Initiation of Traditional Cigarette Smoking after Electronic Cigarette Use Among Tobacco-Naïve US Young Adults

#Discreetshipping: Selling E-cigarettes on TikTok

INTRODUCTION

Youth and young adult use of e-cigarette products continues to remain high despite regulatory approaches to reduce youth access. This study sought to examine TikTok content regarding the sale and distribution of e-cigarettes.

AIMS AND METHODS

TikTok videos (n = 475) and metadata posted between June 2022 and August 2023 were scraped using a TikTok application programming interface and popular hashtags used to sell vaping products (ie, #discreetshipping [40.8 million], #puffbundle [14.8 million], #hiddennic [1.0 million]). After watching the 25 most viewed videos (39 600-868 800 views), a codebook was developed. All metadata were annotated using 11 unique codes: Small business, brand, cannabis, bundled, hidden, fake, international sales, no ID, order via Instagram, order via another method, and cost.

RESULTS

Overall, 367 videos (with an average of 2017 likes) were deemed relevant. Videos advertised popular vaping brands (50.4%) that included cannabis products (45%). Products were described as bundled (28.6%), hidden (8.7%), and able to be shipped internationally (6%) without age verification (45.2%). Some videos (8.2%) evaded algorithms' detection of illegal activity by describing the post as "Fake." Customers were directed to other social media platforms (most often Instagram, 57.5%) and/or other websites/links (58.3%) to purchase products; 22.1% advertised discounts, free shipping, or low costs (ranging from $25-$35).

CONCLUSIONS

Social media platforms, such as TikTok and Instagram, are being used to circumvent e-cigarette regulatory policies. Regulatory agencies should expand enforcement strategies to include social media platforms where users are illegally selling and distributing e-cigarettes internationally to young audiences.

IMPLICATIONS

TikTok users across the globe are violating local, state, and federal laws by selling e-cigarettes concealed inside other products or bundled in packages that avoid detection. TikTok videos posted by self-proclaimed small business owners advertise discreet shipping practices that evade age verification in order to sell nicotine and cannabis bundles worldwide. Accounts used phrases describing the post to be "fake" to avoid detection by algorithms or TikTok administrators. E-cigarette regulatory agencies can partner with social media platforms to close regulatory gaps.

A systematic review and meta-analysis of the association between e-cigarette use among non-tobacco users and initiating smoking of combustible cigarettes

INTRODUCTION

The rapid increase in e-cigarette use over the past decade has triggered an important public health question on the potential association between e-cigarette use and combustible cigarette smoking. Following AMSTAR 2 and PRISMA guidelines, this evidence synthesis sought to identify and characterize any associations between e-cigarette use among individuals not smoking cigarettes and initiation of cigarette smoking.

METHODS

The protocol was registered on September 24, 2018 (PROSPERO 2018 CRD42018108540). Three databases were queried from January 01, 2007 to April 26, 2023. Search results were screened using the PICOS review method.

RESULTS

Among 55 included studies (40 "good" and 15 "fair"; evidence grade: "high") that adjusted for gender, age, and race/ethnicity between groups, generally, there was a significant association between non-regular e-cigarette use and initiation of cigarette smoking, further supported by the meta-analytic results (AOR 3.71; 95% CI 2.86-4.81). However, smoking initiation was most often measured as ever/current cigarette smoking. Two studies (quality: 2 "good") evaluated progression to regular cigarette smoking among individuals with regular use of e-cigarettes, and generally found no significant associations. One study ("good") evaluated smoking initiation among individuals with regular use of e-cigarettes, finding an increasing probability of ever smoking cigarettes with increased e-cigarette use. Twelve studies (10 "good" and two "fair") examining progression to regular smoking among individuals with non-regular use of e-cigarettes reported inconsistent findings.

CONCLUSIONS

Numerous methodological flaws in the body of literature limit the generalizability of these results to all individuals who are not smoking cigarettes with few studies measuring established/regular use/smoking of e-cigarettes and cigarettes. Further, studies did not control adequately for specific confounding variables representing common liabilities between e-cigarette use and cigarette smoking, nor did they account for sufficient follow-up durations. Collectively, these flaws limit the generalizability of findings to the question of an association between e-cigarette use and cigarette smoking initiation.

Understanding the Associations Between Adolescents' Exposure to E-Cigarette Information and Vaping Behavior Through the Theory of Planned Behavior

Adolescents have actively looked for and passively scanned information about electronic cigarettes (e-cigarettes) from a variety of media and interpersonal sources. Despite the evidence that exposure to e-cigarette information is associated with youth's increased vaping intention, there is a paucity of scholarship that differentiates the sources where adolescents obtain e-cigarette information in their investigation, which limits our understanding of the unique association between vaping intention and e-cigarette information acquisition from specific sources. In addition, few studies have systematically examined the mechanism of the aforementioned associations. To fill the gap, an online national survey on a panel of adolescents between 13 to 17 years old was conducted. After controlling for potential confounders, several significant indirect effects were observed. Specifically, adolescents' vaping intention was negatively associated with e-cigarette information seeking from health professionals but positively with e-cigarette information exposure from family and friends, outdoors advertisements, social media, and other online channels, with the theory of planned behavior (TPB) constructs mediating these relationships. The findings not only contribute to the body of scholarship on TPB but also provide important suggestions for regulating outdoor and online e-cigarette information and designing persuasive interventions and campaigns.

Public perceptions of the FDA's marketing authorization of Vuse on Twitter/X

Introduction

On October 12, 2021, the FDA issued its first marketing granted orders for Vuse, the e-cigarette product by R.J. Reynolds Vapor Company. The public perceptions and reactions to the FDA's Vuse authorization are prevalent on social media platforms such as Twitter/X. We aim to understand public perceptions of the FDA's Vuse authorization in the US using Twitter/X data.

Methods

Through the Twitter/X streaming API (Application Programming Interface), 3,852 tweets between October 12, 2021, and October 23, 2021, were downloaded using the keyword of Vuse. With the elimination of retweets, irrelevant tweets, and tweets from other countries, the final dataset consisted of 523 relevant tweets from the US. Based on their attitudes toward the FDA authorization on Vuse, these tweets were coded into three major categories: positive, negative, and neutral. These tweets were further manually classified into different categories based on their contents.

Results

There was a large peak on Twitter/X mentioning FDA's Vuse authorization on October 13, 2021, just after the authorization was announced. Of the 523 US tweets related to FDA's Vuse authorization, 6.12% (n=32) were positive, 26.77% (n=140) were negative, and 67.11% (n=351) were neutral. In positive tweets, the dominant subcategory was Cessation Claims (n=18, 56.25%). In negative tweets, the topics Health Risk (n=43, 30.71%), Criticize Authorization (n=42, 30.00%), and Big Tobacco (n=40, 38.57%) were the major topics. News (n=271, 77.21%) was the most prevalent topic among neutral tweets. In addition, tweets with a positive attitude tend to have more likes.

Discussion

Public perceptions and discussions on Twitter/X regarding the FDA's Vuse authorization in the US showed that Twitter/X users were more likely to show a negative than a positive attitude with a major concern about health risks.

Informing the development of interventions for e-cigarette use and prevention of transition to cigarette smoking in young adults: A qualitative study

E-cigarette use in young individuals may increase risk for cigarette smoking initiation. Over half of young adults who use e-cigarettes voiced their desire to quit e-cigarettes. Mobile-based interventions may allow for an easy-to-use platform to engage young adults in cessation services and reduce risk for cigarette uptake. To inform development of such programs, this study sought to gather information about what young adults want to see included in e-cigarette cessation interventions that also target future smoking risk. Nine online focus groups (n = 33) were conducted in July and August 2022 with young adults who either (1) currently used e-cigarettes, (2) formerly used e-cigarettes, or (3) initiated nicotine use with e-cigarettes but subsequently smoked cigarettes (dual use). Two research team members independently coded the transcripts and identified themes. A third researcher independently reviewed the coding and thematic analysis. Participants believed that mobile-based interventions should include peer support, ways to track cessation progress, education about the harms of e-cigarettes, gamification, and incentivization. They also believed that to prevent future cigarette smoking, interventions need to include education about the harms of smoking, teach refusal skills for offers to smoke, and incorporate personal anecdotes from former smokers. To increase their readiness, motivation, and self-efficacy to quit, participants who continue to use e-cigarettes reported needing effective substitutions to replace e-cigarettes, barriers to hinder their access to e-cigarettes, and social support. Findings from this study may be useful to incorporate when developing interventions designed to reduce e-cigarette use and risk of progression to smoking for young adults.

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.

Beyond the label: current evidence and future directions for the interrelationship between electronic cigarettes and mental health

Electronic cigarette use has dramatically increased over the last decade. With this recent technological development and wide range of constituents in various products, putative adverse effects on the brain and body have been largely unexplored. Here, we review current evidence linking electronic nicotine cigarette use with potential health consequences and provide evidence supporting an association between drug use and depression in humans. We also examine the biological effects of individual constituents in electronic cigarette aerosols, which include labeled ingredients, such as propylene glycol, vegetable glycerin, nicotine, and flavorants, as well as unlabeled ingredients found in the aerosols, such as carbonyls and heavy metals. Lastly, we examine the effects of electronic cigarette use on endogenous metabolism via changes in cytochrome P450 enzymes, which can thereby impact therapeutic outcomes. While the current evidence offers insight into the potential effects of electronic cigarette use on biological processes, further studies are necessary to determine the long-term clinical relevance of aerosol inhalation.

Examining intention to quit using Juul among emerging adults

OBJECTIVES

(1) Describe intention to quit, (2) identify relationships between various factors and intention to quit, (3) explore if Theory of Planned Behavior-informed constructs are associated with intention to quit, and (4) discover if descriptive norms strengthen association with intention to quit among emerging adults currently using Juul. Participants: First-year students currently using Juul at a large public university (N = 182). Methods: A November 2018 online survey assessed sociodemographic characteristics, social influences, patterns of use, quit intention, and attitudes, norms, and perceived behavioral control toward Juul. Results: A quarter of participants reported current use, with nearly half intending to quit within six months. Recent quit attempts was the only factor related to intention. Two models were created that showed association with intention to quit, but only perceived behavioral control was individually significant. Conclusions: Cessation-focused campaigns and interventions are needed on college campuses and could be less tailored than prevention.

Evaluation of the Effect of Electronic Cigarette Devices/Vape on the Color of Dental Ceramics: An In Vitro Investigation

The use of vaping or electronic cigarette devices (ECDs) has recently increased as an alternative to conventional tobacco smoking products. By recording the CIELAB coordinates (L*a*b*) and computing the total color difference (ΔE) values using a spectrophotometer, the effect of ECDs on contemporary aesthetic dental ceramics was investigated in this in-vitro study. A total of seventy-five (N = 75) specimens from five different (n = 15) dental ceramic materials (Pressable ceramics (PEmax); Pressed and layered ceramics (LEmax); Layered zirconia (LZr); Monolithic zirconia (MZr) and Porcelain fused to metal (PFM)) were prepared and exposed to aerosols produced by the ECDs. The color assessment was performed using a spectrophotometer at six time intervals (0 = baseline; 250-puff exposures; 500-puff exposures; 750-puff exposures; 1000-puff exposures; 1250-puff exposures; and 1500-puff exposures). By recording L*a*b* and computing total color difference (ΔE) values, the data were processed. A one-way ANOVA and Tukey procedure for pairwise comparisons were used to assess color differences between tested ceramics (p < 0.05). All test materials demonstrated significant color differences (ΔE) after exposure to vaping (p < 0.05). The LZr group displayed noticeably high ΔE values at all the distinct puff exposure intervals, with the highest ΔE value of (13.67) after 1500 puffs. The lowest (ΔE) values were observed in the PFM group after 250 and 500 puffs (0.85 and 0.97, respectively). With the exception of the group PEmax (p = 0.999), all groups produced readings of "ΔE" that indicated significant differences (p < 0.05) at various degrees of puff exposures. ECDs can noticeably alter the color of the dental ceramics affecting the esthetics of the patients. All the materials tested demonstrated significant color changes (ΔE > 3.33) above the clinically acceptable threshold, except for the PFM and PEmax group (ΔE < 3.33) which showed color stability after exposure to the ECDs.

Association of Electronic Cigarette Use by US Adolescents With Subsequent Persistent Cigarette Smoking

Importance

Many studies have reported a positive association of youth electronic cigarette (e-cigarette) use with subsequent cigarette smoking initiation, but it remains unclear whether e-cigarette use is associated with continued cigarette smoking after initiation.

Objective

To assess the association of youth baseline e-cigarette use with their continued cigarette smoking 2 years after initiation.

Design, Setting, and Participants

The Population Assessment of Tobacco and Health (PATH) Study is a national longitudinal cohort study. This sample consisted of youth who participated in waves 3, 4, and 5 of the study (wave 3 was from October 2015 to October 2016, wave 4 was from December 2016 to January 2018, and wave 5 was from December 2018 to November 2019) and had never used cigarettes (cigarette-naive) by wave 3. The current analysis used multivariable logistic regressions in August 2022 to assess the association between e-cigarette use among cigarette-naive adolescents aged 12 to 17 years in 2015 and 2016 and subsequent continued cigarette smoking. PATH uses audio computer-assisted self-interviewing and computer-assisted personal interviewing to collect data.

Exposures

Ever and current (past 30-day) use of e-cigarettes in wave 3.

Main Outcomes and Measures

Continued cigarette smoking in wave 5 after initiating smoking in wave 4.

Results

The current sample included 8671 adolescents who were cigarette naive in wave 3 and also participated in waves 4 and 5; 4823 of the participants (55.4%) were aged 12 to 14 years, 4454 (51.1%) were male, and 3763 (51.0%) were non-Hispanic White. Overall, regardless of e-cigarette use, few adolescents (362 adolescents [4.1%]) initiated cigarette smoking at wave 4, and even fewer (218 participants [2.5%]) continued smoking at wave 5. Controlling for multiple covariates, the adjusted odds ratio of baseline ever e-cigarette use, compared with never e-cigarette use, was 1.81 (95% CI, 1.03 to 3.18) for continued smoking measured as past 30-day smoking at wave 5. However, the adjusted risk difference (aRD) was small and not significant. The aRD was 0.88 percentage point (95% CI, -0.13 to 1.89 percentage points) for continued smoking, with the absolute risk being 1.19% (95% CI, 0.79% to 1.59%) for never e-cigarette users and 2.07% (95% CI, 1.01% to 3.13%) for ever e-cigarette users. Similar results were found using an alternative measure of continued smoking (lifetime ≥100 cigarettes and current smoking at wave 5) and using baseline current e-cigarette use as the exposure measure.

Conclusions and Relevance

In this cohort study, absolute and relative measures of risks yielded findings suggesting very different interpretations of the association. Although there were statistically significant odds ratios of continued smoking comparing baseline e-cigarette users with nonusers, the minor risk differences between them, along with the small absolute risks, suggest that few adolescents are likely to continue smoking after initiation regardless of baseline e-cigarette use.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPLICATIONS FOR PUBLIC HEALTH

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

How Does Social Media Exposure and Engagement Influence College Students' Use of ENDS Products? A Cross-lagged Longitudinal Study

Electronic nicotine delivery systems (ENDS) products have been marketed heavily on social media throughout the past years, which exerts great influence on young adults' ENDS use. Despite scholars' pioneering efforts in investigating the influence of tobacco and nicotine products marketing on young adults' vaping behavior, scholarly attention has been paid primarily to passive exposure to rather than active engagement with the information on social media. In addition, the majority of existing research has been cross-sectional or focused on the unidirectional path from marketing information to behavior. To extend previous research in tobacco regulatory science on new media, we examined the bidirectional associations between self-reported exposure to and engagement with tobacco and nicotine products messaging on social media, and subsequent use of ENDS products one year later among a large, diverse sample of young adults. Results from cross-lagged panel analyses indicated that pro-tobacco/ENDS engagement and advertising exposure elevated risk whereas anti-tobacco/ENDS engagement decreased risk for the subsequent use of ENDS products one year later. On the other hand, the use of ENDS products positively predicted both pro- and anti-tobacco/ENDS engagement one year later. Findings provide empirical support for the reasoned action approach and the confirmation bias rooted in cognitive dissonance theory through rigorous longitudinal examination. Our findings not only point to the imperativeness of and offer guidance for regulating marketing information on social media, but also suggest social media as a promising platform to prevent young adults from initiating ENDS product use.

Alternative Tobacco Use and Cigarette Smoking Transitions among College Students in Texas

Background: High prevalence of very light cigarette smoking and use of alternative tobacco products (ATPs; i.e. electronic nicotine delivery systems [ENDS], cigars, and hookah) among young adult college students are causes for concern. The purpose of this study is to examine transitions in cigarette smoking (never vs. non-current vs. very light vs. heavier) among college students across 2.5 years and determine if the use of ATPs is related to these transitions. Methods: This study used six waves of data across 2.5 years from Project M-PACT. Participants who were 18-25 years of age at baseline were included in this study (n = 4,806). Cigarette smoking state was categorized as never smoking, non-current smoking [0 cigarettes smoked per day (cpd) in past month], very light smoking (< =5 cpd in past month), and heavier smoking (>5 in past month). Multi-state Markov models were used to examine temporal transitions in the four smoking states and examine the association of time-varying current ATP use with transitions in smoking states. Results: The probabilities of remaining in a smoking state decreased over time. The time-varying current ATP use was significantly related to increased odds of transitioning from never smoking to non-current smoking, from never smoking to very light smoking, and from non-current to very light smoking. Conclusions: Findings highlight the need to prevent ATP use among college students and in turn inhibit initiation and escalation of cigarette smoking.

Sais de Nicotina e Nicotina Sintética: Novos Desafios para um Velho Problema

O tabagismo é reconhecido como uma doença crônica causada pela dependência à nicotina, presente nos produtos à base de tabaco, e está ligado a uma série de doenças tabaco-relacionadas. Somando-se a isso, é considerada uma doença pediátrica. No Brasil, o tratamento para a cessação do tabagismo desde 2004 é oferecido em todos os níveis de complexidade pelo Sistema Único de Saúde (SUS), contudo, os protocolos internacionalmente utilizados parecem ter limitações significativas quando utilizados em populações tabagistas de crianças e adolescentes. Os sais de nicotina apresentam um menor grau de irritação e impacto na boca e na garganta causado pela nicotina, possibilitando o uso de concentrações maiores de nicotina. A nicotina sintética tem se mostrado a cada dia mais viável economicamente falando e já existem no mercado produtos que se utilizam dessa forma de nicotina, entretanto, poucos estudos foram conduzidos no sentido de avaliar seus impactos à saúde. As novas formas de nicotina e sua forma sintética, associadas com produtos com design atraente, especialmente para os mais jovens, trazem desafios técnicos consideráveis para os profissionais da saúde, pois desconhece-se, no momento, protocolos eficazes para tratar a dependência à nicotina originada dessas novas formas de consumo.

E-Cigarettes Reexamined: Product Toxicity

The introduction of e-cigarettes, or electronic nicotine delivery systems (ENDS), has been accompanied by controversy regarding their safety and effectiveness as a cessation aid and by an explosion in their use by youth. Their use does not involve the combustion of tobacco and the creation of harmful combustion products; they have been seen as a "harm reduction" tool that may be of assistance in promoting smoking cessation. Recognition that ENDS can deliver an array of chemicals and materials with known adverse consequences has spurred more careful examination of these products. Nicotine, nitrosamines, carbonyl compounds, heavy metals, free radicals, reactive oxygen species, particulate matter, and "emerging chemicals of concern" are among the constituents of the heated chemical aerosol that is inhaled when ENDS are used. They raise concerns for cardiovascular and respiratory health that merit the attention of clinicians and regulatory agencies. Frequently cited concerns include evidence of disordered respiratory function, altered hemodynamics, endothelial dysfunction, vascular reactivity, and enhanced thrombogenesis. The absence of evidence of the consequences of their long-term use is of additional concern. Their effectiveness as cessation aids and beneficial impact on health outcomes continue to be examined. It is important to ensure that their production and availability are thoughtfully regulated to optimise their safety and permit their use as harm reduction devices and potentially as smoking-cessation aids. It is equally vital to effectively prevent them from becoming ubiquitous consumer products with the potential to rapidly induce nicotine addiction among large numbers of youth. Clinicians should understand the nature of these products and the implications of their use.

Adolescent Use of Flavored Non-Tobacco Oral Nicotine Products

BACKGROUND AND OBJECTIVES

Flavored non-tobacco oral nicotine products (eg, nicotine pouches and nontherapeutic nicotine gum, lozenges, tablets, gummies), are increasingly marketed in the United States. Prevalence of non-tobacco oral nicotine product use among adolescents is unknown.

METHODS

We calculated prevalence of ever and past 6-month use of nicotine pouches, other non-tobacco oral nicotine products (ie, gum, lozenges, tablets, and/or gummies), e-cigarettes, cigarettes, hookah or waterpipe, cigars, cigarillos, and snus among high school students in Southern California between September and December 2021. Generalized linear mixed models tested associations of sociodemographic factors and tobacco-product use with use of any non-tobacco oral nicotine product.

RESULTS

Among the sample (n = 3516), prevalence was highest for e-cigarettes (ever: 9.6%, past 6-month: 5.5%), followed by non-tobacco oral nicotine products (ever: 3.4%, past 6-month: 1.7%), and <1% for other products. Ever users of combustible tobacco (adjusted odds ratio [aOR] = 77.6; 95% confidence interval [CI] = 39.7-152) and ever users of noncombustible tobacco (aOR = 40.4; 95% CI= 24.3-67.0) had higher odds of ever using non-tobacco oral nicotine products, compared to never users of combustible and noncombustible tobacco. Use of any non-tobacco oral nicotine product was greater for Hispanic (versus all other races/ethnicities except Asian, aOR = 2.58; 95% CI = 1.36-4.87), sexual minority (versus heterosexual, aOR=1.63; 95% CI = 1.03-2.57), gender minority (versus male, aOR = 2.83; 95% CI = 1.29-6.19), and female (versus male, aOR=1.92, 95% CI = 1.20-3.06) participants.

CONCLUSIONS

Non-tobacco oral nicotine products were the second most prevalent nicotine product used by adolescents. They were disproportionately used by certain racial or ethnic, sexual, or gender minority groups, and those with a history of nicotine use. Adolescent non-tobacco oral nicotine product use surveillance should be a public health priority.

Genetic deletion or pharmacological blockade of nociceptin/orphanin FQ receptors in the ventral tegmental area attenuates nicotine-motivated behaviour

BACKGROUND AND PURPOSE

The nociceptin/orphanin FQ (N/OFQ)-nociceptin opioid-like peptide (NOP) receptor system is widely distributed in the brain and pharmacological activation of this system revealed therapeutic potential in animal models of substance use disorder. Studies also showed that genetic deletion or pharmacological blockade of NOP receptors confer resistance to the development of alcohol abuse. Here, we have used a genetic and pharmacological approach to evaluate the therapeutic potential of NOP antagonism in smoking cessation.

EXPERIMENTAL APPROACH

Constitutive NOP receptor knockout rats (NOP-/- ) and their wild-type counterparts (NOP+/+ ) were tested over a range of behaviours to characterize their motivation for nicotine. We next explored the effects of systemic administration of the NOP receptor antagonist LY2817412 (1.0 & 3.0 mg·kg-1 ) on nicotine self-administration. NOP receptor blockade was further evaluated at the brain circuitry level, by microinjecting LY2817412 (3.0 & 6.0 μg·μl-1 ) into the ventral tegmental area (VTA), nucleus accumbens (NAc) and central amygdala (CeA).

KEY RESULTS

Genetic NOP receptor deletion resulted in decreased nicotine intake, decreased motivation to self-administer and attenuation of cue-induced nicotine reinstatement. LY2817412 reduced nicotine intake in NOP+/+ but not in NOP-/- rats, confirming that its effect is mediated by inhibition of NOP transmission. Finally, injection of LY2817412 into the VTA but not into the NAc or CeA decreased nicotine self-administration.

CONCLUSIONS AND IMPLICATIONS

These findings indicate that inhibition of NOP transmission attenuates the motivation for nicotine through mechanisms involving the VTA and suggest that NOP receptor antagonism may represent a potential treatment for smoking cessation.

Is Adolescent E-Cigarette Use Associated With Subsequent Smoking? A New Look

INTRODUCTION

Prospective studies have consistently reported a strong association between e-cigarette use and subsequent cigarette smoking, but many failed to adjust for important risk factors.

METHODS

Using longitudinal data from the Population Assessment of Tobacco and Health (PATH) Study, we employed multivariable logistic regressions to assess the adolescent vaping-to-smoking relationship, with four regressions (Models 1-4) sequentially adding more risk factors.Our sample included all waves (waves 1-5) of the PATH Study.

RESULTS

The association between ever e-cigarette use and subsequent cigarette smoking decreased substantially in magnitude when adding more control variables, including respondents' sociodemographic characteristics, exposure to tobacco users, cigarette susceptibility, and behavioral risk factors. Using the most recent data (waves 4-4.5 and waves 4.5-5), this association was not significant in the most complete model (Model 4). Using wave 4.5-5 data, the adjusted odds ratio (aOR) for ever e-cigarette use at initial wave and subsequent past 12-month smoking declined from 4.07 (95% confidence interval [CI, 2.86-5.81) in Model 1, adjusting only for sociodemographic characteristics, to 1.35 (95% CI, 0.84-2.16) in Model 4, adjusting for all potential risk factors. Similarly, the aOR of ever e-cigarette use and past 30-day smoking at wave 5 decreased from 3.26 (95% CI, 1.81-5.86) in Model 1 to 1.21 (95% CI, 0.59-2.48) with all covariates (Model 4).

CONCLUSIONS

Among adolescent never cigarette smokers, those who had ever used e-cigarettes at baseline, compared with never e-cigarette users, exhibited modest or non-significant increases in subsequent past 12-month or past 30-day smoking when adjusting for behavioral risk factors.

Proposed Standard Test Protocols and Outcome Measures for Quantitative Comparison of Emissions from Electronic Nicotine Delivery Systems

This study introduces and demonstrates a comprehensive, accurate, unbiased approach to robust quantitative comparison of electronic nicotine delivery systems (ENDS) appropriate for establishing substantial equivalence (or lack thereof) between inhaled nicotine products. The approach is demonstrated across a family of thirteen pen- and pod-style ENDS products. Methods employed consist of formulating a robust emissions surface regression model, quantifying the empirical accuracy of the model as applied to each product, evaluating relationships between product design characteristics and maximum emissions characteristics, and presenting results in formats useful to researchers, regulators, and consumers. Results provide a response surface to characterize emissions (total particulate matter and constituents thereof) from each ENDS appropriate for use in a computer model and for conducting quantitative exposure comparisons between products. Results demonstrate that emissions vary as a function of puff duration, flow rate, e-liquid composition, and device operating power. Further, results indicate that regulating design characteristics of ENDS devices and consumables may not achieve desired public health outcomes; it is more effective to regulate maximum permissible emissions directly. Three emissions outcome measures (yield per puff, mass concentration, and constituent mass ratio) are recommended for adoption as standard quantities for reporting by manufacturers and research laboratories. The approach provides a means of: (a) quantifying and comparing maximal emissions from ENDS products spanning their entire operating envelope, (b) comparative evaluation of ENDS devices and consumable design characteristics, and (c) establishing comparative equivalence of maximal emissions from ENDS. A consumer-oriented product emissions dashboard is proposed for comparative evaluation of ENDS exposure potential. Maximum achievable power dissipated in the coil of ENDS is identified as a potentially effective regulatory parameter.

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.

[Risk of initiation to smoking with the use of electronic cigarettes: systematic review and meta-analysis]

This article aims to evaluate the association between the use of electronic cigarettes and initiation to smoking, through a systematic review with meta-analysis of longitudinal studies. A bibliographic search was performed on the MEDLINE, Embase, LILACS and PsycInfo databases. Reference selection, data extraction and risk of bias assessment of the studies were independently carried out in pairs, and the disagreements were discussed with a third researcher to reach a consensus. Meta-analysis was performed using the Mantel-Haenszel random effects model. Among the 25 studies included, 22 evaluated the outcome of conventional cigarette experimentation and nine assessed the outcome of current smoking (in the last 30 days). The meta-analysis showed that the use of electronic cigarettes increased the risk of conventional cigarette experimentation by almost three and a half times (RR=3.42; 95%CI 2.81-4.15), and by more than four times the risk of current smoking (RR=4.32; 95%CI 3.13-5.94). The risk of smoking initiation is significantly higher among electronic cigarette users. The marketing authorization of such devices may represent a threat to public health policies in Brazil.

A one year prospective examination of risk factors for pod-vape use among young adults

BACKGROUND

Young adults have the highest prevalence of pod-vape use, compared to adolescents and older adults. Despite the increased use of pod-vapes among young adults, very few studies have explored the determinants associated with pod-vape use.

PURPOSE

The purpose of the current study was to examine the roles of social norms and risk perceptions in subsequent pod-vape use one year later among a cohort of 21-34-year-old young adults.

METHOD

Participants were 3543 young adults from the last two waves (spring 2018 and 2019) of the Marketing and Promotions across Colleges in Texas project (M-PACT). A multivariable logistic regression model was used to examine the role of social norms and risk perceptions on subsequent pod-vape use one year later.

RESULTS

The prevalence of current pod-vape use in the present sample increased by 139.3% between 2018 and 2019. The social norm variables of close friends' pod-vape use and inclination to date someone that uses pod-vapes, but not social acceptability of pod-vapes, predicted subsequent pod-vape use one year later. Neither of the risk perception variables predicted subsequent pod-vape use.

CONCLUSION

The current study highlights the importance of social norms as predictors of subsequent pod-vape use among older young adults (21-34 years old). The rise in pod-vape use indicates that preventative efforts that target young adults are warranted, especially those that consider the role of peers in pod-vape use.

A longitudinal analysis of e-cigarette use and cigar, little cigar or cigarillo initiation among youth and youth adults: 2017-2019

PURPOSE

To examine whether youth and young adult e-cigarette use is associated with initiation of cigars, little cigars, or cigarillos (CLCCs) and current use of flavored CLCCs.

BASIC PROCEDURES

The sample is drawn from the Truth Longitudinal Cohort, a probability-based longitudinal cohort of youth and young adults recruited at ages 15-21 and surveyed every six months. The sample for this study was CLCC-naïve defined as those who had never used CLCCs as of 2017 (N = 5586). The outcomes were the odds of (1) initiating any CLCC use and (2) reporting current (past 30-day) use of flavored CLCCs from 2018 to late 2019. The main predictor was use of e-cigarettes by 2018.

RESULTS

The odds of initiating a CLCC was greater for those who had used ever used JUUL (OR: 3.30, p < 0.001) or were current users of another type of e-cigarette by 2018 (OR: 3.57, p < 0.001). Odds of CLCC initiation was also greater for those who had ever used combustible cigarettes (OR: 1.62, p < 0.05), were current smokers (OR: 3.12, p < 0.001) or had used marijuana (OR: 1.92, p < 0.001) by 2018. E-cigarette use that occurred by 2018 was associated with greater odds of current use of flavored CLCCs compared to non-flavored CLCCs (ever users of JUUL: OR: 2.57, p < 0.01; current users of some other e-cigarette: OR: 3.06, p < 0.05).

CONCLUSION AND RELEVANCE

This study raises new concerns about the effects of e-cigarette use on subsequent combustible tobacco use. Restrictions on CLCCs should be considered in conjunction with current policies designed to reduce the youth vaping epidemic.

Prospective association between use of electronic cigarettes and use of conventional cigarettes: a systematic review and meta-analysis

Objective

The aim of this systematic review and meta-analysis was to assess the association between e-cigarette use and subsequent initiation or recurrence of cigarette smoking.

Data sources

A systematic literature search was finalised on 11 November 2019 using PubMed (including MEDLINE), EMBASE, Cochrane Library, Scopus, PubMed Health, NICE Evidence Search, PROSPERO, CRD and PsycInfo.

Study selection

Studies were included if meeting the following criteria: reporting empirical results; longitudinal observational design with a minimum of 3 months of follow-up; including general population samples; allowing for the comparison between users and nonusers of e-cigarettes. Studies rated as having high risk of bias were excluded. Studies were independently assessed by at least two authors. The procedures described by PRISMA were followed, and the quality of evidence was rated using GRADE.

Data synthesis

30 longitudinal studies from 22 different cohorts assessing e-cigarette use among nonsmokers or never-smokers at baseline, and subsequent use of cigarette smoking at follow-up, were included in this review. A random-effects meta-analysis based on 89 076 participants showed a pooled unadjusted odds ratio (OR) of cigarette smoking among baseline nonsmoker e-cigarette users compared with nonusers of 4.68 (CI 3.64–6.02), while the adjusted OR was 3.37 (CI 2.68–4.24). These results were consistent irrespective of whether the outcome was measured as ever-smoking or as past 30-day smoking. The evidence was graded as moderate.

Conclusions

Use of e-cigarettes may predict the initiation or recurrence of cigarette smoking.

This meta-analysis shows that e-cigarette use increases the risk of future initiation or recurrence of cigarette smoking, even after adjusting for potential confounders, suggesting that e-cigarette use could be considered a predictor of subsequent smokinghttps://bit.ly/3buMccm

Patterns of E-Cigarette Use Among Primary Care Patients at an Urban Community Center

Tobacco use remains the leading cause of preventable disease and death in the US. The number of tobacco products has grown over the past decade. E-cigarette use has increased rapidly in recent years, but patterns and correlates of use have not been thoroughly assessed. We examined relationships among demographic factors, e-cigarette and conventional cigarette use in a large sample (N = 12,409) of adult patients at a community health center in the Northeastern US. Overall, 13% (N = 1675) of the sample reported ever using e-cigarettes. In logistic regression models, ever having used e-cigarettes was associated with younger age (ages 18-25; OR = 3.5, p < 0.001). Being transgender (OR = 1.8, p < 0.001), bisexual (OR = 1.5, p < 0.001), un-partnered (OR = 1.5, p < 0.001), having a lower income (OR = 1.6, p < 0.001) or a high BMI (OR = 1.4, p = 0.009) were associated with increased odds of use, whereas being a woman (OR = 0.7, p < 0.001) or Black/African American (OR = 0.7, p = 0.007) were associated with lower odds of use. Of the participants who reported e-cigarette use, a majority also endorsed current or former use of conventional cigarettes. Individuals who formerly used conventional cigarettes were nearly three times more likely to report daily e-cigarette use than current users. Among primary care patients at a community health center, e-cigarette use was reported by a sizeable portion of the sample. Overall, odds of use were higher in certain patient populations, and individuals who formally used cigarettes were more likely to report e-cigarette use than individuals who currently smoke, suggesting that e-cigarettes may be functioning as a cessation aid or a strategy to reduce conventional cigarette use.

Cigarette, waterpipe, and electronic cigarette use among college fraternity and sorority members and athletes in the United States

To examine the association between fraternity/sorority membership and athlete status with tobacco use by tobacco product type. Participants: Undergraduate college students who participated in the Spring 2017 National College Health Assessment-II Survey (n = 47,821). Methods: Prevalence of current (past-30 day) cigarette smoking, waterpipe tobacco smoking (WTS), and e-cigarette (ECIG) use was examined. Logistic regressions examined associations between fraternity/sorority membership and participation in collegiate athletics with tobacco use. Results: Fraternity/sorority members had the highest current use rates for cigarettes, waterpipe tobacco, and ECIGs and were nearly twice as likely to report cigarette smoking, WTS, and ECIG use relative to non-fraternity/sorority members. Relative to non-varsity athletes, varsity athletes were less likely to report cigarette smoking and WTS, but not ECIG use. Conclusions: Fraternity/sorority members appear to be at risk for use of multiple tobacco products. Varsity athlete status may be protective for some tobacco products, but does not appear no for ECIG use. ECIGs may appeal to groups typically at low risk for other tobacco products.

A content analysis of the tweets of e-cigarette proponents in Australia

ISSUE ADDRESSED

Social media sites have become platforms for public discourse on e-cigarettes, providing proponents with an opportunity to disseminate favourable information about the devices. Research examining the information being presented by Australian proponents of e-cigarettes is limited. Accordingly, this study explored the Twitter feeds of Australian proponents of e-cigarettes to determine the nature of the e-cigarette-related content being disseminated.

METHODS

All publicly available e-cigarette-related tweets and retweets (n = 1397) disseminated over a 15-week period by five Australian e-cigarette proponents were captured and analysed.

RESULTS

The main topics covered in the 1397 tweets analysed related to (a) criticism of the arguments made by public health agencies/advocates who oppose e-cigarettes (29%), (b) Australian e-cigarette policy (19%), (c) the health risks of e-cigarettes (16%) and (d) the efficacy of e-cigarettes as smoking cessation aids (13%). Proponents argued that the precautionary principle adopted by public health agencies/advocates lacks an appropriate evidence base and that legalising e-cigarettes would reduce smoking rates and smoking-related harm. Proponents minimised the risks associated with e-cigarette use and only presented evidence indicating that use facilitates smoking cessation.

CONCLUSIONS

The assessed tweets have the potential to reduce the public's trust in the information being presented by authoritative public health agencies/advocates. The dissemination of information downplaying the health risks associated with e-cigarettes may distort perceptions of the devices. SO WHAT?: To assist tobacco control efforts, results highlight the need for (a) ongoing surveillance of the tweets of e-cigarette proponents and (b) provision of evidence-based counterarguments on social media.

Nicotine Inhalation and Suicide: Clinical Correlates and Behavioral Mechanisms

BACKGROUND AND OBJECTIVES

Extensive evidence links smoking and suicide independently of psychiatric diagnoses, but there are questions about the pathophysiology and specificity of this relationship. We examined characteristics of this linkage to identify potential transdiagnostic mechanisms in suicide and its prevention.

METHODS

We reviewed literature that associated suicide with smoking and e-cigarettes, including the temporal sequence of smoking and suicide risk and their shared behavioral risk factors of sensitization and impulsivity.

RESULTS

Smoking is associated with increased suicide across psychiatric diagnoses and in the general population, proportionately to the number of cigarettes smoked per day. Rapid nicotine uptake into the brain through inhalation of conventional cigarettes, electronic cigarettes (e-cigarette), or even second-hand smoke can facilitate long-term sensitization and short-term impulsivity. Both impair action regulation and predispose to negative affect, continued smoking, and suicidal behavior. Intermittent hypoxia, induced by cigarettes or e-cigarettes, synergistically promotes impulsivity and sensitization, exacerbating suicidality. Two other shared behavioral risks also develop negative urgency (combined impulsivity and negative affect) and cross-sensitization to stressors or to other addictive stimuli. Finally, early smoking onset, promoted by e-cigarettes in never-smokers, increases subsequent suicide risk.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

Prevention or cessation of nicotine inhalation can strategically prevent suicidality and other potentially lethal behavior regardless of psychiatric diagnoses. Medications for reducing smoking and suicidality, especially in younger smokers, should consider the neurobehavioral mechanisms for acute impulsivity and longer-term sensitization, potentially modulated more effectively through glutamate antagonism rather than nicotine substitution. (Am J Addict 2021;30:316-329).

Adolescent nicotine and footshock exposure augments adult nicotine self-administration and drug-seeking without affecting baseline anxiety-like behaviour or stress responsivity in male rats

RATIONALE

Over the past decade, adolescent cigarette smoking has been declining. However, adolescent nicotine consumption via electronic cigarettes is rapidly gaining popularity. Earlier onset nicotine use is associated with increased risk of dependence. A bidirectional relationship between nicotine and stress exists; perceived stress is a predictor for nicotine use, and stress reduction is a commonly reported reason for using nicotine.

OBJECTIVES

We assessed the prolonged impact of adolescent high-dose nicotine and/or footshock exposure on adult nicotine self-administration, anxiety-like behaviour, and hormonal responsivity.

METHODS

During adolescence (postnatal day [P]28-56) male Sprague-Dawley rats were assigned to one of five groups: saline (SALPRE: 1 ml/kg, SC, every day), nicotine (NICPRE: 1 mg/kg, SC, alternating daily with saline; 14 total nicotine injections), footshock (SHOCKPRE: 8 of 0.5 s, 0.8 mA alternating sessions; saline every day), or combination nicotine and footshock (NIC+SHOCK: concurrent and alternating daily with saline, or NIC-SHOCK: alternating with saline on shock sessions). On P70, one cohort underwent spontaneous intravenous nicotine self-administration (0.03 mg/kg/infusion); another cohort was assessed for open-field behaviour (P71), then corticosterone (CORT) response to nicotine or footshock in adulthood (P72-73).

RESULTS

Intermittent adolescent nicotine or footshock alone (NICPRE and SHOCKPRE) did not potentiate adult spontaneous nicotine intake compared to SALPRE. However, both combination groups (NIC+SHOCK, NIC-SHOCK) showed increased adult nicotine consumption without associated differences in baseline anxiety-like behaviour or CORT response.

CONCLUSIONS

Adolescent nicotine and footshock stressors have a synergistic effect on adult nicotine consumption, enhancing nicotine intake. Avenues toward reducing stress in adolescent nicotine users may provide opportunities to reduce vulnerability to adult nicotine consumption.

Prospective estimation of the age of initiation of cigarettes among young adults (18-24 years old): Findings from the Population Assessment of Tobacco and Health (PATH) waves 1-4 (2013-2017)

OBJECTIVES

To prospectively estimate the age of cigarette initiation among young adults (18-24 years old) who were never cigarette users at their first wave of adult study participation overall, by sex, and by race/ethnicity given recent increases in cigarette initiation occurring in young adulthood.

METHODS

Secondary analyses were conducted using the PATH restricted-use adult datasets among young adult never users of cigarettes in waves 1-3 (2013-2016) with outcomes followed-up in waves 2-4 (2014-2017). Interval censoring survival methods were used to estimate the age of initiation of (i) ever, (ii) past 30-day, and (iii) fairly regular cigarette use. Among never cigarette users when they first entered the adult study, interval censoring Cox proportional hazard models were used to explore differences in the estimated age of initiation of the three cigarette use outcomes by sex and by race/ethnicity, controlling for the effect of previous e-cigarette use and the total number of other tobacco products ever used (0-5 products) before cigarette initiation outcomes.

RESULTS

Among the young adults who were never cigarette users at their first wave of adult participation, the highest increase in cigarette initiation occurred between 18 and 19 years old. By age 21, 10.6% (95% CI: 9.5-11.7) initiated ever cigarette use, 7.7% (95% CI: 6.1-8.1) initiated past 30-day of cigarette use, and 1.9% (95% CI: 1.4-2.5) initiated fairly regular cigarette use. After controlling for other tobacco products: (a) males were 83% more likely to initiate past 30-day cigarette use at earlier ages than females; (b) Hispanic and Non-Hispanic Black young adults had increased risk to initiate past 30-day cigarette use at earlier ages than Non-Hispanic White young adults (62% and 34%, respectively).

CONCLUSIONS

The substantial amount of cigarette initiation among young adults reinforces the need for prevention strategies among this population. Although, interventions are needed for all young adult populations, strategies should target 18-21-year-olds, with potentially differential prevention targets by sex and by race/ethnicity.

Associations Between Family and Peer E-Cigarette Use With Adolescent Tobacco and Marijuana Usage: A Longitudinal Path Analytic Approach

INTRODUCTION

Research indicates a link between adolescent e-cigarette use and combustible tobacco cigarette (CTC) initiation, and recent studies suggest their connection with marijuana uptake. Our 3-year longitudinal cohort study investigated the implications of adolescent, peer, and family e-cigarette use with adolescents' expectations and willingness to initiate CTC use, and subsequent CTC and marijuana use.

AIMS AND METHODS

Relationships were examined in a secondary analysis of a 3-year longitudinal cohort subsample involving adolescents enrolled in alternative California high schools (N = 1025). Analyses examined responses over three yearly observations. Family, peer, and respondents' e-cigarette use, respondents' positive cigarette expectancies and willingness to use CTCs were assessed in the study's first year (T1). CTC use in the survey's second year (T2) and marijuana use in the third year (T3) were assessed via path analysis.

RESULTS

Respondents reporting at least one family member or peer using e-cigarettes were more likely to use e-cigarettes at T1 than those whose peers/family members did not. They reported more positive expectancies about CTCs and greater willingness to initiate use. These variables predicted CTC use at T2, which directly anticipated marijuana use in the survey's third year (T3), as did adolescents' use of e-cigarettes at T1. All model relations were statistically significant.

CONCLUSIONS

Analysis demonstrated the strong association of family members' and peers' behaviors with adolescent e-cigarette use, and the temporal precedence of e-cigarette use with subsequent CTC and marijuana uptake. The predictive implications of e-cigarettes for other dangerous substance use should be examined in future prevention campaigns.

IMPLICATIONS

The presented study expands upon existing literature connecting adolescent e-cigarette use and later CTC and marijuana use. The findings indicate the significant implications of exposure to e-cigarette use by parents and peers and demonstrate in a longitudinal 4-year panel survey the direct and indirect predictive implications of e-cigarette use for CTC and marijuana uptake. The research illustrates the utility of programs and campaigns that target peer and family groups to maximize impacts on adolescent willingness to try CTCs, positive expectancies, and possible onset of CTC and marijuana use.

Experimental Test of the Educational Impact of the Newly Proposed FDA Graphic Cigarette Warnings Among U.S. Adults

BACKGROUND

In August 2019, the U.S. Food and Drug Administration proposed a set of 13 new graphic warnings for cigarette packaging and advertisements.

PURPOSE

We evaluated these warnings relative to text-only equivalents for their ability to educate the public regarding harms of smoking and influence outcomes associated with quitting.

METHODS

In an experimental within-subjects design, U.S. adult nonsmokers, smokers, and dual smoker/electronic cigarette (e-cigarette) users (N = 412) recruited from an online internet platform evaluated the newly proposed graphic warnings and corresponding text-only warnings on understandability, perceived new knowledge, worry elicited about the content of the warning, discouragement from smoking, and encouragement to use e-cigarettes.

RESULTS

Graphic warnings were generally rated as providing better understanding, more new knowledge, eliciting more worry about harms of smoking, and providing more discouragement from smoking relative to text-only warnings.

CONCLUSIONS

The newly proposed graphic warnings could influence important responses to warnings associated with motivation to reduce smoking.

E-cigarette use and combustible tobacco cigarette smoking uptake among non-smokers, including relapse in former smokers: umbrella review, systematic review and meta-analysis

OBJECTIVE

To review and summarise the current evidence on the uptake of combustible cigarette smoking following e-cigarette use in non-smokers-including never-smokers, people not currently smoking and past smokers-through an umbrella review, systematic review and meta-analysis.

DESIGN

Umbrella review, systematic review and meta-analysis.

DATA SOURCES

PubMed, Scopus, Web of Science, PsychINFO (Ovid), Medline (Ovid) and Wiley Cochrane Library up to April 2020.

RESULTS

Of 6225 results, 25 studies of non-smokers-never, not current and former smokers-with a baseline measure of e-cigarette use and an outcome measure of combustible smoking uptake were included. All 25 studies found increased risk of smoking uptake with e-cigarette exposure, although magnitude varied substantially. Using a random-effects model, comparing e-cigarette users versus non-e-cigarette users, among never-smokers at baseline the OR for smoking initiation was 3.25 (95% CI 2.61 to 4.05, I2 85.7%) and among non-smokers at baseline the OR for current smoking was 2.87 (95% CI 1.97 to 4.19, I2 90.1%). Among former smokers, smoking relapse was higher in e-cigarette users versus non-users (OR=2.40, 95% CI 1.50 to 3.83, I2 12.3%).

CONCLUSIONS

Across multiple settings, non-smokers who use e-cigarettes are consistently more likely than those avoiding e-cigarettes to initiate combustible cigarette smoking and become current smokers. The magnitude of this risk varied, with an average of around three times the odds. Former smokers using e-cigarettes have over twice the odds of relapse as non-e-cigarettes users. This study is the first to our knowledge to review and pool data on the latter topic.

PROSPERO REGISTRATION NUMBER

CRD42020168596.

Implementation of a cluster randomized controlled trial: Identifying student peer leaders to lead E-cigarette interventions

E-cigarette use has been increasing among middle school students. Intervention programs to prevent e-cigarette initiation administered by authority figures are met with more resistance from youth compared to peer-led programs. Therefore, this study aimed to assess the feasibility, acceptability, and implementation process of using social network analysis (SNA) to identify student peer leaders in schools and train them to deliver e-cigarette prevention programming to their peers. Nine schools were recruited to participate in the study during the 2019-2020 school year. Schools were assigned to one of three conditions: (1) expert; (2) peer-random (selected peer-leaders would teach to random students); and (3) peer-fixed (selected peer-leaders would teach to assigned students based on nominations). Study participation varied by day due to school attendance, with 686 participants at baseline and 608 at posttest. Almost all students who did not complete the study resulted from the interruption of schools being closed due to COVID-19. Implementation issues fell into three categories: (1) scheduling, (2) day-of logistics, and (3) student group dynamics. Overall, the results showed positive satisfaction among teachers, who unanimously found the program appropriate for the grade-level and that peer-leaders worked well within their groups. Peer-led students-both random and assigned-reported having more fun and willing to tell friends to try the program compared to expert-led students. This study demonstrated the feasibility of implementing a peer-led e-cigarette prevention program for 6th grade students, using SNA to provide intervention rigidity and validity.

Prevalence and correlates of lifetime e-cigarette use among adolescents attending public schools in a low income community in the US

INTRODUCTION

The prevalence of e-cigarette use among US adolescents is increasing. However, there is limited research on the prevalence and correlates of e-cigarette use among adolescents in low income and under resourced communities. We report on their e-cigarette susceptibility and use behaviors, and perceived risks of harm and addiction.

METHODS

Students in grades 7, 9, and 11 from a Title I school district in the northeastern US completed an online survey during a class period. Lifetime e-cigarette use and its correlates were tested in bivariate and logistic regression models.

RESULTS

Most students were of Latino ethnicity (66%), and 36% identified as Black/African American. Overall, 55% of the full sample were considered 'susceptible' to e-cigarette use: 19% were lifetime e-cigarette users while 6% were lifetime smokers. Students in 11th grade were more likely (OR = 2.5) to have ever used e-cigarettes compared to students in 7th grade. Those that were more curious (OR = 11.8), intended to use e-cigarettes in the next 12 months (OR = 2.8), and would use the product if it was offered by a friend (OR = 2.4) had greater odds of lifetime e-cigarette use. By contrast, students who perceived at least moderate risks of health harm (OR = 0.44) were less likely to have used e-cigarettes.

CONCLUSIONS

Adolescents from marginalized communities are susceptible to and are using e-cigarettes. Prevention efforts targeting underserved areas may benefit from e-cigarette health education messages that reduce curiosity, interrupt social aspects of initiation, and emphasize health harms.

The effect of e-cigarettes on smoking cessation and cigarette smoking initiation: An evidence-based rapid review and meta-analysis

INTRODUCTION

The contribution made by e-cigarettes to smoking cessation continues to be controversial. Reports suggest that teenagers are becoming increasingly addicted to e-cigarettes and that e-cigarette use in adolescents is associated with subsequent cigarette smoking.

METHODS

Systematic searches of eleven databases were conducted (January 2015 to June 2020). Systematic reviews, randomized controlled trials (RCTs) and cohort studies comparing e-cigarettes with placebo e-cigarettes, nicotine replacement therapy (NRT) or no e-cigarette use were included. The two primary outcomes were smoking cessation among smokers and smoking initiation among non-smoking teenagers. The secondary outcome was adverse events. Data were synthesized using risk ratio (RR) or adjusted odds ratio (AOR) with 95% confidence interval (CI).

RESULTS

Six systematic reviews, 5 RCTs and 24 cohort studies were identified. For smoking cessation, findings from 4 systematic reviews indicated that e-cigarettes contributed to cessation while one found the opposite. Meta-analysis of 5 RCTs suggested that e-cigarettes were superior to NRT or placebo for smoking cessation (RR=1.55; 95% CI: 1.00–2.40; I²=57.6%; low certainty; 5 trials, n=4025). Evidence from 9 cohort studies showed that e-cigarette use was not associated with cessation (AOR=1.16; 95% CI: 0.88–1.54; I²=69.0%; n=22220). Subgroup analysis suggested that intensive e-cigarette use may be associated with cessation. In terms of smoking initiation, adolescents who ever used e-cigarettes had a greater risk for smoking initiation than non-users (AOR=2.91; 95% CI: 2.61–3.23; I²=61.0%; 15 trials, n=68943), the findings were consistent with one included systematic review. No serious adverse events were reported in the included studies.

CONCLUSIONS

Low certainty evidence suggests that e-cigarettes appear to be potentially effective for smoking cessation. The use of e-cigarettes in adolescents may be associated with smoking initiation. No serious adverse events were reported.

Identifying student opinion leaders to lead e-cigarette interventions: protocol for a randomized controlled pragmatic trial

Background

After the US Surgeon General declared youth electronic cigarette (e-cigarette) use an epidemic in 2018, the number of youth e-cigarette users continued to surge, growing from 3.8 million in 2018 to over 5 million 2019. Youth who use e-cigarettes are at a substantially higher risk of transitioning to traditional cigarettes, becoming regular cigarette smokers, and increasing their risk of developing tobacco-related cancer.

A majority of youth are misinformed about e-cigarettes, often believing they are not harmful or contain no nicotine. Middle school students using e-cigarettes have been affected by its normalization leading to influence by their peers. However, social and group dynamics can be leveraged for a school-based peer-led intervention to identify and recruit student leaders to be anti-e-cigarette champions to prevent e-cigarette initiation. This study outlines a project to use social network analysis to identify student opinion-leaders in schools and train them to conduct anti-e-cigarette programming to their peers.

Methods

In the 2019–2020 academic school year, 6th grade students from nine schools in the Pittsburgh area were recruited. A randomized controlled trial (RCT) was conducted with three arms—expert, elected peer-leader, and random peer-leader—for e-cigarette programming. Sixth grade students in each school completed a network survey that assessed the friendship networks in each class. Students also completed pre-intervention and post-intervention surveys about their intention-to-use, knowledge, and attitudes towards e-cigarettes. Within each peer-led arm, social network analysis was conducted to identify peer-nominated opinion leaders. An e-cigarette prevention program was administered by (1) an adult content-expert, (2) a peer-nominated opinion leader to assigned students, or (3) a peer-nominated opinion leader to random students.

Discussion

This study is the first to evaluate the feasibility of leveraging social network analysis to identify 6th grade opinion leaders to lead a school-based e-cigarette intervention.

Trial registration

ClinicalTrials.gov NCT04083469. Registered on September 10, 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-020-04990-z.

E-cigarette use and cigarette smoking initiation among Australian women who have never smoked

INTRODUCTION AND AIM

Evidence regarding the association between e-cigarette use and subsequent initiation of smoking mostly relates to the US population. In Australia, no studies are available investigating the association between the uses of e-cigarettes and smoking initiation among young adults who have never smoked. This study aimed to determine the association between lifetime e-cigarette use and subsequent initiation of cigarette smoking among tobacco-naïve Australian women aged 20-27.

DESIGN AND METHODS

The current study used data (n = 5398) from the third (2015) and fourth (2016) surveys collected from a cohort of Australian women born in 1989-1995 who participated in the Australian Longitudinal Study on Women's Health. Multivariable logistic regression was used to identify the association between lifetime e-cigarette use at the baseline survey and initiation of cigarette smoking (smoked 100 cigarettes or more in the last year) at the follow up adjusting for possible confounders. Effects were expressed as odds ratios with 95% confidence interval.

RESULTS

The mean (± SD) age of the study participants at baseline (third survey) was 22.5 (±1.7). Ever e-cigarette use at baseline was positively associated with smoking initiation at follow up (adjusted odds ratio 3.71; 95% confidence interval 2.33, 5.93). History of depression, binge drinking and higher childhood adversity score were also risk factors for subsequent smoking initiation in the follow up.

DISCUSSION AND CONCLUSIONS

This study identified a strong association between e-cigarette use and subsequent initiation of smoking. Enforcing the existing restriction of sale and supply of e-liquid containing nicotine is essential to prevent never smokers from nicotine addiction via e-cigarettes.

Young adults' intention to quit using JUUL

BACKGROUND

With research indicating some young audiences may desire to quit using JUUL, a high-nicotine e-cigarette, we sought to explore factors that may motivate them to quit.

METHODS

This sequential, mixed methods study included a cross-sectional online survey of college students (n = 631) followed by in-person interviews (n = 51) with survey participants. Data were collected March-April 2019. The survey asked about intention to quit using JUUL. A latent class analysis (LCA) identified participant groups who would quit for various reasons. Participants were also asked 'Can you be too old to JUUL?' during the survey. During the interviews, participants were provided preliminary survey findings and asked about their perceptions of the data. Interview participants were also asked about their expectations for future use of JUUL.

RESULTS

Four classes emerged from the LCA, indicating costs to self (i.e., harm to lungs/brain, price; 46.8%), financial costs (36.6%), all costs (e.g., social, monetary, health; 9.3%), and harm to self (7.3%) may have influenced our sample's decision to quit using JUUL. Interviewees affirmed desires to quit using JUUL, especially after leaving college. Only 27.19% of survey participants reported an age threshold for using JUUL (M = 31.8 years, SD = 10.0); however, several interviewees explained that although someone could not be too old to JUUL, it would be 'immature' or 'childish' for adults who were not trying to quit smoking to use JUUL socially.

DISCUSSION

Comprehensive tobacco control strategies such as taxing e-cigarettes, marketing campaigns, and nicotine cessation programs are needed to help nicotine dependent young adults quit using high-nicotine e-cigarettes.

JUUL E-Cigarette Quit Attempts and Cessation Perceptions in College Student JUUL E-Cigarette Users

PURPOSE

This study describes the frequency of JUUL e-cigarette (referred to as JUUL) quit attempts and identifies characteristics associated with confidence in quitting and perceived difficulty quitting JUUL.

DESIGN

Cross-sectional study from a self-administered online survey.

SETTING

Two public southern California universities.

PARTICIPANTS

A total of 1,001 undergraduate students completed the survey from February to May 2019.

MEASURES

Self-report measures about JUUL included use, history of quit attempts, time to first use, perceived difficulty with cessation/reduction, and confidence in quitting.

ANALYSIS

Binary logistic regressions were used to identify demographic and tobacco-related behavioral correlates of JUUL cessation-related perceptions and behaviors.

RESULTS

Nearly half of ever-JUUL users (47.8%) reported a JUUL quit attempt. Adjusting for demographic factors and other tobacco product use, shorter time to first JUUL use after waking was associated with lower confidence in quitting JUUL (aOR = 0.02, 0.00-0.13) and greater perceived difficulty in quitting JUUL (aOR = 8.08, 2.15-30.35). Previous JUUL quit attempt history was also associated with greater odds of perceived difficulty quitting JUUL (aOR = 5.97, 1.74-20.53).

CONCLUSIONS

History of JUUL quit attempts among college students was common. Those who had previously tried quitting were more likely to perceive difficulty with cessation. Time to first JUUL use, a marker of dependence, was linked with greater perceived cessation difficulty and lower confidence in quitting. These findings suggest that there is a need for cessation and relapse prevention support for college student JUUL users.

The Interplay Between Respiratory Microbiota and Innate Immunity in Flavor E-Cigarette Vaping Induced Lung Dysfunction

Global usage of electronic nicotine delivery systems (ENDS) has been increasing in the last decade. ENDS are non-combustible tobacco products that heat and aerosolize a liquid containing humectants, with added flavorings and often nicotine. Though ENDS are promoted as a less harmful alternative to smoking, current evidence links their use to a wide range of deleterious health effects including acute and chronic lung damage. ENDS can elicit an inflammatory response and impair the innate immune response in the lungs. Exposure to ENDS flavorings results in abnormal activation of the lung epithelial cells and β-defensins, dysfunction of the macrophage phagocytic activity, increased levels of mucin (MUC5AC) and abnormal activation of the neutrophilic response (NETosis). ENDS menthol flavorings disrupt innate immunity and might be associated with allergies and asthma through activation of transient receptor potential ankyrin 1 (TRAP1). Recent studies have expanded our understanding of the relationship between the homeostasis of lung innate immunity and the immunomodulatory effect of the host-microbiota interaction. Alterations of the normal respiratory microbiota have been associated with chronic obstructive pulmonary disease (COPD), asthma, atopy and cystic fibrosis complications which are strongly associated with smoking and potentially with ENDS use. Little is known about the short-and long-term effects of ENDS on the respiratory microbiota, their impact on the innate immune response and their link to pulmonary health and disease. Here we review the interaction between the innate immune system and the respiratory microbiota in the pathogenesis of ENDS-induced pulmonary dysfunction and identify future areas of research.

Further investigation of gateway effects using the PATH study

Background: Interest exists in whether youth e-cigarette use (“vaping”) increases risk of initiating cigarette smoking. Using Waves 1 and 2 of the US PATH study we previously reported adjustment for vaping propensity using Wave 1 variables explained about 80% of the unadjusted relationship. Here data from Waves 1 to 3 are used to avoid over-adjustment if Wave 1 vaping affected variables recorded then.

Methods: Main analyses M1 and M2 concerned Wave 2 never smokers who never vaped by Wave 1, linking Wave 2 vaping to Wave 3 smoking initiation, adjusting for predictors of vaping based on Wave 1 data using differing  propensity indices.  M3 was similar but derived the index from Wave 2 data.  Sensitivity analyses excluded Wave 1 other tobacco product users, included other product use as another predictor, or considered propensity for smoking or any tobacco use, not vaping. Alternative analyses used exact age (not previously available) as a confounder not grouped age, attempted residual confounding adjustment by modifying predictor values using data recorded later, or considered interactions with age.

Results: In M1, adjustment removed about half the excess OR (i.e. OR–1), the unadjusted OR, 5.60 (95% CI 4.52-6.93), becoming 3.37 (2.65-4.28), 3.11 (2.47-3.92) or 3.27 (2.57-4.16), depending whether adjustment was for propensity as a continuous variable, as quintiles, or the variables making up the propensity score. Many factors had little effect: using grouped or exact age; considering other products; including interactions; or using predictors of smoking or tobacco use rather than vaping. The clearest conclusion was that analyses avoiding over-adjustment explained about half the excess OR, whereas analyses subject to over-adjustment explained about 80%.

Conclusions: Although much of the unadjusted gateway effect results from confounding, we provide stronger evidence than previously of some causal effect of vaping, though doubts still remain about the completeness of adjustment.

An update on controversies in e-cigarettes

E-cigarettes are electronic nicotine delivery systems (ENDS) which mimic tobacco smoking without the combustion of tobacco. These devices have been misleadingly marketed as "less harmful" alternatives to conventional smoking tobacco products. The e-liquid in e-cigarettes include nicotine, a humectant and other additives including flavourings, colourants, or adulterants such as bacterial and fungal products. In this review, we discuss the contrasting views of the tobacco lobby and most professional societies. We describe the epidemiology of the use of these devices, with a widespread and significant rise in youth e-cigarette use seen in both the USA and Europe. We also describe what is known about the toxicity and mechanisms of EVALI (e-cigarette or vaping associated lung injury). This characterised by respiratory failure with an intense inflammatory response. The presentations are diverse and clinicians should consider vaping as a possible cause of any unusual respiratory illness in patients who have a history of vaping or other use of e-cigarette-related products. Second hand exposure to e-cigarettes is also harmful through respiration and transdermal absorption. E-cigarettes have a worse acute toxicity than tobacco and their long-term toxicity is unknown, and we advocate for the immediate, most vigorous anti-vaping legislation possible.

Association of flavored electronic nicotine delivery system (ENDS) use with self-reported chronic obstructive pulmonary disease (COPD): Results from the Population Assessment of Tobacco and Health (PATH) study, Wave 4

INTRODUCTION

Flavors other than tobacco flavor have been identified as a major reason for electronic nicotine delivery system (ENDS) initiation in youth and are thought to contribute to the continued use of ENDS in users of all ages. Our previous research showed a significant association between overall ENDS use and COPD. This study aims to identify the association of ENDS flavor categories with self-reported COPD.

METHODS

The data analysis included 4909 adults from Population Assessment of Tobacco and Health (PATH) Wave 4 data who were ever established ENDS users and responded to an item about diagnosis of COPD. Weighted multivariable logistic regression models were used to examine the association between different ENDS flavors and self-reported COPD considering complex sampling design.

RESULTS

Among 4909 ever established ENDS users, 418 adults (weighted percentage 9.8%) had self-reported COPD. Self-reported COPD prevalence differed between different ENDS flavor categories, with the highest (weighted percentage 19.9%) occurring among tobacco flavor users. Compared to non-tobacco flavor categories, tobacco flavor category showed significantly higher association with self-reported COPD (AOR=2.05; 95% CI: 1.20–3.53), after adjusting for potential confounding variables. No significant associations with self-reported COPD were found for other examined ENDS flavor categories including menthol/mint, fruit, candy/ desserts/other-sweets, and other flavors, compared to their corresponding non-users.

CONCLUSIONS

Tobacco flavored ENDS use was significantly associated with self-reported COPD. Future studies are needed to confirm the biological and epidemiological association of flavored ENDS use with COPD.

Interventions to prevent periodontal disease in tobacco-, alcohol-, and drug-dependent individuals

Substance abuse affects more than one sixth of the world's population. More importantly, the nature of the abuse and the type of addictive substances available to individuals is increasing exponentially. All substances with abusive potential impact both the human immuno-inflammatory system and oral microbial communities, and therefore play a critical role in the etiopathogenesis of periodontal diseases. Evidence strongly supports the efficacy of professionally delivered cessation counseling. Dentists, dental therapists, and hygienists are ideally placed to deliver this therapy, and to spearhead efforts to provide behavioral and pharmacologic support for cessation. The purpose of this review is to examine the biologic mechanisms underlying their role in disease causation, to understand the pharmacologic and behavioral basis for their habituation, and to investigate the efficacy of population-based and personalized interventions in prevention of periodontal disease.

Cigarette and electronic vapor product use among high school students in Georgia, 2015-2018

Adolescent use of electronic vapor products (EVP) is increasing; however, changes in EVP use in the context of cigarette smoking is less certain. We analyzed trends in EVP and cigarette use among high school students in the state of Georgia. We used self-reported EVP and cigarette use from the annual Georgia Student Health Survey 2.0 for 2015 to 2018 (N = 1,405,108). Users were categorized as exclusive EVP users, exclusive cigarette users, or dual users. We assessed current (≥1 day in past 30 days) use of EVPs, cigarettes, and dual users of both products, as well as number of days the products were used among current users. We compared current users, as well as number of days used, across adjacent years using tests for proportion and Wilcoxon t-tests, respectively. The proportion of current exclusive EVP users and dual users increased during 2017-2018 (4.2% to 6.9% and 1.6% to 3.7%, p < 0.001, respectively) after declining during 2015-2017, while the proportion of exclusive cigarette users declined during 2015-2018 (2.0% to 1.0%, p < 0.001). Similarly, the mean number of days of EVP use increased among exclusive EVP and dual users, and mean number of days of cigarette use increased among dual users during 2017-2018 (p < 0.001). These findings reinforce the importance of continued efforts to reduce all forms of tobacco products use among Georgia high school students.

Cigalike electronic nicotine delivery systems e-liquids contain variable levels of metals

Electronic nicotine delivery systems (ENDS) are prefilled, battery-operated products intended to deliver nicotine to the user via an inhaled complex aerosol formed by heating a liquid composed of propylene glycol and glycerol, also referred to as vegetable glycerin and collectively called e-liquid, that contains nicotine and various flavor ingredients. Since their introduction in 2006, the number of ENDS on the market has increased exponentially. Despite their growing ubiquity, the possible health risks associated with ENDS use remain poorly understood. One potential concern is the presence of toxic metals in the e-liquid and aerosol. Herein, we report the evaluation of the metal content in the e-liquids from a series of commercially available cigalike ENDS brands (various flavors) determined using inductively coupled plasma mass spectrometry (ICP-MS) following e-liquid extraction. Each brand of cigalike ENDS was purchased at least three times at retail outlets in the Baltimore, Maryland metropolitan region over a period of six months (September 2017 to February 2018). This allowed for comparison of batch-to-batch variability. Several potentially toxic metals, including lead, chromium, copper, and nickel were detected in the e-liquids. In addition, high variability in metal concentrations within and between brands and flavors was observed . The internal assembled parts of each cartridge were analyzed by X-ray imaging, before dissembling so that the materials used to manufacture each cartridge could be evaluated to determine the metals they contained. Following washing to remove traces of e-liquid, lead, chromium, copper and nickel were all detected in the cigalike ENDS prefilled cartridges, suggesting one potential source for the metals found in the e-liquids. Collectively, these findings can inform further evaluation of product design and manufacturing processes, including quantification of metal concentrations in e-liquids over foreseeable storage times, safeguards against high concentrations of metals in the e-liquid before and after aerosolization (by contact with a metal heating coil), and control over batch-to-batch variability.

Electronic nicotine delivery system design and aerosol toxicants: A systematic review

BACKGROUND

Electronic nicotine delivery systems (ENDS; e-cigarettes), consisting of a battery, heating element and e-liquid, have evolved significantly with wide variation in design, components, operating powers, and chemical constituents. Generated aerosols have been reported to contain potentially toxic substances. We conducted a systematic review to assess what is known about the presence of toxicants in ENDS aerosols in order to inform how system design could mitigate risk.

METHODS

Articles reporting on or evaluating design characteristics of ENDS and aerosol constituents were included and summarized.

RESULTS

The search identified 2,305 articles, of which 92 were included after full-text review. Findings were grouped into 6 major categories of potentially harmful chemicals: carbonyls, volatile organic chemicals, trace elements, reactive oxygen species and free radicals, polycyclic aromatic hydrocarbons, and tobacco-specific nitrosamines. In general, higher concentrations of aerosol toxicants are associated with increased power or voltage. Aerosol toxicants are also associated with e-liquid flavoring agents existing as primary ingredients or as products of thermal degradation.

CONCLUSIONS

Improved ENDS design can reduce toxicant levels. Additional research is needed to develop a framework for optimizing system characteristics to minimize exposure, especially with respect to heating power and e-liquids. Both manufacturers and regulatory agencies have roles in reducing toxicants and potential health risks from ENDS.

Carbonyls and Carbon Monoxide Emissions from Electronic Cigarettes Affected by Device Type and Use Patterns

Dangerous levels of harmful chemicals in electronic cigarette (e-cigarette) aerosols were reported by several studies, but variability in e-cigarette design and use patterns, and a rapid development of new devices, such as JUUL, hamper efforts to develop standardized testing protocols and understand health risks associated with e-cigarette use. In this study, we investigated the relative importance of e-cigarette design, power output, liquid composition, puff topography on e-cigarette emissions of carbonyl compounds, carbon monoxide (CO), and nicotine. Four popular e-cigarette devices representing the most common e-cigarette types (e.g., cig-a-like, top-coil, 'mod', and 'pod') were tested. Under the tested vaping conditions, a top-coil device generated the highest amounts of formaldehyde and CO. A 'pod' type device (i.e., JUUL) emitted the highest amounts of nicotine, while generating the lowest levels of carbonyl and CO as compared to other tested e-cigarettes. Emissions increased nearly linearly with puff duration, while puff flow had a relatively small effect. Flavored e-liquids generated more carbonyls and CO than unflavored liquids. Carbonyl concentrations and CO in e-cigarette aerosols were found to be well correlated. While e-cigarettes emitted generally less CO and carbonyls than conventional cigarettes, daily carbonyl exposures from e-cigarette use could still exceed acute exposure limits, with the top-coil device potentially posing more harm than conventional cigarettes.

Is e-cigarette use in non-smoking young adults associated with later smoking? A systematic review and meta-analysis

OBJECTIVE

The aim of this review was to investigate whether e-cigarette use compared with non-use in young non-smokers is associated with subsequent cigarette smoking.

DATA SOURCES

PubMed, Embase, Web of Science, Wiley Cochrane Library databases, and the 2018 Society for Research on Nicotine and Tobacco and Society for Behavioural Medicine conference abstracts.

STUDY SELECTION

All studies of young people (up to age 30 years) with a measure of e-cigarette use prior to smoking and an outcome measure of smoking where an OR could be calculated were included (excluding reviews and animal studies).

DATA EXTRACTION

Independent extraction was completed by multiple authors using a preprepared extraction form.

DATA SYNTHESIS

Of 9199 results, 17 studies were included in the meta-analysis. There was strong evidence for an association between e-cigarette use among non-smokers and later smoking (OR: 4.59, 95% CI: 3.60 to 5.85) when the results were meta-analysed in a random-effects model. However, there was high heterogeneity (I2 =88%).

CONCLUSIONS

Although the association between e-cigarette use among non-smokers and subsequent smoking appears strong, the available evidence is limited by the reliance on self-report measures of smoking history without biochemical verification. None of the studies included negative controls which would provide stronger evidence for whether the association may be causal. Much of the evidence also failed to consider the nicotine content of e-liquids used by non-smokers meaning it is difficult to make conclusions about whether nicotine is the mechanism driving this association.