The Role of Nicotine and Flavor in the Abuse Potential and Appeal of Electronic Cigarettes for Adult Current and Former Cigarette and Electronic Cigarette Users: A Systematic Review

Estimating human pharmacokinetic parameters forelectronic nicotine delivery system products from chemical analyses of their aerosols

The ability of Electronic Nicotine Delivery Systems (ENDS) to deliver nicotine is central to their function to substitute for cigarettes, allowing people who smoke to switch away from smoking, thus reducing their exposure to harmful chemicals in cigarette smoke. The nicotine concentration in ENDS e-liquid has proved to be a poor predictor of nicotine uptake in users. Using meta-analytic methods to analyze 12 pharmacokinetic studies of nicotine-salt closed-system ENDS, this paper examines whether the mass of nicotine/puff of aerosol can predict Cmax in pharmacokinetic studies. Cmax values were available for 38 products, in 58 use conditions (including both controlled [3 s] and ad libitum puffing), comprising 1769 participant observations. Nicotine/puff data reflected chemical analyses of aerosol obtained under nonintense (3 s) or intense (6 s) machine puffing. Meta-regression analyses (weighted by reliability of Cmax estimate) assessed the relationship of nicotine/puff to Cmax. In some models, empirical data were used to impute the variation in Cmax or the nicotine/puff value under intense puffing. In simple linear models, Cmax was significantly associated with nicotine/puff under all combinations of intense/nonintense and controlled/ad-libitum conditions, with R2 values of 0.71-0.77. More complex models based on quadratic effects or log[nicotine/puff] did not generally improve upon more parsimonious linear models. Application of the model illustrates the divergence between nicotine concentration in e-liquids and expected Cmax when other ENDS parameters vary. The meta-analytic model may have utility in settings where clinical pharmacokinetic data are not available, including product development.

Evaluating trends in recruitment challenges in vape shop research, e-cigarette product characteristics and use among shop customers from 2019 to 2023: A mixed-methods study

INTRODUCTION

Brick-and-mortar vape shops specialize in the sale of e-cigarettes and remain a primary source for purchasing emerging e-cigarette products. New regulatory policies have been implemented at local-, state- and federal-level; the retail environment at vape shops and product preferences among vape shop customers shifted accordingly.

METHODS

From 2019 to 2023, we collected anonymous interview data from vape shop customers (n=572) from 83 vape shops in Southern California. We aggregated the data by month and treated each month as the unit of analysis to document changes in recruitment efforts among the vape shops in relation to major policy implementations over 4 years. We also examined the systematic fluctuations and trends in customers' e-cigarette product preferences and nicotine content in these products.

RESULTS

The monthly average shop-level consent rate was 52.9% (SD=8.7), with an overall decreasing trend over time. It was necessary for our data collection team to approach a greater number of vape shops to obtain consent with implementation of various state and federal tobacco regulations and following COVID-19. We observed an increase in the purchase of disposable products and nicotine concentrations in the products, while the average use frequency remained the same.

CONCLUSIONS

Our findings demonstrated that user preferences, product characteristics and challenges in research involving vape shops are closely associated to changes in regulations. We documented a dramatic increase in nicotine concentration in products. Future policies restricting the amount of nicotine in tobacco products at the federal level are necessary to protect consumers from further nicotine addiction. This study provides documentation over time of the drastic increases in nicotine concentration among e-cigarette users as a result of the fluctuations in the product market. Regulating nicotine content in tobacco products could safeguard against further unsafe modifications in e-cigarettes and other types of tobacco products.

Non-tobacco nicotine E-cigarette use and flavored E-cigarette use among young adults in the United States

BACKGROUND

E-cigarette flavors can create sensations of sweetness and coolness while masking the aversiveness of nicotine. Recently, non-tobacco nicotine (NTN) products were introduced to the market, but little is known about flavors in NTN e-cigarette use. We examined associations between flavors (i.e., sweet, mint/menthol) and susceptibility to and use of NTN e-cigarettes.

METHODS

1239 US young adults (18-25 years) completed an anonymous, online survey in Fall 2021. The analytic sample included 520 participants who had used e-cigarettes and heard of NTN. Multinomial logistic regression models analyzed associations of flavored e-cigarette use (sweet and mint/menthol) with NTN e-cigarette use status (i.e., current [past-month] use, past [ever but not current] use, susceptible to use, and non-susceptible to use [reference]).

RESULTS

Overall, 46.2% of participants reported current NTN use, 14.8% reported past use, 16.7% were susceptible to use, and 22.3% reported no susceptibility. Participants reported dual-use of sweet and mint/menthol NTN e-cigarette flavors (56.5%), sweet flavors use (24.8%), and mint/menthol flavor use (1.7%). Ever dual use of sweet and mint/menthol flavors was associated with current (OR = 9.64, 95%CI: 3.21-28.98) and past NTN e-cigarette use (8.30, [2.10-32.80]). Ever sweet flavor use was associated with current NTN use (3.80, 95%CI: 1.44-10.03) and susceptibility to future use (4.25, [1.53-11.81]). Similar findings were observed for mint/menthol flavors (current: 5.03, [1.41-17.99]; susceptible: 5.65, [1.64-19.51]).

CONCLUSION

The use of sweet and mint/menthol flavors was significantly associated with NTN e-cigarette use among US young adults, highlighting the need for ongoing surveillance of flavored NTN e-cigarettes and appropriate regulations to discourage use.

Exploring the opinions and potential impact of unflavoured e-liquid on smoking cessation among people who smoke and smoking relapse among people who previously smoked and now use e-cigarettes: findings from a UK-based mixed methods study

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).

Adult harm perceptions, purchase, and use related to synthetic vs. tobacco-derived nicotine vaping products: A mixed-methods study

Objective

Synthetic nicotine (SN) e-cigarettes emerged on the market as an alternative to tobacco-derived nicotine (TDN) vaping products. It is critical to understand the harm perceptions, purchase, and use of SN vs. TDN e-cigarettes.

Methods

From November 2021 to February 2023, we conducted intercept interviews with 263 adult customers at 37 vape shops in Southern California. Self-reported use and harm perceptions towards SN vs TDN e-cigarettes were examined. A qualitative analysis of researcher-obtained photographs of vaping items just purchased by customer participants was conducted.

Results

Past 30-day SN e-cigarette use was reported by 44 (16.7 %) customers. Past 30-day SN e-cigarette users vs. non-users reported vaping on more days in the past month (29.3 vs. 26.1 days, p = 0.02). Overall, 23.8 % of participants perceived SN e-cigarettes as less harmful than TDN ones; never-smoking vapers and dual users perceived SN e-cigarettes as less harmful than salt-based TDN e-cigarettes. Among 44 customers who purchased SN products (verified through qualitative analysis of photographs), only 13 (29.6 %) self-reported using SN products in the past month, while 5 (11.4 %) indicated they were not aware of the existence of SN products. Most SN vaping products (71.4 %) displayed a modified "tobacco-free" warning label.

Conclusions

Misperceptions about SN e-cigarettes were documented in this study, including the perception that SN is either less or more harmful than TDN. Further, some customers may be unknowingly purchasing and using SN e-cigarettes. Regulating "tobacco-free nicotine" terminology in SN vaping products marketing is suggested. SN product labeling should not imply that SN is safe/safer than TDN.

Impact of Electronic Cigarette use on Cardiovascular Health: Current Evidence, Causal Pathways, and Public Health Implications

Electronic cigarette (e-cigarette) use is increasing in Europe and the USA. While mounting evidence exists regarding an array of associated adverse health effects, to date limited evidence exists regarding the health effects of e-cigarette use on cardiovascular (CV) disease (CVD). The present review summarizes the effects of e-cigarette use on CV health. A search strategy of in vivo experimental, observational studies (including population-based cohort studies), and interventional studies was conducted in PubMed, MEDLINE, and Web of Science (April 1, 2009-April 1, 2022). The main findings revealed that the influence of e-cigarette on health are attributed mainly to the individual and interactive effects of flavors and additives used in e-cigarette fluids, along with the extended heating. The above collectively stimulate prolonged sympathoexcitatory CV autonomic effects, such as increased heart rate and diastolic blood pressure (BP), as well as decreased oxygen saturation. Hence, e-cigarette users are at increased risk of developing atherosclerosis, hypertension, arrhythmia, myocardial infarction, and heart failure. Such risks are anticipated to increase, especially among the young who are increasingly adopting e-cigarette use particularly with flavored additives. Further investigations are urgently needed to evaluate the long-term effects of e-cigarette use, particularly among susceptible population groups such as youth.

Effects of liquid nicotine concentration and flavour on the acceptability of electronic nicotine delivery systems (ENDS) among people who smoke participating in a randomised controlled trial to reduce cigarette consumption

BACKGROUND

Research is needed to understand the acceptability of electronic nicotine delivery systems (ENDS) as a smoking reduction aid. This study examines the acceptability of ENDS by liquid nicotine concentration and flavour among people who smoke using ENDS to reduce their smoking.

METHODS

People who smoke cigarettes but were naïve to ENDS participated in a double-blind randomised controlled trial to reduce conventional cigarette smoking. Participants were randomised to either a control cigarette substitute (CS) or one of three ENDS groups; 0 mg/mL, 8 mg/mL or 36 mg/mL nicotine concentration. ENDS flavour was chosen by the participant (tobacco or menthol). Participants reported their CS, ENDS and cigarettes per day (CPD) from the past 7 days at 1-month, 3-month and 6-month follow-up visits. Participants also reported side effects and measures of satisfaction, psychological reward, aversion and craving relief. Outcome variables were modelled using linear mixed effects by the following groups: liquid nicotine concentration, flavour and a flavour-nicotine concentration interaction.

RESULTS

Participants (n=520) were 41.2% male, 67.3% white, had a mean age of 46.2 years and smoked a mean of 18.6 CPD (SD=7.74) at baseline. All flavour and concentration groups decreased CPD from baseline to all follow-up visits with the 36 mg/mL experiencing the greatest reduction, compared with the 0 mg/mL and 8 mg/mL groups. All groups except the 36 mg/mL group decreased their product use over time. The use of menthol flavour was associated with fewer side effects at 3 months (p=0.02) and lesser aversion at 1 month (p=0.03) compared with tobacco-flavoured ENDS. The 36 mg/mL group experienced the greatest craving relief and greatest aversion compared with other groups.

CONCLUSIONS

Both nicotine concentration and flavour appear to have independent, as well as interactive, effects that influence ENDS acceptability among people who use cigarettes.

A randomized controlled trial of potential tobacco policies prohibiting menthol flavor in cigarettes and e-cigarettes: a study protocol

BACKGROUND

Menthol cigarette use remains a large public health problem and disproportionately affects Black adults in the United States. The Food and Drug Administration has proposed prohibiting menthol flavor in cigarettes to protect public health. However, e-cigarettes are available in menthol flavor and are a popular alternative product adults might switch to if menthol is prohibited in cigarettes. Research is needed to understand how availability of menthol (vs. tobacco) flavored e-cigarettes could impact cigarette use among adults who smoke menthol cigarettes.

METHODS

We will recruit 150 adults who currently smoke menthol cigarettes and will randomize them to 1 of 3 conditions modeling different regulatory scenarios. We will recruit equal numbers of participants identifying as Black vs. non-Black and will stratify randomization by race. To promote standardization and adherence, cigarette and e-cigarette products will be provided for 8 weeks based on the assigned condition: (A) no menthol restriction (menthol cigarette and menthol flavored e-cigarette), (B) menthol prohibited in cigarettes only (non-menthol cigarette and menthol flavored e-cigarette), (C) menthol prohibited in both cigarettes and e-cigarettes (non-menthol cigarette and tobacco flavored e-cigarette). A follow-up visit will occur at week 12 to assess tobacco use status. The study aims are to (1) examine the impact of prohibiting menthol flavor in cigarettes and e-cigarettes on smoking behavior and (2) investigate whether outcomes differ by race to understand the impact of menthol policies on Black (vs. non-Black) individuals given high rates of menthol cigarette use in this population. The primary outcome will evaluate changes in the number of cigarettes smoked per day during the 8-week study period and will examine differences by regulatory scenario. Secondary outcomes will compare percent days smoke-free, changes in nicotine dependence, and motivation, confidence, and intentions to quit smoking by the regulatory scenarios. We will examine whether changes in the outcomes differ by Black vs. non-Black participants to compare the magnitude of the effect of the various menthol policy scenarios by race.

DISCUSSION

Results will contribute critical information regarding menthol in cigarettes and e-cigarettes to inform regulatory policies that maximize reductions in cigarette smoking and reduce tobacco-related health disparities.

TRIAL REGISTRATION

NCT05259566. Yale IRB protocol #2000032211, last approved 12/8/2023.

Evaluation of Cytotoxicity and Oxidative Stress of Whole Aerosol from Vuse Alto ENDS Products

Assessment of in vitro cytotoxicity is an important component of tobacco product toxicological evaluations. However, current methods of regulatory testing involve exposing monolayer cell cultures to various preparations of aerosols from cigarettes or other emerging products such as electronic nicotine delivery systems (ENDS), which are not representative of human exposure. In the present study, a whole aerosol (WA) system was used to expose lung epithelial cultures (2D and 3D) to determine the potential of six Vuse Alto ENDS products that varied in nicotine content (1.8%, 2.4%, and 5%) and flavors (Golden Tobacco, Rich Tobacco, Menthol, and Mixed Berry), along with a marketed ENDS and a marked cigarette comparator to induce cytotoxicity and oxidative stress. The WA from the Vuse Alto ENDS products was not cytotoxic in the NRU and MTT assays, nor did it activate the Nrf2 reporter gene, a marker of oxidative stress. In summary, Vuse Alto ENDS products did not induce cytotoxic or oxidative stress responses in the in vitro models. The WA exposures used in the 3D in vitro models described herein may be better suited than 2D models for the determination of cytotoxicity and other in vitro functional endpoints and represent alternative models for regulatory evaluation of tobacco products.

Abuse liability of two electronic nicotine delivery systems compared with combustible cigarettes and nicotine gum from an open-label randomized crossover study

An assessment of the likelihood of use and abuse potential for new tobacco products is an important part of tobacco product regulation in the United States and abroad. This paper reports the results of a randomized, open-label, crossover clinical study that assessed factors related to product adoption and abuse liability (AL), comparing two closed electronic nicotine delivery system (ENDS) products to combustible cigarettes and nicotine gum, high- and low-AL comparator products, respectively. During an 11-day confinement period that included multiple product familiarization sessions, healthy adult smokers participated in AL test sessions to evaluate the abuse liability of each product. During these test sessions, changes in subjective measures; speed and amount of nicotine uptake; and maximum changes in physiological effects before, during, and after use of each assigned product were assessed over 4 h. Positive subjective effects measures scores such as product-liking and overall intent to use again were highest for cigarettes, followed by the Vuse ENDS, with nicotine gum consistently having the lowest scores. The PK results (Cmax and Tmax) of the Vuse ENDS products are between UB cigarettes and nicotine gum, which correlates with the subjective effects. All nicotine uptake measures for the Vuse ENDS products were lower than that of usual brand (UB) cigarettes, including peak nicotine uptake and overall nicotine uptake, and were either similar to or lower than nicotine gum. The time course of nicotine uptake after use of the ENDS was more similar to that of combustible cigarettes than nicotine gum. The results indicate that the AL of each ENDS product is lower than that of UB cigarettes and similar to that of nicotine gum.

Patterns of flavored e-cigarette use among adult vapers in the USA: an online cross-sectional survey of 69,233 participants

BACKGROUND

Flavored e-cigarettes remain a controversial topic with regulators planning or already implementing restrictions worldwide. In this study, we examined patterns of flavor use in e-cigarettes among a convenience sample of US adult vapers.

METHODS

Participants aged ≥ 18 years who reported ever using an e-cigarette were included in the study (N = 69,233) and responded to an online questionnaire. Their smoking status was recorded as well as patterns of flavor use at e-cigarette use initiation, at the time of the survey and at the time of smoking cessation (for participants who used to smoke and were using e-cigarettes at the time of quitting).

RESULTS

The most popular flavors at e-cigarette use initiation were fruit (82.8%), followed by dessert/pastry/bakery (68.6%) and candy/chocolate/sweet (52.2%). Slightly higher prevalence of using fruit and dessert/pastry/bakery flavors was observed in those who never smoked compared to those who were currently and formerly smoking. Tobacco flavors were used by 20.8% of the participants and was by far the least prevalent among participants who never smoked. Similar patterns were observed with participants' choices at the time of the survey, but tobacco flavor use was substantially reduced (7.7%). Only 2.1% reported tobacco as the single most often used flavor. The most prevalent flavor at the time of quitting smoking was again fruit (83.3%), followed by dessert/pastry/bakery (68.0%) and candy/chocolate/sweet (44.5%). These flavors were considered the most helpful for quitting smoking. Tobacco flavor use at the time of smoking cessation was reported by 15.0%, while 9.3% considered it helpful for quitting smoking.

CONCLUSION

Non-tobacco flavors were popular among the US adult vapers who participated in the study, and were popular choices at the time of quitting smoking for those who formerly smoked. Tobacco flavor use prevalence was low and was further reduced over time. Regulators should consider the flavor choice of adult consumers, especially those who quit smoking, when preparing legislation on flavored e-cigarettes.

Clinical guidance for e-cigarette (vaping) cessation: Results from a modified Delphi panel approach

Individuals seek help to stop their use of e-cigarettes from their healthcare practitioners. However, there is a paucity of published work addressing e-cigarette cessation methods empirically, and what evidence that is available is weak. Therefore, we developed an expert informed clinical resource to guide practitioners helping their clients quit using e-cigarettes. We conducted a modified Delphi process between September and December 2021 to reach consensus on clinical recommendations for e-cigarette cessation. Expert and Peer Panel members (n = 28) voted and provided feedback on the recommendations through three rounds of structured surveys, a discussion board, and one intermediate survey. The penultimate knowledge products underwent usability testing and were finalized based on user feedback. The Expert Panel maintained a 100% response rate for rounds 1 and 2 and 96% for round 3; the Peer Panel achieved a 100% response rate for all three rounds of the modified Delphi process. Consensus was reach on 24 recommendations and 2 statements spanning eight domains: severity and dependence; general approaches; treatment approaches; dual use; pharmacotherapy strategies; behavioural therapy strategies; harm reduction; and relapse prevention. Two additional 'no agreement' statements that did not reach consensus are included in the guidance resource. The recommendations were also contextualized for the following groups: adults; youth; people who are pregnant, breastfeeding and/or chestfeeding; and people with mental illness and/or substance use issues. The recommendations listed in the resource provide general clinical guidance on e-cigarette cessation to assist healthcare practitioners in the treatment planning process.

An experimental evaluation of the effects of banning the sale of flavored tobacco products on adolescents' and young adults' future nicotine vaping intentions

BACKGROUND

Some U.S. states and municipalities have banned the sale of flavored tobacco products to help curb youth vaping. However, evidence supporting such bans is limited. This experiment tested whether removing flavored tobacco products from a retail setting diminished adolescents' (ages 11-20) future intentions to use vaping products.

METHODS

The study was implemented in the RAND StoreLab, a life-sized model convenience store. The display of flavored tobacco products in the store was manipulated with these conditions: 1) tobacco, sweet, and menthol/mint flavors displayed; 2) only tobacco and menthol/mint displayed; and 3) only tobacco flavors displayed. Participants were randomly assigned to shop in one of these conditions and completed measures of future vaping intentions post-shopping. Separate logistic regression models assessed effect of condition on future intentions to use different flavors (tobacco-, menthol/mint-, and sweet-flavored) and any flavor (composite score across flavor categories) of vaping products.

RESULTS

Study condition was not associated with intentions to use menthol/mint-, sweet-flavored, or any flavor. Compared to the condition in which all flavored products were displayed, removing menthol/mint- and sweet-flavored products significantly increased future intentions to use tobacco-flavored vaping products (OR = 3.97, 95 % CI [1.01, 15.58], p < .05). This effect was only observed among adolescents with history of vaping (OR = 11.30, 95 % CI [1.42, 89.96], p = .02).

CONCLUSIONS

Flavor bans may not affect adolescents' intentions to use menthol/mint, sweet, or "any" flavor of vaping products but may increase intentions to use tobacco-flavored products for teens who have already started vaping.

Pharmacological effects of nicotine salts on dopamine release in the nucleus accumbens

With the growing number of individuals regularly using e-cigarettes, it has become increasingly important to understand the psychobiological effects of nicotine salts. Nicotine increases the release of dopamine (DA) into the nucleus accumbens (NAc), causing feelings of satisfaction. However, the differences in the DA-increasing effects of different nicotine salts have not been reported. In this study, we used a G protein-coupled receptor-activated DA fluorescent probe (GRABDA1m) and optical fiber photometric recording equipment to monitor the dynamic changes and kinetics of DA release in the NAc of mice exposed to different e-cigarette aerosols, including nicotine, nicotine benzoate, nicotine tartrate, nicotine lactate, nicotine levulinic acid, nicotine malate, and nicotine citrate. The results of this study were as follows: 1) Different types of nicotine salts could increase the release of DA in the NAc. 2) The slopes and half-effective concentrations of the fitted curves were different, suggesting that each nicotine salt had a difference in the efficiency of increasing DA release with concentration changes. 3) The absorption rates of different nicotine salts containing the same original nicotine concentration were significantly different by measuring the blood nicotine content. The effect of nicotine salts on increasing DA was directly proportional to the blood nicotine level. In conclusion, by observing the effects of nicotine salts on DA release in real time in vivo, differences in the pharmacological effects of nicotine salts are revealed to better understand the mechanism underlying the regulatory effects of nicotine salts on the brain.

Nicotine flux as a powerful tool for regulating nicotine delivery from e-cigarettes: Protocol of two complimentary randomized crossover clinical trials

INTRODUCTION

Electronic cigarette (EC) use has increased rapidly in the last decade, especially among youth. Regulating nicotine delivery from ECs could help curb youth uptake and leverage EC use in harm reduction yet is complicated by varying device and liquid variables that affect nicotine delivery. Nicotine flux, the nicotine emission rate, is a parameter that incorporates these variables and focuses on the performance rather than the design of an EC. Nicotine flux therefore could be a powerful regulatory tool if it is shown empirically to predict nicotine delivery and subjective effects related to dependence.

METHODS AND ANALYSIS

This project consists of two complementary clinical trials. In Trial I, we will examine the relationship between nicotine flux and the rate and dose of nicotine delivery from ECs, hence, impacting abuse liability. It will also examine the extent to which this relationship is mediated by nicotine form (i.e., freebase versus protonated). At Yale School of Medicine (YSM), study participants will puff EC devices under conditions that differ by flux and form, while arterial blood is sampled in high time resolution. In Trial II, we will assess the relationship between nicotine flux, form, and subjective effects. At the American University of Beirut (AUB), participants will use EC devices with varying nicotine fluxes and forms, while dependency measures, such as the urge to use ECs, nicotine craving, and withdrawal symptoms, will be assessed. We will also monitor puffing intensity and real-time exposure to toxicants.

ETHICS AND DISSEMINATION

The protocol of Trial I and Trial II was approved by YSM and AUB IRBs, respectively. We will disseminate study results through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION

NCT05706701 for Trial I and NCT05430334 for Trial II.

Perceptions, intentions, and actual use of a consumer nicotine gum

BACKGROUND

Little is known about perceptions, use intentions, and behaviors of adults regarding nicotine gum that is marketed and regulated as a consumer product rather than as a medicinal nicotine replacement therapy (NRT).

METHODS

Survey data were collected from a Qualtrics online panel (N = 1000) of adults who had never used a consumer nicotine gum, recruited based on smoking behavior, and from current and former purchasers of one commercially available nicotine gum product (LUCY Chew and Park), recruited via emails to a customer database (N = 500). In addition to descriptive cross-sectional analyses, logistic regression was used to estimate the probability of intent to try and of product appeal among these different groups.

RESULTS

Among online panel respondents, individuals who smoked with and without plans to quit showed high intention to try the product (odds ratios 15.6 [95% CI 9.3, 27.6] and 9.8 [95% CI 5.8, 17.3] respectively, compared to people who formerly smoked) and persons who had never smoked showed low intentions to try. These results stood regardless of flavor. Among current and former purchasers of the study product, 43.4% of persons who had smoked cigarettes regularly indicated they were motivated to try the product "to help me quit smoking." Only 0.6% of young adult consumers of the nicotine gum (aged 21-30) had not tried tobacco products previously.

CONCLUSIONS

Consumer nicotine gum does not appear to attract those who have never used a tobacco product and the results for young adults suggest minimal appeal to youth. The study product was used primarily by individuals who currently smoke and/or use e-cigarettes but who wished to quit or reduce consumption. These results suggest that a consumer nicotine gum may reduce harm by substituting for higher-risk products such as combustible cigarettes.

Evaluation of statewide restrictions on e-cigarette nicotine strength-United States, 2017-2022

AIMS

To evaluate statewide policies restricting e-cigarette nicotine strength.

DESIGN

A difference-in-difference regression analysis was used to compare e-cigarette sales in states that restrict nicotine strength with states with no restrictions. Because flavor restrictions might affect sales and nicotine strength, states with flavor restrictions were also assessed.

SETTING AND CASES

United States e-cigarette retail sales data during January 2017 to March 2022 were licensed from Information Resources Incorporated. States with restrictions included Massachusetts (restricted maximum nicotine strength to 3.5% and nontobacco flavored e-cigarette sales in December 2019); Utah (restricted nicotine strength to 3.6% in September 2021); and Rhode Island, New York and Washington (restricted nontobacco flavor sales in October 2019, May 2020 and October 2019 to January 2020, respectively). These were compared with data from 34 states with no e-cigarette nicotine strength or flavor restrictions.

MEASUREMENTS

Weighted mean nicotine strength and total unit sales. Total unit sales per 1000 state population were summed into 4-week periods by state. Models controlled for emergency responses, state demographics, tobacco control policies, time and state fixed effects.

FINDINGS

Restricting both nicotine strength and flavors in Massachusetts was associated with a 2.04 percentage point (pp) reduction in mean nicotine strength and 86.76-unit reduction in monthly unit sales per 1000 persons compared with states with no restrictions (all P < 0.01). Restricting nicotine strength only in Utah was associated with a 1.77 pp (P < 0.01) reduction in mean nicotine strength; however, there was no impact on unit sales. Restricting nontobacco flavor sales only in Rhode Island, New York and Washington slightly reduced mean nicotine strength (0.21, 0.62 and 0.19 pp, respectively) and sales (36.66, 34.51 and 16.37 units, respectively) (all P < 0.01).

CONCLUSIONS

United States statewide policies restricting e-cigarette nicotine strength appear to be associated with reductions in average nicotine strength in sales within that state; however, there appears to be no impact on unit sales. When these policies are implemented along with flavor restrictions; reductions in average nicotine strength occur in addition to reduced unit sales.

Characterization of Ad Libitum Use Behavior of On! Nicotine Pouches

Objectives: Actual use of nicotine pouch products is not well studied. The objectives of this study were to characterize on ® nicotine pouch (Test Products (TP)) use behavior, including association with cigarette and smokeless tobacco (ST) product use. Methods: Adults who smoke cigarettes (AS) and/or adults who use ST (ASTU) (N=1147) that were not planning to quit and had expressed interest in trying and using TP after a 5-day trial were offered ad libitum use of TPs (7 flavors at 5 nicotine levels) for 6 weeks. Results: Participants used a median of ~5-6 pouches/day of a variety of flavors and nicotine levels. In the final week of the study, 27% of AS and 71% of ASTU reported no use of cigarettes or ST respectively, while reporting continued use of TPs. Additionally, 39% of AS and 14% of ASTU reduced consumption of cigarettes or ST products respectively by 50%-99%, compared to reported use at screening. We found a statistically significant inverse relationship between TP flavor varieties and number of cigarettes/ST. Conclusions: These data suggest that TPs can be potential substitutes for cigarettes/ST products, and complete switching may offer harm reduction potential for AS and ASTU not interested in quitting.

Part two: an unblinded, parallel, randomized study to assess nicotine pharmacokinetics of four Vuse Solo ENDS flavors in smokers

We report the findings from a randomized, parallel study designed to evaluate nicotine pharmacokinetics (PK) following 10 min of ad libitum use of electronic nicotine delivery system (ENDS) in four flavor variants. Subjects were randomized an investigational product (IP) and blood samples were collected for PK assessments during a test session. Primary endpoints were baseline-adjusted values of maximum plasma nicotine concentration (C_max) and area under the nicotine concentration-vs-time curve up to 60 min (AUC_nic0-60). Baseline-adjusted mean C_max ranged from 6.53 to 8.21 ng/mL, and mean AUC_nic0-60 ranged from 206.87 to 263.52 ng min/mL for all ENDS IPs. Results of geometric mean C_max and AUC_nic0-60 values were within 95% confidence intervals (CI) among the ENDS IP flavor variants tested.

An exploration of flavours in studies of e-cigarettes for smoking cessation: secondary analyses of a systematic review with meta-analyses

AIMS

To estimate associations between e-cigarette flavour and smoking cessation and study product use at 6 months or longer.

METHODS

Secondary analysis of data from a living systematic review, with meta-analyses and narrative synthesis, incorporating data up to January 2022. Included studies provided people who smoked combustible cigarettes with nicotine e-cigarettes for the purpose of smoking cessation compared with no treatment or other stop smoking interventions. Measurements included smoking cessation and study product use at 6 months or longer reported as risk ratios (RR) with 95% confidence intervals (CI); and flavour use at any time-points.

RESULTS

We included 16 studies (n = 10 336); 14 contributed to subgroup analyses and 10 provided participants with a choice of e-cigarette flavour. We judged nine, five and two studies at high, low and unclear risk of bias, respectively. Subgroup analyses showed no clear associations between flavour and cessation or product use. In all but one analysis, tests for subgroup differences resulted in I2 values between 0 and 35%. In the comparison between nicotine e-cigarettes and nicotine replacement therapy (NRT) (I2  = 65.2% for subgroup differences), studies offering tobacco flavour e-cigarettes showed evidence of a greater proportion of participants still using at 6 months or longer (RR = 3.81; 95% CI = 1.45-10.05; n = 1181; I2  = 84%), whereas there was little evidence for greater 6-month use when studies offered a choice of flavours (RR = 1.44; 95% CI = 0.80-2.56; n = 454; I2  = 82%). However, substantial statistical heterogeneity within subgroups makes interpretation of this result unclear. In the 10 studies where participants had a choice of flavours, and this was tracked over time, some switching between flavours occurred, but there were no clear patterns in flavour preferences.

CONCLUSIONS

There does not appear to be a clear association between e-cigarette flavours and smoking cessation or longer-term e-cigarette use, possibly due to a paucity of data. There is evidence that people using e-cigarettes to quit smoking switch between e-cigarette flavours.

Do e-cigarettes have a part to play in peri-implant diseases?

DESIGN

Systematic review.

DATA SOURCES

The following databases were searched for publications up to May 2022: Medline, EMBASE, Scopus, Web of Science, LILACS, Cochrane and Open Grey. Additionally, four journals were hand searched.

STUDY SELECTION

Clear inclusion and exclusion criteria were provided. A focused question was outlined using PICO format. A full search protocol was supplied, and all study designs were considered.

DATA EXTRACTION AND SYNTHESIS

Two reviewers screened 97 articles after de-duplication. Fourteen full-text articles were assessed. Data were collected using a spreadsheet.

RESULTS

Four cross-sectional studies were included in the systematic review, all reporting on male participants. Meta-analysis was performed highlighting worse outcomes in electronic cigarette (e- cigarette) user group regarding increased bone loss, probing depth, plaque index and bleeding on probing, as well as increased levels of inflammatory cytokines, when compared to never-smokers.

CONCLUSIONS

From the limited number of studies available, e-cigarettes appear to have a negative impact on dental implant outcomes in male patients.

Understanding perceived addiction to and addictiveness of electronic cigarettes among electronic cigarette users: a cross-sectional analysis of the International Tobacco Control Smoking and Vaping (ITC 4CV) England Survey

BACKGROUND AND AIMS

The addictive potential of electronic cigarettes (e-cigarettes) remains to be fully understood. We identified patterns and correlates of perceived addiction to e-cigarettes and perceived addictiveness of e-cigarettes relative to tobacco cigarettes (relative addictiveness) in dual users as well as exclusive e-cigarette users.

DESIGN, SETTING AND PARTICIPANTS

Observational study using cross-sectional survey data from England (2016) from the International Tobacco Control Project (ITC) Four Country Smoking and Vaping (4CV) survey. The study comprised 832 current e-cigarette users who had been vaping for at least 4 months.

MEASUREMENTS

Perceived addiction to e-cigarettes and relative addictiveness of e-cigarettes were examined. Socio-demographic factors were age, gender and education; markers of addiction included urge to vape, time to first vape after waking and nicotine strength used; vaping and smoking characteristics included frequency and duration of e-cigarette use, intention to quit, adjustable power or temperature, enjoyment, satisfaction relative to tobacco cigarettes and tobacco cigarette smoking status.

FINDINGS

A total of 17% of participants reported feeling very addicted to e-cigarettes, while 40% considered e-cigarettes equally/more addictive than tobacco cigarettes. Those who felt very addicted had higher odds of regarding e-cigarettes as more addictive than tobacco cigarettes (odds ratio 3.4, 95% confidence interval 2.3-5.1). All markers of addiction, daily use and enjoyment were associated with higher perceived addiction, whereas time to first vape after waking, daily vaping and perceiving vaping as less satisfying than smoking were associated with relative addictiveness.

CONCLUSIONS

Markers of addiction to e-cigarettes appear to correspond with perceived addiction to e-cigarettes, suggesting that self-reported perceived addiction might serve as an indicator of addiction. Prevalence both of markers of addiction and perceived addiction were comparatively low overall, suggesting a limited but relevant addictive potential of e-cigarettes. Additionally, positive and negative reinforcement, reflected here by enjoyment and relative satisfaction, might play a role in e-cigarette addiction.

Vaping Flavors and Flavor Representation: A Test of Youth Risk Perceptions, Novelty Perceptions, and Susceptibility

INTRODUCTION

Whether novelty-flavored vaping devices should be available in the marketplace has been a hotly contested debate. From one perspective, the variety of different flavors, such as fruit and mint, may help adult cigarette smokers who are seeking to switch to reduced-harm nicotine products. However, these flavors are also wildly popular among youth, creating concerns about new nicotine product use among minors.

AIMS AND METHODS

This experiment (n = 176) tests whether vaping flavors (tobacco vs fruit) and flavor representations on packages (flavor color, flavor image) influence how middle school youth perceive vaping products.

RESULTS

While results show no difference in risk perceptions based on condition, novelty perceptions (eg, how fun, interesting) and susceptibility to vaping are highest among those who view the fruit-flavored vaping product with flavor color and flavor image. Those who viewed this condition reported higher novelty perceptions and susceptibility than those who viewed the fruit-flavored vaping product with no flavor color and no flavor image. Additionally, they reported higher novelty perceptions than those who viewed the tobacco-flavored vaping product with flavor color and flavor image. A post-hoc analysis in supplemental data shows that youth who report lower risk perceptions and higher susceptibility have higher behavioral intentions to vape in the next year.

CONCLUSION

Findings suggest that restricting flavor representation on packaging might reduce how fun and interesting youth perceive these products to be and how susceptible they are to using them.