Association of Electronic Cigarette Use by US Adolescents With Subsequent Persistent Cigarette Smoking

Electronic cigarettes and subsequent cigarette smoking in young people: A systematic review

AIMS

To assess the evidence for a relationship between the use of e-cigarettes and subsequent smoking in young people (≤29 years), and whether this differs by demographic characteristics.

METHODS

Systematic review with association direction plots (searches to April 2023). Screening, data extraction and critical appraisal followed Cochrane methods. Our primary outcome was the association between e-cigarette use, availability or both, and change in population rate of smoking in young people. The secondary outcomes were initiation, progression and cessation of smoking at individual level. We assessed certainty using Grading of Recommendations, Assessment, Development and Evaluations (GRADE).

RESULTS

We included 126 studies. For our primary outcome, there was very low certainty evidence (limited by risk of bias and inconsistency) suggesting that e-cigarette use and availability were inversely associated with smoking in young people (i.e. as e-cigarettes became more available and/or used more widely, youth smoking rates went down or, conversely, as e-cigarettes were restricted, youth smoking rates went up). All secondary outcomes were judged to be very low certainty due to very serious risk of bias. Data consistently showed direct associations between vaping at baseline and smoking initiation (28 studies) and smoking progression (5 studies). The four studies contributing data on smoking cessation had mixed results, precluding drawing any conclusion on the direction of association. There was limited information to determine whether relationships varied by sociodemographic characteristics.

CONCLUSION

At an individual level, people who vape appear to be more likely to go on to smoke than people who do not vape; however, it is unclear if these behaviours are causally linked. Very low certainty evidence suggests that youth vaping and smoking could be inversely related.

Preventing and addressing youth vaping in British Columbia, Canada: Evidence from triangulation of a scoping review of vaping policy and qualitative interviews with school-aged youth

Objectives

Vaping remains a widespread and ongoing epidemic among youth, with research demonstrating that well-designed policies can play a critical role in curbing this growing issue.

Methods

The present study provides a Canadian case-study examination of vaping policy by triangulating a scoping review of federal (Canada, n = 3), provincial (British Columbia, n = 4), and regional (Okanagan, n = 26) policies (N = 33) from 2000 to 2024 with qualitative interviews with secondary school students aged 12 to 18 (N = 25). The scoping review, conducted in 2020 and updated in 2024, followed the Arksey and O'Malley framework and incorporated guidelines from PRISMA to ensure comprehensive identification of relevant policies across government, health, and educational domains. The interviews, conducted in 2020 and 2021 in the Okanagan region of British Columbia, were analyzed using NVivo software through conventional content analysis, an inductive approach where two coders collaboratively identified categories and sub-categories from participant responses using a finalized codebook.

Results

The policy review identified gaps in comprehensiveness, public accessibility, and enforcement, particularly at regional levels, where policies often lack comprehensiveness and fail to address vaping-specific challenges. Interview findings revealed youth perceptions of school policies as poorly implemented, reactive, and overly punitive, highlighting the need for proactive, educational approaches to address vaping behaviors.

Conclusions

Findings emphasize the importance of clear, accessible, and targeted policies that address possession, distribution, and marketing while involving youth, educators, and parents in awareness and prevention efforts. This case study provides insights applicable to other jurisdictions, offering a framework for designing dynamic, equitable, and effective vaping policies internationally.

Role of social-cognitive factors in the relationship between e-cigarette use and subsequent cigarette smoking among U.S. youth: A causal mediation analysis

OBJECTIVE

E-cigarette use is associated with subsequent cigarette smoking among youth. The current study examined the mediating role of social-cognitive factors in this association.

METHODS

Data from four waves of the Population Assessment of Tobacco and Health study (2013/4 - 2017/8) were analyzed. Among youth who had heard about e-cigarettes at Wave 1 but never used cigarettes before Wave 2, we conducted both causal and traditional mediation analyses to examine the mediated effect of social-cognitive factors (including relative harm perception of e-cigarettes versus cigarettes, harm perception of e-cigarette use, perceptions of addictiveness of e-cigarette use, and e-cigarette use among best friends) in the association between e-cigarette use and subsequent cigarette ever or current smoking, adjusting for covariates. We included sampling weights in all analyses; hence, results are generalizable to the U.S. youth (12 - 14 years) from the 2013-2014 cohort.

RESULTS

Results from causal mediation analyses indicated that the total effect of e-cigarette use, compared to no use, increased the risk of cigarette ever smoking (20.9 %) and current smoking (4.6 %). A portion of this effect (4.2 % - 15.1 % for ever smoking; less than 10.6 % for current smoking) can be attributed to changes in social-cognitive factors induced by e-cigarette use. However, these mediated effects were small in magnitude relative to their standard errors and not statistically significant. Results from the traditional mediation analyses largely aligned with these findings, except for a few small sized pathways.

CONCLUSIONS

For the U.S. youth population, social-cognitive factors may only minimally or not at all mediate the association between e-cigarette use and subsequent cigarette smoking. Further investigation into the mediation role of social-cognitive factors is warranted. Tobacco control interventions that focus on cigarette smoking initiation among youth should target other mediating factors.

The Public Health Impact of a Ban on Flavored Cigars: A Decision-Theoretic Policy Framework

INTRODUCTION

Half of adult cigar users report flavored cigars as their usual brand. The Food and Drug Administration proposed prohibiting "all characterizing flavors in cigars" and "menthol… in cigarettes." We provide evidence on cigar and cigarette transitions and a framework to assess the impact of a U.S. flavored cigar ban.

AIMS AND METHODS

Using Population Assessment of Tobacco and Health survey waves 1-4, we estimated use patterns and annual transitions among flavored cigars, non-flavored cigars, cigarettes, and among adults aged 18-34 and aged ≥35. We also consider electronic nicotine delivery systems (ENDS)-related transitions. We developed a decision-theoretic framework for examining the impact of a flavored cigar ban alone, and the impact of a flavored cigar with a menthol cigarette ban with and without a non-tobacco flavored ENDS ban.

RESULTS

Cigar users exhibited less stable use than cigarette users, with a large portion of cigar users switching to cigarette use each year. Past studies provide limited information on transitions between cigar and ENDS use. Our policy framework suggests that imposing a flavored cigar ban alone may be partially undermined by the substitution of menthol cigarettes for flavored cigars. While adding a menthol cigarette to a flavored cigar ban is expected to improve public health, a simultaneously implemented ENDS may offset some of the gains.

CONCLUSIONS

Our analysis suggests the information necessary to gauge the public health impact of a cigar flavor ban alone and with flavor bans on cigarettes and ENDS. Further research is needed on ENDS vis-a'-vis cigar use, and the impact of enforcement and non-flavor-related policies on flavor ban effectiveness.

IMPLICATIONS

Unlike menthol cigarette use and menthol bans, flavored cigar use and flavored cigar bans have received minimal attention. Transitions from cigars, especially dual and flavored use, are generally common compared to cigarettes. Our policy framework suggests important public health impacts. A flavored cigar ban absent a menthol cigarette ban may be partially undermined by the substitution of menthol cigarettes for flavored cigars. Adding a menthol cigarette ban is expected to offset such substitution and improve public health. However, simultaneously adding an ENDS with a flavored cigar and menthol cigarette ban may reduce the public health impact of a menthol cigarette and cigar flavor ban since flavored cigar users would be less able to substitute a lower-risk alternative.

What Do Dental Students Know About E-Cigarettes? A Cross-Sectional Survey from One Palestinian Dental School

Owing to the vital role played by dentists in patient education and due to the growing popularity of e-cigarette use among the younger population, this cross-sectional study aimed to assess the use, knowledge, beliefs, and attitudes toward e-cigarettes among dental students. A cross-sectional questionnaire was given between March and June of 2024 to undergraduate dental students in the Faculty of Dentistry at the Arab American University in Palestine. A 32-item questionnaire with five sections, namely demographics, smoking habits, knowledge, beliefs and attitude, and education about e-cigarettes was sent to all appropriate participants (N = 1050). The response rate was 31% (N = 325). About 11.7% of the respondents were current e-cigarette smokers. The two most commonly cited reasons for initial use of e-cigarettes were curiosity (52.8%) and a desire to quit conventional smoking (27.8%). The average knowledge score was 6.63 (3.08) out of 12, demonstrating a generally inadequate level of knowledge about e-cigarettes. Conventional cigarette smokers were more knowledgeable about e-cigarettes than non-smokers (OR = 1.928; 95% CI: 1.061-3.505; p-value = 0.031). The majority of students (92%) considered the level of education they received in the dental school about e-cigarettes as inadequate, and more than half (53.2%) received information from social media. In conclusion, the prevalence of e-cigarette use among Palestinian dental students is relatively high compared with that reported for other dental students worldwide. Since the students showed a generally inadequate level of knowledge about e-cigarettes, this study casts doubt on the competency of Palestinian dental students to offer cessation counseling, highlighting the necessity to revise the dental curricula to foster positive knowledge and belief conducive to ideal behaviors.

Temporal changes and correlates of tobacco and E-cigarettes use among school-going students in Albania: insights from global youth tobacco surveys (2015-2020)

Tobacco use often starts during adolescence, with many adults beginning before 21. This study investigated the patterns and factors associated with tobacco and e-cigarette use among school-aged adolescents in Albania. Data were analyzed from two Albania Global Youth Tobacco Surveys (GYTS) conducted in 2015 and 2020. Participants included 7th-10th grade students (ages 12-16) who completed the survey (n = 9985). Descriptive statistics depicted demographic characteristics, tobacco, and e-cigarette use across survey years. Logistic regression assessed temporal changes and the odds of use across independent variables, adjusting for age and sex. From 2015 to 2020, tobacco and e-cigarette use among students aged 13-15 increased from 12.86 to 14.49% and from 6.8 to 8.8%, respectively. Cigarette smoking declined from 8.4 to 4.3%, but the use of other tobacco products nearly doubled, from 6.4 to 12.3%. Higher odds of use were found among males, older students, and those with more pocket money. Environmental factors like family, peer, and media exposure to smoking increased the likelihood of use. Anti-tobacco messages had no significant impact, while advertising strongly influenced usage. Knowledge of tobacco harms and anti-smoking attitudes correlated with lower odds of use. Increased availability of cigarettes near schools was linked to higher odds of tobacco use. The study highlights gaps in anti-tobacco messaging and the strong influence of advertising, underscoring the need for targeted and effective tobacco control strategies in Albania.

Transitions between smoking and vaping: Evidence (or lack thereof) on potential differences by gender and sex

OBJECTIVE

To synthesize existing evidence on possible differential effects by sex and gender from two Cochrane reviews evaluating vaping and smoking transitions.

METHODS

We screened included studies from two Cochrane reviews for studies reporting smoking outcomes based on gender or sex. The first review examines the effects of using e-cigarettes to help people quit smoking and includes randomized controlled trials and uncontrolled intervention studies published to July 2023. The second review aims to assess the evidence on the relationship between the use and availability of e-cigarettes and subsequent smoking in young people (aged 29 and younger) and includes quasi-experimental and cohort studies published to April 2023. Due to the paucity and heterogeneity of data, we report results narratively.

RESULTS

10 of 161 studies included in the two relevant reviews met our criteria. Only five reported analyzing whether observed effects or associations varied based on sex and/or gender. A further three provided relevant descriptive information, and two did not report overall outcomes regarding vaping and smoking transitions but did investigate whether these differed by sex/gender. Synthesized data were largely inconclusive, but there was some suggestion that vaping was more strongly associated with subsequent smoking in young males than females. No studies reported data on nonbinary participants.

CONCLUSIONS

Despite plausible reasons why sex and gender may be moderators of vaping and smoking transitions, there is little evidence investigating this. Future studies of vaping and smoking transitions should conduct and report analyses investigating potential differences based on sex and gender.

Effects of E-Cigarettes on the Lung and Systemic Metabolome in People with HIV

The popularity of e-cigarettes (vaping) has soared, creating a public health crisis among teens and young adults. Chronic vaping can induce gut inflammation and reduce intestinal barrier function through the production of the proinflammatory molecule hydrogen sulfide (H2S). This is particularly concerning for people with HIV (PWH) as they already face impaired immune function and are at a higher risk for metabolic dysregulation, diabetes, and chronic liver disease. Furthermore, PWH experience unhealthy behaviors, making it crucial to understand the systemic metabolic dysregulation and pathophysiological mechanisms associated with vaping in this population. Here, we employed liquid chromatography-mass spectrometry (LC-MS)-based metabolomics to investigate the upper respiratory, circulation, and gut metabolic profiles of PWH who vape (n = 7) and smoke combustible tobacco/marijuana (n = 6) compared to control participants who did not vape or smoke (n = 10). This hypothesis-generating exploratory study revealed systemic alterations in purine, neurotransmitter, and vitamin B metabolisms and tissue-specific changes in inflammatory pathways and cryptic sulfur cycling associated with vaping and combustible tobacco/marijuana smoking in PWH. In addition, this study provides the first link between microbial-derived metabolite 2,3-dihydroxypropane-1-sulfonate (DHPS) and vaping/smoking (tobacco and marijuana)-induced metabolic dyshomeostasis in the gut. These findings highlight the importance of identifying the full biological and clinical significance of the physiological changes and risks associated with vaping.

Measures of youth e-cigarette use: strengths, weaknesses and recommendations

This perspective discusses how to best define "e-cigarette use" among youth in a way that is relevant to individual and human health. Commonly-used definitions of youth e-cigarette use have been adapted from measures validated for tobacco cigarette smoking among adults, but may not carry the same meaning for a different product (with a much lower risk profile and very different patterns of use) and a different population (whose use is more often transient and experimental, rather than frequent and persistent). We discuss strengths and weaknesses of different definitions, and recommend improvements in defining youth e-cigarette use. We find that current literature employs a range of definitions of e-cigarette use, from lifetime use ("even a puff") to daily use. More lenient measures capture more potentially at-risk youth, but much of this is transient experimentation that has negligible risks in and itself, if not persistent. More stringent measures such as daily use are more relevant to individual and public health. Future research should examine possible improvements to definitions which include intensity of use (e.g., number of puffs per day) and persistence/duration of use, either via self-report or technology-assisted data capture.

E-cigarettes and Youth: The Known, the Unknown, and Implications for Stakeholders

ABSTRACT

Despite the decline in the prevalence of e-cigarette use among youth during the coronavirus disease 2019 pandemic, more than 2.5 million of US high and middle schoolers are still using e-cigarettes. Furthermore, those who use e-cigarettes are starting at a younger age and are using them more intensely, reflecting, at least in part, a high addiction liability of modern e-cigarettes. Beyond addiction, accumulating evidence suggests that, in the short-term, e-cigarettes are associated with cardiovascular and pulmonary effects, whereas the long-term effects of e-cigarette use are yet to be established. The aim of this review is to synthesize current knowledge on e-cigarette use among youth, including established and potential risks and efforts to date to curb youth exposure to e-cigarettes. In addition, we provide recommendations for health care providers, researchers, and other stakeholders to address this significant public health issue.

The "Gateway" hypothesis: evaluation of evidence and alternative explanations

BACKGROUND

Electronic nicotine delivery systems (ENDS) offer a substantial harm reduction opportunity for adults who smoke and are unlikely to quit. However, a major concern about ENDS is their use by non-smoking youth, and particularly whether ENDS are acting as a "gateway" that leads youth to later start smoking cigarettes. However, evidence for the gateway hypothesis can be interpreted in alternative ways, e.g. that youth who have certain characteristics were already predisposed to use both ENDS and cigarettes ("common liability" explanation).

AIMS

This commentary provides an evaluation of the gateway hypothesis that is accessible by a lay audience. This paper first reviews and evaluates the evidence interpreted as supporting the gateway hypothesis. Important alternative explanations (i.e., common liability) are discussed, as are different types of evidence (i.e., population-level trends) that can help differentiate between these competing explanations.

OVERVIEW

Evidence for the gateway hypothesis is based on the finding that youth who use ENDS are more likely to also smoke cigarettes. However, this evidence suffers from an important flaw: these studies fail to fully account for some youths' pre-existing tendency to use products containing nicotine, and inappropriately interpret the results as ENDS use causing some youth to smoke. Common liability studies suggest that ENDS use does not, in and of itself, directly cause youth to later smoke cigarettes, beyond their pre-existing tendency to use products containing nicotine. Population-level trends show that youth cigarette smoking declined faster after ENDS use became common, which contradicts the central prediction of the gateway hypothesis (i.e. that youth smoking would be more common following ENDS uptake, than otherwise be expected).

CONCLUSION

Evidence offered in support of the gateway hypothesis does not establish that ENDS use causes youth to also smoke cigarettes. Instead, this evidence is better interpreted as resulting from a common liability to use both ENDS and cigarettes. Population-level trends are inconsistent with the gateway hypothesis, and instead are consistent with (but do not prove) ENDS displacing cigarettes. Policies based on misinterpreting a causal gateway effect may be ineffective at best, and risk the negative unintended consequence of increased cigarette smoking.

A systematic review and meta-analysis of the association between e-cigarette use among non-tobacco users and initiating smoking of combustible cigarettes

INTRODUCTION

The rapid increase in e-cigarette use over the past decade has triggered an important public health question on the potential association between e-cigarette use and combustible cigarette smoking. Following AMSTAR 2 and PRISMA guidelines, this evidence synthesis sought to identify and characterize any associations between e-cigarette use among individuals not smoking cigarettes and initiation of cigarette smoking.

METHODS

The protocol was registered on September 24, 2018 (PROSPERO 2018 CRD42018108540). Three databases were queried from January 01, 2007 to April 26, 2023. Search results were screened using the PICOS review method.

RESULTS

Among 55 included studies (40 "good" and 15 "fair"; evidence grade: "high") that adjusted for gender, age, and race/ethnicity between groups, generally, there was a significant association between non-regular e-cigarette use and initiation of cigarette smoking, further supported by the meta-analytic results (AOR 3.71; 95% CI 2.86-4.81). However, smoking initiation was most often measured as ever/current cigarette smoking. Two studies (quality: 2 "good") evaluated progression to regular cigarette smoking among individuals with regular use of e-cigarettes, and generally found no significant associations. One study ("good") evaluated smoking initiation among individuals with regular use of e-cigarettes, finding an increasing probability of ever smoking cigarettes with increased e-cigarette use. Twelve studies (10 "good" and two "fair") examining progression to regular smoking among individuals with non-regular use of e-cigarettes reported inconsistent findings.

CONCLUSIONS

Numerous methodological flaws in the body of literature limit the generalizability of these results to all individuals who are not smoking cigarettes with few studies measuring established/regular use/smoking of e-cigarettes and cigarettes. Further, studies did not control adequately for specific confounding variables representing common liabilities between e-cigarette use and cigarette smoking, nor did they account for sufficient follow-up durations. Collectively, these flaws limit the generalizability of findings to the question of an association between e-cigarette use and cigarette smoking initiation.

E-cigarette attitudes and behaviours amongst 15-30-year-olds in the UK

BACKGROUND

The use of e-cigarettes has been rising in the UK, particularly by young people. This study investigated behaviours, attitudes and beliefs about e-cigarettes amongst 15-30-year-olds in the UK.

METHODS

An online survey was administered to a sample of 1009 15-30-year-olds in the UK.

RESULTS

About one in five participants currently used e-cigarettes at least monthly, with 1 in 10 using them daily. Amongst those using e-cigarettes at least monthly, 90% had used e-cigarettes containing nicotine. E-cigarettes were mainly obtained from vape shops and used at home. Having friends who used e-cigarettes and using them to help quit/reduce smoking were the most common reasons for vaping. About half of participants had been exposed to e-cigarette advertising, especially online, and warning labels on e-cigarettes. Most participants agreed that e-cigarettes are addictive (75%), help people quitting smoking (64%) and are bad for health (63%). Previous or current tobacco smokers were 9 and 22 times more likely to use e-cigarettes than never smokers, respectively. Perceiving e-cigarettes as harmful was associated with a 40% lower likelihood of use.

CONCLUSION

Raising awareness on the uncertain long-term consequences of vaping and regulation of marketing and sales are crucial to protect young people in the UK.

Declining trend in cigarette smoking among U.S. adults over 2008-2018: A decomposition analysis

The United States (U.S.) witnessed considerable reduction in cigarette smoking prevalence in the recent past. While the correlates of smoking prevalence and related disparities among U.S. adults are well documented, there is limited information on how this success was shared among different population sub-groups. Based on data from the National Health Interview Surveys, 2008 and 2018, representative of non-institutionalized U.S. adults (18 years and above), we applied the threefold Kitawaga-Oaxaca-Blinder linear decomposition analysis. We decomposed the trends in cigarette smoking prevalence, smoking initiation, and successful cessation into changes in population characteristics holding smoking propensities constant (compositional change), changes in smoking propensities by population characteristics holding population composition constant (structural change), and the unmeasured macro-level changes affecting smoking behavior in different population sub-groups at differential rates (residual change) to quantify the shares of population sub-groups by sex, age, race/ethnicity, education, marital status, employment status, health insurance coverage, family income, and region of residence in the overall change in smoking rates. The analysis shows that decreases in smoking propensities regardless of the changes in population composition accounted for 66.4% of the reduction in smoking prevalence and 88.7% of the reduction in smoking initiation. The major reductions in smoking propensity were among Medicaid recipients and young adults (ages 18-24 years). The 25-44-year-olds experienced moderate increase in successful smoking cessation, while the overall successful smoking cessation rate remained steady. Taken together, consistent reduction in smoking among U.S. adults by all major population characteristics, accompanied by disproportionately larger reduction in smoking propensities among the population sub-groups with initially higher smoking propensity compared to the national average, characterized the decline in overall cigarette smoking. Strengthening proven tobacco control measures with targeted interventions to reduce smoking propensities among underserved populations is key to continued success in reducing smoking overall and remedying inequities in smoking and population health.