Variable Voltage, Tank-Style ENDS Do Not Always Deliver Nicotine

Transitions in device and liquid characteristic groupings among US adults frequently using electronic nicotine delivery systems (ENDS) over three timepoints, 2020-2021

INTRODUCTION

Electronic nicotine delivery system (ENDS) and liquid characteristics affect nicotine and toxicant exposure and use behaviors. Little is known about how adults who frequently use ENDS transition between ENDS device/liquid groupings.

METHODS

A total of 379 US adults (≥21 years) using ENDS frequently (≥5 days/week) self-reported and uploaded photos of their most used ENDS device and liquid in three waves of online surveys (May 2020 - November 2021). Device/liquid grouping was defined by device (i.e. disposable/refillable tank/refillable pod or cartridge/disposable pod or cartridge, adjustable/no adjustable settings) and liquid (i.e. salt/freebase) characteristics. Participants using the same grouping across waves were considered stable users.

RESULTS

The most prevalent wave (W) 1 grouping was tank (freebase, adjustable settings; 36.8%). From W1 to W3, the number of disposable device (salt, no adjustable settings) users increased 156.4% and the number of disposable pod/cartridge (salt, no adjustable settings) users decreased 15.2%. In W2 and W3, compared to stable users, participants using tank (freebase, adjustable settings) in W1 and another grouping in W2 and/or W3 reported significantly higher nicotine concentrations (mg/mL) (W2: 15.1 vs 5.5, p<0.001; W3: 22.9 vs 5.6, p<0.001) and lower device power (watt) (W2: 46.8 vs 58.7, p=0.02; W3: 34.0 vs 57.2, p<0.001).

CONCLUSIONS

Over a 1.5-year period, a rapid growth in disposable device (salt, no adjustable settings) use and a decrease in disposable pod/cartridge (salt, no adjustable settings) use were observed. Participants who transitioned from tank (freebase, adjustable settings) to other groupings were more likely to increase liquid nicotine concentration and reduce device power compared to stable users.

Cardiopulmonary Impact of Electronic Cigarettes and Vaping Products: A Scientific Statement From the American Heart Association

Vaping and electronic cigarette (e-cigarette) use have grown exponentially in the past decade, particularly among youth and young adults. Cigarette smoking is a risk factor for both cardiovascular and pulmonary disease. Because of their more limited ingredients and the absence of combustion, e-cigarettes and vaping products are often touted as safer alternative and potential tobacco-cessation products. The outbreak of e-cigarette or vaping product use-associated lung injury in the United States in 2019, which led to >2800 hospitalizations, highlighted the risks of e-cigarettes and vaping products. Currently, all e-cigarettes are regulated as tobacco products and thus do not undergo the premarket animal and human safety studies required of a drug product or medical device. Because youth prevalence of e-cigarette and vaping product use was as high as 27.5% in high school students in 2019 in the United States, it is critical to assess the short-term and long-term health effects of these products, as well as the development of interventional and public health efforts to reduce youth use. The objectives of this scientific statement are (1) to describe and discuss e-cigarettes and vaping products use patterns among youth and adults; (2) to identify harmful and potentially harmful constituents in vaping aerosols; (3) to critically assess the molecular, animal, and clinical evidence on the acute and chronic cardiovascular and pulmonary risks of e-cigarette and vaping products use; (4) to describe the current evidence of e-cigarettes and vaping products as potential tobacco-cessation products; and (5) to summarize current public health and regulatory efforts of e-cigarettes and vaping products. It is timely, therefore, to review the short-term and especially the long-term implications of e-cigarettes and vaping products on cardiopulmonary health. Early molecular and clinical evidence suggests various acute physiological effects from electronic nicotine delivery systems, particularly those containing nicotine. Additional clinical and animal-exposure model research is critically needed as the use of these products continues to grow.

Predictors of electronic cigarette dependence among non-smoking electronic cigarette users: User behavior and device characteristics

INTRODUCTION

ECIGs differ in their ability to deliver nicotine to the user and, consequently, they may differ in their ability to produce dependence. This study examined individual device characteristics, device type, and user behaviors as predictors of ECIG dependence in a sample of never-smoking ECIG users.

METHODS

Participants (N = 134) completed an online survey that assessed demographics, ECIG use behavior, and ECIG dependence as measured via the Penn State Electronic Nicotine Dependence Index (PSECDI) and E-cigarette Dependence Scale (EDS-4). Participants uploaded a picture of their personal ECIG device/liquid, which was coded by raters to identify product features. Multivariable linear regressions examined device characteristics (e.g., adjustable power, nicotine concentration) and device type (e.g., vape pen, mod, pod, modern disposable) as predictors of dependence controlling for demographics and user behaviors (e.g., ECIG use duration and frequency, other tobacco use).

RESULTS

Longer durations of ECIG use and more use days/week were associated significantly with higher PSECDI (β's = 0.91 and 1.90, respectively; p's < 0.01) and EDS-4 scores (β's = 0.16 and 0.28, respectively; p's < 0.01). Higher nicotine concentrations were associated with higher PSECDI scores only (β = 0.07, p =.011). Dependence scores did not differ as a function of ECIG device types after controlling for covariates.

CONCLUSIONS

ECIG dependence was observed among the never-smoking ECIG users in this sample, regardless of their ECIG device/liquid features. Findings suggest that regulatory efforts aimed at reducing the dependence potential of ECIGs in never smokers should focus on overall nicotine emissions rather than product features.

Device features and user behaviors as predictors of dependence among never-smoking electronic cigarette users: PATH Wave 4

INTRODUCTION

Electronic cigarettes (ECIGs) vary greatly in their ability to deliver nicotine, which suggests they may also vary in their ability to produce dependence. This study examined individual and combined ECIG device features, and also user behaviors, as predictors of dependence in never-smoking ECIG users. Methods Data were collected from 711 current ECIG users who had smoked <100 cigarettes in their lifetime at Wave 4 of the Population Assessment of Tobacco and Health (PATH) Study. Multivariable linear regressions examined individual (e.g., contains nicotine, uses a tank, flavor preference) and combined (e.g., refillable tanks, refillable mods) device features, and user behaviors (e.g., uses/day) as predictors of dependence, withdrawal, and craving after accounting for demographic variables. Results Results for ECIG dependence and craving showed a similar pattern; higher levels were observed for older age, more frequent past 30-day use, using an ECIG containing nicotine (vs no nicotine), and using a non-refillable cartridge or refillable tank style (vs disposables). Higher withdrawal levels were observed for higher education levels and individual device features of tank (vs no tank), cartridge (vs no cartridge), refillable (vs non-refillable), and "other" flavor preference (vs tobacco flavor). Lower withdrawal levels were associated with a preference for sweet/fruit flavor(s) (vs tobacco flavor). Conclusions Few use behaviors and device features, whether examined alone or in combination, predicted dependence-related outcomes. Findings underscore the challenge with regulating ECIG products in the current marketplace, which is inundated with a myriad of device types.

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

Introduction

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

Aims and Methods

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

Results

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

Conclusions

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

Implications

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