Cessation outcomes in adult dual users of e-cigarettes and cigarettes: the Population Assessment of Tobacco and Health cohort study, USA, 2013-2016

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.

Effects of Pictorial Health Warning Labels on Intention to Quit Waterpipe in Lebanon: A Mediation Analysis

INTRODUCTION

Pictorial health warning labels (HWLs) on waterpipe (WP) tobacco packages represent a better strategy for communicating the health risks associated with WP use and promoting quit intention than text-only. However, the mechanism by which these warnings lead to higher intentions to quit remains unknown.

AIMS AND METHODS

This study explores how pictorial warnings versus text-only induces higher quit intention among a sample of young adult WP smokers in Lebanon. An online randomized cross-over experimental study was conducted in August 2021 among 276 young adult WP smokers who were exposed to two conditions: pictorial HWLs and text-only warnings on WP tobacco packages in random order. After each image, participants completed post-exposure assessments of health communication outcomes (eg, attention and negative affect). Using serial and parallel mediation analysis, we examined the role of attention, negative affect, cognitive elaboration, and perceived harm in mediating the relationship between exposure to HWLs and intention to quit.

RESULTS

Using serial mediation, exposure to pictorial warnings versus text-only was found to affect intention to quit through the following pathways: attention and negative affect, which accounted for 17.28% of the total effect, and through negative affect and cognitive elaboration, which accounted for 21.53% of the total effect. Results of parallel mediation showed that the indirect effect pathways via negative affect (β = 0.063; [95% bootstrap CI = 0.004 to 0.149]) and cognitive elaboration (0.047; [0.001 to 0.114]) were statistically significant.

CONCLUSIONS

The findings call on designing and implementing attention-grabbing, emotionally evocative, and cognitively persuasive pictorial warnings in Lebanon and other countries to curb WP tobacco smoking.

IMPLICATIONS

This is among the first experimental studies looking at multiple mediators underlying the effect of exposure to pictorial HWLs on intention to quit in a sample of current WP smokers in Lebanon. The findings showed that using attention-grabbing, emotionally evocative, and persuasive pictures with a clear textual warning is crucial to maximizing the impact of implementing WP-HWLs regulations in Lebanon and other countries to curb WP tobacco smoking.

Trajectories of ENDS and cigarette use among dual users: analysis of waves 1 to 5 of the PATH Study

INTRODUCTION

Concurrent electronic nicotine delivery system (ENDS) and cigarette (dual) use is harmful. Identifying longitudinal trajectories of ENDS and cigarette use among dual users can help to determine the public health impact of ENDS and inform tobacco control policies and interventions.

OBJECTIVES

(1) To identify independent and joint trajectories of ENDS and cigarette use among wave (W) 1 adult dual users across W1 to W5 of the Population Assessment of Tobacco and Health (PATH) Study; and (2) identify W1 predictors of ENDS and cigarette joint trajectory group membership.

METHODS

We used group-based trajectory modelling to estimate independent and joint trajectories of ENDS and cigarette use from wave 1 (W1; 2013-2014) to wave 5 (W5; 2018-2019) among W1 adult established dual users of ENDS and cigarettes (n=545) from the PATH Study. We used multinomial logistic regression to identify W1 predictors of joint trajectories.

RESULTS

Two ENDS (early quitters=66.0%, stable users=34.0%) and three cigarette (stable users=55.2%, gradual quitters=27.3%, early quitters=17.5%) trajectories of W1 were identified. In joint trajectory analysis, 41.6% of participants were early ENDS quitters and stable cigarette users; 14.8% early ENDS quitters and gradual cigarette quitters; 14.6% stable ENDS users and stable cigarette users; 11.2% stable ENDS users and gradual cigarette quitters; 10.3% early ENDS quitters and early cigarette quitters; and 7.4% stable ENDS users and early cigarette quitters. Cigarette and ENDS use frequency, nicotine dependence, cannabis use and other non-combusted tobacco product use predicted trajectory group membership (p values <0.05).

CONCLUSIONS

Most dual users maintained long-term cigarette smoking or dual use, highlighting the need to address cessation of both products. Continued monitoring of trajectories and their predictors is needed, given ongoing changes to the ENDS marketplace.

In Utero Exposure to Maternal Electronic Nicotine Delivery System use Demonstrate Alterations to Craniofacial Development

OBJECTIVE

Develop a model for the study of Electronic Nicotine Device (ENDS) exposure on craniofacial development.

DESIGN

Experimental preclinical design followed as pregnant murine dams were randomized and exposed to filtered air exposure, carrier exposure consisting of 50% volume of propylene glycol and vegetable glycine (ENDS Carrier) respectively, or carrier exposure with 20 mg/ml of nicotine added to the liquid vaporizer (ENDS carrier with nicotine).

SETTING

Preclinical murine model exposure using the SciReq exposure system.

PARTICIPANTS

C57BL6 adult 8 week old female pregnant mice and exposed in utero litters.

INTERVENTIONS

Exposure to control filtered air, ENDS carrier or ENDS carrier with nicotine added throughout gestation at 1 puff/minute, 4 h/day, five days a week.

MAIN OUTCOME MEASURES

Cephalometric measures of post-natal day 15 pups born as exposed litters.

RESULTS

Data suggests alterations to several facial morphology parameters in the developing offspring, suggesting electronic nicotine device systems may alter facial growth if used during pregnancy.

CONCLUSIONS

Future research should concentrate on varied formulations and exposure regimens of ENDS to determine timing windows of exposures and ENDS formulations that may be harmful to craniofacial development.

Challenges and opportunities associated with e-cigarettes in Australia: A qualitative study

OBJECTIVE

The use of e-cigarettes in Australia has increased significantly in recent years. To assist with identifying policy and practice priorities, this study sought to provide a greater understanding of the population-level challenges and opportunities associated with these products.

METHODS

Semi-structured interviews were conducted with 34 public health experts working in tobacco- and/or nicotine-related policy, practice and research. Interview transcripts were subject to reflexive thematic analysis.

RESULTS

Several challenges associated with e-cigarettes were identified, with uptake of use among youth, the potential for use to lead to smoking and industry interference the most frequently mentioned. Recommended means of addressing these challenges included improved regulation and increased enforcement of existing laws. Most interviewees acknowledged some potential for e-cigarettes to assist with smoking cessation.

CONCLUSIONS

Despite strong restrictions on e-cigarettes in Australia, experts working in this field reported that these products, and the companies behind them, present several challenges to public health.

IMPLICATIONS FOR PUBLIC HEALTH

Tighter regulation and increased enforcement are needed to address the challenges posed by e-cigarettes. Controlled access to liquid nicotine under a pharmaceutical model offers an opportunity for smokers to access the behavioural support that may help them to quit while also restricting e-cigarette availability.

Changes in Dependence Over One Year among US Adults Who Smoke Cigarettes and Switched Completely or Partially to Use of the JUUL-Brand Electronic Nicotine Delivery System

Background

Electronic nicotine delivery systems (ENDS) are substitute sources of nicotine for adults who smoke cigarettes. Understanding changes in dependence as people switch from cigarettes to ENDS is relevant to public health. This study assessed changes in dependence among adults who switched completely or partially (dual users) from cigarettes to JUUL-brand ENDS over 12 months.

Methods

US adults who smoke and purchased a JUUL Starter Kit (n = 17,619) completed a baseline assessment and were invited to 1-, 2-, 3-, 6-, 9- and 12-month follow-ups. Dependence on cigarettes at baseline and on JUUL at follow-ups was assessed with the Tobacco Dependence Index (TDI; Range 1-5). Analyses estimated the minimal important difference (MID) for the scale, compared JUUL dependence to baseline cigarette dependence and assessed changes in JUUL dependence over 1-year, including among those using JUUL at all follow-ups.

Results

Participants who switched at month 2 had month 1 JUUL TDI scores 0.24 points greater than those who continued smoking (p<0.001); thus MID=0.24. Among both switchers and dual users overall, dependence on JUUL 1 and 12 months later was lower than baseline dependence on cigarettes (ps<0.001); participants who smoked every day showed more consistent and larger reductions. Among participants who persistently used JUUL without smoking, dependence increased 0.01 points per month (p<0.001), but was leveling off over time.

Conclusions

Dependence on JUUL was lower than baseline cigarette dependence. Increases in JUUL dependence were small over 12 months of continual JUUL use. These data indicate that ENDS, including JUUL, have lower dependence potential than cigarettes.

Predictors of electronic nicotine product quit attempts and cessation: Analysis of waves 3 and 4 of the PATH study

INTRODUCTION

Identifying theory-based predictors of electronic nicotine product (ENP) quit attempts and cessation can guide the development of effective vaping cessation interventions, which are currently limited. This study examined predictors of ENP quit attempts and cessation among adult ENP users.

METHODS

Using data from wave 3 (W3; 2015-2016) current established ENP users in the Population Assessment of Tobacco and Health study, we used multivariable logistic regression to identify predictors of (i) wave 4 (W4; 2016-2018) quit attempts (unweighted n = 1,135); and (ii) W4 cessation among those who made a quit attempt (unweighted n = 610). Predictors included Social Cognitive Theory (SCT)-based cognitive (interest in quitting, self-efficacy to quit, outcome expectancies, risk perception), behavioral (smoking status, and use of combustibles, non-combustibles, cannabis, and alcohol), and socio-environmental (perceived disapproval, household rules, exposure to advertising) factors.

RESULTS

Between W3 and W4, 51.7% of W3 ENP users made a quit attempt. Among those who tried quitting, 68.4% stopped using ENPs. SCT-based predictors of ENP quit attempts included higher interest in quitting ENPs (aOR = 1.18), greater self-efficacy to quit ENPs (aOR = 1.31), and currently using cigarettes (vs non-smoker; aOR = 1.71), non-combustibles (aOR = 2.25), and cannabis (aOR = 1.80). Predictors of ENP cessation included greater self-efficacy to quit ENPs (aOR = 1.33), greater perceived risk of ENPs (aOR = 1.35), and being a current smoker (vs non-smoker; aOR = 3.28).

CONCLUSIONS

ENP cessation interventions should address cognitive factors, particularly self-efficacy, as it predicted quit attempts and cessation. Cigarette smoking among dual users should be monitored and addressed to ensure that those who quit using ENPs do not maintain cigarette use.

The Health Effects of Real-World Dual Use of Electronic and Conventional Cigarettes versus the Health Effects of Exclusive Smoking of Conventional Cigarettes: A Systematic Review

BACKGROUND

A high prevalence of dual use of e-cigarettes and conventional cigarettes has been reported across the world.

METHODS

A systematic search was carried out. We included original articles on any topic relevant to health, excluding mental health, in all languages. The PRISMA guidelines were followed. Both reviewers independently screened and read all publications. We compared dual use with exclusive smoking of conventional cigarettes (ESCC).

RESULTS

Fifty-two publications (49 studies) were included. Thirteen papers/10 studies were prospective. There was great heterogeneity across studies. Many methodological weaknesses, such as inaccurate exposure measurement, lack of adjustment for former tobacco consumption, and lack of significance testing were identified. Most prospective studies found dual use to be at least as harmful as ESCC. The longest follow-up was six years. Most of the best available cross-sectional studies found dual use associated with the same and, in several studies, significantly higher risk of self-reported symptoms/disease than in ESCC. The intensity of cigarette smoking seems associated with worse health.

CONCLUSION

Existing studies indicate that dual use is at least as, or probably even more, harmful than ESCC. Due to the predominance of cross-sectional studies and the methodological weaknesses we judged the overall certainty of the evidence as "low certainty".

Urgent Need for Novel Investigations of Treatments to Quit E-cigarettes: Findings from a Systematic Review

E-cigarette use has been increasing globally over the past decade. Many use e-cigarettes as an alternative or method to quit cigarette smoking, whereas others use these products recreationally. As technology has advanced, many individuals have reported symptoms of dependence on these products and continue to use them beyond achieving abstinence from smoking. Despite individuals reporting interest in quitting, little is known about e-cigarette cessation. This systematic review sought to identify and evaluate all human subjects literature published on the outcome of e-cigarette cessation through September 2021. Of the 79 articles identified, 56 were cross-sectional, 6 were qualitative, 5 were cohort studies, 3 were experimental, 2 were mixed methods, and 7 reported intervention or case studies of e-cigarette cessation. Results showed youth generally had high intent to quit e-cigarettes, whereas results were mixed with adult samples. Youth were motivated to quit e-cigarettes by health concerns, whereas adults were motivated to quit e-cigarettes by cost, lack of satisfaction, and psychologic factors. Adults were more likely to report past e-cigarette quit attempts, most commonly "cold turkey." Few interventions tested strategies for e-cigarette cessation, with a majority targeted for youth. Given the lack of information on e-cigarette cessation, recommendations for future studies are outlined.

Overall quit in triple users of conventional cigarette, e-cigarette and heated tobacco product among healthy adults: a Korea Medical Institute health check-up study

OBJECTIVE

While multiuse patterns of e-cigarettes (EC) or heated tobacco products (HTP) with conventional cigarettes (CC) have been reported, smoking cessation of multiusers is not well known. We aimed to analyse overall quit in triple users of CC, EC and HTP among healthy adults.

METHODS

A questionnaire was conducted on 89 360 adults who visited the Korea Medical Institute health check-ups in Seoul, Korea, from May 2018 to September 2019. Among 38 812 ever smokers, 9252 were ever triple users of CC, EC and HTP. Frequency and related factors of overall quit were analysed in the cross-sectional study.

RESULTS

The average age was 38.8±9.0 years, and 8458 (91.4%) were men. There were 5329 (57.6%) current triple users, 3547 (38.3%) single or dual product quitters and 376 (4.1%) overall quitters. Among the former triple users, the most common tobacco product use pattern was 'dual quit of EC and HTP (eg, current CC use)' both in men (21.3%) and women (26.3%). Age 60s or older (OR 8.5, 95% CI 5.2 to 13.8), women (OR 1.7, 95% CI 1.1 to 2.5), no hyperlipidaemia and married status were significantly related to overall quit.

CONCLUSION

The most common pathway for 'ever triple users' of the three tobacco products was 'current triple users', and the second was 'CC users'. Single or dual product quitters could continue to smoke by EC or HTP instead of quit. Further research on overall quit will be needed to develop effective regulations.

Electronic Nicotine Product Cessation and Cigarette Smoking: Analysis of Waves 3 and 4 From the PATH Study

INTRODUCTION

Identifying predictors of electronic nicotine product (ENP) cessation can inform ENP cessation interventions. High rates of cooccurring ENP and cigarette (dual) use and transitions between these products underscore the importance of considering cigarette smoking status when assessing and addressing ENP cessation.

AIMS AND METHODS

We analyzed waves 3 (W3) and 4 (W4) of the Population Assessment of Tobacco and Health (PATH) study to identify (1) W3 socio-demographics, tobacco and ENP use characteristics, and psychosocial correlates of W3 cigarette smoking status (non-smoker, former, and current) among W3 adult ENP users, and (2) W3 predictors of W4 combined ENP and cigarette smoking abstinence relative to use of one or both products.

RESULTS

At W3, 65.6% of ENP users concurrently smoked cigarettes. Adjusted multinomial regression results indicated that different W3 socio-demographics, tobacco and ENP use characteristics, and psychosocial correlates were significantly associated with distinct W3 cigarette use profiles. At W4, 9.9% of individuals were abstinent from both products. These individuals were less likely to: (1) be current smokers (vs. non-smokers) or be advised to quit using tobacco, compared with cigarette only or dual users, and (2) use ENPs daily or live in a household allowing ENP use, compared with ENP only or dual users (p < .05).

CONCLUSIONS

ENP cessation approaches need to be tailored to the distinct cigarette use profiles of ENP users. Dual users and daily ENP users may require more intensive interventions to achieve the cessation of both products. Supportive physical environments, such as home vape-free policies, may facilitate ENP cessation.

IMPLICATIONS

This analysis contributes to advancing the nascent literature on predictors of electronic nicotine product (ENP) cessation, which can guide the development of ENP cessation interventions by indicating which populations, psychosocial and environmental constructs, and cooccurring behaviors interventions should target. This research also highlights the importance of considering cigarette smoking status when designing ENP cessation interventions and defining intervention outcomes.

Differences in switching away from cigarettes and JUUL use characteristics among adult menthol and nonmenthol smokers who purchased the JUUL System

OBJECTIVES

Studies have assessed switching away from cigarettes among adult smokers who use electronic nicotine delivery systems (ENDS), but there is little data assessing differences in likelihood of switching or ENDS use characteristics by menthol smoking.

METHODS

Adult (age ≥ 21) established smokers who purchased a JUUL Starter Kit (N = 15,036) completed baseline and 1-, 2-, 3-, 6-, 9- and 12-month assessments. Switching (no past-30-day cigarette smoking) and flavor use were assessed at each follow-up. Repeated-measure logistic regression models evaluated association of menthol smoking and switching across 1 year.

RESULTS

Across the 6 follow-ups, more menthol smokers primarily used Menthol/Mint-flavored JUULpods (53.8%) than nonmenthol smokers (22.9%). Only 6.4% of menthol smokers primarily used Tobacco flavors (vs. 25.9% of nonmenthol smokers). Across all follow-ups menthol smokers (41.2% of sample) were more likely to switch than nonmenthol smokers (42.6% vs. 38.8%: OR [95% CI] = 1.17 [1.11, 1.23]); this association remained significant after adjustment for sociodemographic, smoking and JUUL use covariates (aOR [95% CI] = 1.13 [1.05, 1.21]). Nonmenthol smokers, but not menthol smokers, were significantly more likely to switch when primarily using Menthol/Mint-flavored (vs. Tobacco-flavored) JUULpods (aOR [95% CI] = 1.14 [1.04, 1.25]). Differences in baseline smoking characteristics between menthol and nonmenthol smokers were small in magnitude.

CONCLUSIONS

Adult menthol (vs. nonmenthol) smokers using JUUL were more likely to switch. More than twice as many menthol (vs. nonmenthol) smokers primarily used Menthol/Mint-flavor JUULpods; few menthol smokers used tobacco flavors. Given these pronounced differences in flavor preferences, availability of ENDS in menthol flavors may be particularly important for menthol smokers, but may also benefit some nonmenthol smokers.

Correlates of e-cigarette use among adults initiating smoking cessation treatment

BACKGROUND

Little is known about the correlates of e-cigarette (EC) use among adults seeking smoking cessation treatment, and it is unclear how EC use affects smoking treatment outcomes.

METHODS

Participants were 649 adult smokers enrolled in smoking cessation treatment. Participants completed a baseline (pre-quit) assessment with follow-up at 4-, 12-, and 26-weeks after a scheduled combustible cigarette (CC) cessation date. EC use was described before and after the CC cessation date, and the impact of baseline EC use on CC cessation at follow-up was evaluated.

RESULTS

At baseline, 66.6 % of participants had ever-used ECs and 23.1 % reported past 30-day EC use. Past 30-day EC users were younger, more socioeconomically disadvantaged, more CC dependent, and less likely to report Black race compared to non-users. At the 4-, 12-, and 26-week follow-ups, 6.4 %, 7.4 %, and 8.1 % reported dual EC/CC use; and 2.7 %, 3.4 %, and 2.7 % had switched to exclusive EC use. Past 30-day EC use at baseline was not associated with CC cessation at any follow-up. However, among baseline past 30-day EC users (n = 150), using ECs ≥ once per week was associated with a lower likelihood of CC cessation at 26-week follow-up (adjusted OR 0.346, 95 % CI: 0.120, 0.997).

CONCLUSION

Findings indicated that dual users of CCs and ECs at baseline differed from CC-only users on sociodemographic and smoking characteristics. Baseline EC use did not impact smoking cessation overall. However, among past 30-day users, more frequent EC use at baseline adversely impacted longer-term cessation outcomes, perhaps due to greater baseline CC/nicotine dependence.

A Descriptive Analysis of Transitions from Smoking to Electronic Nicotine Delivery System (ENDS) Use: A Daily Diary Investigation

OBJECTIVES

We aimed to examine patterns in smoking and electronic nicotine delivery system (ENDS) use over an extended period of time (up to 20 weeks) in people who smoked and who had never previously made a successful quit attempt using an ENDS.

DESIGN AND SETTING

We conducted a longitudinal mixed-methods study in Dunedin, New Zealand, during 2018 and 2019.

PARTICIPANTS

Purposively selected participants (N = 45; age (≥18 years), gender, ethnicities, cigarettes/day) who wished to quit smoking.

INTERVENTIONS

Participants were provided with a second-generation ENDS device (vape pen or starter "tank" device) at the start of their quit attempt, and asked to complete smartphone-based daily diary surveys assessing smoking and ENDS use.

OUTCOME MEASURES

Sunburst plots and a sequence plot were used to describe weekly and daily patterns of smoking and ENDS use (smoking only, ENDS use only, dual use, abstinent).

RESULTS

The most frequently reported movements among participants, classified according to their study week behaviour, occurred between dual use and exclusive ENDS use (and vice versa). A smaller group reported moving from dual use to exclusive smoking (and often back to dual use), and a small number reported moving between abstinence and different ENDS and smoked tobacco usage behaviours. Data visualisations focussing on those participants who had provided data during each of weeks 9-12 indicate that only a minority reported sustained dual use; instead, most participants indicated varied smoked tobacco and ENDS use, which included periods of dual use.

CONCLUSIONS

The considerable variety observed within and between study participants suggests that high variability is typical rather than exceptional. Transitions from smoking to ENDS use may involve considerable periods of dual use, which is likely to be dynamic and potentially sustained over several months.

Differences in Switching Away From Smoking Among Adult Smokers Using JUUL Products in Regions With Different Maximum Nicotine Concentrations: North America and the United Kingdom

Introduction

Electronic nicotine delivery systems (ENDS) may improve public health if they facilitate smokers switching away from cigarettes. Conceptually, switching is facilitated when ENDS provide adequate nicotine delivery. Switching rates among smokers who purchased the JUUL System (“JUUL”) were compared in the United Kingdom (UK), where regulations limit nicotine concentration to 20 mg/mL versus North America (N.Am.; United States and Canada), where higher concentrations are available.

Aims and Methods

Adult established smokers (age ≥21, smoked ≥100 cigarettes, smoking some days or every day at baseline) who newly purchased JUUL were recruited into a longitudinal study (UK: N = 1247; N.Am.: N = 8835). Complete switching (no smoking for ≥30 days) was assessed 1, 3, and 6 months after purchase; propensity score matching (PSM) and logistic regression compared switching after adjusting for baseline characteristics.

Results

In both N.Am. and UK, ≥82% of participants reported using the highest JUUL nicotine concentration available (UK: 18 mg/mL; N.Am.: 59 mg/mL). Unadjusted switching rates did not differ at 1 month (17%–18%); unadjusted and adjusted rates were significantly higher in N.Am. (vs. UK) at 3 and 6 months. In the PSM sample, after additional covariate adjustment, rates were significantly higher in N.Am. (vs. UK) at 3 months (31.5% vs. 22.7%; odds ratio [95% confidence interval, CI] = 1.59 [1.25, 2.02]) and 6 months (38.0% vs. 26.0%; odds ratio [95% CI] = 1.79 [1.37, 2.35]).

Conclusions

These results suggest availability of ENDS in nicotine concentrations greater than 20 mg/mL may be associated with increased switching among adult smokers. Differences in smoking and ENDS use characteristics did not explain associations of location and switching; however, between-country differences may be affected by unmeasured factors.

Implications

Switching rates were lower among smokers who purchased the JUUL System (“JUUL”) in the UK, where regulations limit nicotine concentration to 20 mg/mL versus N.Am. (United States and Canada), where higher concentrations are available—before and after controlling for differences in smoking and ENDS use characteristics. These results suggest availability of ENDS in nicotine concentrations greater than 20 mg/mL may be associated with increased switching among adult smokers. Between-country differences may be affected by unmeasured factors; future research should consider these factors and the extent to which regulatory policy environments may explain differences in switching among adult smokers.