j.neubiorev.2016.11.013 }}</ref> Vaping seems to be a gateway to using traditional cigarettes in adolescents.<ref name=PetersonHecht2017>{{cite journal | vauthors = Peterson LA, Hecht SS | title = Tobacco, e-cigarettes, and child health | journal = Current Opinion in Pediatrics | volume = 29 | issue = 2 | pages = 225–230 | date = April 2017 | pmid = 28059903 | pmc = 5598780 | doi = 10.1097/MOP.0000000000000456 }}</ref> Youth who use e-cigarettes are more likely to go on to use traditional cigarettes.<ref name=SGUSFactSheet2016>{{cite web|url=https://e-cigarettes.surgeongeneral.gov/documents/2016_SGR_Fact_Sheet_508.pdf|title=E-Cigarette Use Among Youth and Young Adults A Report of the Surgeon General: Fact Sheet|publisher=Surgeon General of the United States|year=2016}}{{PD-notice}}</ref>{{sfn|Stratton|2018|loc=Summary; p. 16}} The evidence suggests that young people who vape are also at greater risk for subsequent long-term tobacco use.<ref name=ACS2018>{{cite web|url=https://www.cancer.org/healthy/stay-away-from-tobacco/e-cigarette-position-statement.html|title=American Cancer Society Position Statement on Electronic Cigarettes|publisher=American Cancer Society|date=February 2018}}</ref> E-cigarettes are expanding the nicotine market by attracting low-risk youth who would be unlikely to initiate nicotine use with traditional cigarettes.<ref name=GlantzBareham2018>{{cite journal | vauthors = Glantz SA, Bareham DW | title = E-Cigarettes: Use, Effects on Smoking, Risks, and Policy Implications | journal = Annual Review of Public Health | volume = 39 | issue = 1 | pages = 215–235 | date = April 2018 | pmid = 29323609 | pmc = 6251310 | doi = 10.1146/annurev-publhealth-040617-013757 }}{{CC-notice|cc=by4|url=http://www.annualreviews.org/doi/pdf/10.1146/annurev-publhealth-040617-013757|author(s)=Stanton A. Glantz and David W. Bareham}}</ref> Data from a longitudinal cohort study of children with alcoholic parents found that adolescents (both middle and late adolescence) who used cigarettes, marijuana, or alcohol were significantly more likely to have ever used e-cigarettes.<ref name=SGUSReport2016/> Adolescents were more likely to initiate vaping through flavored e-cigarettes.<ref name=Cormet-BoyakaZare2018>{{cite journal | vauthors = Zare S, Nemati M, Zheng Y | title = A systematic review of consumer preference for e-cigarette attributes: Flavor, nicotine strength, and type | journal = PLOS ONE | volume = 13 | issue = 3 | pages = e0194145 | year = 2018 | pmid = 29543907 | pmc = 5854347 | doi = 10.1371/journal.pone.0194145 | doi-access = free | bibcode = 2018PLoSO..1394145Z }}{{CC-notice|cc=by4|url=http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0194145|author(s)=Samane Zare, Mehdi Nemati, and Yuqing Zheng}}</ref> Among youth who have ever tried an e-cigarette, a majority used a flavored product the first time they tried an e-cigarette.<ref name=SGUSReport2016>{{cite web|url=https://e-cigarettes.surgeongeneral.gov/documents/2016_SGR_Full_Report_non-508.pdf|title=E-Cigarette Use Among Youth and Young Adults: A Report of the Surgeon General|publisher=Surgeon General of the United States|pages=1–298|year=2016}}{{PD-notice}}</ref> Vaping is the most common form of tobacco use among youth, as of 2019.<ref>{{cite web|url=https://www.lung.org/stop-smoking/smoking-facts/e-cigarettes-and-lung-health.html|title=E-cigarettes|date=22 February 2019|publisher=American Lung Association}}</ref> There is a greater likelihood of past or present and later cannabis use among youth and young adults who have vaped.<ref name=ChadiSchroeder2019>{{cite journal | vauthors = Chadi N, Schroeder R, Jensen JW, Levy S | title = Association Between Electronic Cigarette Use and Marijuana Use Among Adolescents and Young Adults: A Systematic Review and Meta-analysis | journal = JAMA Pediatrics | volume = 173 | issue = 10 | pages = e192574 | date = October 2019 | pmid = 31403684 | pmc = 6692686 | doi = 10.1001/jamapediatrics.2019.2574 }}</ref>

Most youth are not vaping to help them quit tobacco.<ref name=Chapman2014/> Adolescent vaping is unlikely to be associated with trying to reduce or quit tobacco.<ref name=EbbertAgunwamba2015/> Adolescents who vape but do not smoke are more than twice as likely to intend to try smoking than their peers who do not vape.<ref name=ZhongCao2016/> Vaping is correlated with a higher occurrence of cigarette smoking among adolescents, even in those who otherwise may not have been interested in smoking.<ref name=ChatterjeeAlzghoul2016>{{cite journal | vauthors = Chatterjee K, Alzghoul B, Innabi A, Meena N | title = Is vaping a gateway to smoking: a review of the longitudinal studies | journal = International Journal of Adolescent Medicine and Health | volume = 30 | issue = 3 | date = August 2016 | pmid = 27505084 | doi = 10.1515/ijamh-2016-0033 | s2cid = 23977146 }}</ref> Adolescence experimenting with e-cigarettes appears to encourage continued use of traditional cigarettes.<ref name=KnorstBenedetto2014>{{cite journal | vauthors = Knorst MM, Benedetto IG, Hoffmeister MC, Gazzana MB | title = The electronic cigarette: the new cigarette of the 21st century? | journal = Jornal Brasileiro de Pneumologia | volume = 40 | issue = 5 | pages = 564–572 | date = October 2014 | pmid = 25410845 | pmc = 4263338 | doi = 10.1590/S1806-37132014000500013 }}</ref> A 2015 study found minors had little resistance to buying e-cigarettes online.<ref name=Hildick-SmithPesko2015/> An emerging concern is that nicotine, fruit flavors, and other e-liquid additives could incite teenagers and children to start using traditional cigarettes.<ref name=BushHolsinger2016>{{cite journal | vauthors = Bush AM, Holsinger JW, Prybil LD | title = Employing the Precautionary Principle to Evaluate the Use of E-Cigarettes | journal = Frontiers in Public Health | volume = 4 | pages = 5 | year = 2016 | pmid = 26870723 | pmc = 4740382 | doi = 10.3389/fpubh.2016.00005 | doi-access = free }}</ref> Teenagers may not admit using e-cigarettes, but use, for instance, a hookah pen.<ref name=Schraufnagel2015/> As a result, self-reporting may be lower in surveys.<ref name=Schraufnagel2015/> Experts suggest that candy-like flavors could lead youths to experiment with vaping.{{sfn|WHO|2014|p=6}} [[Electronic cigarette and e-cigarette liquid marketing#Youth exposure to e-cigarette advertising|E-cigarette advertisements seen by youth]] could increase the likelihood among youths to experiment with vaping.<ref name=SinghMarynak2016>{{cite journal | vauthors = Singh T, Marynak K, Arrazola RA, Cox S, Rolle IV, King BA | title = Vital Signs: Exposure to Electronic Cigarette Advertising Among Middle School and High School Students - United States, 2014 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 64 | issue = 52 | pages = 1403–1408 | date = January 2016 | pmid = 26741522 | doi = 10.15585/mmwr.mm6452a3 | doi-access = free }}</ref> A 2016 review found "The reasons for the increasing use of e-cigarettes by minors (persons between 12 and 17 years of age) may include robust marketing and advertising campaigns that showcase celebrities, popular activities, evocative images, and appealing flavors, such as cotton candy."<ref name=DinakarLongo2016>{{cite journal | vauthors = Dinakar C, O'Connor GT | title = The Health Effects of Electronic Cigarettes | journal = The New England Journal of Medicine | volume = 375 | issue = 14 | pages = 1372–1381 | date = October 2016 | pmid = 27705269 | doi = 10.1056/NEJMra1502466 }}</ref> A 2014 survey stated that vapers may have less social and behavioral stigma than cigarette smokers, causing concern that vaping products are enticing youth who may not under other circumstances have used these products.<ref name=JenssenWilson2017>{{cite journal | vauthors = Jenssen BP, Wilson KM | title = Tobacco Control and Treatment for the Pediatric Clinician: Practice, Policy, and Research Updates | journal = Academic Pediatrics | volume = 17 | issue = 3 | pages = 233–242 | date = April 2017 | pmid = 28069410 | doi = 10.1016/j.acap.2016.12.010 }}</ref> The frequency of vaping is higher in adolescent with asthma than in adolescent who do not have asthma.<ref name=ClappJaspers2017>{{cite journal | vauthors = Clapp PW, Jaspers I | title = Electronic Cigarettes: Their Constituents and Potential Links to Asthma | journal = Current Allergy and Asthma Reports | volume = 17 | issue = 11 | pages = 79 | date = October 2017 | pmid = 28983782 | pmc = 5995565 | doi = 10.1007/s11882-017-0747-5 }}</ref>

<div style="text-align:center;"><div style="width:750px; display:inline-block;">
{{Image frame|content=
<div style="border:1px solid purple; margin:0; padding:0.5em 1em 0.5em 1em; font-size:130%; text-align:left;">
<span style="font-size:120%">'''Appeal to Young People'''</span>
<div style="color:#585858;">
Youth and young adults cite a variety of reasons for using e-cigarettes.

These include:

* Use by a friend or family member
* Taste, including the flavors available in e-cigarettes
* The belief that e-cigarettes are less harmful than other tobacco products
* Curiosity

Flavored e-cigarettes are very popular among youth and young adults. In 2014, more than 9 of 10 young adult e-cigarette users said they use e-cigarettes flavored to taste like menthol, alcohol, candy, fruit, chocolate, or other sweets. In 2018, more than 6 of 10 high school students who use e-cigarettes said they use flavored e-cigarettes.

<div style="color:black;font-size:75%;padding:0;">
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'''Source:''' [https://www.cdc.gov/mmwr/volumes/67/wr/mm6706a5.htm MMWR, Reasons for Electronic Cigarette Use Among Middle and High School Students]
<br/>
'''Source:''' [https://www.cdc.gov/mmwr/volumes/67/wr/mm6745a5.htm MMWR, Notes from the Field: Use of Electronic Cigarettes and Any Tobacco Product Among Middle and High School Students – 2011-2018.] 
</div>
</div>
</div>
|caption=Content from the 2019 [[Surgeon General of the United States|US Surgeon General]]'s report entitled ''Appeal to Young People''.<ref name=SGUS-2019>{{cite web|url=https://e-cigarettes.surgeongeneral.gov/getthefacts.html#did-you-know|title=Did You Know? – Appeal to Young People|publisher=Surgeon General of the United States|year=2019}}{{PD-notice}}</ref>
}}
</div></div>

== Motivation ==

{{multiimage
|direction=vertical
|image1=Clearomizer Electronic Vapor E-Cig Liquid Tanks (12067034894).jpg
|caption1=E-cigarettes can have a high-tech look.<ref name=NACCHO2012/>
|alt=The first image is displaying a variety of colorful, high-tech e-cigarettes. The second image is displaying a variety of e-liquid flavors.
|image2=E-Cigarette E-liquid by Vaping Monkey (9628487175).jpg
|caption2=[[Construction of electronic cigarettes#E-cigarette liquid|E-liquid]] comes in candy, fruit and coffee flavors, etc.<ref name=GranaLing2014>{{cite journal | vauthors = Grana RA, Ling PM | title = "Smoking revolution": a content analysis of electronic cigarette retail websites | journal = American Journal of Preventive Medicine | volume = 46 | issue = 4 | pages = 395–403 | date = April 2014 | pmid = 24650842 | pmc = 3989286 | doi = 10.1016/j.amepre.2013.12.010 }}</ref>
|}}

There are varied reasons for e-cigarette use.<ref name=Rahman2014>{{cite journal | vauthors = Rahman MA, Hann N, Wilson A, Worrall-Carter L | title = Electronic cigarettes: patterns of use, health effects, use in smoking cessation and regulatory issues | journal = Tobacco Induced Diseases | volume = 12 | issue = 1 | pages = 21 | year = 2014 | pmid = 25745382 | pmc = 4350653 | doi = 10.1186/1617-9625-12-21 }}</ref> Most users' motivation is related to trying to quit smoking, but a large proportion of use is recreational.<ref name=Rahman2014/> Adults cite predominantly three reasons for trying and using e-cigarettes: as an aid to smoking cessation, as a safer alternative to traditional cigarettes, and as a way to conveniently get around [[smoking ban|smoke-free laws]].<ref name=GlantzBareham2018/> Some users vape for the enjoyment of the activity.<ref name=Pepper2013/> Many e-cigarette users use them because they believe they are safer than traditional cigarettes.<ref name=Tomashefski2016>{{cite journal | vauthors = Tomashefski A | title = The perceived effects of electronic cigarettes on health by adult users: A state of the science systematic literature review | journal = Journal of the American Association of Nurse Practitioners | volume = 28 | issue = 9 | pages = 510–515 | date = September 2016 | pmid = 26997487 | doi = 10.1002/2327-6924.12358 | s2cid = 42900184 }}</ref> People who think they pose less risk than cigarette smoking are more likely to vape.<ref name=Wang2016>{{cite journal | vauthors = Wang M, Wang JW, Cao SS, Wang HQ, Hu RY | title = Cigarette Smoking and Electronic Cigarettes Use: A Meta-Analysis | journal = International Journal of Environmental Research and Public Health | volume = 13 | issue = 1 | pages = 120 | date = January 2016 | pmid = 26771624 | pmc = 4730511 | doi = 10.3390/ijerph13010120 | doi-access = free }}</ref> A 2017 report found that smokers who previously vaped and quit though continued smoking, 51.5% believed that vaping is less risky than smoking.{{sfn|McNeill|2018|p=178}} In contrast, 90% of former-smokers who vape believed vaping as less risky than cigarettes.{{sfn|McNeill|2018|p=178}} A 2017 report found that a minority of the respondents believed that replacing cigarettes with e-cigarettes would be helpful for their health.{{sfn|McNeill|2018|p=179}} Many users vape because they believe it is healthier than smoking for themselves or bystanders.<ref name=Pepper2013/> Usually, only a small proportion of users are concerned about the potential adverse [[health effect]]s.<ref name=Pepper2013/> Some people say they want to quit smoking by vaping, but others vape to circumvent smoke-free laws and policies, or to cut back on cigarette smoking.<ref name=Grana2014>{{cite journal | vauthors = Grana R, Benowitz N, Glantz SA | title = E-cigarettes: a scientific review | journal = Circulation | volume = 129 | issue = 19 | pages = 1972–1986 | date = May 2014 | pmid = 24821826 | pmc = 4018182 | doi = 10.1161/circulationaha.114.007667 }}</ref> 56% of respondents in a US 2013 survey had tried vaping to quit or reduce their smoking.<ref name=Siu2015/> In the same survey, 26% of respondents would use them in areas where smoking was banned.<ref name=Siu2015>{{cite journal | vauthors = Siu AL | title = Behavioral and Pharmacotherapy Interventions for Tobacco Smoking Cessation in Adults, Including Pregnant Women: U.S. Preventive Services Task Force Recommendation Statement | journal = Annals of Internal Medicine | volume = 163 | issue = 8 | pages = 622–634 | date = October 2015 | pmid = 26389730 | doi = 10.7326/M15-2023 | doi-access = free }}</ref> Continuing dual use among smokers is correlated with trying to cut down on smoking and to get around smoking bans, increased desire to quit smoking, and a decreased smoking dependence.<ref name=SimonaviciusMcNeill2017/> Seniors seem to vape to quit smoking or to get around smoke‐free policies.<ref name=QasimKarim2017>{{cite journal | vauthors = Qasim H, Karim ZA, Rivera JO, Khasawneh FT, Alshbool FZ | title = Impact of Electronic Cigarettes on the Cardiovascular System | journal = Journal of the American Heart Association | volume = 6 | issue = 9 | pages = e006353 | date = August 2017 | pmid = 28855171 | pmc = 5634286 | doi = 10.1161/JAHA.117.006353 }}</ref> Concerns over avoiding stains on teeth or odor from smoke on clothes in some cases prompted interest in or use of e-cigarettes.<ref name=Pepper2013/> Some e-cigarettes appeal considerably to people curious in technology who want to customize their devices.<ref name=GibsonCreamer2017>{{cite journal | vauthors = Gibson LA, Creamer MR, Breland AB, Giachello AL, Kaufman A, Kong G, Pechacek TF, Pepper JK, Soule EK, Halpern-Felsher B | display-authors = 6 | title = Measuring perceptions related to e-cigarettes: Important principles and next steps to enhance study validity | journal = Addictive Behaviors | volume = 79 | pages = 219–225 | date = April 2018 | pmid = 29175027 | pmc = 5807230 | doi = 10.1016/j.addbeh.2017.11.017 }}</ref> There appears to be a hereditary component to tobacco use, which probably plays a part in transitioning of e-cigarette use from experimentation to routine use.<ref name=Weaver2014/>

It is conceivable that former smokers may be tempted to use nicotine again as a result of e-cigarettes, and possibly start smoking again.<ref name=DropeCahn2017>{{cite journal | vauthors = Drope J, Cahn Z, Kennedy R, Liber AC, Stoklosa M, Henson R, Douglas CE, Drope J | display-authors = 6 | title = Key issues surrounding the health impacts of electronic nicotine delivery systems (ENDS) and other sources of nicotine | journal = CA: A Cancer Journal for Clinicians| volume = 67 | issue = 6 | pages = 449–471 | date = November 2017 | pmid = 28961314 | doi = 10.3322/caac.21413 | doi-access = free }}</ref> E-liquid flavors are enticing to a range of smokers and non-smokers.<ref name=ShieldsBerman2017/> Non-smoking adults tried e-cigarettes due to curiosity, because a relative was using them, or because they were given one.<ref name=Cooke2015>{{cite journal | vauthors = Cooke A, Fergeson J, Bulkhi A, Casale TB | title = The Electronic Cigarette: The Good, the Bad, and the Ugly | journal = The Journal of Allergy and Clinical Immunology. In Practice | volume = 3 | issue = 4 | pages = 498–505 | year = 2015 | pmid = 26164573 | doi = 10.1016/j.jaip.2015.05.022 }}</ref> College students often vape for experimentation.<ref name=Orellana-Barrios2015>{{cite journal | vauthors = Orellana-Barrios MA, Payne D, Mulkey Z, Nugent K | title = Electronic Cigarettes—A Narrative Review for Clinicians | journal = The American Journal of Medicine | volume = 128 | issue = 7 | pages = 674–681 | date = July 2015 | pmid = 25731134 | doi = 10.1016/j.amjmed.2015.01.033 }}</ref> Millions of dollars spent on marketing aimed at smokers suggests e-cigarettes are "newer, healthier, cheaper and easier to use in smoke-free situations, all reasons that e-cigarette users claim motivate their use".<ref name=Crowley2015>{{cite journal | vauthors = Crowley RA | title = Electronic nicotine delivery systems: executive summary of a policy position paper from the American College of Physicians | journal = Annals of Internal Medicine | volume = 162 | issue = 8 | pages = 583–584 | date = April 2015 | pmid = 25894027 | doi = 10.7326/M14-2481 | doi-access = free }}</ref> Marketing messages echo well-established cigarette themes, including freedom, good taste, romance, sexuality, and sociability as well as messages stating that e-cigarettes are healthy, are useful for smoking cessation, and can be used in smoke free environments.<ref name=GlantzBareham2018/> These messages are mirrored in the reasons that adults and youth cite for using e-cigarettes.<ref name=GlantzBareham2018/> Exposure to e-cigarette advertising influences people to try them.<ref name=Schraufnagel2015>{{cite journal | vauthors = Schraufnagel DE | title = Electronic Cigarettes: Vulnerability of Youth | journal = Pediatric Allergy, Immunology, and Pulmonology | volume = 28 | issue = 1 | pages = 2–6 | date = March 2015 | pmid = 25830075 | pmc = 4359356 | doi = 10.1089/ped.2015.0490 }}</ref>

The belief that e-cigarettes are safer than traditional cigarettes could widen their use among pregnant women.<ref name=EbbertAgunwamba2015/> If tobacco businesses persuade women that e-cigarettes are a small risk, non-smoking women of reproductive age might start using them and women smoking during pregnancy might switch to their use or use these devices to reduce smoking, instead of quitting smoking altogether.<ref name=England2015/> Traditional cigarette users who have not used e-cigarettes had mixed ideas about their possible satisfaction and around a third thought that e-cigarettes might taste bad.<ref name=Pepper2013/> Among current e-cigarette users, e-liquid flavor availability is very appealing.<ref name=HefnerValentine2017>{{cite journal | vauthors = Hefner K, Valentine G, Sofuoglu M | title = Electronic cigarettes and mental illness: Reviewing the evidence for help and harm among those with psychiatric and substance use disorders | journal = The American Journal on Addictions | volume = 26 | issue = 4 | pages = 306–315 | date = June 2017 | pmid = 28152247 | doi = 10.1111/ajad.12504 | s2cid = 24298173 }}{{PD-notice}}</ref> They feel or taste similar to traditional cigarettes, and vapers disagreed about whether this was a benefit or a drawback.<ref name=Pepper2013/> Some users liked that e-cigarettes resembled traditional cigarettes, but others did not.<ref name=Pepper2013/> E-cigarettes users' views about saving money from using e-cigarettes compared to traditional cigarettes are inconsistent.<ref name=Pepper2013/> The majority of committed e-cigarette users interviewed at an e-cigarette convention found them cheaper than traditional cigarettes.<ref name=Pepper2013/>

[[File:Reasons for initiating e-cigarette use (EU 2018).jpg|thumb|upright=1.5|Reasons for initiating e-cigarette use in the [[European Union]] according to a [[Eurobarometer]] poll (2018).<ref>{{cite news|url=https://www.europeandatajournalism.eu/index.php/eng/News/Data-news/Lung-cancer-deaths-on-the-rise-in-two-thirds-of-European-countries|title=Lung cancer deaths on the rise in two thirds of European countries| vauthors = Aguilar C |publisher=VoxEurop/The European Data Journalism Network (EDJNet)|date=11 June 2018}}</ref>]]

Some users stopped vaping due to issues with the devices.<ref name=Pepper2013/> Dissatisfaction and concerns over safety can discourage ongoing e-cigarette use.{{sfn|McNeill|2015|p=11}} Commonly reported issues with using e-cigarettes were that the devices were hard to refill, the cartridges might leak and that altering the dose was hard.<ref name=Dagaonkar2014>{{cite journal | vauthors = Dagaonkar RS, Udwadi ZF | title = Water pipes and E-cigarettes: new faces of an ancient enemy | journal = The Journal of the Association of Physicians of India | volume = 62 | issue = 4 | pages = 324–328 | date = April 2014 | pmid = 25327035 | url = http://www.japi.org/april_2014/05_ra_water_pipes.pdf }}</ref> Smokers mainly quit vaping because it did not feel similar to traditional cigarettes, did not aid with cravings, and because they wanted to use them only to know what they were like.<ref name=SimonaviciusMcNeill2017/> A small number of US surveys showed that smokers’ chief reasons for stopping vaping were that they did not feel similar to smoking cigarettes, were too costly, or were only experimenting.<ref name=SimonaviciusMcNeill2017>{{cite journal | vauthors = Simonavicius E, McNeill A, Arnott D, Brose LS | title = What factors are associated with current smokers using or stopping e-cigarette use? | journal = Drug and Alcohol Dependence | volume = 173 | pages = 139–143 | date = April 2017 | pmid = 28246049 | pmc = 5380653 | doi = 10.1016/j.drugalcdep.2017.01.002 }}</ref> A 2016 US survey reported that 77% of current smokers stated e-cigarettes were not as satisfying as traditional cigarettes and quit vaping.<ref name=Smith2016/> E-cigarette do not provide nicotine to the blood as fast as cigarettes and fall short of the throat-hit that cigarettes give, causing some to turn back to traditional cigarettes.<ref name=Caputi2016>{{cite journal | vauthors = Caputi TL | title = Industry watch: heat-not-burn tobacco products are about to reach their boiling point | journal = Tobacco Control | volume = 26 | issue = 5 | pages = 609–610 | date = September 2016 | pmid = 27558827 | doi = 10.1136/tobaccocontrol-2016-053264 | s2cid = 46170776 }}</ref> In the small number of published studies on reasons for discontinuation of e-cigarette use in young users, adolescent and young adult smokers have cited lack of satisfaction and e-cigarettes' poor taste and cost as reasons for discontinuing.<ref name=SGUSReport2016/> Additional reasons have included negative physical effects (e.g., feeling lightheaded) and loss of interest.<ref name=SGUSReport2016/> In one study of young adults aged 18–35, former and never smokers of traditional cigarettes also cited the idea that e-cigarettes were "bad for their health" as a reason for discontinuation.<ref name=SGUSReport2016/> E-cigarette users have contradictory views about using them to get around smoking bans.<ref name=Pepper2013/> Some surveys found that a small percentage of users' motives were to avoid smoking bans, but other surveys found that over 40% of users said they used the device for this reason.<ref name=Pepper2013/> The extent to which traditional cigarette users vape to avoid smoking bans is unclear.<ref name=Pepper2013>{{cite journal | vauthors = Pepper JK, Brewer NT | title = Electronic nicotine delivery system (electronic cigarette) awareness, use, reactions and beliefs: a systematic review | journal = Tobacco Control | volume = 23 | issue = 5 | pages = 375–384 | date = September 2014 | pmid = 24259045 | pmc = 4520227 | doi = 10.1136/tobaccocontrol-2013-051122 }}</ref>

E-cigarette marketing with themes of health and lifestyle may encourage youth who do not smoke to try e-cigarettes, as they may believe that e-cigarettes are less harmful and more socially acceptable.<ref name=GranaLing2014/> This belief may decrease ones concerns relating to nicotine addiction.<ref name=GranaLing2014/> E-cigarette marketing may entice adults and children.{{sfn|Bauld|2014|p=10}} E-cigarette websites regularly contain marketing statements that might appeal to a younger audience.<ref name=GranaLing2014/> Companies sell an array of flavors like bubblegum, fruit, and chocolate, potentially to entice young people to vape.<ref name=JankowskiBrożek2017>{{cite journal | vauthors = Jankowski M, Brożek G, Lawson J, Skoczyński S, Zejda JE | title = E-smoking: Emerging public health problem? | journal = International Journal of Occupational Medicine and Environmental Health | volume = 30 | issue = 3 | pages = 329–344 | date = May 2017 | pmid = 28481369 | doi = 10.13075/ijomeh.1896.01046 | doi-access = free }}</ref> Adolescent experimenting with e-cigarettes may be related to [[sensation seeking]] behavior, and is not likely to be associated with tobacco reduction or quitting smoking.<ref name=EbbertAgunwamba2015/> Youth may view e-cigarettes as a symbol of rebellion.<ref name=Bullen2014/> Children and adolescents may be tempted by flavored e-cigarettes.<ref name=Rom2014/> Vaping may entice adolescents for many reasons which include the perceived absence of [[adverse effects of electronic cigarettes|harmful adverse effects]].<ref name=GogliettinoPotenza2016>{{cite journal | vauthors = Gogliettino AR, Potenza MN, Yip SW | title = White matter development and tobacco smoking in young adults: A systematic review with recommendations for future research | journal = Drug and Alcohol Dependence | volume = 162 | pages = 26–33 | date = May 2016 | pmid = 26948756 | pmc = 4833590 | doi = 10.1016/j.drugalcdep.2016.02.015 }}</ref> The main reasons youth experimented with e-cigarettes were due to curiosity, flavors, and peer influences.<ref>{{cite journal | vauthors = Kong G, Morean ME, Cavallo DA, Camenga DR, Krishnan-Sarin S | title = Reasons for Electronic Cigarette Experimentation and Discontinuation Among Adolescents and Young Adults | journal = Nicotine & Tobacco Research | volume = 17 | issue = 7 | pages = 847–854 | date = July 2015 | pmid = 25481917 | pmc = 4674436 | doi = 10.1093/ntr/ntu257 }}</ref> A 2016 study using longitudinal surveys from middle and high school students found flavoring is the second most important factor determining whether students try e-cigarettes, after curiosity and a 2015 study also reported the same finding.<ref name=Cormet-BoyakaZare2018/> E-cigarettes may appeal to youth because of their high-tech design, large assortment of flavors, and easy accessibility online.<ref name=NACCHO2012>{{cite web|url=http://www.naccho.org/advocacy/positions/upload/12-04-e-Cigarettes.pdf|title=Regulation of Electronic Cigarettes ("E-Cigarettes")|publisher=National Association of County and City Health Officials|archive-url=https://web.archive.org/web/20141106220210/http://www.naccho.org/advocacy/positions/upload/12-04-e-Cigarettes.pdf|archive-date=6 November 2014}}</ref> Tempting candy and fruit flavors e-cigarettes are designed to appeal to youth.<ref name=HSF2014>{{cite web|archive-url=https://web.archive.org/web/20141006173717/http://www.heartandstroke.com/site/c.ikIQLcMWJtE/b.9207931/k.D09C/Heart_and_Stroke_Foundation_Ecigarettes_in_Canada.htm|url=http://www.heartandstroke.com/site/c.ikIQLcMWJtE/b.9207931/k.D09C/Heart_and_Stroke_Foundation_Ecigarettes_in_Canada.htm|title=Heart and Stroke Foundation: E-cigarettes in Canada|archive-date=6 October 2014|publisher=Heart and Stroke Foundation|date=September 2014}}</ref> The colors, flavors, and scents of e-liquids attract children.<ref name=Smith2016>{{cite journal | vauthors = Smith L, Brar K, Srinivasan K, Enja M, Lippmann S | title = E-cigarettes: How "safe" are they? | journal = The Journal of Family Practice | volume = 65 | issue = 6 | pages = 380–385 | date = June 2016 | pmid = 27474819 }}</ref> E-liquids are sold in a myriad of candy and fruit flavors, such as bubble gum, cherry and chocolate, which may appeal to youth and children.<ref name=Chapman2015>{{cite web|url=https://www.cdph.ca.gov/Programs/CCDPHP/DCDIC/CTCB/CDPH%20Document%20Library/Policy/ElectronicSmokingDevices/StateHealthEcigReport.pdf|title=State Health Officer's Report on E-Cigarettes: A Community Health Threat|publisher=California Department of Public Health|date=January 2015}}{{PD-notice}}</ref> Infants and toddlers could ingest the e-liquid from an e-cigarette device out of curiosity.<ref name=Chatham-Stephens2014>{{cite web|url=http://www.medscape.com/viewarticle/832938 | vauthors = Chatham-Stephens K |publisher=Medscape|title=Young Children and e-Cigarette Poisoning|date=20 October 2014}}</ref> Flavored tobacco has been shown to have a large market share among youth aged 12 to 17 years, confirming the attractiveness of these products to new and young smokers and their likely contribution to smoking initiation.<ref name=FranckFilion2016>{{cite journal | vauthors = Franck C, Filion KB, Kimmelman J, Grad R, Eisenberg MJ | title = Ethical considerations of e-cigarette use for tobacco harm reduction | journal = Respiratory Research | volume = 17 | issue = 1 | pages = 53 | date = May 2016 | pmid = 27184265 | pmc = 4869264 | doi = 10.1186/s12931-016-0370-3 }}{{CC-notice|cc=by4|url=https://respiratory-research.biomedcentral.com/articles/10.1186/s12931-016-0370-3|author(s)=Caroline Franck, Kristian B. Filion, Jonathan Kimmelman, Roland Grad and Mark J. Eisenberg}}</ref> Infants and children liked sweet and salty flavors more than adults.<ref name=HoffmanSalgado2016>{{cite journal | vauthors = Hoffman AC, Salgado RV, Dresler C, Faller RW, Bartlett C | title = Flavour preferences in youth versus adults: a review | journal = Tobacco Control | volume = 25 | issue = Suppl 2 | pages = ii32–ii39 | date = November 2016 | pmid = 27633764 | pmc = 5127592 | doi = 10.1136/tobaccocontrol-2016-053192 }}</ref> The bright packaging of e-cigarette products play a part in their allure to young children.<ref name=BiyaniDerkay2017>{{cite journal | vauthors = Biyani S, Derkay CS | title = E-cigarettes: An update on considerations for the otolaryngologist | journal = International Journal of Pediatric Otorhinolaryngology | volume = 94 | pages = 14–16 | date = March 2017 | pmid = 28167004 | doi = 10.1016/j.ijporl.2016.12.027 }}</ref> The vivid colors, strongly aromatic, and scented flavors for e-liquid bottles are particularly enticing to young children.<ref name=MakadiaRoper2017>{{cite journal | vauthors = Makadia LD, Roper PJ, Andrews JO, Tingen MS | title = Tobacco Use and Smoke Exposure in Children: New Trends, Harm, and Strategies to Improve Health Outcomes | journal = Current Allergy and Asthma Reports | volume = 17 | issue = 8 | pages = 55 | date = August 2017 | pmid = 28741144 | doi = 10.1007/s11882-017-0723-0 | s2cid = 22360961 }}</ref> Among US student respondents to the National Youth Tobacco Survey reporting ever using e-cigarettes in 2016, the most commonly selected reasons for use were used by "friend or family member" (39%), availability of "flavors such as mint, candy, fruit, or chocolate" (31%), and the belief that "they are less harmful than other forms of tobacco such as cigarettes" (17%).<ref name=TsaiWalton2018/> The least commonly selected reasons were "they are easier to get than other tobacco products, such as cigarettes" (5%), "they cost less than other tobacco products such as cigarettes" (3%), and "famous people on TV or in movies use them" (2%).<ref name=TsaiWalton2018>{{cite journal | vauthors = Tsai J, Walton K, Coleman BN, Sharapova SR, Johnson SE, Kennedy SM, Caraballo RS | title = Reasons for Electronic Cigarette Use Among Middle and High School Students - National Youth Tobacco Survey, United States, 2016 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 67 | issue = 6 | pages = 196–200 | date = February 2018 | pmid = 29447148 | pmc = 5815490 | doi = 10.15585/mmwr.mm6706a5 }}{{PD-notice}}</ref> A 2016 study of Finnish adolescents found that e-liquids with nicotine were more popular with ever smokers while e-liquids without nicotine were more popular with never smokers.<ref name=Cormet-BoyakaZare2018/>

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<span style="font-size:120%">'''Teen Beliefs'''</span>
<div style="color:#585858;">
Youth tobacco use in any form, including e-cigarettes, is unsafe. A recent national survey showed that about 10% of U.S. youth believe e-cigarettes cause no harm, 62% believe they cause little or some harm, and 28% believe they cause a lot of harm when they are used some days but not every day. In 2014, nearly 20% of young adults believe e-cigarettes cause no harm, more than half believe that they are moderately harmful, and 26.8% believe they are very harmful.

Young people who believe e-cigarettes cause no harm are more likely to use e-cigarettes than those who believe e-cigarettes cause a lot of harm.

<div style="color:black;font-size:75%;padding:0;">
----
'''Source:''' Adolescent health brief - [https://www.sciencedirect.com/science/article/abs/pii/S1054139X18300120?via%3Dihub ''Harm Perceptions of Intermittent Tobacco Product Use Among U.S. Youth, 2016'']
</div>
</div>
</div>
|caption=Content from the 2019 [[Surgeon General of the United States|US Surgeon General]]'s report entitled ''Teen Beliefs''.<ref name=SGUS2019>{{cite web|url=https://e-cigarettes.surgeongeneral.gov/getthefacts.html#did-you-know|title=Did You Know? – Teen Beliefs|publisher=Surgeon General of the United States|year=2019}}{{PD-notice}}</ref>
}}
</div></div>

== Progression ==

Many users may begin by using a disposable e-cigarette.<ref name=Brandon2015>{{cite journal | vauthors = Brandon TH, Goniewicz ML, Hanna NH, Hatsukami DK, Herbst RS, Hobin JA, Ostroff JS, Shields PG, Toll BA, Tyne CA, Viswanath K, Warren GW | display-authors = 6 | title = Electronic nicotine delivery systems: a policy statement from the American Association for Cancer Research and the American Society of Clinical Oncology | journal = Clinical Cancer Research | volume = 21 | issue = 3 | pages = 514–525 | date = February 2015 | pmid = 25573384 | doi = 10.1158/1078-0432.CCR-14-2544 | doi-access = free }}</ref> Users often start with e-cigarettes resembling traditional cigarettes, eventually moving to a later-generation device.<ref name=Yingst2015/> Most later-generation e-cigarette users shifted to their present device to get a "more satisfying hit",<ref name=Yingst2015>{{cite journal | vauthors = Yingst JM, Veldheer S, Hrabovsky S, Nichols TT, Wilson SJ, Foulds J | title = Factors Associated With Electronic Cigarette Users' Device Preferences and Transition From First Generation to Advanced Generation Devices | journal = Nicotine & Tobacco Research | volume = 17 | issue = 10 | pages = 1242–1246 | date = October 2015 | pmid = 25744966 | pmc = 4592341 | doi = 10.1093/ntr/ntv052 }}</ref> and users may adjust their devices to provide more vapor for better "throat hits".<ref name=Sanford2014>{{cite journal | vauthors = Sanford Z, Goebel L | title = E-cigarettes: an up to date review and discussion of the controversy | journal = The West Virginia Medical Journal | volume = 110 | issue = 4 | pages = 10–15 | year = 2014 | pmid = 25322582 }}</ref> A 2014 study reported that experienced users preferred rechargeable e-cigarettes over disposable ones.<ref name=Cormet-BoyakaZare2018/> The most commonly used e-cigarettes in the UK are devices with refillable tanks.{{sfn|McNeill|2018|p=14}} Most users used either closed systems or open systems, and rarely used both.<ref name=Cormet-BoyakaZare2018/> Women were found to prefer disposable e-cigarettes, and young adults were found to pay more attention to modifiability.<ref name=Cormet-BoyakaZare2018/> Modifiability also was found to increase the probability of initiating e-cigarettes among adolescents.<ref name=Cormet-BoyakaZare2018/>

A 2013 study found that about three-fourths of smokers used a tank system, which allows users to choose flavors and strength to mix their own liquid.<ref name=Cormet-BoyakaZare2018/> Experienced e-cigarette users even ranked the ability to customize as the most important characteristic.<ref name=Cormet-BoyakaZare2018/> Users ranked nicotine strength as an important factor for choosing among various e-cigarettes, though such preference could vary by smoking status, e-cigarette use history, and gender.<ref name=Cormet-BoyakaZare2018/> Non-smokers and inexperienced e-cigarettes users tended to prefer no nicotine or low nicotine e-cigarettes while smokers and experienced e-cigarettes users preferred medium and high nicotine e-cigarettes.<ref name=Cormet-BoyakaZare2018/> There is an abundance of colors, designs, carrying cases, and accessories to accommodate the diversity in personal preferences.<ref name=Brandon2015/>

==Other uses==

[[File:Eliq cannabis.png|thumb|right|upright=0.5|An e-liquid containing a mixture of [[cannabinoid]] concentrates.<ref name=Giroudde2015/>|alt=An e-liquid containing a mixture of cannabinoid concentrates.]]

The introduction of e-cigarettes has given [[cannabis (drug)|cannabis]] smokers a different way of inhaling [[cannabinoid]]s.<ref name=Giroudde2015/> E-cigarettes are unlike traditional cannabis cigarettes in several respects.<ref name=Giroudde2015/> It is assumed that vaporizing cannabinoids at lower temperatures is safer because it produces smaller amounts of toxicants than the hot combustion of a cannabis cigarette.<ref name=Giroudde2015/> Recreational cannabis users can individually "vape" deodorized or flavored cannabis extracts with minimal annoyance to the people around them and less chance of detection, known as "stealth vaping".<ref name=Giroudde2015/> While cannabis is not readily soluble in the liquid used for e-cigarettes, recipes containing synthetic cannabinoids which are soluble are available online.<ref name=Giroudde2015/> Companies also make synthetic cannabinoids liquid cartridges for use in e-cigarettes.<ref name=Castellanos2016/> This is likely the result of companies capitalizing on the rise of e-cigarette use among young people.<ref name=Castellanos2016>{{cite journal | vauthors = Castellanos D, Gralnik LM | title = Synthetic cannabinoids 2015: An update for pediatricians in clinical practice | journal = World Journal of Clinical Pediatrics | volume = 5 | issue = 1 | pages = 16–24 | date = February 2016 | pmid = 26862498 | pmc = 4737689 | doi = 10.5409/wjcp.v5.i1.16 }}</ref> E-cigarettes are being used to inhale MDMA, cocaine powder, crack cocaine, synthetic cathinones, mephedrone, α-PVP, synthetic cannabinoids, opioids, heroin, fentanyl, tryptamines, and ketamine.<ref name=BreitbarthMorgan2018>{{cite journal | vauthors = Breitbarth AK, Morgan J, Jones AL | title = E-cigarettes-An unintended illicit drug delivery system | journal = Drug and Alcohol Dependence | volume = 192 | pages = 98–111 | date = November 2018 | pmid = 30245461 | doi = 10.1016/j.drugalcdep.2018.07.031 | doi-access = free }}</ref>

[[File:Animated Infographic- Monitoring the Future 2015 Survey Results.webm|thumb|left|National Institute on Drug Abuse's animated infographic regarding the [[Monitoring the Future]] 2015 survey findings.<ref>{{cite web|url=https://www.drugabuse.gov/related-topics/trends-statistics/infographics/monitoring-future-2015-survey-results|title=Animated Infographic: Monitoring the Future 2015 Survey Results|publisher=National Institute on Drug Abuse|date=December 2015}}</ref>|alt=National Institute on Drug Abuse's animated infographic regarding the Monitoring the Future 2015 survey findings.]]

Looming concerns exist with the potential misuse with liquids containing the active ingredients of [[cannabis]] by youth, and with e-cigarette devices that could potentially be used to deliver other psychoactive drugs, including methamphetamine, cocaine, heroin, or [[substituted cathinone|cathinones]].<ref name=Giroudde2015/> Being exposed to nicotine early on can lead to greater risk of dependence later in life for nicotine and other drugs such as alcohol.<ref name=KorpidenHollander2015>{{cite journal | vauthors = Korpi ER, den Hollander B, Farooq U, Vashchinkina E, Rajkumar R, Nutt DJ, Hyytiä P, Dawe GS | display-authors = 6 | title = Mechanisms of Action and Persistent Neuroplasticity by Drugs of Abuse | journal = Pharmacological Reviews | volume = 67 | issue = 4 | pages = 872–1004 | date = October 2015 | pmid = 26403687 | doi = 10.1124/pr.115.010967 | doi-access = free }}</ref> Nicotine obtained from vaping is frequently used in combination with alcohol.<ref name=CrossLotfipour2016>{{cite journal | vauthors = Cross SJ, Lotfipour S, Leslie FM | title = Mechanisms and genetic factors underlying co-use of nicotine and alcohol or other drugs of abuse | journal = The American Journal of Drug and Alcohol Abuse | volume = 43 | issue = 2 | pages = 171–185 | date = March 2017 | pmid = 27532746 | pmc = 5493323 | doi = 10.1080/00952990.2016.1209512 }}</ref> E-cigarettes users are much more likely to [[alcohol abuse|misuse alcohol]] than non-e-cigarette users.<ref name=TarrenBartlett2016>{{cite journal | vauthors = Tarren JR, Bartlett SE | title = Alcohol and nicotine interactions: pre-clinical models of dependence | journal = The American Journal of Drug and Alcohol Abuse | volume = 43 | issue = 2 | pages = 146–154 | date = March 2017 | pmid = 27740856 | doi = 10.1080/00952990.2016.1197232 | s2cid = 205472934 }}</ref> Nicotine and alcohol can have reinforce enhancing effects that may encourage co-use.<ref name=DermodyHendershot2017>{{cite journal | vauthors = Dermody SS, Hendershot CS | title = A Critical Review of the Effects of Nicotine and Alcohol Coadministration in Human Laboratory Studies | journal = Alcoholism: Clinical and Experimental Research | volume = 41 | issue = 3 | pages = 473–486 | date = March 2017 | pmid = 28247555 | doi = 10.1111/acer.13321 | s2cid = 30554481 }}</ref> Vaping increases alcohol drinking among adolescents.<ref name=Abreu-VillaçaManhães2017>{{cite journal | vauthors = Abreu-Villaça Y, Manhães AC, Krahe TE, Filgueiras CC, Ribeiro-Carvalho A | title = Tobacco and alcohol use during adolescence: Interactive mechanisms in animal models | journal = Biochemical Pharmacology | volume = 144 | pages = 1–17 | date = November 2017 | pmid = 28599850 | doi = 10.1016/j.bcp.2017.06.113 | s2cid = 42781307 }}</ref> Smoking blunt cigars is associated with vaping.<ref name=SchauerRosenberry2017>{{cite journal | vauthors = Schauer GL, Rosenberry ZR, Peters EN | title = Marijuana and tobacco co-administration in blunts, spliffs, and mulled cigarettes: A systematic literature review | journal = Addictive Behaviors | volume = 64 | pages = 200–211 | date = January 2017 | pmid = 27654966 | doi = 10.1016/j.addbeh.2016.09.001 }}</ref> The very limited data found that from a small community of 55 users, suggest that cannabis vaping via e-cigarettes or e-vaporizers are infrequent behaviors among cannabis users, and mostly practiced by middle-aged men.<ref name=Giroudde2015>{{cite journal | vauthors = Giroud C, de Cesare M, Berthet A, Varlet V, Concha-Lozano N, Favrat B | title = E-Cigarettes: A Review of New Trends in Cannabis Use | journal = International Journal of Environmental Research and Public Health | volume = 12 | issue = 8 | pages = 9988–10008 | date = August 2015 | pmid = 26308021 | pmc = 4555324 | doi = 10.3390/ijerph120809988 | doi-access = free }}{{CC-notice|cc=by4|url=http://www.mdpi.com/1660-4601/12/8/9988/htm|author(s)=Christian Giroud, Mariangela de Cesare, Aurélie Berthet, Vincent Varlet, Nicolas Concha-Lozano, and Bernard Favrat}}</ref> A 2015 study found that 5.4% of US middle and high school students were vaping cannabis using e-cigarettes and 18% of vapers had also tried vaping cannabis using their e-cigarette.<ref name=MeierHatsukami2016>{{cite journal | vauthors = Meier E, Hatsukami DK | title = A review of the additive health risk of cannabis and tobacco co-use | journal = Drug and Alcohol Dependence | volume = 166 | pages = 6–12 | date = September 2016 | pmid = 27476751 | doi = 10.1016/j.drugalcdep.2016.07.013 }}</ref> A 2015 [[Monitoring the Future]] survey findings on e-cigarette use highlights uncertainty about what teens are actually inhaling when using vaping devices, and at least 6% report they are using the vaporizers to inhale cannabis.<ref name=NIDA2016/> About 6% do not know what substance they last vaped.<ref name=NIDA2016>{{cite web|url=https://www.drugabuse.gov/news-events/news-releases/2016/08/teens-using-e-cig-devices-not-just-nicotine|title=Teens using e-cig devices not just for nicotine|publisher=National Institute on Drug Abuse|date=26 August 2016}}{{PD-notice}}</ref>

Some personal vaporizer devices can be used with cannabis plant material or a concentrated resin form of cannabis called "wax".<ref name=SGUSReport2016/> E-cigarettes can be altered to use [[hash oil]], wax concentrated with [[tetrahydrocannabinol]] (THC), or dried cannabis leaves.<ref name=CollacoMcGrath-Morrow2017>{{cite journal | vauthors = Collaco JM, McGrath-Morrow SA | title = Electronic Cigarettes: Exposure and Use Among Pediatric Populations | journal = Journal of Aerosol Medicine and Pulmonary Drug Delivery | volume = 31 | issue = 2 | pages = 71–77 | date = April 2018 | pmid = 29068754 | pmc = 5915214 | doi = 10.1089/jamp.2017.1418 }}</ref> E-liquids may be filled with substances other than nicotine, thus serving as a way to deliver other psychoactive drugs, for example THC.<ref name=Giroudde2015/> Cannabinoid-enriched e-liquids require lengthy, complex processing, some being readily available online despite lack of quality control, expiry date, conditions of preservation, or any toxicological and clinical assessment.<ref name=Giroudde2015/> The health effects specific to vaping these cannabis preparations is largely unknown.<ref name=Giroudde2015/>

[[File:E-cigarettes - Behavior Risks.png|thumb|center|750px|Graphic from the 2019 [[Surgeon General of the United States|US Surgeon General]]'s report entitled ''Behavior Risks''.<ref name=SGUS-BehaviorRisks-2019>{{cite web|url=https://e-cigarettes.surgeongeneral.gov/knowtherisks.html#behavior-risks|title=Know The Risks: E-Cigarettes & Young People – Behavior Risks|publisher=Surgeon General of the United States|year=2019}}{{PD-notice}}</ref>|alt=Graphic from the 2019 US Surgeon General's report entitled ''Behavior Risks''. The accompanied text states, "E-cigarette use among youth and young adults is strongly linked to the use of other tobacco products, such as regular cigarettes, cigars, hookah, and smokeless tobacco. Some evidence suggests that e-cigarette use is linked to alcohol use and other substance use, such as marijuana. And certain e-cigarette products can be used to deliver other drugs like marijuana."]]

== Gallery ==

<gallery caption="E-cigarette related videos" widths="165" heights="175" class="center">
File:Robbing the Future.webm|alt=Robbing the Future explores the various ways the tobacco industry targets young people, the growing popularity of emerging products, such as e-cigarettes, and the dangers associated with those products.|Robbing the Future - Advertising Aimed at Children.
File:Real California teens talk about vaping.webm|alt=California teens talk about their real experiences with vaping.|California teens talk about their real experiences with vaping.
File:Tobacco Use By Youth Is Rising – February 2019 – Vital Signs.webm|alt=2019 Centers for Disease Control and Prevention video titled: Tobacco Use By Youth Is Rising – February 2019 – Vital Signs.|Tobacco Use By Youth Is Rising – February 2019 – Vital Signs.
File:Nicotine & Vaping - Don't Get Hacked - The Real Cost.webm|alt=Nicotine & Vaping - Don't Get Hacked - The Real Cost.|Nicotine & Vaping - Don't Get Hacked - The Real Cost.
File:Julius Dein Performs A Magic Trick on a Vape - The Real Cost.webm|alt=Julius Dein Performs A Magic Trick on a Vape.|Julius Dein Performs A Magic Trick on a Vape.
</gallery>

== Notes ==
{{reflist|group=notes}}

== Bibliography ==
{{refbegin}}
* {{cite web| vauthors = McNeill A, Brose LS, Calder R, Bauld L, Robson D |url= https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/684963/Evidence_review_of_e-cigarettes_and_heated_tobacco_products_2018.pdf|title=Evidence review of e-cigarettes and heated tobacco products 2018|location=UK|publisher=Public Health England|pages=1–243|date=February 2018|ref={{harvid|McNeill|2018}}}}
*{{Cite book| veditors = Stratton K, Kwan LY, Eaton DL, ((National Academies of Sciences, Engineering, and Medicine)), ((Health and Medicine Division)), ((Board on Population Health and Public Health Practice)), ((Committee on the Review of the Health Effects of Electronic Nicotine Delivery Systems)) |url= https://www.nap.edu/resource/24952/012318ecigaretteHighlights.pdf |title=Public Health Consequences of E-Cigarettes|publisher=[[National Academies of Sciences, Engineering, and Medicine]]|agency=[[National Academies Press]]|pages=1–774|date=January 2018|doi=10.17226/24952|pmid=29894118|ref={{harvid|Stratton|2018}}|isbn=978-0-309-46834-3 |last1= National Academies Of Sciences |first1= Engineering |last2= Health Medicine |first2= Division |author3= Board on Population Health Public Health Practice |author4= Committee on the Review of the Health Effects of Electronic Nicotine Delivery Systems |last5= Eaton |first5= D. L. |last6= Kwan |first6= L. Y. |last7= Stratton |first7= K. }}
* {{cite web| vauthors = McNeill A, Brose LS, Calder R, Hitchman SC, Hajek P, McRobbie H |url= https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/454516/Ecigarettes_an_evidence_update_A_report_commissioned_by_Public_Health_England.pdf|title=E-cigarettes: an evidence update|location=UK|publisher=Public Health England|pages=1–113|date=August 2015|ref={{harvid|McNeill|2015}}}}
* {{cite web| vauthors = Wilder N, Daley C, Sugarman J, Partridge J |title=Nicotine without smoke: Tobacco harm reduction|url=https://www.rcplondon.ac.uk/projects/outputs/nicotine-without-smoke-tobacco-harm-reduction-0|location=UK|publisher=Royal College of Physicians|pages=1–191|date=April 2016|ref={{harvid|Wilder|2016}}}}
* {{cite web| vauthors = Bauld L, Angus K, de Andrade M |url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/311491/Ecigarette_uptake_and_marketing.pdf|title=E-cigarette uptake and marketing|location=UK|publisher=Public Health England|pages=1–19|date=May 2014|ref={{harvid|Bauld|2014}}}}
* {{cite web|url=http://apps.who.int/gb/fctc/PDF/cop6/FCTC_COP6_10-en.pdf|title=Electronic nicotine delivery systems|publisher=World Health Organization|pages=1–13|date=21 July 2014|ref={{harvid|WHO|2014}}}}
{{refend}}

== References ==
{{reflist}}

== External links ==
* {{Commons category-inline|Electronic cigarettes}}
{{Electronic cigarettes}}
{{Authority control}}

[[Category:Cigarette types]]
[[Category:Chinese inventions]]
[[Category:Smoking cessation]]
[[Category:2003 introductions]]
[[Category:Electronic cigarettes]]