A Longitudinal Analysis of Nicotine Dependence and Transitions From Dual Use of Cigarettes and Electronic Cigarettes: Evidence From Waves 1-3 of the PATH Study

Evidence update on e-cigarette dependence: A systematic review and meta-analysis

INTRODUCTION

We conducted this review to examine the risk of e-cigarette dependence in different populations by updating the review on this topic by the National Academies of Science, Engineering, and Medicine.

METHODS

Six academic databases were searched for studies published between September 2017 and December 2023. We included peer-reviewed human, animal, cell/in vitro original studies examining associations of e-cigarette use and dependence but excluded qualitative studies. Three types of e-cigarette exposure were examined: acute, short-to-medium term, and long-term. Meta-analysis were conducted when possible. Different risk of bias tools were used for assessing quality of the included human studies.

RESULTS

We included 107 studies, of which 34 studies were included in the subgroup analysis. Meta-analyses showed that non-smoker current vapers had no statistically significant difference in level or prevalence of dependence compared to non-vaper current smokers and dual users. However, never smoker current vapers had a lower level of dependence (SMD -0.723, p < 0.01) compared to dual users, which was also supported by ANOVA test. Narrative review findings suggest that nicotine vapers had higher level of dependence than non-nicotine vapers and e-cigarette dependence is positively associated with nicotine concentration, frequency, and duration of use. No strong relationship was found between dependence and product types or features. Socio-demographic factor-based subgroup findings were inconclusive.

CONCLUSIONS

The level and prevalence of e-cigarette dependence is similar to cigarette dependence. There was high variability in the definitions and methods used for defining populations and assessing dependence. Further research and monitoring are crucial.

Personal Characteristics Associated With Switching From Cigarettes to Noncombustible Tobacco and Nicotine Products Among U.S. Adults: Findings From PATH Study Waves 1-5

INTRODUCTION

Reducing the disease burden from tobacco smoking may encompass switching to noncombustible (NCs), along with cessation. This study evaluates factors associated with switching to NCs (e-cigarettes, smokeless, and snus) versus continued smoking, complete cessation, or dual use.

AIMS AND METHODS

Population Assessment of Tobacco and Health adult data were analyzed in three 2-year wave pairs across 2013-2019 to assess product transitions among people who exclusively smoked tobacco. Generalized estimating equations examined demographics, smoking characteristics, perceptions, and messaging exposure as predictors of transitions from cigarette smoking.

RESULTS

Ages 18-44 years (ref = 65+; aORs = 3.79-5.92), males (aOR = 1.18, 95% CI [1.01, 1.37]), and perceiving NCs as less harmful than smoking (ref = not; aOR = 1.47, 95% CI [1.28, 1.69]) were positively associated with switching to NCs versus continued smoking, while being Black (ref = White; aOR = 0.36, 95% CI [0.26, 0.48]) or Hispanic (ref = non-Hispanic; aOR = 0.59, 95% CI [0.45, 0.78]) were negatively associated. Ages 18-64 years (aORs = 2.49-5.89), noticing promotional ads (ref = not; aOR = 1.34, 95% CI [1.14, 1.58]), daily light or heavy smoking (ref = nondaily; aORs = 2.33-3.72), and smoking within 30 minutes of waking (ref=>30 minutes; aOR = 1.47, 95% CI [1.18, 1.85]) were positively associated with switching to NCs versus cessation, while being Black (aOR = 0.55, 95% CI [0.38, 0.74]) or Hispanic (aOR = 0.52, 95% CI [0.38, 0.71]) were negatively associated. Incomes of $10 000-≥$100 000 (ref ≤ $10 000; aORs = 2.08-3.13) and daily heavy smoking (aOR = 1.96, 95% CI [1.11, 3.48]) were positively associated with switching to NCs versus dual use, while being male (aOR = 0.44, 95% CI [0.29, 0.65]) was negatively associated.

CONCLUSIONS

Transitioning to NCs was unequally distributed among sociodemographic groups and smoking characteristics. The mere availability of NCs may not promote health equity. Continued market and regulatory efforts that promote both smoking cessation and transitioning to NCs among various populations may promote public health gains.

IMPLICATIONS

This study examines factors associated with transitioning from smoking to noncombustible tobacco product use. We examined three different product use scenarios that may be associated with varied levels of exposure to harm. We observed that younger ages and perceiving NCs as less harmful than cigarettes were more likely to transition to NCs as compared to continued smoking and cessation, while Black or Hispanic individuals were less likely to transition to NCs. This highlights the need for more focused harm reduction efforts for racial and ethnic minority populations as a complementary strategy to cessation to reduce health disparities from smoking.

Understanding the motivational mechanisms for smoking and vaping among dual users and exclusive smokers

BACKGROUND

Understanding the motivational processes that influence e-cigarette use in a laboratory setting may help elucidate mechanisms that support long-term ecigarette use, which could have significant clinical and public health consequences.

METHODS

Secondary analyses were conducted on data from exclusive smokers (N=47) and dual users (N=88) who underwent a laboratory ad lib use session. Participants were given 10minutes to smoke (exclusive smokers) or vape (dual users) as much as they wanted. Withdrawal was assessed pre- and post-use. Smoking and vaping behavior was coded from session videos. Person-level predictors included cigarette/ecigarette craving-relief expectancies, demographics, and cigarette/e-cigarette use and dependence. Smoking and vaping status was assessed at Year 1 using self-reported 30-day point prevalence. Data were analyzed using general linear models and logistic regressions.

RESULTS

Both groups reported reductions in withdrawal after product use, including cigarette craving. Baseline e-cigarette craving-relief expectancies, pre-session ecigarette craving, heaviness of e-cigarette use, and relative e-cigarette dependence were significant univariate predictors of continued vaping in dual users at Year 1 (ORs>1.04, ps<.05). Dual users and exclusive smokers did not differ on use behavior (i.e., average number of puffs, ps>.16).

CONCLUSIONS

E-cigarette use alleviated withdrawal, including cigarette and e-cigarette craving, in dual users. Laboratory use behavior did not differ between dual users using e-cigarettes and exclusive smokers using cigarettes. Greater e-cigarette craving-relief expectancies, e-cigarette craving, heaviness of e-cigarette use, and morning product use pattern ('relative dependence') may reflect mechanisms that sustain e-cigarette use.

Longitudinal Assessment of Association Between Tobacco Use and Tobacco Dependence Among Adults: Latent Class Analysis of the Population Assessment of Tobacco and Health Study Waves 1-4

INTRODUCTION

With increasing tobacco product varieties, understanding tobacco use (TU) profiles and their associations with tobacco dependence (TD) has also become increasingly challenging.

AIMS AND METHODS

We aimed to identify TU profiles and their associations with TD over time, and to identify subgroups with high risk of TD. We included 3463 adult recent tobacco users who had complete TU and TD data across waves 1-4 of the Population Assessment of Tobacco and Health (PATH) study. We used a composite index of TD and a summed TD score from an established 16-item TD measure. We applied a latent class analysis to identify TU profiles based on participants' usage of eight common tobacco product groups at each survey wave and to check the stability of the TU profiles over time. We then used generalized estimating equations regressions to evaluate the longitudinal TU-TD association, adjusting for potential confounders.

RESULTS

We identified three distinct TU profiles that remained consistent across four survey waves: Dominant cigarette users (62%-68%), poly users with high propensity of using traditional cigarettes, e-cigarettes, and cigars (24%-31%), and dominant smokeless product users (7%-9%). Covariate-adjusted models showed that TD was significantly lower among the poly users and the dominant smokeless users, compared to that among the dominant cigarette users.

CONCLUSIONS

Both TU profiles and their associations with TD were stable over time at the population level. Poly users and smokeless product users were consistently associated with lower TD than cigarette-dominant users, suggesting the need for tailored tobacco cessation interventions for users with different TU profiles.

IMPLICATIONS

The finding of consistent TU profiles across four survey waves extends the current literature in capturing TU patterns in an evolving tobacco product landscape. The finding of the overall higher level of TD among the cigarette-dominant users compared to the other TU latent profiles (the Cig+eCig+Cigar dominant poly users and the dominant smokeless product users) can help identify high-risk groups for potential interventions. Our application of innovative statistical methods to high-quality longitudinal data from the PATH study helps improve the understanding of the dynamic TU-TD relationship over time.

Cigarette and ENDS dual use longitudinal transitions among adults in the Population Assessment of Tobacco and Health (PATH) Study, Waves 4-5 (2016-2019)

Introduction

The study assessed longitudinal transitions among adult (18 and older) past 30-day daily and non-daily dual users of cigarettes and electronic nicotine delivery systems (ENDS).

Methods

Using data from Wave 4 (W4; 2016/17) and Wave 5 (W5; 2018/19) of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative, longitudinal cohort study of US adults, multivariable regressions were conducted among W4 dual users of cigarettes and ENDS to examine past 30-day cigarette smoking at W5. The study also analyzed changes in frequency of past 30-day smoking and cigarettes smoked per day between W4 and W5, stratified by W4/W5 daily/non-daily ENDS use among W4 daily and non-daily cigarette smokers.

Results

Among W4 dual users, those smoking daily and using ENDS non-daily had higher odds of daily cigarette smoking at W5 than daily users of both products (AOR: 2.32, 95 % CI: 1.38-3.90). W4 daily smokers who used ENDS daily at Wave 5 smoked cigarettes on fewer days at Wave 5 than W4 daily smokers who were either daily ENDS users at Wave 4 (B = -4.59; SE = 1.43, p < 0.01) or non-daily ENDS users at Wave 4 (B = -4.55; SE = 1.24, p < 0.001). Among W4 non-daily cigarette smokers, W4 non-daily ENDS users who used daily at W5 smoked cigarettes on fewer days (B = -4.04, SE = 1.82) at W5 than those who were non-daily ENDS users at W4 and W5.

Conclusions

Findings highlight the importance of frequency of ENDS use in reducing cigarette smoking and could inform smoking cessation interventions among daily cigarette smokers.

Expanding on cross-price elasticity: Understanding tobacco product demand and substitution from the cross-price purchase task

We examine whether cigarettes serve as substitutes for electronic nicotine delivery systems (ENDS) among ENDS users and demonstrate methodological extensions of data from a cross-price purchase task to inform policies and interventions. During a clinical laboratory study, n = 19 exclusive ENDS users and n = 17 dual cigarette/ENDS users completed a cross-price purchase task with cigarettes available at a fixed price while prices of own-brand ENDS increased. We estimated cross-price elasticity using linear models to examine substitutability. We defined five additional outcomes: nonzero cross-price intensity (purchasing cigarettes if ENDS were free), constant null demand (not purchasing cigarettes at any ENDS price), cross-product crossover point (first price where participants purchased more cigarettes than ENDS), dual-demand score (percentage of prices where both products were purchased), and dual-use break point (minimum relative price to force complete substitution). The cross-price elasticity results indicated that cigarettes could serve as substitutes for ENDS among ENDS users on average, but this average effect masked substantial heterogeneity in profiles of demand (here, a measure of the drug's reinforcement potential). Policies and regulations that increase ENDS prices appear unlikely to steer most exclusive ENDS users toward cigarette use, as most would not purchase cigarettes at any ENDS price, but they could prompt some dual users to substitute cigarettes completely while others remain dual users. This heterogeneity in consumer responses suggests additional indices of cross-product demand are useful to characterize the anticipated and unanticipated effects of tobacco price policies more fully.

Relative Efficacy of an Acceptance and Commitment Therapy-Based Smartphone App with a Standard US Clinical Practice Guidelines-Based App for Smoking Cessation in Dual Users of Combustible and Electronic Cigarettes: Secondary Findings from a Randomized Trial

BACKGROUND

While smartphone apps for smoking cessation have shown promise for combustible cigarette smoking cessation, their efficacy in helping dual users of combustible and electronic cigarettes (e-cigarettes) to quit cigarettes remains unknown. This study utilized data from a randomized trial to determine if an Acceptance and Commitment Therapy (ACT)-based app (iCanQuit) was more efficacious than a US Clinical Practice Guidelines-based app (QuitGuide) for combustible cigarette smoking cessation among 575 dual users.

METHODS

The primary cessation outcome was self-reported, complete-case 30-day abstinence from combustible cigarettes at 12 months. Logistic regression assessed the interaction between dual use and treatment arm on the primary outcome in the full trial sample (N = 2,415). We then compared the primary outcome between arms among dual users (iCanQuit: n = 297; QuitGuide: n = 178). Mediation analyses were conducted to explore mechanisms of action of the intervention: acceptance of cues to smoke and app engagement. Results: There was an interaction between dual use of combustible and e-cigarettes and treatment arm on the primary outcome (p = 0.001). Among dual users, 12-month abstinence from cigarettes did not differ between arms (23% for iCanQuit vs. 27% for QuitGuide, p = 0.40). Mediation analysis revealed a significant positive indirect effect of the iCanQuit app on 12-month abstinence from cigarettes through acceptance of emotions that cue smoking (p = 0.004).

CONCLUSIONS

Findings from this study of dual users of combustible and e-cigarettes showed no evidence of a difference in quit rates between arms. Acceptance of emotions that cue smoking is a potential mechanism contributing to cigarette smoking abstinence among dual users.

Changes in Tobacco Dependence and Association With Onset and Progression of Use by Product Type From Waves 1 to 3 of the Population Assessment of Tobacco and Health (PATH) Study

INTRODUCTION

This study examined trajectories of tobacco dependence (TD) in relationship to changes in tobacco product use, and explored the effects of product-specific adding, switching, or discontinued use on dependence over time.

AIMS AND METHODS

Data were analyzed from the first three waves from the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative, longitudinal study of adults and youth in the United States. Data included 9556 wave 1 (2013-2014) adult current established tobacco users aged 18 or older who completed all three interviews and had established use at ≥2 assessments. Mutually exclusive groups included: users of cigarettes only, e-cigarettes only, cigars only, hookah only, any smokeless only, cigarette + e-cigarette dual users, and other multiple product users. A validated 16-item scale assessed TD across product users.

RESULTS

People who used e-cigarettes exclusively at wave 1 had small increases in TD through wave 3. Wave 1 multiple product users' TD decreased across waves. TD for all other wave 1 user groups remained about the same. For wave 1 cigarette only smokers, switching to another product was associated with lower levels of TD than smokers whose use stayed the same. Movement to no established use of any tobacco product was consistently associated with lower TD for all product users.

CONCLUSIONS

Except for wave 1 e-cigarette only users (who experienced small increases in TD), TD among U.S. tobacco product users was stable over time, with daily users less likely to vary from baseline.

IMPLICATIONS

The level of TD among most U.S. tobacco users was stable over the first three waves of the PATH Study and trends in levels of TD were predominantly unrelated to changes in patterns of continued product use. Stable levels of TD suggest a population at persistent risk of health impacts from tobacco. Wave 1 e-cigarette users experienced small increases in levels of TD over time, perhaps due to increases in quantity or frequency of their e-cigarette use or increasing efficiency of nicotine delivery over time.

Dependence motives and use contexts that predicted smoking cessation and vaping cessation: A two-year longitudinal study with 13 waves

INTRODUCTION

Prior studies examining the impact of e-cigarette use, dependence, cessation motivation/goals, and environmental restriction on smoking cessation were based on cross-sectional or shorter-term longitudinal data with binary outcomes. There is also a critical knowledge gap in corresponding impact on vaping cessation. This study aims to fill in these gaps by investigating these factors' effects on speed of progression to smoking and vaping cessation.

METHODS

This study conducted secondary analysis of data from 13 waves of assessment of adult cigarette users in Wisconsin from October 2015 through July 2019. Cox regression was employed to examine baseline predictors' effects on speed of progression to smoking cessation (past-month abstinence) among 405 exclusive combustible cigarette users and dual users of combustible and electronic cigarettes, as well as progression to vaping cession among 178 dual users.

RESULTS

Dual use of e-cigarettes with cigarettes, lower primary dependence motives of smoking, higher secondary dependence motives of smoking, higher motivation to quit smoking, more ambitious future goals to quit smoking, and more restrictive environment for smoking all contributed to quicker progression to smoking cessation. Dual users with higher secondary dependence motives of smoking or with lower primary dependence motives of vaping progressed faster to vaping cessation.

CONCLUSIONS

The findings support that nicotine dependence is product-specific with two distinct constructs: the primary dependence motives are associated with more difficulty to quit, whereas the secondary dependence motives have the opposite effect. Dual users with strong instrumental reasons for smoking may not find e-cigarettes as an effective substitute for cigarettes.

Predictors of Discontinued E-Cigarette Use at One-Year Follow-Up in a Sample of Young Adults

BACKGROUND

Currently, the research on factors associated with young adults' discontinuation of e-cigarette use behavior is limited. This study tested the predictors of self-reported e-cigarette abstinence at one-year follow-up among young adult baseline current e-cigarette users. The following variables were tested as predictors: demographics, cigarette smoking, e-cigarette use dependence, e-cigarette use duration, harm perceptions, and preferred aspects of e-cigarette use, including sensations, flavor, and device characteristics.

METHODS

Data were provided at two time-points one year apart by 435 ethnically diverse young adults (M age = 22.3, SD = 3.1; 63% women) who reported current e-cigarette use at baseline.

RESULTS

Approximately 42% of those who reported current e-cigarette use at baseline (i.e., 184 out of 435 participants) reported discontinuation of e-cigarette use at one-year follow-up. Results indicated that higher e-cigarette dependence, longer history of e-cigarette use, lower e-cigarette harm perceptions, greater preference for both menthol and sweet flavors, for open-pod-based devices, and for e-cigarette use sensations such as buzz, taste and smell of flavors, and throat hit at baseline were associated with lower likelihood of e-cigarette use discontinuation at one-year follow-up.

CONCLUSIONS

Characteristics associated with nicotine (e.g., dependence) and flavors (e.g., taste and smell) appear to drive the continuation/discontinuation of e-cigarette use among young adults. Thus, cessation strategies may need to be developed with a focus on dependence and harm perceptions related to nicotine and flavors. Furthermore, better regulating open-pod-based devices and sweet-menthol flavors may help e-cigarette use prevention.

Changes in Nicotine Dependence Among Smokers Using Electronic Cigarettes to Reduce Cigarette Smoking in a Randomized Controlled Trial

INTRODUCTION

How nicotine dependence will be affected when current smokers initiate electronic cigarette (e-cigarette) use to reduce cigarette smoking is unknown. This study evaluated cigarette, e-cigarette, and total nicotine dependence more than 6 months among smokers reducing cigarette consumption by replacing with e-cigarettes.

AIMS AND METHODS

Adult cigarette smokers were randomized to one of four conditions (36 mg/ml e-cigarette, 8 mg/ml e-cigarette, 0 mg/ml e-cigarette, or cigarette-substitute [CS] [provided at no cost]) and instructed to reduce their cigarette smoking by 75% at 1 month. Participants completed follow-up at 1, 3, and 6 months. The Penn State Nicotine Dependence Index (PSNDI) measured dependence on cigarettes (PSCDI) and e-cigarettes (PSECDI). Urine cotinine measured total nicotine exposure. Linear mixed effects models for each outcome were conducted and included interaction terms between visit and condition.

RESULTS

Participants (n = 520) were 58.8% female, 67.3% White, and 48.0 years old. At baseline, the median number of cigarettes smoked per day was 17.3 and the mean PSCDI score was 13.4, with no significant differences between conditions. Participants in the e-cigarette conditions reported significantly lower PSCDI scores, compared with baseline, and with the CS condition at all follow-up visits. Those in the 36 mg/ml e-cigarette condition reported greater PSECDI scores at 6 months, compared with baseline and the 0 mg/ml and 8 mg/ml conditions. At all follow-up visits, there were no differences in total nicotine exposure compared to baseline, nor between any conditions.

CONCLUSIONS

E-cigarette use was associated with reduced cigarette dependence, compared to the CS, without significant increases in total nicotine exposure.

IMPLICATIONS

Initiation of electronic cigarette use while continuing to smoke could potentially increase nicotine dependence. In this randomized trial aimed at helping smokers to reduce their cigarette intake, we found that use of an e-cigarette was associated with a reduction in cigarette dependence and an increase in e-cigarette dependence (in the condition with the highest nicotine concentration only), with no long term increase in total nicotine dependence or nicotine exposure.

RETRACTED: Changes in Tobacco Dependence and Association With Onset and Progression of Use by Product Type From Wave 1 to Wave 3 of the Population Assessment of Tobacco and Health (PATH) Study

INTRODUCTION

This study examined trajectories of tobacco dependence (TD) in relation to changes in tobacco product use and explored the effects of product-specific adding, switching, or discontinued use on dependence over time.

AIMS AND METHODS

Data were analyzed from the first three waves of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative, longitudinal study of adults and youth in the United States. Data included 9556 Wave 1 (2013/2014) adult current established tobacco users who completed all three interviews and had established use at ≥2 assessments. Groups included cigarettes-only users, e-cigarettes-only users, cigars-only users, hookah-only users, any smokeless-only users, cigarette + e-cigarette dual users, and multiple product users. A validated 16-item scale assessed TD across product users.

RESULTS

Wave 1 e-cigarette-only users' who maintained exclusive e-cigarette use increased levels of TD through Wave 3 as did those who added or switched to another product. Wave 1 multiple product users' TD decreased across waves. TD for all other Wave 1 user groups remained about the same. For Wave 1 cigarette-only smokers, switching to another product or moving to a pattern of no established use was associated with lower levels of TD than smokers whose use stayed the same. Movement to no established use of any tobacco product was consistently associated with lower TD for all other product users.

CONCLUSIONS

Except for Wave 1 e-cigarette-only users, TD among US tobacco product users was stable over time, with daily users less likely to vary from baseline.

IMPLICATIONS

The level of TD among most US tobacco users was stable over the first three waves of the PATH Study and trends in levels of TD were predominantly unrelated to changes in patterns of continued product use. Stable levels of TD suggest a population at persistent risk of health impacts from tobacco. Wave 1 e-cigarette users, including those maintaining exclusive e-cigarette use, experienced increasing levels of TD over time, perhaps because of increases in quantity or frequency of their e-cigarette product use or increasing efficiency of nicotine delivery over time.

Smoke and mirrors: Support from psychiatrists for nicotine e-cigarette availability in Australia

The Royal Australian and New Zealand College of Psychiatrists' (RANZCP) 2018 position statement supports increased, regulated availability of e-cigarettes (ECs) as a harm-reduction measure and recommends further research into their use. Aligned with this recommendation, we aimed to critically evaluate the RANZCP's stance on this issue through a literature review focused on the areas identified in the position statement as requiring further investigation: (1) the adverse health effects attributable to ECs; (2) use of ECs for smoking cessation (particularly for people living with severe mental illness); and (3) EC-associated risks for nicotine naïve young people. We identified and summarised evidence of harm attributable to ECs that is particularly relevant to young people through direct adverse health sequelae, onset of nicotine dependence and increased risk of combustible cigarette (CC) use. A small number of studies suggest ECs can be used for harm-reduction purposes in people diagnosed with nicotine dependence and severe mental illness. However, these results must be considered alongside robust evidence supporting the effectiveness of existing pharmacological interventions for smoking cessation in people with severe mental illness. The position statement is in urgent need of review in line with the available evidence.

Toward a better understanding of adult dual use of cigarettes and e-cigarettes based on use intensity and reasons for dual use

BACKGROUND

Dual use of combustible cigarettes and e-cigarettes is an emerging phenomenon among U.S. adults. Literature suggests two primary reasons for this emerging use (i.e., to help quit smoking and to stealth vape). This study investigated user profiles based on use intensity and the reasons for dual use.

METHODS

A total of 1,151 U.S. adult dual users were drawn from the 2018-2019 Tobacco Use Supplement to the Current Population Survey. We divided them into four groups: daily dual users (n = 189), predominant smokers (n = 608), predominant vapers (n = 143), and non-daily dual users (n = 211). We performed weighted multivariable logistic regressions to identify factors associated with the two primary reasons for dual use.

RESULTS

3 in 10 of U.S. adult dual users used e-cigarettes to help quit smoking while 2 in 10 of U.S. adult dual users used e-cigarettes to stealth vape. Compared to daily dual users, predominant smokers [adjusted odds ratio (AOR) = 0.61, 95% CI = 0.23, 0.62] were less likely to use e-cigarettes to help quit smoking whereas predominant vapers (AOR = 1.80, 95% CI = 1.04, 3.13) were more likely to use e-cigarettes to help quit smoking and less likely to use e-cigarettes to stealth vape (AOR = 0.30, 95% CI = 0.10, 0.89).

CONCLUSIONS

There was notable heterogeneity among the four groups of dual users. As the landscape of tobacco use is rapidly changing with an increasing popularity of e-cigarettes, reasons as well as behaviors of dual users need to be regularly monitored for effective tobacco control.

Unintended Side Effects of Electronic Cigarettes in Otolaryngology: A Scoping Review

OBJECTIVE

Electronic cigarettes (E-cigs) are nicotine delivery systems with increasing popularity. The US Food and Drug Administration defines side effects as unwanted or unexpected events or reactions. Our objective was to examine the unintended otolaryngology-related side effects associated with E-cigs.

DATA SOURCES

Medline, EMBASE, CINAHL, Web of Science, and CENTRAL databases.

REVIEW METHODS

Study selection was independently performed by 2 authors in accordance with the PRISMA-ScR statement (Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews); discrepancies were resolved by the senior author. English studies from database inception to May 1, 2020, with a sample size >5 were included. In vitro, animal, and lower respiratory tract studies were excluded. The main outcome was defined as otolaryngology-related side effects following E-cig use. Levels of evidence per the Oxford Centre for Evidence-Based Medicine were used to determine study quality.

RESULTS

From 1788 articles, 32 studies were included. The most common unintended side effects were throat irritation (n = 16), cough (n = 16), mouth irritation (n = 11), and oral mucosal lesions (n = 8). A large proportion of participants also reported conventional tobacco use in addition to E-cigs. Eight studies investigated the effectiveness of vaping on smoking cessation. The quality of the literature was level 2 to 4. Given the significant heterogeneity in the studies, meta-analysis was not performed.

CONCLUSION

The most reported side effects were throat and mouth irritation, followed by cough. The long-term impact of E-cigs is not known given the recent emergence of this technology. Future studies are warranted.

Prospective association between e-cigarette use frequency patterns and cigarette smoking abstinence among adult cigarette smokers in the United States

AIMS

To estimate the association of longitudinal patterns of e-cigarette use with cigarette smoking abstinence, after accounting for time-dependent confounding and selection bias.

DESIGN

Secondary analysis of longitudinal national cohort data. Using marginal structural models and four waves of the population assessment of tobacco and health (wave 1, 2013-14; wave 2, 2014-15; wave 3, 2015-16; wave 4, 2016-18), we estimated the association of vaping frequency across waves 2 and 3 with 12-month sustained cigarette smoking abstinence at wave 4, adjusting for time-dependent confounders at waves 1 and 2 and selection bias due to drop-out with inverse probability of treatment and censoring weights.

SETTING

United States.

PARTICIPANTS/CASES

A total of 5699 adults (18+ years) who smoked cigarettes and did not vape at wave 1.

MEASUREMENTS

The exposure was vaping frequency at waves 2 and 3 (non-use, non-daily use, daily use), representing nine possible combinations of vaping frequency across two waves. Non-use at both waves was the exposure reference group. The primary outcome was sustained 12-month cigarette smoking abstinence at wave 4.

FINDINGS

Among 5699 adults who smoked cigarettes at wave 1, a total of 560 (9.8%) reported smoking abstinence at wave 4. Compared with nonuse at both waves, daily vaping at both waves [risk ratio (RR) = 3.82, 95% confidence interval (CI) = 2.59-5.64] and non-use at wave 2 followed by daily vaping at wave 3 (RR = 2.50, 95% CI = 1.66-3.77) were positively associated with smoking abstinence; non-daily vaping at both waves was inversely associated with smoking abstinence (RR = 0.28, 95% CI = 0.11-0.75). Results persisted after accounting for misclassification of e-cigarette use and cigarette smoking abstinence and after restricting to participants with plans to quit smoking.

CONCLUSIONS

In a US cohort of adult smokers, longitudinal patterns of vaping frequency appear to predict smoking abstinence, even after accounting for several sources of systematic error. Consistent daily vaping is associated with increased chances of cigarette smoking abstinence, while consistent non-daily vaping is associated with decreased chances of smoking abstinence.

Dual Use of Combustible Cigarettes and E-cigarettes: a Narrative Review of Current Evidence

Purpose of Review

E-cigarette use (vaping) among adults has increased, and various patterns of concurrent smoking and vaping (i.e., "dual use") have emerged. Understanding dual use is important for mitigating tobacco-related harm. This narrative review summarizes recent research on dual use, including prevalence and types of dual use, sociodemographic and psychiatric characteristics, nicotine dependence, reasons for dual use, harm perceptions, toxicant exposure, trajectories of dual use, and emerging treatments for dual use.

Recent Findings

Nearly half of e-cigarette users concurrently use cigarettes, and many smoke more frequently than they use e-cigarettes. This is concerning because dual users are exposed to both cigarette and potential e-cigarette toxicants and the data are mixed regarding the ability of e-cigarettes to promote smoking cessation.

Summary

Further work is needed to identify ways to increase complete smoking abstinence and optimize harm reduction among dual users, including strategies to encourage e-cigarette cessation after stopping smoking.

Tobacco use among Appalachian adolescents: An urgent need for virtual scale out of effective interventions

Tobacco use, typically initiated during adolescence, can escalate into young adulthood, even among experimenting or intermittent users. Despite declines in cigarette smoking among US adolescents, use of other tobacco products and poly-tobacco are on the rise among Appalachian adolescents. Unfortunately, Appalachian adolescent tobacco users also are less likely to receive effective tobacco interventions due to various barriers: a) accessibility (e.g. service and provider shortages, affordability, and transportation; b) acceptability (e.g. issues of privacy and stigma); and c) cultural relevance. The present review provides critical considerations synthesized from an extensive body of literature on the suitability of virtual tobacco interventions, the need for well-timed interventions that address complex tobacco use, and the rationale for leveraging and scaling evidence-based interventions inform novel interventions for Appalachian adolescent tobacco users. Borrowing strength from existing in-person evidence-based adolescent tobacco interventions and state-of-the-art virtual health services, a well-planned virtual scale out of tobacco interventions holds potential to minimize barriers unique to Appalachia.

Motivations for E-cigarette use and associations with vaping frequency and smoking abstinence among adults who smoke cigarettes in the United States

INTRODUCTION

In observational studies, vaping daily is positively associated with cigarette smoking abstinence, while non-daily vaping is associated with less smoking abstinence (versus no e-cigarette use). It remains unknown whether cigarette smokers who vape daily have different motivations for using e-cigarettes than those who vape non-daily.

METHODS

Using latent class analysis and 10 self-reported reasons for vaping, we identified sub-groups of participants based on vaping motivations among 1544 adult (≥18 y) dual users of e-cigarettes and cigarettes at wave 4 of the Population Assessment of Tobacco and Health (2016-2018). We examined the association of motivation sub-groups with vaping frequency at wave 4, and subsequent cigarette smoking abstinence at wave 5 (2018-2019). Additional analyses examined the association of vaping frequency with smoking abstinence before and after adjustment for motivation sub-groups.

RESULTS

Four distinct sub-groups of e-cigarette users emerged, including 54 % of participants who were "Vaping Enthusiasts", 20 % who vaped for "Convenience and Social Acceptability", 10 % classified as "Experimenters", and 16 % who vaped for "Quitting Smoking and Harm Reduction." The Convenience and Social Acceptability sub-group were less likely than "Vaping Enthusiasts" (AOR=0.29, 95 %CI[0.20-0.42]) and "Quitting Smoking and Harm Reduction" (AOR=0.41, 95 %CI[0.24-0.71]) classes to vape daily (versus non-daily). Sub-groups were not associated with smoking abstinence after one year. Adjustment for motivation sub-groups did not attenuate a positive association of daily vaping with smoking abstinence.

CONCLUSIONS

Cigarette smokers who vaped for convenience and social acceptability were less frequent e-cigarette users than those with other vaping motivations. Vaping motivations were not associated with subsequent smoking abstinence.

Subtypes of Dual Users of Combustible and Electronic Cigarettes: Longitudinal Changes in Product Use and Dependence Symptomatology

INTRODUCTION

Cross-sectional surveys found behavioral heterogeneity among dual users of combustible and electronic cigarettes. Yet, prior classification did not reflect dynamic interactions between cigarette and e-cigarette consumption, which may reveal changes in product-specific dependence. The contexts of dual use that could inform intervention were also understudied.

METHODS

This study conducted secondary analysis on 13 waves of data from 227 dual users who participated in a 2-year observational study. The k-means method for joint trajectories of cigarette and e-cigarette consumption was adopted to identify the subtypes of dual users. The time-varying effect model was used to characterize the subtype-specific trajectories of cigarette and e-cigarette dependence. The subtypes were also compared in terms of use contexts.

RESULTS

The four clusters were identified: light dual users, predominant vapers, heavy dual users, and predominant smokers. Although heavy dual users and predominant smokers both smoked heavily at baseline, by maintaining vaping at the weekly to daily level the heavy dual users were able to considerably reduce cigarette use. Yet, the heavy dual users' drop in cigarette dependence was not as dramatic as their drop in cigarette consumption. Predominant vapers appeared to engage in substitution, as they decreased their smoking and increased their e-cigarette dependence. They were also more likely to live in environments with smoking restrictions and report that their use of e-cigarettes reduced cigarette craving and smoking frequency.

CONCLUSIONS

Environmental constraints can drive substitution behavior and the substitution behavior is able to be sustained if people find the substitute to be effective.

IMPLICATIONS

This study characterizes subtypes of dual users based on the dynamic interactions between cigarette use and e-cigarette use as well as product-specific trajectories of dependence. The subtypes differ in not only sociodemographic characteristics but also contexts of cigarette and e-cigarette use. Higher motivation to use e-cigarettes to quit smoking and less permissive environment for smoking may promote substitution of cigarettes by e-cigarettes.

Associations Between Nicotine Knowledge and Smoking Cessation Behaviors Among US Adults Who Smoke

INTRODUCTION

Misperceptions about nicotine's contribution to smoking-related health harms could complicate efforts to reduce the public health burden of smoking. Study goals were to describe nicotine knowledge among adults who smoke and investigate whether misperceiving nicotine as a source of health harm was associated with beneficial health behaviors, or lower uptake of using less harmful sources of nicotine to support smoking cessation attempts.

METHOD

This study used longitudinal data from 9140 adults who participated in four waves of the Population Assessment of Tobacco and Health Study and were current smokers during the first wave. Logistic regressions estimated odds ratios for correct responses across six aspects of nicotine knowledge assessed in Wave 4. Longitudinal models estimated associations between misperceptions and cigarette consumption, and odds of making a quit attempt; self-reported cessation; e-cigarette use; and use of NRT or e-cigarettes to support quit attempts.

RESULTS

Participants who were non-White, older, and had lower educational attainment or income tended to be least knowledgeable about nicotine. Misperceiving nicotine as harmful to health was associated with increased odds of quit attempts (AOR: 1.12, 95% CI: 1.03, 1.23), lower odds of cessation success (AOR: 0.84, 95% CI: 0.73, 0.98) and e-cigarette use (AOR: 0.79, 95% CI: 0.72, 0.86), and lower odds of using NRT (AOR: 0.84, 95% CI: 0.71, 0.99) or e-cigarettes to support quit attempts (AOR: 0.59, 95% CI: 0.49, 0.71).

CONCLUSION

Harm reduction efforts may be impeded by misperceptions about nicotine. Further work should evaluate the effects of correcting such misperceptions through public education.

IMPLICATIONS

This study provides longitudinal evidence that among adult smokers, misperceiving nicotine as a primary cause of smoking-related diseases may be associated with reduced cessation success and lower likelihood of using less harmful nicotine products. These misperceptions may therefore impede efforts to encourage smokers ready to quit to use evidence-based cessation support such as nicotine replacement during quit attempts and limit the success of policies designed to shift smokers to less harmful sources of nicotine. Further work should evaluate the longitudinal effects of correcting nicotine misperceptions through public education targeted toward adults who smoke.

A pragmatic randomised comparative trial of e-cigarettes and other nicotine products for quitting or long-term substitution in smokers

INTRODUCTION

Tobacco harm reduction has potential to improve individual and population health. However, little research exists on low-intensity interventions, such as encouraging longer-term NRT or e-cigarette use. We aimed to determine whether: 1) encouraging use of nicotine products as long-term tobacco substitutes is more effective for smoking abstinence than standard treatment, and 2) offering e-cigarettes is more effective than NRT.

METHODS

An open-label, parallel group randomised trial was conducted in Australia between 2014 and 2015, with 1563 adult daily smokers, randomised to: A) Standard cessation advice and NRT: advice to use NRT short-term B) Quit or substitute advice and NRT: advice to use NRT as a longer-term substitute for smoking if required to maintain smoking cessation or C) Quit or substitute advice and NRT and/or e-cigarettes. Participants were offered an initial supply of products they could then purchase for up to 7 months. The primary outcome was self-reported continuous smoking abstinence at 7 months. Point prevalence, dual use, and cigarette reduction were secondary outcomes.

RESULTS

At 7 months, 2.8% (N=9) of group A (N=324) were abstinent, compared with 1.8% (N=11) in B (N=620) and 1.3% (N=8) in C (N=619) (Adjusted ORs: B vs A 0.66, 95% CI: 0.27-1.63; C vs A 0.46, 95% CI: 0.17-1.21; C vs B 0.69, 95% CI 0.27-1.73). There were no suspected unexpected serious adverse reactions associated with trial products.

CONCLUSION

A free trial of NRT and first generation e-cigarettes and advice on long-term substitution was no better for smoking abstinence than usual care.

IMPLICATIONS

This pragmatic trial allowed the comparison of existing and alternative policy options under semi-realistic conditions, such as product choice and financial cost. All trial arms had low rates of smoking cessation. The findings suggest that providing unflavoured cigalike e-cigarettes without additional support may not increase quitting compared with advice to use standard NRT in a general population of Australians who smoke. More intensive support and education, and/or opportunity to try a range of e-cigarette products, may be required to motivate quit attempts using e-cigarettes.

Age of Initiation of Dual Tobacco Use and Binge Drinking among Youth (12-17 Years Old): Findings from the Population Assessment of Tobacco and Health (PATH) Study

Earlier exposure to binge drinking and tobacco use is associated with higher odds of substance use disorders. Using national youth data from the PATH study, we prospectively estimate the age of initiating past 30-day use of (1) cigarettes, e-cigarettes, and binge drinking, and (2) cigarettes, cigarillos, and binge drinking. Cox proportional hazard models were used to estimate differences in the age of initiation by sex, race/ethnicity, and previous use of other tobacco products. By age 21, 4.4% (95% CI: 3.7-5.2) and 2.0% (95% CI: 1.2-2.8) of youth reported initiation of past 30-day use outcomes (1) and (2), respectively. After controlling for sex and previous use of other tobacco products, statistically significant differences in the age of initiation by race/ethnicity were found for each outcome: Hispanic and non-Hispanic Black youth were less likely than non-Hispanic White youth to initiate past 30-day use of both outcomes (1) and (2) at earlier ages. Although the initiation of both outcomes remained relatively low by age 21, these incidences represent 1.56 million and 700,000 youth, respectively. This study provides the public with evidence to identify the particular ages at which education campaigns may be most effective to prevent youth from initiating these three substances. Further research is needed to estimate the age of initiation of other dual tobacco use patterns with binge drinking.