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Past 30-day point prevalence abstinence from smoking at the 3-month assessment. Self-reported past 30-day point prevalence abstinence from cigarette smoking associated with using a JUUL vaporizer for three months, stratified by place of first purchase of a JUUL Starter Kit and sample type
Source publication
Background
JUUL is the fastest growing and highest selling brand of e-cigarette/vapor products in the USA. Assessing the effect of JUUL vapor products on adult smokers’ use of conventional tobacco cigarettes can help inform the potential population health impact of these products.
Methods
Online surveys assessed past 30-day use of conventional cig...
Similar publications
Introduction
Evidence suggests that cigarette smokers who switch to electronic nicotine delivery systems (ENDS) reduce their exposure to harmful toxicants and carcinogens. It is unclear if dual use is associated with decreases in exposure to toxicants.
Methods
This parallel-group confinement study assessed changes in biomarkers of exposure (BOEs)...
The chemical constituents of JUUL Virginia Tobacco pods with 3.0% and 5.0% nicotine by weight (VT3 and VT5) were characterized by non-targeted analyses, an approach to detect chemicals that are not otherwise measured with dedicated methods or that are not known beforehand. Aerosols were generated using intense and non-intense puffing regimens and a...
Citations
... When initially quitting, similarity to smoking and tobacco flavour may be important, but Farsalinos et al. [19] found that flavour variability is very important to people who use e-cigarettes who have successfully stopped smoking. In line with our findings, other research has shown people who smoke report using a preferred flavour when starting to vape, which may take some trial and error to find, but some people continue to seek variety [8] and many people who vape regularly use multiple flavours [17,43,44]. Our survey results support this, with most participants reporting using a variety of flavours rather than one specific flavour (Additional file 2: Table S5). ...
Background
Although electronic cigarettes (e-cigarettes) appear to be effective in helping people who smoke to stop smoking, concerns about use of e-cigarettes among young people have led to restrictions on non-tobacco flavoured e-liquids in some countries and some US states. These restrictions could reduce the appeal of these products to non-smoking youth but could have negative consequences for people who smoke or use e-cigarettes.
Methods
In this mixed methods study, we recruited UK adults who smoked or used to smoke and subsequently vaped to explore their opinions of unflavoured e-liquids and their beliefs about how they would be impacted by hypothetical e-liquid flavour restrictions. Participants trialled an unflavoured e-liquid instead of their usual nicotine product for four hours and completed a survey and an online interview.
Results
Using Interpretive Phenomenological Analysis and graphically presented data, we found differences in participants’ opinions of unflavoured e-liquid. If only unflavoured, tobacco flavoured, and menthol flavoured e-liquids remained on the UK market, some people who smoke or vape may be unaffected, but some may relapse to smoking or continue smoking. Despite most wanting to prevent young people from initiating vaping, participants had varying opinions on whether flavour restrictions would be an effective method.
Conclusions
The findings highlight that people who smoke and vape could be impacted by flavour restrictions in a range of ways, some of which could have a potential adverse impact on harm reduction efforts in the UK (e.g., by making smoking more appealing than vaping).
... Two naturalistic longitudinal studies of U.S. adults who smoke cigarettes and purchased a JUUL-brand ENDS starter kit on their own found that over 40% reported switching 3 months after purchase (i.e., reported no past 30-day smoking), with rates increasing to 47%-54% at 6 months Russell et al., 2019aRussell et al., , 2019bShiffman & Hannon, 2023). However, these studies involved participants relatively committed to JUUL use who were sufficiently motivated to purchase a JUUL Starter Kit, leaving open the question of how much switching would occur in a general population of adults who smoke cigarettes and have not taken such action to adopt JUUL. ...
... Some observational studies suggest that participants using ENDS in nontobacco flavors are more likely to switch than those using tobacco flavors (Chen, 2018;Friedman & Xu, 2020;Gendall & Hoek, 2021;Glasser et al., 2020;Gravely et al., 2020;Jones et al., 2019;Li et al., 2021;Mok et al., 2023), and that adults who smoke cigarettes often transition from tobacco to nontobacco flavors as they switch (Du et al., 2020;Russell et al., 2018), whereas other studies have not found significant associations between use of flavored ENDS and switching or quit attempts (Kasza, Edwards, Gravely, et al., 2021;Liber et al., 2023;Lindson et al., 2023;Schneller et al., 2019). U.S. adults who smoke and purchased JUUL products predominantly used nontobacco flavors, but evidence on the association of flavors and switching is mixed Russell et al., 2019aRussell et al., , 2019b. Further, given the observational designs of these studies, with self-selection of flavors, it is difficult to make causal attributions. ...
... Past 30-Day Switching at Follow-up Switching was defined as a "No" response to the question, "In the past 30 days, have you smoked a cigarette, even one or two puffs?" as in the previous research (Kalkhoran et al., 2020;McDermott et al., 2021;Russell et al., 2019aRussell et al., , 2019b. In accordance with the recommended guidelines for randomized smoking-cessation trials (i.e., intent-to-treat), participants who were lost to follow-up or missing smoking data were coded as having smoked (Piper et al., 2020;West et al., 2005). ...
Observational studies show high rates of switching away from cigarettes among adult purchasers of JUUL-brand electronic nicotine delivery system (ENDS); data are needed to evaluate switching with JUUL in randomized general population trials. The association of ENDS flavor availability and switching is pertinent. This study assessed switch rates and smoking reduction among participants randomized to use JUUL in a choice of flavors or tobacco-only, compared to a condition provided smoking-cessation materials. U.S. adults who smoke cigarettes (N = 837; Mage [SD] = 45.99 years [11.48]; 18.76 cigarettes/day [SD = 7.86]; 50.2% female) from an address-based representative panel were randomized to receive JUUL for 6 months (5.0% nicotine; only Virginia Tobacco [N = 285] or choice of flavors [N = 281]), or smoking-cessation materials (quit advice [QA]; N = 271). Self-reported past 30-day smoking and cigarette consumption were assessed at 1, 3, and 6 months. Repeated-measure regressions assessed differences in smoking outcomes between groups. Only 2% of participants were planning to quit smoking within 30 days. Across the 6-month intervention, participants randomized to JUUL (vs. QA) had 6.57-fold greater odds of reporting past 30-day switching (95% CI [3.72−11.63]). Participants in the JUUL (vs. QA) group smoked 27% fewer cigarettes/day versus baseline (Rate Ratio [95% CI] = 0.73 [0.68−0.77]). Over half (51.8%) of the Virginia Tobacco group used other flavors (36.7% nontobacco flavors), contaminating randomized flavor-conditions. JUUL flavor groups did not differ in smoking outcomes (p > .48). Use of JUUL products may support complete switching away from cigarettes, including among those not ready to quit smoking. Results suggest a preference for nontobacco-flavored ENDS among adults who smoke, although smoking outcomes did not differ by flavor.
... We included twelve longitudinal studies of ENDS flavors and smoking cessation outcomes. Nine studies were conducted within the US, five of which used Population Assessment of Tobacco and Health [PATH] data, Chen, 2018 ;Friedman 2020 ;Glasser et al., 2021 ;Harlow et al., 2021 ; three used online consumer surveys, ( Russell et al., 2019a( Russell et al., , 2019bWeaver et al., 2018 ) and one employed an in-person survey ( Rest et al., 2022 ). Two were clinical trials conducted in the UK ( Dyer et al., 2021 ;McKeganey et al., 2018 ). ...
... Eleven longitudinal studies produced twelve outcomes of successful smoking cessation split by the flavor of ENDS used ( Dyer et al., 2021 ;Friedman 2020 ;Glasser et al., 2021 ;Goldenson et al., 2022 ;Harlow et al., 2021 ;Li et al., 2021 ;McKeganey et al., 2018 ;Rest et al., 2022 ;Russell et al., 2019aRussell et al., , 2019bWeaver et al., 2018 ). Studies used a range of measures of quit success. ...
... Overall, eight studies producing nine outcomes reported adjusted odds of quit success by ENDS flavor used ( Dyer et al., 2021 ;Friedman 2020 ;Glasser et al., 2021 ;Goldenson et al., 2022 ;Harlow et al., 2021 ;Li et al., 2021 ;Russell et al., 2019bRussell et al., , 2019a. Four of seven outcomes using adjusted odds ratios reported that persons using nontobacco-flavored ENDS had significantly higher odds of quit success than those using tobacco-flavored ENDS. ...
Background:
Electronic nicotine delivery systems (ENDS) come in numerous flavors and may aid smoking cessation. This systematic review examines evidence on the role of ENDS flavors in smoking cessation.
Methods:
We searched EMBASE OVID, PsychInfo, and Medline databases for studies that: 1) examined cigarette cessation outcomes for persons using ENDS (intent, attempts, and success) and 2) reported results separated by respondent's ENDS flavor used. We extracted crude and adjusted odds ratios for associations between cessation outcomes and types of ENDS flavors used (nontobacco vs. tobacco/unflavored; nontobacco and nonmenthol vs. tobacco/unflavored and menthol). We did not consider cessation outcomes among people not using ENDS. We evaluated the evidence using the GRADE approach, focusing on consistency and reliability of findings across studies.
Results:
29 studies met inclusion criteria, producing 36 odds ratios (ORs) comparing cessation outcomes across ENDS flavor groups. Three ORs examined quit intent, five examined quit attempts, and 28 examined quit success. Using GRADE, we reached Low levels of certainty that there was not an association between ENDS flavor use and intention to quit smoking or making a quit attempt. There were Very Low levels of certainty that nontobacco flavored versus tobacco/unflavored ENDS use was not associated with smoking cessation success, with similar findings for nonmenthol and nontobacco compared to tobacco and menthol flavored ENDS.
Conclusion:
The evidence about the role of different flavored ENDS use and smoking cessation outcomes is inconclusive, reflecting highly heterogeneous study definitions and methodological limitations. More high-quality evidence, ideally from randomized controlled trials, is required.
... Vaping products, for example, may or may not be good goods, depending upon which aspects of these products is considered. Juul and other vaping firms have argued that their pods make it easier for cigarette smokers to quit smoking, and there is some evidence that this claim is true (Russell et al. 2019). The pods use nicotine salts to deliver a nicotine buzz deep within the lungs. ...
Social commentators and ethicists alike have begun to suggest that the disappearance of rituals can lead to an increase in wrongdoing (Han, The disappearance of rituals. Polity Press, 2020). Such a claim seems intuitively plausible. To the extent that virtues are habits born of repeated actions, a loss of rituals (which are also repetitive) might undermine the development of sound ethical character. If ritual builds and sustains community, then the loss of ritual might lead individuals to feel less sympathy and empathy for other members of the community and to be less committed to justice understood as the practice of ensuring that each person is rendered his or her due. If rituals create differentiation and establish boundaries, their disappearance might also lead to a failure to respect property rights, personal boundaries, and all sorts of other domains that depend upon a clear distinction of mine and thine. Some commentators have gone so far as to attribute the rise of materialism, consumerism, and pornography (all three of which may be connected with greed) to the demise of rituals (Han, The disappearance of rituals. Polity Press, 2020).This chapter examines the nature and various functions of rituals and the numerous ways in which Confucian rituals can support, reinforce, and even ground virtuous and respectful and thoughtful behavior in the workplace and beyond. In this chapter, I focus primarily on how rituals function within Confucian ethics because Confucius was arguably the first ethical thinker to discuss in detail the importance of li or rituals. Part One loosely defines rituals and sets up a typology of them. Part Two considers specific ethical features of Confucian rituals. Part Three explores the relevance of Confucian rituals to the workplace and the possible benefits attendant upon ritualizing employee behavior.KeywordsConfuciusRitualsSelf-refinementHumorThinkingHarmony
... Vaping products, for example, may or may not be good goods, depending upon which aspects of these products is considered. Juul and other vaping firms have argued that their pods make it easier for cigarette smokers to quit smoking, and there is some evidence that this claim is true (Russell et al. 2019). The pods use nicotine salts to deliver a nicotine buzz deep within the lungs. ...
What is humane work? What does such work look like in a business context? This paper articulates two ways of thinking about humane work using an Aristotelian and a Confucian virtue ethics approach. This approach reveals the need to think about (1) work’s connection not merely with autonomy but with self-refinement and self-perfection, with craft, and with the production of genuinely good goods; (2) possible dangers (e.g., the risk of generating envy) of focusing too much on pay issues in connection with humane work; (3) the relation between humane work and political regimes; and (4) the role played by stakeholders other than managers in the humanizing of work.
... The second part of the e-cig, analogous to the white paper wrapping of a traditional cigarette, contains the electronics, including the controller and battery. Users can alter many of the products of e-cigs, and there are engineering differences between brands (Table 1, Figure 1) [5,[7][8][9], thereby altering the amount of nicotine and other chemicals delivered to the user. Though e-cigs have been on the market for decades, there is little information about their toxicity due to the lack of quality control [5]. ...
The US Food and Drug Administration (FDA) recently approved the marketing of an electronic cigarette (e-cig) brand called Vuse (RJ Reynolds Vapor Company, US) to help aid in smoking cessation for adult smokers. It was believed that the consumption of traditional cigarettes and their harmful effects would be reduced given the availability of newer e-cigarettes. However, adolescent use of tobacco and nicotine products rather increased with the availability of the same e-cigarettes, and the FDA-approved market boom only worsened this problem. Although the FDA underlines the importance of marketing e-cigarettes as a possible solution for adult traditional smoking, its consequences on adolescents' health raise many concerns, which we narrated in this review article.
... 21,27,62,64,[68][69][70][71][72][73][74][75] For cigarette smokers who recently bought a JUUL e-cigarette online, mint and mango were the most commonly used flavors. 76 Mint and fruit flavors were also the most preferred JUUL flavors for college student and adult JUUL ever-users. 77,78 These preferences replicate in subpopulations such as pregnant or racial and ethnic minority e-cigarette users (eg, Asian American/ Pacific Islander or Maori). ...
... Compared with using tobacco or unflavored e-liquids alone, cigarette smokers who used one or multiple nontobacco flavored e-liquids were more likely to have reduced or quit smoking. 76,[85][86][87] Another study also found that flavored e-cigarette use was associated with fewer cigarettes smoked per day; however, it found no change in number of days smoked per month or nicotine dependence compared with unflavored and tobacco flavored e-liquids. 88 The number of flavors used may also be important, as one study found that the number of flavors used was associated with increased cigarette smoking cessation for dual users. ...
Introduction:
Many adult cigarette smokers use electronic cigarettes (e-cigarettes) to cut down on or quit smoking cigarettes. E-cigarettes with higher abuse potential and appeal might facilitate complete switching. E-liquid nicotine concentration and flavor are two of the characteristics that may affect the abuse potential and appeal of e-cigarettes. The objective of this systematic review was to compile results from survey, animal, human laboratory, and clinical studies to understand the possible effects of nicotine concentration and flavor on abuse potential and appeal of e-cigarettes in adult current and former cigarette and e-cigarette users.
Methods:
A comprehensive literature search was conducted in Ovid Medline and PsycINFO followed by citation tracking in Web of Science Core Collection. Peer-reviewed studies published in English between 2007 and August 2020 were selected that analyzed differences between e-liquid nicotine concentration and/or flavors, had outcome measures related to abuse potential and/or appeal, and included adult humans (18+) or animals. 1624 studies were identified and screened. A qualitative synthesis of results was performed.
Results:
Results from 104 studies included in this review suggest that higher nicotine concentration and access to a variety of flavors are likely to be associated with higher abuse potential and appeal of e-cigarettes for adult current and former cigarette and e-cigarette users.
Conclusions:
Higher nicotine concentrations and the availability of a variety of flavors in e-cigarettes might facilitate complete substitution for cigarettes. Future e-cigarette regulations should take into account their impact on smokers, for whom e-cigarettes may be a cessation tool or reduced-harm alternative.
Implications:
E-cigarettes may provide a reduced-harm alternative to cigarettes for smokers unwilling/unable to quit or serve as a path for quitting all nicotine products. Higher nicotine concentrations and flavor variety are associated with higher abuse potential and appeal of e-cigarettes. Higher abuse potential and appeal products may help facilitate complete switching from cigarettes to e-cigarettes. Regulation of nicotine concentration and flavors aimed at decreasing naïve uptake may inadvertently decrease uptake and complete switching among smokers, reducing the harm reduction potential of e-cigarettes. Evidence-based effects of regulating nicotine concentration and flavors must be considered for the population as a whole, including smokers.
... The Test Products are available in a variety of avors and nicotine levels (seven avor varieties: wintergreen, mint, cinnamon, coffee, citrus, berry, and original; ve nicotine levels per avor: 1.5 mg, 2 mg, 3.5 mg, 4 mg, and 8 mg) that provide choices for ATCs. The availability of multiple avors and nicotine levels may facilitate the transition away from cigarettes, thus offering a potentially reduced harm alternative to adult smokers unable or unwilling to quit (11)(12)(13)(14)(15). However, to date there are no available published reports on the impact of using the Test Products on the continued use of or switching behavior from more harmful forms of tobacco. ...
Background
Oral tobacco-derived nicotine (OTDN) products are a rapidly emerging, innovative category of noncombustible tobacco products. These products are tobacco-leaf free and do not contain or generate many of the harmful and potentially harmful constituents (HPHCs) found in combustible cigarettes or smokeless tobacco (ST) products. OTDN products may therefore offer adult tobacco consumers a potentially reduced harm alternative. However, little is known about OTDN product use patterns or their ability to substitute for more harmful tobacco products.
Methods
We conducted an open-label, 2-phase, actual use study designed to characterize OTDN pouch product (on!® nicotine pouches - NP) use patterns, including impact on other tobacco use behaviors among adult tobacco consumers interested in using NP. Adult current cigarette smokers (AS) and/or adult ST users (ASTU) (n = 1,147 complete) who were not planning to quit were offered free choice of a portfolio of NP (seven flavors at five nicotine levels) to use at-home, ad-libitum, for 6-weeks following an initial 5-day trial. Participants responded to daily electronic surveys that captured the amount, frequency, and topography (e.g., time in mouth, placement in mouth) of NP and other tobacco product use.
Results
The majority (99 to 100%) of study participants used NP throughout the 6-week period. Participants used ~5-6 pouches/day of a variety of flavors and nicotine levels. At the end of 6 weeks, a modest proportion of AS (27%) and a substantial proportion of ASTU (71%) reported no use of cigarettes or ST respectively, while reporting continued use of NPs. Additionally, 39% of AS and 14% of ASTU reduced daily consumption of cigarettes or ST products, respectively by 50-99%.
Conclusions
Participants found NPs acceptable with a sizeable proportion completely switching away from or substantially reducing (50-99%) their cigarette or ST consumption by week 6. Availability of a variety of flavors and nicotine levels appeared to facilitate the conversion to NP. These data suggest that, under the conditions of the study, NP can be a potential substitute for cigarettes or ST products and may offer harm reduction potential for adult smokers and smokeless tobacco users not interested in quitting.
Trial Registration
Note: This study is an observational study with tobacco products currently available in the marketplace for adult tobacco consumers. Since there is no intervention per se and we did not collect any biosamples this is not a “clinical study” and there is no appropriate registry for such behavioral observational studies, we do not believe that this requirement is applicable.
... The Test Products are available in a variety of avors and nicotine levels (seven avor varieties: wintergreen, mint, cinnamon, coffee, citrus, berry, and original; ve nicotine levels per avor: 1.5 mg, 2 mg, 3.5 mg, 4 mg, and 8 mg) that provide choices for ATCs. The availability of multiple avors and nicotine levels may facilitate the transition away from cigarettes, thus offering a potentially reduced harm alternative to adult smokers unable or unwilling to quit (11)(12)(13)(14)(15). However, to date there are no available published reports on the impact of using the Test Products on the continued use of or switching behavior from more harmful forms of tobacco. ...
Background:
Oral tobacco-derived nicotine (OTDN) products are a rapidly emerging, innovative category of noncombustible tobacco products. These products are tobacco-leaf free and do not contain or generate many of the harmful and potentially harmful constituents (HPHCs) found in combustible cigarettes or smokeless tobacco (ST) products. OTDN products may therefore offer adult tobacco consumers a potentially reduced harm alternative. However, little is known about OTDN product use patterns or their ability to substitute for more harmful tobacco products.
Methods:
We conducted an open-label, 2-phase, actual use study designed to characterize OTDN pouch product (on!® nicotine pouches - NP) use patterns, including impact on other tobacco use behaviors among adult tobacco consumers interested in using NP. Adult current cigarette smokers (AS) and/or adult ST users (ASTU) (n = 1,147 complete) who were not planning to quit were offered free choice of a portfolio of NP (seven flavors at five nicotine levels) to use at-home, ad-libitum, for 6-weeks following an initial 5-day trial. Participants responded to daily electronic surveys that captured the amount, frequency, and topography (e.g., time in mouth, placement in mouth) of NP and other tobacco product use.
Results:
The majority (99 to 100%) of study participants used NP throughout the 6-week period. Participants used ~5-6 pouches/day of a variety of flavors and nicotine levels. At the end of 6 weeks, a modest proportion of AS (27%) and a substantial proportion of ASTU (71%) reported no use of cigarettes or ST respectively, while reporting continued use of NPs. Additionally, 39% of AS and 14% of ASTU reduced daily consumption of cigarettes or ST products, respectively by 50-99%.
Conclusions:
Participants found NPs acceptable with a sizeable proportion completely switching away from or substantially reducing (50-99%) their cigarette or ST consumption by week 6. Availability of a variety of flavors and nicotine levels appeared to facilitate the conversion to NP. These data suggest that, under the conditions of the study, NP can be a potential substitute for cigarettes or ST products and may offer harm reduction potential for adult smokers and smokeless tobacco users not interested in quitting.
Trial Registration:
Note: This study is an observational study with tobacco products currently available in the marketplace for adult tobacco consumers. Since there is no intervention per se and we did not collect any biosamples this is not a “clinical study” and there is no appropriate registry for such behavioral observational studies, we do not believe that this requirement is applicable.
... 11 Two studies found that substantial proportions of US adult smokers who purchased a JUUL Starter Kit (henceforth "JUUL") reported switching away from smoking (ie, no past 30-day smoking) 3 and 6 months later. 12,13 However, the JUUL products in those studies contained 5.0% nicotine by weight (59 mg/mL), and it is unknown whether switch rates would be affected with lower nicotine concentrations. ...
... As observed in previous studies of US smokers who purchased JUUL, switching rates increased over the 6-month follow-up period. 12,13 Importantly, there was no intervention in the current study: participants purchased JUUL products on their own and received no instructions or advice regarding smoking. Although the switch rates observed in this observational study are not directly comparable to cessation trials, temporal patterns of increased switching over time stand in contrast to the pattern seen in traditional smoking-cessation trials, where rates of abstinence, including point prevalence abstinence, decline steeply over time. 2 Consistent with other studies of switching among JUUL purchasers, 12,13 participants generally continued use of JUUL across the study period; this pattern was also observed in a trial of ENDS for smoking cessation in the UK and is critical for noncombustible products intended as substitutes for cigarettes. ...
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.