Changes in puffing topography and subjective effects over a 2-week period in e-cigarette naïve smokers: Effects of device type and nicotine concentrations

The potential of new nicotine and tobacco products as tools for people who smoke to quit combustible cigarettes - a systematic review of common practices and guidance towards a robust study protocol to measure cessation efficacy

New types of nicotine and tobacco products like electronic cigarettes (ECs), heated tobacco products or nicotine pouches have been discussed as less harmful alternatives to combustible cigarettes and other toxic forms of tobacco products. Their harm reduction potential lay in the efficient transition away from smoking to those new products. Numerous studies addressing the cessation efficacy of ECs have been published with contradictory outcomes. Yet, a comprehensive Cochrane review concluded with high certainty on the cessation efficacy of ECs. This prompted us to perform a review to identify weaknesses in common study designs and to summarize best practices for the study design on the potential of new nicotine products as cessation aids. 120 articles retrieved from Medline were found to be eligible. Most of the studies in the field were interventional trials while observational studies played a minor role in the evaluation of smoking cessation. Efficacy was predominantly assessed for ECs in 77% of the reports while heated tobacco (17%) and non-combustible products (11%) were less frequently investigated up to now. Measures to determine the efficacy were questionnaire-based assessments as well as use documentation/prevalence and abstinence rates. Studies varied largely in their duration and sample size with medians of 3 months and 156.5 participants, respectively.With the help of this review, we identified several weaknesses in the common study designs. One major limitation in longitudinal trials was the lack of compliance measures suited to verify the use status over longer time periods, relying solely on self-reports. Moreover, the motivation of the participants to quit was rarely defined and a profound familiarization period was not taken into account for the majority of the studies. To what extent such weaknesses influence the outcome of the studies was beyond the scope of this review. We encourage researchers to consider the recommendations which resulted from this review in order to determine the abuse liability and cessation efficacy of the products in a more robust manner. Finally, we like to call attention to the missing data for low- and middle-income countries which would require quitting strategies most urgently to combat the tobacco smoking epidemic.

Partial Nicotine Reduction and E-Cigarette Users' Puffing Behaviors Among Adults Aged 21 to 35 Years: A Randomized Crossover Clinical Trial

Importance

The advent of salt-based, high-nicotine electronic nicotine delivery systems [e-cigarettes] has contributed to their epidemic use among young people in the US, necessitating the need for policies to address the addictiveness of these products.

Objective

To evaluate the effect of partial nicotine reduction on new-generation e-cigarette users' puffing behaviors.

Design, Setting, and Participants

This randomized crossover clinical trial was conducted at the Clinical Research Lab for Tobacco Smoking at Florida International University in Miami between April 15, 2022, and October 17, 2023. Using a volunteering sampling method by distributing flyers and advertisements, current e-cigarette users (who preferred 5% nicotine concentration), aged 21 to 35 years, were included.

Intervention

In a crossover design, participants completed 2 sessions of the same product (JUUL or NJOY) that differed by nicotine concentration (3% [JUUL] or 2.4% [NJOY] and 5% [JUUL or NJOY]) in random order. In each session, participants vaped up to 60 minutes ad libitum, preceded by 12 hours of nicotine abstinence.

Main Outcomes and Measures

The primary outcomes were puffing topography parameters (eg, total session time, puffing time, total puffing number, interpuff interval, total inhaled volume, average puff volume, duration, and flow rate) measured during each session and plasma nicotine measured before and after each session.

Results

Among 735 participants who were approached for eligibility, 675 were excluded, and 10 did not complete session 2. Of the 50 remaining current e-cigarette users (mean [SD] age, 23 [3] years; 56% men), 23 (46%) were low nicotine dependent. The median topography parameters were significantly higher during the e-cigarette use sessions with 3% or 2.4% nicotine concentration compared with 5% nicotine concentration for 3 outcomes: puffing time (1.3 minutes [IQR, 0.3-9.4 minutes] vs 1.2 minutes [IQR, 0.2-5.6 minutes]; P = .02), puff duration (2.6 seconds [IQR, 0.8-6.9 seconds] vs 2.4 seconds [IQR, 0.4-6.6 seconds]; P = .02), and total inhaled volume (1990.0 mL [IQR, 279.0-24 400.0 mL] vs 1490.0 mL [IQR, 148.0-14 300.0 mL]; P = .05). The median plasma nicotine boost observed in the 5% nicotine concentration condition (0.0060 mg/L [IQR, 0.0001-0.0249 mg/L]) was significantly higher than that in the 3% or 2.4% session (0.0043 mg/L [IQR, 0.0008-0.0225 mg/L]) (P = .001). Additionally, deeper puffing (increased average puff duration and average puff volume) was observed in participants with higher nicotine dependence (1.42 seconds [95% CI, 1.12-1.80 seconds]; P = .03) and male users (1.38 mL [95% CI, 1.09-1.75 mL]; P = .04) in response to nicotine reduction.

Conclusions and Relevance

This randomized crossover clinical trial provides direct evidence that partial nicotine reduction in salt-based e-cigarettes was associated with acute compensatory puffing and the potential for increased exposure to toxicants. However, given the reduced nicotine delivery associated with nicotine reduction, the acute compensatory response observed in this study may not preclude a population benefit due to the marketing of less addictive products. These results suggest that at least for current e-cigarette users, partial nicotine reduction can lead to enhanced exposure to some toxicants in the short term.

Trial Registration

ClinicalTrials.gov Identifier: NCT05205382.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol by heating an e-liquid. People who smoke, healthcare providers and regulators want to know if ECs can help people quit smoking, and if they are safe to use for this purpose. This is a review update conducted as part of a living systematic review.

OBJECTIVES

To examine the safety, tolerability and effectiveness of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term smoking abstinence, in comparison to non-nicotine EC, other smoking cessation treatments and no treatment.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register to 1 February 2023, and Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 July 2023, and reference-checked and contacted study authors.

SELECTION CRITERIA

We included trials in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention as these studies have the potential to provide further information on harms and longer-term use. Studies had to report an eligible outcome.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Critical outcomes were abstinence from smoking after at least six months, adverse events (AEs), and serious adverse events (SAEs). We used a fixed-effect Mantel-Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in pairwise and network meta-analyses (NMA).

MAIN RESULTS

We included 88 completed studies (10 new to this update), representing 27,235 participants, of which 47 were randomized controlled trials (RCTs). Of the included studies, we rated ten (all but one contributing to our main comparisons) at low risk of bias overall, 58 at high risk overall (including all non-randomized studies), and the remainder at unclear risk. There is high certainty that nicotine EC increases quit rates compared to nicotine replacement therapy (NRT) (RR 1.59, 95% CI 1.29 to 1.93; I2 = 0%; 7 studies, 2544 participants). In absolute terms, this might translate to an additional four quitters per 100 (95% CI 2 to 6 more). There is moderate-certainty evidence (limited by imprecision) that the rate of occurrence of AEs is similar between groups (RR 1.03, 95% CI 0.91 to 1.17; I2 = 0%; 5 studies, 2052 participants). SAEs were rare, and there is insufficient evidence to determine whether rates differ between groups due to very serious imprecision (RR 1.20, 95% CI 0.90 to 1.60; I2 = 32%; 6 studies, 2761 participants; low-certainty evidence). There is moderate-certainty evidence, limited by imprecision, that nicotine EC increases quit rates compared to non-nicotine EC (RR 1.46, 95% CI 1.09 to 1.96; I2 = 4%; 6 studies, 1613 participants). In absolute terms, this might lead to an additional three quitters per 100 (95% CI 1 to 7 more). There is moderate-certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 5 studies, 1840 participants). There is insufficient evidence to determine whether rates of SAEs differ between groups, due to very serious imprecision (RR 1.00, 95% CI 0.56 to 1.79; I2 = 0%; 9 studies, 1412 participants; low-certainty evidence). Due to issues with risk of bias, there is low-certainty evidence that, compared to behavioural support only/no support, quit rates may be higher for participants randomized to nicotine EC (RR 1.88, 95% CI 1.56 to 2.25; I2 = 0%; 9 studies, 5024 participants). In absolute terms, this represents an additional four quitters per 100 (95% CI 2 to 5 more). There was some evidence that (non-serious) AEs may be more common in people randomized to nicotine EC (RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low-certainty evidence; 4 studies, 765 participants) and, again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 0.89, 95% CI 0.59 to 1.34; I2 = 23%; 10 studies, 3263 participants; very low-certainty evidence). Results from the NMA were consistent with those from pairwise meta-analyses for all critical outcomes, and there was no indication of inconsistency within the networks. Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued EC use. Very few studies reported data on other outcomes or comparisons, hence, evidence for these is limited, with CIs often encompassing both clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that ECs with nicotine increase quit rates compared to NRT and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain due to risk of bias inherent in the study design. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, with no difference in AEs between nicotine and non-nicotine ECs nor between nicotine ECs and NRT. Overall incidence of SAEs was low across all study arms. We did not detect evidence of serious harm from nicotine EC, but the longest follow-up was two years and the number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up-to-date information to decision-makers, this review is a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

E-cigarette puffing topography: The importance of assessing user behaviour to inform emissions testing

Analysis of the chemical composition of e-cigarette emissions is an important step in determining whether e-cigarettes offer both individual and population-level harm reduction potential. Commonly, e-cigarette emissions for chemical analysis are collected when using e-cigarettes according to standardised puffing regimens, such as those recommended by the International Organization for Standardization (ISO) or the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA). While the use of such standard puffing regimens affords a degree of uniformity between studies and are also recommended by regulatory authorities who require the submission of e-cigarette emissions data to make decisions regarding allowing a product to be commercially marketed, the standardised regimens do not necessarily reflect human puffing behaviour. This can lead to under- or over-estimating real-world emissions from e-cigarettes and inaccuracy in determining their harm reduction potential. In this review, we describe how human puffing behaviour (topography) information can be collected both in the clinical laboratory and in the real world using a variety of different methodologies. We further discuss how this information can be used to dictate e-cigarette puffing regimens for collecting emissions for chemical analyses and how this may lead to better predictions both of human yields of e-cigarette emissions constituents and of risk assessments to predict e-cigarette tobacco harm reduction potential.

An assessment of nicotine pharmacokinetics and subjective effects of the pulze heated tobacco system compared with cigarettes

Nicotine delivery and subjective effects are determinants of the ability of potentially less harmful tobacco products such as heated tobacco products (HTPs) to support adult smokers in switching away from cigarettes, and therefore to support tobacco harm reduction. This open-label, randomised, crossover, clinical study in 24 healthy adult smokers study assessed nicotine pharmacokinetics and subjective effects of the Pulze Heated Tobacco System (HTS; Pulze HTP device and three iD stick variants-Intense American Blend, Regular American Blend and Regular Menthol) compared with subjects' usual brand cigarettes (UBC). Cmax and AUCt were highest for UBC and significantly lower for each Pulze HTS variant. Cmax and AUCt were significantly higher for Intense American Blend compared with Regular American Blend, while AUCt was significantly higher for Intense American Blend compared with Regular Menthol. Median Tmax was lowest (i.e., nicotine delivery was fastest) for subjects' usual brand cigarettes and similar across the iD stick variants, although no between-product differences were statistically significant. All study products reduced urges to smoke; this effect was greatest for cigarettes although this was not statistically significant. Product evaluation scores for each Pulze HTS variant in the domains of 'satisfaction', 'psychological reward' and 'relief' were similar, and lower than those for UBC. These data demonstrate that the Pulze HTS effectively delivers nicotine and generates positive subjective effects, including satisfaction and reduced urge to smoke. This supports the conclusion that the Pulze HTS may be an acceptable alternative to cigarettes for adult smokers while having a lower abuse liability than cigarettes.

Actual Use Behavior Assessment of a Novel Puff Recording Electronic Nicotine Delivery System: Observation Study

BACKGROUND

Compared with combustible cigarettes, electronic cigarettes (e-cigarettes) can deliver a sufficient amount of nicotine with a significantly reduced emission of toxicants, which renders them as potential harm reduction candidates for tobacco and smoking replacement. However, the use of e-cigarettes is not harm free and the long-term health effect of using e-cigarettes is yet to be established. Given the high prevalence of e-cigarette use across the globe and its potential health concerns, it is imperative to conduct actual use behavior assessments to better understand how e-cigarettes are being consumed in real-world conditions. However, with the currently available technologies, there is still a lack of noninvasive, noninterventional, and convenient instruments for the real-time and real-world use behavior monitoring of e-cigarette product use. Novel technology-based systems that do not primarily rely on self-report or intrusive measurements to monitor e-cigarette use behaviors are therefore highly desired.

OBJECTIVE

The primary goal of this study is to investigate the e-cigarette actual use behaviors in the real world via a novel puff recording electronic nicotine delivery system (PR-ENDS). Specifically, we aim to analyze and summarize the survey and PR-ENDS use data and to study the relationships and effects of different factors on these variables.

METHODS

In real-world conditions, 61 enrolled UK e-cigarette users were instructed to use PR-ENDS as the primary source of nicotine with their selected e-liquids for at least 3 weeks (21 days). A baseline survey was conducted to collect information about participants' demographics and nicotine use history (cigarette and ENDS). The puff data (ie, puff number, puff duration for each puff, device power, e-liquid nicotine concentrations) were directly recorded by PR-ENDS and uploaded to the cloud for further analyses. The nicotine emission and nicotine consumption were estimated based on recorded puff data.

RESULTS

Middle-aged adults with a nicotine history represented the major user profile during the PR-ENDS trial. A wide range of device power and e-liquid nicotine concentrations was applied and their combinations during actual use were found to be rather complex. Various puff parameters (ie, puff duration, puff number, nicotine emission) were assessed with contributing factors from device, e-liquid, and user nicotine history in different effect sizes. The real-time observation revealed substantial intra- and interindividual variabilities in PR-ENDS use behaviors. The use pattern of a quick adaptation followed by consistent product use was recognized for at least 3 weeks during actual use.

CONCLUSIONS

The actual use behavior assessment of PR-ENDS was conducted as a proof-of-concept application. The complex interactions of product attributes and significant intra- and interindividual variabilities in e-cigarette use behaviors provided new insights of compensatory behavior, which can inspire future studies in the field of nicotine addiction and abuse liability behavior assessment.

A Novel Puff Recording Electronic Nicotine Delivery System for Assessing Naturalistic Puff Topography and Nicotine Consumption During Ad Libitum Use: Ancillary Study

BACKGROUND

Assessing the naturalistic puff topography and associated nicotine consumption during e-cigarette use is important as such information will not only unveil how these products are being consumed in real-world conditions, but also enable investigators and regulatory bodies to conduct quantitative, accurate, and realistic harmful exposure and nicotine abuse liability risk assessments based on actual e-cigarette use. Conventional approaches cannot accurately, conveniently, and noninvasively determine e-cigarette puff topography in a natural use environment. Thus, novel technology-enabled systems that do not primarily rely on self-report mechanisms or intrusive measurements to monitor e-cigarette product use behaviors are highly desired.

OBJECTIVE

This study aimed to explore and demonstrate the feasibility of a novel puff recording electronic nicotine delivery system (PR-ENDS) device for measuring naturalistic puff topography and estimating nicotine consumption during the ad libitum use of products among smokers and vapers.

METHODS

An ancillary data analysis based on a completed parent study was conducted. The parent study was a 1-way randomized controlled open-label puff topography and nicotine pharmacokinetic assessment carried out in 24 healthy adults (12 smokers and 12 vapers). Participants were assigned a randomized product use sequence of a PR-ENDS device within 5 site visits for both controlled and ad libitum product use sessions. Blood samples were obtained for plasma nicotine analysis, and questionnaires were administered at various time points. During the ad libitum use session, puff topography was measured using a Clinical Research Support System (CReSS) device as a benchmark, as well as the PR-ENDS device with a built-in puff recording feature.

RESULTS

There were no significant differences in representative puff topography parameters (number of puffs, total puff duration, and average puff duration) between the PR-ENDS and CReSS devices at the populational level across different device powers, e-liquid nicotine strengths, and flavors. The nicotine consumption estimated by the PR-ENDS device suggested that this device can be employed as a convenient monitoring tool for estimating nicotine use without measuring e-liquid weight loss between puffs. The linear relationship between nicotine consumption estimated by the PR-ENDS device and the pharmacokinetic parameter AUC_{ad lib} (plasma concentration-time curve for 1-hour ad libitum use) substantiated the potential of using this device as a pragmatic, noninvasive, and convenient means for estimating nicotine intake in the human body without blood collection.

CONCLUSIONS

The novel PR-ENDS device was feasible for assessing naturalistic puff topography and estimating nicotine consumption and intake in the human body during ad libitum use. Several key factors can influence users' puff topography, including device power levels, e-liquid nicotine strengths, and flavors. The study results pave the way for further research in the real-time measurement of naturalistic puff topography and puffing behaviors in the real world.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol by heating an e-liquid. Some people who smoke use ECs to stop or reduce smoking, although some organizations, advocacy groups and policymakers have discouraged this, citing lack of evidence of efficacy and safety. People who smoke, healthcare providers and regulators want to know if ECs can help people quit smoking, and if they are safe to use for this purpose. This is a review update conducted as part of a living systematic review.

OBJECTIVES

To examine the effectiveness, tolerability, and safety of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term smoking abstinence.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 July 2022, and reference-checked and contacted study authors.  SELECTION CRITERIA: We included randomized controlled trials (RCTs) and randomized cross-over trials, in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention. Studies had to report abstinence from cigarettes at six months or longer or data on safety markers at one week or longer, or both.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking after at least six months follow-up, adverse events (AEs), and serious adverse events (SAEs). Secondary outcomes included the proportion of people still using study product (EC or pharmacotherapy) at six or more months after randomization or starting EC use, changes in carbon monoxide (CO), blood pressure (BP), heart rate, arterial oxygen saturation, lung function, and levels of carcinogens or toxicants, or both. We used a fixed-effect Mantel-Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in meta-analyses.

MAIN RESULTS

We included 78 completed studies, representing 22,052 participants, of which 40 were RCTs. Seventeen of the 78 included studies were new to this review update. Of the included studies, we rated ten (all but one contributing to our main comparisons) at low risk of bias overall, 50 at high risk overall (including all non-randomized studies), and the remainder at unclear risk. There was high certainty that quit rates were higher in people randomized to nicotine EC than in those randomized to nicotine replacement therapy (NRT) (RR 1.63, 95% CI 1.30 to 2.04; I2 = 10%; 6 studies, 2378 participants). In absolute terms, this might translate to an additional four quitters per 100 (95% CI 2 to 6). There was moderate-certainty evidence (limited by imprecision) that the rate of occurrence of AEs was similar between groups (RR 1.02, 95% CI 0.88 to 1.19; I2 = 0%; 4 studies, 1702 participants). SAEs were rare, but there was insufficient evidence to determine whether rates differed between groups due to very serious imprecision (RR 1.12, 95% CI 0.82 to 1.52; I2 = 34%; 5 studies, 2411 participants). There was moderate-certainty evidence, limited by imprecision, that quit rates were higher in people randomized to nicotine EC than to non-nicotine EC (RR 1.94, 95% CI 1.21 to 3.13; I2 = 0%; 5 studies, 1447 participants). In absolute terms, this might lead to an additional seven quitters per 100 (95% CI 2 to 16). There was moderate-certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 5 studies, 1840 participants). There was insufficient evidence to determine whether rates of SAEs differed between groups, due to very serious imprecision (RR 1.00, 95% CI 0.56 to 1.79; I2 = 0%; 8 studies, 1272 participants). Compared to behavioural support only/no support, quit rates were higher for participants randomized to nicotine EC (RR 2.66, 95% CI 1.52 to 4.65; I2 = 0%; 7 studies, 3126 participants). In absolute terms, this represents an additional two quitters per 100 (95% CI 1 to 3). However, this finding was of very low certainty, due to issues with imprecision and risk of bias. There was some evidence that (non-serious) AEs were more common in people randomized to nicotine EC (RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low certainty; 4 studies, 765 participants) and, again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 1.03, 95% CI 0.54 to 1.97; I2 = 38%; 9 studies, 1993 participants).  Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued EC use. Very few studies reported data on other outcomes or comparisons, hence evidence for these is limited, with CIs often encompassing clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that ECs with nicotine increase quit rates compared to NRT and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain. More studies are needed to confirm the effect size. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, with no difference in AEs between nicotine and non-nicotine ECs nor between nicotine ECs and NRT. Overall incidence of SAEs was low across all study arms. We did not detect evidence of serious harm from nicotine EC, but longest follow-up was two years and the number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates, but further RCTs are underway. To ensure the review continues to provide up-to-date information to decision-makers, this review is a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

"When I Don't Have a Cigarette It's Helpful, but It Really Don't Satisfy:" Qualitative Study of Electronic Nicotine Delivery Systems (ENDS) Use among Low-Income Smokers

BACKGROUND

Little is known about the use of electronic nicotine delivery systems (ENDS) among low-income adult cigarette smokers, who experience severe tobacco-related health disparities.

METHODS

This study conducted interviews to examine experiences and perceptions associated with ENDS use among predominantly low-income adult smokers (n = 30; mean age 30.2 ± 12.9; 60% male, 46.7% African American, 30% white, 10% more than one race; 76.7% annual household income ≤USD 24,000). Interviews were transcribed verbatim and coded in NVivo 11.

RESULTS

Overall, participants reported complementing rather than substituting their smoking with ENDS use (e.g., using ENDS only when smoking is not allowed). Predominant reasons for vaping were convenience, smoking reduction/cessation, stress management, social acceptability, lower long-term costs than smoking, and appealing flavors. Common reasons for not switching to exclusive vaping were that ENDS did not satisfy cigarette cravings and concerns about ENDS health effects. Participants indicated higher likelihood of switching to exclusive ENDS use if the products were more affordable, perceived as substantially less harmful, tasted and felt more like smoking a cigarette, and more effective for reducing cravings.

CONCLUSIONS

Continued research is needed to maximize any harm reduction potential of ENDS and ensure that these products do not contribute to worsening health disparities.