Young people and vaping: an increased risk of starting to smoke

Among adolescents and young adults who had never smoked, e-cigarette use is consistently associated with a significantly higher likelihood of subsequently trying combustible cigarettes. The best available syntheses estimate an average risk increase of two to fourfold, with results consistent across countries and observation periods. A meta-analysis published in August 2025[1] confirms a significant and repeated association between vaping and tobacco initiation.

The existence of a bridging effect between vaping and smoking among young people has been the subject of recurring discussions, including among health professionals. Critics cite confounding factors that are difficult to completely eliminate in observational studies, such as a general appetite for risky behaviors, peer influence, or family context. However, work published in recent years provides converging elements that reinforce the hypothesis of a bridging effect, particularly among adolescents and young adults who have never smoked. High-level syntheses that aggregate longitudinal cohorts repeatedly show a higher risk of smoking initiation among young people who vape, with consistency across countries and periods, a respected temporality, dose-response effects, and a specific role of nicotine. These results do not mean that every young person who vapes will become a smoker, but indicate that the probability of moving on to trial and, for some of them, to regular tobacco use is significantly increased. At the same time, the decline in smoking rates at the population level in several countries does not contradict these individual findings, because these are phenomena observed at different levels of analysis.

What major studies show

When we pool the results of dozens of studies conducted in several countries, the observation is very clear: among adolescents and young adults who had never smoked, those who vape at inclusion are much more likely to subsequently try cigarettes. A large synthesis published in JAMA Pediatrics estimates that this probability is approximately 3.6 times higher (i.e. +260 %). It also shows that at the time of follow-up, young people who vaped at inclusion are approximately four times more likely to report having smoked at least one cigarette in the previous month [2].

Another meta-analysis published in Tobacco Control[3] results in a very close estimate, with a probability of starting to smoke approximately 4.6 times higher for young vapers at the time of inclusion compared to those who did not vape.

In BMC Public Health[4], a review focusing on adolescents in Europe and North America estimates that the likelihood of initiating smoking is about 4.1 times higher among youth who vape, and about 3.7 times higher when only the highest-quality studies are included. Focusing on youth who reported, in the first questionnaire, having vaped at least once in the previous 30 days, their likelihood of subsequently trying cigarettes at follow-up is about 2.1 times higher than among those who neither vaped nor smoked at baseline.

An “umbrella review” (BMJ Open)[5] which aggregates several reviews and meta-analyses concludes that the risk of starting to smoke is on average tripled among vapers who were initially non-smokers. And the probability of becoming a long-term smoker is almost tripled. The publication also reports an increased risk of relapse among adolescent ex-smokers who have vaped.

More recently, a 2024 meta-analysis[6] confirms an adjusted increase of approximately 3.7 times in cigarette initiation after initial vaping, while highlighting that data on the progression to "regular" smoking are currently less numerous. Finally, an "umbrella" review published in 2025 in Tobacco Control[7] reviews 56 journals covering 384 studies and again finds a consistent association between youth vaping and the onset of tobacco use, with estimates clustered around a roughly threefold increased risk.

Taken together, these studies indicate that a young person who does not smoke but vapes is, on average, two to four times more likely to subsequently try cigarettes than a young person who does not vape.

Consistent signals over time

What studies that follow the same young people over several months or years show is, first of all, a clear chain of events: vaping comes before trying cigarettes, then the probability of smoking increases markedly among those who vaped initially. Among American high school students who had never smoked at the time of inclusion in the study, having vaped is associated with a probability of subsequently trying a combustible product that is approximately 2.5 to 3 times higher in the following 6 to 12 months.[8].

This signal is found in other countries and in much larger samples. In Canada, a cohort of approximately 19,000 students shows that young people who reported vaping “in the past 30 days” at baseline were about twice as likely to have smoked at least one cigarette one year later. More importantly, their likelihood of having become daily smokers at one year was nearly twice as high, suggesting that the effect is not limited to a simple “first try.”[9]. Using representative data from American adolescents, a study published in JAMA Network Open concludes that e-cigarette use is associated with a substantial increase in the transition to smoking among young people, particularly among those initially considered "low risk" of smoking. The authors estimate that, at the population level, vaping could measurably contribute to new initiations into smoking among adolescents[10].

More recent estimates, based on population models, suggest that this contribution is not marginal: in the United States, more than half a million adolescents are estimated to have started smoking cigarettes during the study period as a result of prior vaping, once several factors, including age, sex, and ethnicity, are taken into account. In other words, beyond individual trajectories, the rise of vaping among young people may translate into a significant absolute number of new cigarette experiments at the national level.[11].

These results remain observational and do not, on their own, “prove” causality in the strict sense. But their consistency across contexts, their temporality (exposure precedes outcome), and their repeated magnitude in longitudinal analyses reinforce the idea that, among adolescents who did not smoke, vaping significantly increases the likelihood of trying and, for a proportion of them, of progressing to more regular cigarette use.[12].

Nicotine and frequency of use matter

Two factors clearly influence the transition from vaping to cigarettes among young people: intensity of use and the presence of nicotine. The more often a person vapes, the greater the risk of subsequently trying cigarettes. And when vaping contains nicotine—a substance that creates addiction and reinforces the habit of use—this risk is significantly higher than when it does not.[13].

Regarding frequency, longitudinal data on thousands of adolescents show a clear gradient. Among youth followed over multiple survey waves, those who vaped at least 3 days per month at baseline had approximately 80% higher odds of experimenting with cigarettes at follow-up, compared to those who did not vape. Among those who vaped 1 to 2 days per month, the increase was more modest and statistically less clear. In other words, the likelihood of “switching to cigarettes” increases with the regularity of vaping use.

This "dose-response" trend also emerges from large methodological syntheses: when young people are classified into experimenters, infrequent users and frequent users, the relative risk of subsequently smoking increases at each level, which is consistent with an effect of the intensity of exposure.[14].

Regarding nicotine, a follow-up study of adolescents in Finland specifically distinguished between e-cigarettes with and without nicotine. Among young people who had never smoked at baseline, experimenting with nicotine vapes was associated with a probability of becoming a regular daily smoker that was about three times higher than among those who did not vape. Conversely, experimenting with nicotine-free vapes was not linked to a significant increase in the risk of becoming a smoker. This contrast reinforces the idea that nicotine is a key driver of the transition to tobacco.[15]-[16].

Taken together, these results point to the same observation: the combination of “vaping frequency + nicotine” accounts for the majority of the risk of starting to smoke. From a prevention perspective, these data encourage the adoption of strict nicotine thresholds, monitoring of high-nicotine delivery products, and measures targeting regular use among minors, in addition to controlling access and marketing.[17]-[18].

From trial to regular tobacco use

The question is not only whether vaping opens the door to the first attempt at smoking, but whether it then facilitates a subsequent anchoring in smoking. The available studies show a more heterogeneous signal than for initiation, but several results converge towards a measurable progression, particularly when vaping is regular and nicotine-rich.

In a large Canadian cohort of approximately 19,000 high school students who had never smoked at baseline, adolescents who reported vaping "in the past 30 days" were about twice as likely to have smoked at least one cigarette a year later. More importantly, their likelihood of becoming daily smokers was about 80% higher than among those who did not vape. In other words, the observed effect is not limited to the "first attempt," but also concerns the stabilization of regular consumption.[19].

Syntheses that bring together numerous studies provide additional insight. An umbrella review published in a peer-reviewed medical journal estimates that, among young people who had never smoked at baseline, having vaped is associated with a risk of becoming a smoker at the follow-up survey that is approximately 2.9 times higher. This measure of "current use" does not necessarily equate to daily smoking, but it does indicate a lasting switch to combustible tobacco in a significant proportion of young people exposed to vaping. The same review highlights an increased risk of relapse among adolescent ex-smokers who vape, suggesting that vaping can also reactivate previous smoking.[20].

These findings are reflected in population analyses that estimate the overall contribution of vaping to the increase in the number of young smokers. By aggregating representative data from the United States, researchers conclude that prior exposure to vaping could fuel tens of thousands of new smoking initiations in a few years, which, on the scale of a healthcare system, is not marginal.

Two factors appear to amplify the risk of progression to regular smoking. First, the frequency of vaping: the more regular the use at the outset, the greater the likelihood of progressing to frequent or daily smoking. Second, the presence of nicotine: follow-ups that distinguish between e-cigarettes with and without nicotine show that the excess risk of becoming a daily smoker is significantly higher when the vape contains nicotine, whereas it is absent or much lower with nicotine-free products.

Methodological limitations should be noted: definitions vary from one study to another (“current smoker,” “daily smoker,” “established use”), behaviors are generally self-reported, and factors such as risk propensity or peer influence can never be completely ruled out. Despite this, the overall consistency—progression observed in cohorts, signal reinforced by frequency and nicotine, confirmations by large-scale reviews—supports the idea that a significant fraction of young people who vape go beyond experimentation to regular tobacco cigarette use.

©Generation Without Tobacco

AE

[1] Golder S, Hartwell G, Barnett LM, et al bVaping and harm in young people: umbrella review Tobacco Control Published Online First: 19 August 2025. doi: 10.1136/tc-2024-059219

[2] Soneji S, Barrington-Trimis JL, Wills TA, Leventhal AM, Unger JB, Gibson LA, Yang J, Primack BA, Andrews JA, Miech RA, Spindle TR, Dick DM, Eissenberg T, Hornik RC, Dang R, Sargent JD. Association Between Initial Use of e-Cigarettes and Subsequent Cigarette Smoking Among Adolescents and Young Adults: A Systematic Review and Meta-analysis. JAMA Pediatr. 2017 Aug 1;171(8):788-797. doi: 10.1001/jamapediatrics.2017.1488. Erratum in: JAMA Pediatr. 2018 Jan 1;172(1):92-93. doi: 10.1001/jamapediatrics.2017.4200. Erratum in: JAMA Pediatr. 2018 Jan 1;172(1):98. doi: 10.1001/jamapediatrics.2017.4322. Erratum in: JAMA Pediatr. 2020 May 1;174(5):509. doi: 10.1001/jamapediatrics.2020.0480. PMID: 28654986; PMCID: PMC5656237.

[3] Khouja JN, Suddell SF, Peters SE, et al. Tob Control Epub ahead of print: [please include Day Month Year]. doi:10.1136/tobaccocontrol-2019-055433

[4] O'Brien, D., Long, J., Quigley, J. et al. Association between electronic cigarette use and tobacco cigarette smoking initiation in adolescents: a systematic review and meta-analysis. BMC Public Health 21, 954 (2021). https://doi.org/10.1186/s12889-021-10935-1

[5] Baenziger ON, Ford L, Yazidjoglou A, et al E-cigarette use and combustible tobacco cigarette smoking uptake among non-smokers, including relapse in former smokers: umbrella review, systematic review and meta-analysis BMJ Open 2021;11:e045603. doi: 10.1136/bmjopen-2020-045603

[6] Kim MM, Steffensen I, Miguel RTD, Babic T, Carlone J. A systematic review and meta-analysis of the association between e-cigarette use among non-tobacco users and initiating smoking of combustible cigarettes. Harm Reduct J. 2024 May 22;21(1):99. doi:10.1186/s12954-024-01013-x. PMID: 38773514; PMCID: PMC11110305.

[7] Golder S, Hartwell G, Barnett LM, et al Vaping and harm in young people: umbrella review Tobacco Control Published Online First: 19 August 2025. doi: 10.1136/tc-2024-059219

[8] Leventhal AM, Strong DR, Kirkpatrick MG, et al. Association of Electronic Cigarette Use With Initiation of Combustible Tobacco Product Smoking in Early Adolescence. JAMA. 2015;314(7):700–707. doi:10.1001/jama.2015.8950

[9] Electronic cigarette use and smoking initiation among youth: a longitudinal cohort study David Hammond, Jessica L. Reid, Adam G. Cole, Scott T. Leatherdale CMAJ Oct 2017, 189 (43) E1328-E1336; DOI: 10.1503/cmaj.161002

[10] Berry KM, Fetterman JL, Benjamin EJ, et al. Association of Electronic Cigarette Use With Subsequent Initiation of Tobacco Cigarettes in US Youths. JAMA Netw Open. 2019;2(2):e187794. doi:10.1001/jamanetworkopen.2018.7794

[11] Harlow AF, Stokes AC, Brooks DR, Benjamin EJ, Barrington-Trimis JL, Ross CS. e-Cigarette Use and Combustible Cigarette Smoking Initiation Among Youth: Accounting for Time-Varying Exposure and Time-Dependent Confounding. Epidemiology. 2022 Jul 1;33(4):523-532. doi: 10.1097/EDE.0000000000001491. Epub 2022 Mar 29. PMID: 35394965; PMCID: PMC9156560.

[12] Leventhal AM, Strong DR, Kirkpatrick MG, et al. Association of Electronic Cigarette Use With Initiation of Combustible Tobacco Product Smoking in Early Adolescence. JAMA. 2015;314(7):700–707. doi:10.1001/jama.2015.8950

[13] Kim, MM, Steffensen, I., Miguel, RTD et al. A systematic review and meta-analysis of the association between e-cigarette use among non-tobacco users and initiating smoking of combustible cigarettes. Harm Reduct J 21, 99 (2024). https://doi.org/10.1186/s12954-024-01013-x

[14] Kim MM, Steffensen I, Miguel RTD, Babic T, Carlone J. A systematic review and meta-analysis of the association between e-cigarette use among non-tobacco users and initiating smoking of combustible cigarettes. Harm Reduct J. 2024 May 22;21(1):99. doi:10.1186/s12954-024-01013-x. PMID: 38773514; PMCID: PMC11110305.

[15] Kinnunen JM, Ollila H, Minkkinen J, Lindfors PL, Timberlake DS, Rimpelä AH. Nicotine matters in predicting subsequent smoking after e-cigarette experimentation: A longitudinal study among Finnish adolescents. Drug Alcohol Depends. 2019 Aug 1;201:182-187. doi: 10.1016/j.drugalcdep.2019.04.019. Epub 2019 Jun 19. PMID: 31238240.

[16] Jaana M. Kinnunen, Hanna Ollila, Jaana Minkkinen, Pirjo L. Lindfors, David S. Timberlake, Arja H. Rimpelä, Nicotine matters in predicting subsequent smoking after e-cigarette experimentation: A longitudinal study among Finnish adolescents, Drug and Alcohol Dependence, Volume 201, 2019, Pages 182-187, ISSN 0376-8716, https://doi.org/10.1016/j.drugalcdep.2019.04.019.

[17] Kinnunen JM, Ollila H, Minkkinen J, Lindfors PL, Timberlake DS, Rimpelä AH. Nicotine matters in predicting subsequent smoking after e-cigarette experimentation: A longitudinal study among Finnish adolescents. Drug Alcohol Depends. 2019 Aug 1;201:182-187. doi: 10.1016/j.drugalcdep.2019.04.019. Epub 2019 Jun 19. PMID: 31238240.

[18] Harlow AF, Stokes AC, Brooks DR, Benjamin EJ, Barrington-Trimis JL, Ross CS. e-Cigarette Use and Combustible Cigarette Smoking Initiation Among Youth: Accounting for Time-Varying Exposure and Time-Dependent Confounding. Epidemiology. 2022 Jul 1;33(4):523-532. doi: 10.1097/EDE.0000000000001491. Epub 2022 Mar 29. PMID: 35394965; PMCID: PMC9156560.

[19] Electronic cigarette use and smoking initiation among youth: a longitudinal cohort study

David Hammond, Jessica L. Reid, Adam G. Cole, Scott T. Leatherdale

CMAJ Oct 2017, 189 (43) E1328-E1336; DOI: 10.1503/cmaj.161002

[20] Baenziger ON, Ford L, Yazidjoglou A, Joshy G, Banks E. E-cigarette use and combustible tobacco cigarette smoking uptake among non-smokers, including relapse in former smokers: umbrella review, systematic review and meta-analysis. BMJ Open. 2021 Mar 30;11(3):e045603. doi: 10.1136/bmjopen-2020-045603. PMID: 33785493; PMCID: PMC8011717.