Invalidity of an Oft-Cited Estimate of the Relative Harms of Electronic Cigarettes

Current perspective on e-cigarette use and respiratory variables: mechanisms and messaging

INTRODUCTION

There has been an increasing amount of research on the consequences of e-cigarette use for respiratory variables, which is significant for public health and respiratory medicine. We discuss recent findings and lay out implications for prevention and treatment.

AREAS COVERED

Based on literature searches using several databases (PubMed, Web of Science, Google Scholar) for keywords, including synonyms, 'e-cigarettes,' with 'pulmonary function,' 'oxidative stress' and 'inflammation,' we review studies on acute effects of e-cigarette use for measures of pulmonary function and discuss selected laboratory studies on mechanisms of effect with a focus on processes of known relation to respiratory disease; oxidative stress and inflammation. We discuss available studies that have tested the effectiveness of communication strategies for prevention of e-cigarette use oriented to different audiences, including nonsmoking adolescents and adult smokers.

EXPERT OPINION

We conclude that the evidence presents a mixed picture. Some evidence is found for harm reduction while evidence is also found on adverse consequences of e-cigarette use for measures of lung function and two biological processes. How to best communicate these results to a complex audience of users, from younger susceptible adolescents to long-term adult smokers interested in quitting, is a question of significant interest and empirically-validated communication strategies are greatly needed.

Challenges in current inhalable tobacco toxicity assessment models: A narrative review

Emerging tobacco products such as electronic nicotine delivery systems (ENDS) and heated tobacco products (HTPs) have a dynamic landscape and are becoming widely popular as they claim to offer a low-risk alternative to conventional smoking. Most pre-clinical laboratories currently exploit in vitro, ex vivo, and in vivo experimental models to assess toxicological outcomes as well as to develop risk-estimation models. While most laboratories have produced a wide range of cell culture and mouse model data utilizing current smoke/aerosol generators and standardized puffing profiles, much variation still exists between research studies, hindering the generation of usable data appropriate for the standardization of these tobacco products. In this review, we discuss current state-of-the-art in vitro and in vivo models and their challenges, as well as insights into risk estimation of novel products and recommendations for toxicological parameters for reporting, allowing comparability of the research studies between laboratories, resulting in usable data for regulation of these products before approval by regulatory authorities.

The potential impact of removing a ban on electronic nicotine delivery systems using the Mexico smoking and vaping model (SAVM)

Objective

To develop the Mexico Smoking and Vaping Model (Mexico SAVM) to estimate cigarette and electronic nicotine delivery systems (ENDS) prevalence and the public health impact of legalizing ENDS use.

Methods

SAVM, a cohort-based discrete-time simulation model, compares two scenarios. The ENDS-Restricted Scenario estimates smoking prevalence and associated mortality outcomes under the current policy of an ENDS ban, using Mexico-specific population projections, death rates, life expectancy, and smoking and e-cigarette prevalence. The ENDS-Unrestricted Scenario projects smoking and vaping prevalence under a hypothetical scenario where ENDS use is allowed. The impact of legalizing ENDS use is estimated as the difference in smoking- and vaping-attributable deaths (SVADs) and life-years lost (LYLs) between the ENDS-Restricted and Unrestricted scenarios.

Results

Compared to a national ENDS ban, The Mexico SAVM projects that legalizing ENDS use could decrease smoking prevalence by 40.1% in males and 30.9% in females by 2049 compared to continuing the national ENDS ban. This reduction in prevalence would save 2.9 (2.5 males and 0.4 females) million life-years and avert almost 106 (91.0 males and 15.5 females) thousand deaths between 2025 and 2049. Public health gains decline by 43% to 59,748 SVADs averted when the switching rate is reduced by half and by 24.3% (92,806 SVADs averted) with a 25% ENDS risk level from that of cigarettes but increased by 24.3% (121,375 SVADs averted) with the 5% ENDS risk.

Conclusions

Mexico SAVM suggests that greater access to ENDS and a more permissive ENDS regulation, simultaneous with strong cigarette policies, would reduce smoking prevalence and decrease smoking-related mortality. The unanticipated effects of an ENDS ban merit closer scrutiny, with further consideration of how specific ENDS restrictions may maximize public health benefits.

Nicotine and Cardiovascular Health: When Poison is Addictive - a WHF Policy Brief

Nicotine is universally recognized as the primary addictive substance fuelling the continued use of tobacco products, which are responsible for over 8 million deaths annually. In recent years, the popularity of newer recreational nicotine products has surged drastically in many countries, raising health and safety concerns. For decades, the tobacco industry has promoted the myth that nicotine is as harmless as caffeine. Nonetheless, evidence shows that nicotine is far from innocuous, even on its own. In fact, numerous studies have demonstrated that nicotine can harm multiple organs, including the respiratory and cardiovascular systems. Tobacco and recreational nicotine products are commercialized in various types and forms, delivering varying levels of nicotine along with other toxic compounds. These products deliver nicotine in profiles that can initiate and perpetuate addiction, especially in young populations. Notably, some electronic nicotine delivery systems (ENDS) and heated tobacco products (HTP) can deliver concentrations of nicotine that are comparable to those of traditional cigarettes. Despite being regularly advertised as such, ENDS and HTP have demonstrated limited effectiveness as tobacco cessation aids in real-world settings. Furthermore, ENDS have also been associated with an increased risk of cardiovascular disease. In contrast, nicotine replacement therapies (NRT) are proven to be safe and effective medications for tobacco cessation. NRTs are designed to release nicotine in a slow and controlled manner, thereby minimizing the potential for abuse. Moreover, the long-term safety of NRTs has been extensively studied and documented. The vast majority of tobacco and nicotine products available in the market currently contain nicotine derived from tobacco leaves. However, advancements in the chemical synthesis of nicotine have introduced an economically viable alternative source. The tobacco industry has been exploiting synthetic nicotine to circumvent existing tobacco control laws and regulations. The emergence of newer tobacco and recreational nicotine products, along with synthetic nicotine, pose a tangible threat to established tobacco control policies. Nicotine regulations need to be responsive to address these evolving challenges. As such, governments should regulate all tobacco and non-medical nicotine products through a global, comprehensive, and consistent approach in order to safeguard tobacco control progress in past decades.

[Intended and unintended effects of e-cigarettes in clinical studies: a plea for (more) transparency]

E-cigarettes are used in clinical trials to facilitate smoking cessation. Due to the health risks associated with the use of e-cigarettes, the results of clinical trials should be fully reported, including continued exclusive use and dual use of tobacco and e-cigarettes. Nicotine cessation outcomes should be reported as the primary endpoint as well as the analysis of tobacco cessation alone. As there is currently no robust evidence that reducing cigarette consumption provides substantial health benefits, cigarette consumption reduction should not be used as a health outcome in clinical trials. Continued nicotine dependence should be included as an "adverse event" in the reporting of trial results.

Emerging ENDS products and challenges in tobacco control toxicity research

Electronic nicotine delivery systems (ENDS) continue to rapidly evolve. Current products pose unique challenges and opportunities for researchers and regulators. This commentary aims to highlight research gaps, particularly in toxicity research, and provide guidance on priority research questions for the tobacco regulatory community. Disposable flavoured ENDS have become the most popular device class among youth and may contain higher nicotine levels than JUUL devices. They also exhibit enhanced harmful and potentially harmful constituents production, contain elevated levels of synthetic coolants and pose environmental concerns. Synthetic nicotine and flavour capsules are innovations that have recently enabled the circumvention of Food and Drug Administration oversight. Coil-less ENDS offer the promise of delivering fewer toxicants due to the absence of heating coils, but initial studies show that these products exhibit similar toxicological profiles compared with JUULs. Each of these topic areas requires further research to understand and mitigate their impact on human health, especially their risks to young users.

The smoking and vaping model, A user-friendly model for examining the country-specific impact of nicotine VAPING product use: application to Germany

BACKGROUND

Simulation models play an increasingly important role in tobacco control. Models examining the impact of nicotine vaping products (NVPs) and smoking tend to be highly specialized and inaccessible. We present the Smoking and Vaping Model (SAVM),a user-friendly cohort-based simulation model, adaptable to any country, that projects the public health impact of smokers switching to NVPs.

METHODS

SAVM compares two scenarios. The No-NVP scenario projects smoking rates in the absence of NVPs using population projections, deaths rates, life expectancy, and smoking prevalence. The NVP scenario models vaping prevalence and its impact on smoking once NVPs became popular. NVP use impact is estimated as the difference in smoking- and vaping-attributable deaths (SVADs) and life-years lost (LYLs) between the No-NVP and NVP scenarios. We illustrate SAVM's adaptation to the German adult ages 18+ population, the Germany-SAVM by adjusting the model using population, mortality, smoking and NVP use data.

RESULTS

Assuming that the excess NVP mortality risk is 5% that of smoking, Germany-SAVM projected 4.7 million LYLs and almost 300,000 SVADs averted associated with NVP use from 2012 to 2060. Increasing the excess NVP mortality risk to 40% with other rates constant resulted in averted 2.8 million LYLs and 200,000 SVADs during the same period.

CONCLUSIONS

SAVM enables non-modelers, policymakers, and other stakeholders to analyze the potential population health effects of NVP use and public health interventions.

Quantifying PG : VG ratio and nicotine content in commercially available e-liquids using handheld Raman spectroscopy

Electronic cigarettes are a popular nicotine consumption product that have risen in popularity as an alternative to cigarettes. However, their recent meteoric rise in market size and various controversies have resulted in the analyses of e-liquid ingredients to be focused on powerful laboratory-based slow methods such as chromatography and mass spectrometry. Here we present a complementary technology based on Raman spectroscopy combined with chemometrics as a fast, inexpensive, and highly portable screening tool to detect and quantify the propylene glycol : glycerol (PG : VG) ratio and nicotine content of e-cigarette liquids. Through this, the PG : VG ratio of 20 out of 23 commercial samples was quantified to within 3% of their stated value, while nicotine was successfully quantified to within 1 mg g-1 for 16 out of 23 samples without the need for accurate knowledge of flavonoid composition. High linearity was also achieved when flavours were kept constant. Finally, the limitations of Raman spectroscopy are discussed, and potential solutions are suggested.

Predicting the long-term effects of electronic cigarette use on population health: a systematic review of modelling studies

OBJECTIVE

To systematically review and synthesise the findings of modelling studies on the population impacts of e-cigarette use and to identify potential gaps requiring future investigation.

DATA SOURCE AND STUDY SELECTION

Four databases were searched for modelling studies of e-cigarette use on population health published between 2010 and 2023. A total of 32 studies were included.

DATA EXTRACTION

Data on study characteristics, model attributes and estimates of population impacts including health outcomes and smoking prevalence were extracted from each article. The findings were synthesised narratively.

DATA SYNTHESIS

The introduction of e-cigarettes was predicted to lead to decreased smoking-related mortality, increased quality-adjusted life-years and reduced health system costs in 29 studies. Seventeen studies predicted a lower prevalence of cigarette smoking. Models that predicted negative population impacts assumed very high e-cigarette initiation rates among non-smokers and that e-cigarette use would discourage smoking cessation by a large margin. The majority of the studies were based on US population data and few studies included factors other than smoking status, such as jurisdictional tobacco control policies or social influence.

CONCLUSIONS

A population increase in e-cigarette use may result in lower smoking prevalence and reduced burden of disease in the long run, especially if their use can be restricted to assisting smoking cessation. Given the assumption-dependent nature of modelling outcomes, future modelling studies should consider incorporating different policy options in their projection exercises, using shorter time horizons and expanding their modelling to low-income and middle-income countries where smoking rates remain relatively high.

E-cigarette effects on vascular function in animals and humans

Smoking tobacco cigarettes is a significant (cardiovascular) health risk factor. Although the number of tobacco cigarette users declined over the last decades, shisha smoking and e-cigarette vaping partially compensated for this health benefit. E-cigarettes may create highly addicted dual users (vaping and smoking). E-cigarettes seem not to represent a healthier alternative to tobacco smoking, although they may be less harmful. E-cigarette vaping causes oxidative stress, inflammation, endothelial dysfunction, and associated cardiovascular sequelae. This is primarily due to a significant overlap of toxic compounds in the vapor compared to tobacco smoke and, accordingly, a substantial overlap of pathomechanistic features between vaping and smoking. Whereas the main toxins in vapor are reactive aldehydes such as formaldehyde and acrolein, the toxic mixture in smoke is more complex, comprising particulate matter, reactive gases, transition metals, volatile organic compounds, and N-nitrosamines. However, it seems that both lifestyle drugs impair endothelial function to a quite similar extent, which may be due to the role of oxidative stress as the central pathomechanism to mediate endothelial dysfunction and vascular damage. Finally, the main selling argument for e-cigarette use that they help to quit smoking and get rid of nicotine addiction may be false because it seems that e-cigarettes instead trigger the opposite-younger entrance age and more frequent use. With our review, we summarize the adverse health impact of tobacco cigarettes and e-cigarettes, emphasizing the detrimental effects on endothelial function and cardiovascular health.

[Electronic cigarettes: harm reduction or harm prolongation?]

This paper deals with the question of whether electronic cigarettes (e-cigarettes) can minimize the proven harm of smoking tobacco or may lead to a long-term harm. While the British Royal College of Physicians recommends smokers to use e-cigarettes as a substitute for tobacco products, the German Society for Pneumology and Respiratory Medicine advises smokers against using e-cigarettes. The harm reduction strategy is based on three hypotheses. Hypothesis 1: It is assumed that e-cigarettes cause less damage to health than tobacco cigarettes. Hypothesis 2: It is postulated that smokers are motivated to switch from conventional cigarettes to e-cigarettes. Hypothesis 3: It is assumed that e-cigarettes are an effective means for quitting smoking with few side effects. Although the long-term health consequences of e-cigarette use remain unknown, there is increasing evidence that e-cigarettes are toxic, harmful to cardiovascular system, respiratory health and potentially carcinogenic. Population-representative epidemiological surveys have shown that three-quarters of all current e-cigarette users in Germany smoke tobacco at the same time. In a few randomized clinical trials, e-cigarettes showed higher success rates compared to nicotine replacement products. As over-the-counter consumer products, a large number of studies have found no advantage for e-cigarettes under real conditions. In addition, e-cigarettes prolong nicotine dependence compared to nicotine replacement products. According to the current state of knowledge, the hypotheses behind the harm minimization strategy using e-cigarettes must be regarded as refuted. It therefore appears ethically problematic when doctors recommend e-cigarettes to their patients as a substitute for smoking.

Smoke and mirrors: Support from psychiatrists for nicotine e-cigarette availability in Australia

The Royal Australian and New Zealand College of Psychiatrists' (RANZCP) 2018 position statement supports increased, regulated availability of e-cigarettes (ECs) as a harm-reduction measure and recommends further research into their use. Aligned with this recommendation, we aimed to critically evaluate the RANZCP's stance on this issue through a literature review focused on the areas identified in the position statement as requiring further investigation: (1) the adverse health effects attributable to ECs; (2) use of ECs for smoking cessation (particularly for people living with severe mental illness); and (3) EC-associated risks for nicotine naïve young people. We identified and summarised evidence of harm attributable to ECs that is particularly relevant to young people through direct adverse health sequelae, onset of nicotine dependence and increased risk of combustible cigarette (CC) use. A small number of studies suggest ECs can be used for harm-reduction purposes in people diagnosed with nicotine dependence and severe mental illness. However, these results must be considered alongside robust evidence supporting the effectiveness of existing pharmacological interventions for smoking cessation in people with severe mental illness. The position statement is in urgent need of review in line with the available evidence.

In Vitro Toxicological Investigation and Risk Assessment of E-Cigarette Aerosols Based on a Novel Solvent-Free Extraction Method

Cigarettes, potentially safer alternatives to combustible cigarettes, have been reported to increase the health risk for long-term users, so accumulating information about their potential toxicity is of great concern. However, toxicological evaluations of e-cigarette aerosols are limited, which may be attributed to the lack of a simple and efficient extraction method. Here, we developed a high-speed centrifugal method for extracting e-cigarette aerosol collected mass (ACM) and prepared ACM samples of 26 representative e-cigarettes, and 10 samples were further selected based on their cytotoxicity for systematic toxicological assessments. The average extraction efficiency of ACM, primary aerosol components, and typical carbonyls exceeded 85%. The toxicological evaluation showed that the IC₅₀ value range of e-cigarettes for cytotoxicity was 2-52 mg/mL ACM, all e-cigarettes can induce the risk of DNA damage, mitochondrial depolarization, and c-Jun-related signal disturbances; most e-cigarettes significantly caused disturbance of oxidative stress balance. E-cigarettes with higher cytotoxicity appeared to cause a higher degree of damage, while no e-cigarette promoted mutagenicity and cytochrome c release. The toxicity difference among e-cigarettes using nicotine equivalent was significantly lower than that of ACM. This study provides a novel extraction method and a comprehensive in vitro toxicity risk profile of e-cigarette aerosols.

Reply to: "Nicotine or tobacco abstinence?"

9 years ago, in July 2013, a group of 12 experts, many who had previously expressed support for e-cigarettes, rated the relative harm of 12 nicotine-containing products by using 14 criteria addressing harms to the users and others [1]. The group concluded e-cigarettes were substantially less harmful than combustible cigarettes. The popular media have taken up these results and promoted e-cigarettes as “95% less risky” or “95% less harmful” than combustible cigarettes. However, the authors acknowledged, “a limitation of this study is the lack of hard evidence for the harms of most products on most of the criteria” [1].

The true impact of vaping on health will manifest over the coming decades, but the evidence to date on the deleterious effects of e-cigarettes on health justifies the recommendation to abstain from the consumption of inhaled nicotine and other productshttps://bit.ly/3Dn4riC

'95% less harmful'? Exploring reactions to quantitative modified risk claims for snus and e-cigarettes

OBJECTIVES

Studies examining perceptions of 'modified risk tobacco product' (MRTP) messages for e-cigarettes and smokeless tobacco have indicated consumers want statistics and quantification of harm reduction. However, limited research exists on reactions to quantitative MRTP messages.

DESIGN

We conducted 12 focus groups in the USA in 2019-6 focused on e-cigarette messages and 6 on snus messages. Eight groups were with current smokers (ages 21-66) and four with young adult (ages 18-25) non-smokers (n=57). Participants discussed messages stating that use of snus and vaping products have been estimated by scientists to be about 90% and 95% less harmful than smoking cigarettes, respectively.

RESULTS

Several participants agreed the messages strongly communicated that the products are less harmful than cigarettes, were attention getting and could be 'convincing'. However, participants expressed scepticism about the source and accuracy of the stated figures, and some noted the claims could be misleading and attractive to young people. Comments also reflected some claim misunderstandings (eg, that e-cigarettes only pose a 5% chance of harm). Participants also agreed that stating e-cigarette risks 'are unlikely to exceed 5% of cigarette smoking harms' was confusing and less impactful than the '95% less harmful' wording.

CONCLUSIONS

Quantitative claims suggesting high levels of reduced risk when comparing e-cigarettes or smokeless tobacco/snus relative to cigarettes may be successful in gaining attention and being persuasive for some audiences, particularly, if from more credible sources. However, message developers, users and evaluators should be mindful of message limitations and aim to mitigate unintended consequences.

A Decision-Theoretic Public Health Framework for Heated Tobacco and Nicotine Vaping Products

Markets for nicotine vaping products (NVPs) and heated tobacco products (HTPs) have grown as these products became positioned as harm-reduction alternatives to combusted tobacco products. Herein, we present a public health decision-theoretic framework incorporating different patterns of HTP, NVP, and cigarette use to examine their impacts on population health. Our framework demonstrates that, for individuals who would have otherwise smoked, HTP use may provide public health benefits by enabling cessation or by discouraging smoking initiation and relapse. However, the benefits are reduced if more harmful HTP use replaces less harmful NVP use. HTP use may also negatively impact public health by encouraging smoking by otherwise non-smokers or by encouraging initiation or relapse into smoking. These patterns are directly influenced by industry behavior as well as public policy towards HTPs, NVPs, and cigarettes. While substantial research has been devoted to NVPs, much less is known about HTPs. Better information is needed to more precisely define the health risks of HTPs compared to cigarettes and NVPs, the relative appeal of HTPs to consumers, and the likelihood of later transitioning to smoking or quitting all products. While our analysis provides a framework for gaining that information, it also illustrates the complexities in distinguishing key factors.

The Australia Smoking and Vaping Model: The Potential Impact of Increasing Access to Nicotine Vaping Products

BACKGROUND

We model the potential impact of relaxing current nicotine vaping product (NVP) restrictions on public health in Australia.

AIMS AND METHODS

A Restricted NVP Scenario was first developed to project current smoking and vaping rates, where a U.S. smoking model was calibrated to recent Australian trends. To model less restrictive NVP policies, a Permissive NVP Scenario applied rates of switching from smoking to vaping, initiation into NVP and cigarette use, and cessation from smoking and vaping based on U.S. trends. The model measures vaping risk relative to the excess mortality rate of smoking. The public health impacts are measured as the difference between smoking- and vaping-attributable deaths (SVADs) and life years lost (LYLs) in the Restricted and Permissive NVP Scenarios. Sensitivity analysis is conducted regarding the NVP excess risk and other factors.

RESULTS

Assuming an NVP excess risk of 5% that of smoking, 104.2 thousand SVADs (7.7% reduction) and 2.05 million LYLs (17.3% reduction) are averted during 2017-2080 in the Permissive NVP Scenario compared to the Restricted NVP Scenario. Assuming 40% NVP excess risk, 70 thousand SVADs and 1.2 million LYLs are averted. The impact is sensitive to the rate at which smokers switch to NVPs and quit smoking, and relatively insensitive to the smoking initiation and NVP initiation and cessation rates.

CONCLUSIONS

The model suggests the potential for public health gains to be achieved by relaxing NVP access regulations. However, the model would benefit from better information regarding the impact of NVPs on smoking under a relaxation of current restrictions.

IMPLICATIONS

Australia has implemented a strong array of cigarette-oriented policies, but has restricted access to NVPs. The Smoking and Vaping Model offers a framework for modeling hypothetical policy scenarios. The Australian model shows the potential for public health gains by maintaining cigarette-oriented policies while relaxing the current restrictive NVP policy. Modeling results under a permissive NVP policy are particularly sensitive to the estimated rates of smoking cessation and switching to vaping, which are not well established and will likely depend on past and future cigarette-oriented policies and the specific NVP policies implemented in Australia.

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.

Time course of changes in inflammatory and oxidative biomarkers in lung tissue of mice induced by exposure to electronic cigarette aerosol

Significance

Electronic cigarettes (e-cigarettes) have become a popular way to smoke all over the world. Chronic exposure to e-cigarette aerosol may influence lung health. This study uses an animal model to explore the time course of the effect of exposure to e-cigarette aerosols on the lung.

Methods

Lung samples were collected after exposure of Balb/c mice to e-cigarette aerosols for 1 h/day (6 times/week) for 1, 2 and 4 weeks and compared to sham-exposed controls. Examined biomarkers including inflammatory cells, tumor necrosis factor α (TNFα), interleukin-6 (IL-6), interleukin-10 (IL-10), reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GPx), catalase, superoxide dismutase (SOD), and Thiobarbituric acid reactive substances (TBARS).

Results

Exposure of animals to e-cigarette aerosols induced significant increases (P < 0.05) in total inflammatory cells, eosinophils, macrophages and TNFα in the lung tissue after 1, 2 and 4 weeks of exposure. Furthermore, level of IL-10 significantly decreased, whereas levels of neutrophils and basophils significantly increased (P < 0.05) after 1 week of exposure. Exposure of animals to e-cigarette aerosol also induced significant decreases (P < 0.05) in the GSH/GSSG ratio, and GPx levels after 2 and 4 weeks of exposures. The activity of catalase was also reduced (P < 0.05) after 4 weeks of exposure. Level of TBARS showed a trend of elevation with time and it reached a significant elevation after 4 weeks (P < 0.01).

Conclusion

Current results indicate that inhalation of unflavored e-cigarette aerosol might be associated with inflammation in lung tissue that worsen as the duration of exposure increases. Further experiments including more time points, histopathology and pulmonary physiology experiments are needed to confirm the current results.

Aerosol, vapor, or chemicals? College student perceptions of harm from electronic cigarettes and support for a tobacco-free campus policy

Objective: This study is the first to examine the influence of e-cigarette emission phrasing on perceived harm of secondhand exposure, and whether harm perception was associated with support for a tobacco-free campus policy. Participants: In the fall 2018 and spring 2019 semesters, 52 sections of a college English course (N = 791 students) were cluster randomized to one of three conditions ("vapor," "aerosol," or "chemicals") assessing harm of secondhand exposure to e-cigarette emissions. Methods: Regression models adjusted for demographic characteristics, tobacco use, and other potential confounders. Results: Compared to the "vapor" condition, "chemicals" and "aerosol" conditions were associated with increased odds of perceiving secondhand exposure to e-cigarettes to be harmful/very harmful (AOR = 2.0, p < 0.01). Greater perceived harm of secondhand e-cigarette exposure was associated with increased odds of supporting a tobacco-free campus policy (AOR = 2.22, p < 0.001). Conclusions: Health campaigns should use accurate terminology to describe e-cigarette emissions, rather than jargon that conveys lower risk.

Research progress of E-cigarette-A bibliometric analysis during 2010–2022

Introduction

Electronic cigarettes have been widely used all over the world. It is not clear what the advantages and disadvantages of a novelty in daily life are that is attracting increasing attention. Up to now, no bibliometric studies on e-cigarettes have been published in databases. Therefore, we are willing to explore directions and research hotspots in this emerging field by using bibliometrics to analyze research areas, publishing countries and institutions, high-output authors, and future trends of e-cigarettes in recent years. Compared with the traditional review, the bibliometric study can provide some information on core journals, articles, researchers, institutions, and countries concentrating on this topic to guide experimentation strategies and funding decisions.

Methods

A bibliometric analysis was performed by CiteSpace and VOSviewer up to April 2022 in the core collection of Web of Science. HistCite, VOSviewer, CiteSpace, and the R-based Bibliometrix 4.1.0 packages were used to analyze literature information, including year, journal, country, institute, author, keywords, and co-cited references.

Results

Research related to e-cigarettes has proliferated since its inception around 2010. A total of 2,302 studies were published in 689 journals by our search method. Nicotine and tobacco research was the most published journal. The most prolific country was the United States, while the most influential institution was Virginia Commonwealth University. Eight of the top ten authors were from the United States. Oxidative stress, high school students, smoking cessation, delivery, behavioral economics, and exposure were the top topics.

Conclusions

As an emerging social phenomenon, research on e-cigarettes has increased significantly over the past decade, particularly from 2015 to 2020. The top three core journals are Nicotine and Tobacco Research, the International Journal of Environmental Research, and Public Health. Eisenberg-Thomas had published numerous articles on e-cigarettes that had been co-cited in many papers. Oxidative stress, high school students, and smoking cessation are the top three areas of e-cigarette-related research, which were also important areas for further investigation.

Cigarette smoking and liver diseases

Cigarette smoking is a preventable risk factor for premature morbidity and mortality. A history of smoking is observed in approximately 40% of patients with liver disease, while a growing number of studies are investigating the potential impact of smoking in chronic liver diseases. This review discusses the effects of smoking on liver diseases, at multiple levels, with a focus on its potential causal role. Clinical evidence indicates that cigarette smoking negatively impacts the incidence and severity of fatty liver disease, fibrosis progression, hepatocellular carcinoma development, and the outcomes of patients with advanced liver disease. The underlying mechanisms are complex and involve different pathophysiological pathways including oxidative stress and oncogenic signals. Importantly, smoking promotes cardiovascular disease and extrahepatic cancers in patients with steatohepatitis and in transplant recipients. We discuss how promoting smoking cessation could improve the rates of treatment response (in clinical trials) and fibrosis regression, while reducing the risk of hepatocellular carcinoma and improving liver transplant outcomes. Finally, we discuss current challenges such as the referral of smokers to specialised units for smoking cessation.

E-Cigarette-Related Nicotine Misinformation on Social Media

Background. Twitter provides an opportunity to examine misperceptions about nicotine and addiction as they pertain to electronic nicotine delivery systems (ENDS). The purpose of this study was to systematically examine a sample of ENDS-related tweets that presented information about nicotine or addiction for the presence of potential misinformation.Methods. A total of 10.1 million ENDS-related tweets were obtained from April 2018 through March 2019 and were filtered for unique tweets containing keywords for nicotine and addiction. A subsample (n = 3,116) were human coded for type of account (individual, group, commercial, or news) and presence of potential misinformation.Results. Of tweets that presented ENDS-related nicotine or addiction information (n = 904), 41.7% (n = 377) contained potential misinformation coded as anti-vaping exaggeration, pro-vaping exaggeration, nicotine is not addictive or is never harmful, or unproven health benefits.Conclusions. Anti-vaping exaggeration tweets distorted or embellished claims about ENDS nicotine and addiction; pro-vaping exaggeration tweets misinterpreted results from scientific studies. Misinformation that nicotine is not addictive or is never harmful or has unproven health benefits appeared less but are potentially problematic. ENDS-related messaging should be designed to be easily understood by the public and monitored to detect the spread of misinterpretation or misinformation on social media.

State-specific prevalence of current e-cigarette use by disability status and disability type-United States, BRFSS 2016-2018

BACKGROUND

Cigarette smoking is the leading cause of preventable disease and death in the United States. The tobacco product landscape has diversified to include electronic cigarettes (e-cigarettes). Adults with disabilities are more likely than adults without disabilities to smoke cigarettes, but within the current body of literature, there is limited information on the use of e-cigarettes among adults with disabilities.

OBJECTIVE

To assess overall and state-specific prevalence of current e-cigarette use among adults by disability status, disability type, sex, and age.

METHODS

Disability was defined as having serious difficulty with vision, hearing, mobility, cognition, or any difficulty with self-care or independent living. The Behavioral Risk Factor Surveillance System cross-sectional survey data (2016-2018; n = 1,150,775) were used to estimate state and District of Columbia prevalence of current e-cigarette use among adults (aged ≥18 years) with and without disabilities, overall and by disability type, sex, and age group.

RESULTS

Median prevalence of current e-cigarette use was higher among adults with than without disabilities (6.5% vs. 4.3%, P < 0.05). Among adults with disabilities, use varied from 2.5% in DC to 10.0% in Colorado; median use was highest among those with cognitive disabilities (10.0%) and those aged 18-24 years (18.7%).

CONCLUSIONS

Prevalence of current e-cigarette use was higher among adults with than without disabilities and varied across states by disability status, type, and age group. The findings underscore the need to monitor e-cigarette use among adults with disabilities and specifically include them in tobacco control policies and programs addressing e-cigarette use.

Lebensstil und kardiovaskuläre Gesundheit – wie schädlich sind E-Zigaretten und Shisha-Rauchen?

Tabakrauchen ist ein Hauptauslöser chronischer nicht übertragbarer Krankheiten und ein Risikofaktor für kardiovaskuläre und pulmonale Erkrankungen. Obwohl der weltweite Tabakkonsum während der letzten 2 Jahrzehnte reduziert wurde, zeigt der Gebrauch von E-Zigaretten und Wasserpfeifen (Shisha) eine pandemische Zunahme mit hohem Anteil jüngerer Anwender. E-Zigaretten sind keine komplett schadensfreie Alternative zu herkömmlichen Tabakzigaretten, auch weil die zahlreichen Geschmacksaromen und die einfache/schnelle Verwendung eine steigende Zahl von abhängigen Anwendern hervorbringt. E-Zigaretten sind nicht unbedingt geeignet, die Nikotinabhängigkeit hinter sich zu lassen. Diese Arbeit bietet eine Übersicht über die kardiovaskulären Gesundheitsauswirkungen des Shisharauchens und E-Zigaretten-Dampfens mit Fokus auf die negativen Effekte auf die Endothelfunktion. Die schädlichen biologischen Auswirkungen der toxischen Inhaltsstoffe dieser Produkte werden vor allem im Hinblick auf oxidativen Stress und Entzündungsreaktionen diskutiert. Abschließend wird der aktuelle Stand hinsichtlich der Empfehlungen, gesetzlichen Regelungen und kommerziellen Werbung kurz zusammengefasst.

Improving on estimates of the potential relative harm to health from using modern ENDS (vaping) compared to tobacco smoking

BACKGROUND

Although the harm to health from electronic nicotine delivery systems (ENDS) compared to smoked tobacco remains highly uncertain, society and governments still need to know the likely range of the relative harm to inform regulatory policies for ENDS and smoking.

METHODS

We identified biomarkers with specificity of association with different disease groupings e.g., volatile organic compound (VOCs) for chronic obstructive pulmonary disease; and tobacco-specific N´-nitrosamines (TSNAs) and polycyclic aromatic hydrocarbons (PAHs) for all cancers. We conducted a review of recent studies (post January 2017) that compared these biomarkers between people exclusively using ENDS and those exclusively smoking tobacco. The percentage differences in these biomarkers, weighted by study size and adjusted for acrolein from other sources, were used as a proxy for the assumed percentage difference in disease harm between ENDS and smoking. These relative differences were applied to previously modelled estimates of smoking-related health loss (in health-adjusted life-years; HALYs).

RESULTS

The respective relative biomarker levels (ENDS vs smoking) were: 28% for respiratory diseases (five results, three studies); 42% for cancers (five results, four studies); and 35% for cardiovascular (seven results, four studies). When integrated with the HALY impacts by disease, the overall harm to health from ENDS was estimated to be 33% that of smoking.

CONCLUSIONS

This analysis, suggests that the use of modern ENDS devices (vaping) could be a third as harmful to health as smoking in a high-income country setting. But this estimate is based on a limited number of biomarker studies and is best be considered a likely upper level of ENDS risk given potential biases in our method (i.e., the biomarkers used being correlated with more unaccounted for toxicants in smoking compared to with using ENDS).

Successful countering of tobacco industry efforts to overturn Thailand's ENDS ban

BACKGROUND

After Thailand enacted laws to ban the import and sale of all types of electronic nicotine delivery systems (ENDS, including e-cigarettes and heated tobacco products (HTPs)) in 2015, pro-ENDS advocacy groups pressured the government to lift the ban, particularly after Philip Morris International (PMI) started promoting its HTP IQOS in 2017.

METHODS

We reviewed information related to ENDS in Thailand between 2014 and 2019 from Thai newspaper articles, meeting minutes and letters submitted to government agencies, websites and social media platforms of pro-ENDS networks and Thai tobacco control organisations.

RESULTS

The tobacco industry and the pro-ENDS groups used five tactics to try to reverse the Thai ban on ENDS: creating front groups, lobbying decision-makers, running public relations campaigns, seeking to discredit tobacco control advocates and funding pro-tobacco harm reduction research. ENDS Cigarette Smoking Thailand (ECST), a pro-ENDS group in Thailand, worked in parallel to Philip Morris Thailand Limited (PMTL) to oppose the ban. The group connected with international coalitions that promote harm reduction through the PMI-funded Foundation for a Smoke-Free World.

CONCLUSION

Although ECST and PMTL continuously worked to revoke the ban since 2017, the government still kept ENDS illegal as of October 2020. This decision resulted from the strong commitment and collaboration among Thai tobacco control organisations and their shared vision to protect the public's health from harmful tobacco products. The similar strategies used by the pro-ENDS movement in Thailand and the tobacco companies could inform health advocates and policy-makers in other low and middle income countries facing pressure to market ENDS.

"You have to vape to make it through": E-cigarette Outcome Expectancies among Youth and Parents

Objectives: Outcome expectancies are central to explaining health behavior and have been shown to predict tobacco use. Research on outcome expectancies for e-cigarette use among youth is scarce but increasingly important given the growing rates of use, particularly of high-nicotine pod devices and the recent outbreak of e-cigarette related lung disease. Methods: In 2019, we conducted 3 focus groups with middle school youth (N=25), 5 with high school youth (N=38), and 4 with parents (N=27). Youth and parents were not related and groups included both users and non-users. Participants discussed reasons for e-cigarette use and bad and good things that might happen to a person who vapes. Results: Participants described positive and negative psychoactive/sensory, social, and health-related outcome expectancies. Both youth and parents mentioned stress relief and appearing older as positive outcome expectancies, and e-cigarette flavors, acting rebellious, and structural opportunities as other reasons for initiating e-cigarette use. Social consequences and health outcomes were negative outcome expectancies deterring use. Conclusions: Regulations and public communication campaigns can counteract the positive outcome expectancies (flavor regulation, providing stress reduction tips) and capitalize on negative ones (communicating negative health outcomes) to decrease youth e-cigarette use.

Association between e-cigarette use and asthma: a systematic review and meta-analysis

OBJECTIVE

Increasing e-cigarette use combined with emerging evidence of their respiratory effects raises concerns about their potential impact on asthma prevalence. This review evaluates the most recent available evidence on the association of e-cigarette use and asthma world-wide.

METHODS

A literature search was performed in PubMed, Scopus, CINAHL, Cochrane Library, Web of Science and ProQuest in March 2021. This study was conducted in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) registered with PROSPERO (registration number: CRD42020211812).

STUDY SELECTIONS

Cross-sectional and cohort studies assessing the association between e-cigarette use and asthma were eligible for inclusion. Studies examining exacerbations in asthma symptoms and severity were excluded. The quality of the included studies was assessed using the Appraisal tool for Cross-Sectional Studies (AXIS).

RESULTS

Thirteen cross-sectional studies with the sample size of 1,039,203 met the eligibility criteria. Odds ratios were pooled using a random effects model. Pooled analysis found a significant association between current e-cigarette use and asthma (pOR = 1.36, 95% CI 1.21-1.52) and ever e-cigarette use and asthma (pOR = 1.24 95% CI 1.13-1.36).

CONCLUSION

Our review found that e-cigarette use and ever e-cigarette use are correlated with asthma. However, heterogeneity and inconsistencies between covariates limited the interpretation of the results. This warrants further studies to investigate any potential causal association between e-cigarette use and asthma. No funding was received for this systematic review.

Updated Health and Cost Impacts of Electronic Nicotine Delivery Systems, Using Recent Estimates of Relative Harm for Vaping Compared to Smoking

BACKGROUND

Measuring population health and costs effects of liberalizing access to electronic nicotine delivery systems (ENDS) is an evolving field with high persisting uncertainty. A critical area of uncertainty for policy-makers are estimates of net harms from ENDS relative to cigarettes, therefore, we model these harms using updated estimates incorporating disease specificity.

METHODS

We use updated estimates of relative harm of vaping vs smoking, based upon relevant biomarker studies to model the impact of liberalizing access to ENDS in New Zealand (NZ), relative to a ban (where ENDS are not legally available), in an existing proportional multi-state life-table model of 16 tobacco-related diseases.

RESULTS

This modeling suggests that ENDS liberalization results in an expected gain of 195 000 quality-adjusted life-years (QALYs) over the remainder of the NZ population's lifespan. There was wide uncertainty in QALYs gained (95% uncertainty interval [UI] = -8000 to 406 000) with a 3.2% probability of net health loss (based upon the number of simulation runs returning positive QALY gains). The average per capita health gain was 0.044 QALYs (equivalent to an extra 16 days of healthy life). Health system cost-savings were expected to be NZ$2.8 billion (US$2.1 billion in 2020 US$; 95%UI: -0.3 to 6.2 billion [2011 NZ$]), with an estimated 3% chance of a net increase in per capita cost.

CONCLUSIONS

This updated modeling around liberalizing ENDs in NZ, still suggests likely net health and cost-saving benefits-but of lesser magnitude than previous work and with a small possibility of net harm to population health.

IMPLICATIONS

This study found evidence using updated biomarker studies that ENDS liberalization could result in QALY gains across the New Zealand population lifespan that are also cost-saving to the health system. Governments should include the information from these types of modeling studies in their decision-making around potentially improving access to ENDS for existing smokers, while at the same further reducing access to tobacco.

Balancing Consideration of the Risks and Benefits of E-Cigarettes

The topic of e-cigarettes is controversial. Opponents focus on e-cigarettes' risks for young people, while supporters emphasize the potential for e-cigarettes to assist smokers in quitting smoking. Most US health organizations, media coverage, and policymakers have focused primarily on risks to youths. Because of their messaging, much of the public-including most smokers-now consider e-cigarette use as dangerous as or more dangerous than smoking. By contrast, the National Academies of Science, Engineering, and Medicine concluded that e-cigarette use is likely far less hazardous than smoking. Policies intended to reduce adolescent vaping may also reduce adult smokers' use of e-cigarettes in quit attempts. Because evidence indicates that e-cigarette use can increase the odds of quitting smoking, many scientists, including this essay's authors, encourage the health community, media, and policymakers to more carefully weigh vaping's potential to reduce adult smoking-attributable mortality. We review the health risks of e-cigarette use, the likelihood that vaping increases smoking cessation, concerns about youth vaping, and the need to balance valid concerns about risks to youths with the potential benefits of increasing adult smoking cessation.

Vaping in the Workplace: Prevalence and Attitudes Among Employed US Adults

Describe workplace vaping, prevalence of observed use, attitudes, and perceptions among US adults.

An investigation of factors encouraging and deterring EC use: a thematic analysis of accounts from UK adults

OBJECTIVE

This study aimed to explore E-cigarette (EC) accounts from a small sample of UK adults with varied smoking/EC experiences. This was to contribute to existing knowledge of adult perceptions and understand the factors that encourage or deter use to inform health messaging aimed at professionals, policy makers and the general public.

DESIGN

Twelve participants, five men and seven women aged 23-55 years (mean age 32.43) with mixed smoking/EC backgrounds took part in face-to-face interviews, analysed using semantic-level inductive thematic analysis.

RESULTS

The analysis identified three key themes. Social influence (1) relates to the understanding of the social representations of ECs. Representation and knowledge (2) captures the impact of varied EC related communication on perception. Aspects of addiction (3) conveys aspects of nicotine addiction and how this influences EC use.

CONCLUSION

ECs were generally perceived as more socially acceptable than cigarettes by non-smokers, although there were varying levels of acceptability depending on the type of EC device used. There was also unanimity concerning uncertainty surrounding the devices. Behavioural/sensory elements and personal enjoyment of ECs were consistent elements that encouraged or deterred use. Although non-smokers/vapers did not use the devices, they expressed similar apprehensions to those who did.

Categorizing IQOS-Related Twitter Discussions

(1) Background: The heated tobacco product IQOS, by Philip Morris International, is now available in over 55 countries, including the United States. Social media sites such as Twitter are often used to promote or discuss tobacco products, though prior research has not examined how IQOS is presented on Twitter. (2) Methods: This study collected and categorized Twitter conversations involving IQOS. A manual content analysis was performed on N = 3916 English tweets related to IQOS published internationally between 1 January 2020 and 30 June 2020. (3) Results: Most tweets were either online marketing for IQOS (32.3%) or personal testimonials related to IQOS use (34.2%). Personal testimonial tweets made harm reduction claims about IQOS either as an avenue to quit smoking/tobacco use (3.4%), or in comparison to combustible cigarettes (2.0%). Tobacco policy-related tweets were detected (13.9%), split between discussions of United States (4.9%) and international (4.4%) policies. News media tweets (14.2%) were also detected. (4) Conclusions: Our study suggests IQOS may be understood as a less harmful alternative to vaping and combustible cigarettes. Discussions also suggest IQOS is likely to be used to avoid clean air policies or used in areas in which smoking is restricted.

Public health implications of vaping in the USA: the smoking and vaping simulation model

Background

Nicotine vaping products (NVPs) are increasingly popular worldwide. They may provide public health benefits if used as a substitute for smoking, but may create public health harms if used as a gateway to smoking or to discourage smoking cessation. This paper presents the Smoking and Vaping Model (SAVM), a user-friendly model which estimates the public health implications of NVPs in the USA.

Methods

SAVM adopts a cohort approach. We derive public health implications by comparing smoking- and NVP-attributable deaths and life-years lost under a No-NVP and an NVP Scenario. The No-NVP Scenario projects current, former, and never smoking rates via smoking initiation and cessation rates, with their respective mortality rates. The NVP Scenario allows for smoking- and NVP-specific mortality rates, switching from cigarette to NVP use, separate NVP and smoking initiation rates, and separate NVP and smoking cessation rates. After validating the model against recent US survey data, we present the base model with extensive sensitivity analyses.

Results

The SAVM projects that under current patterns of US NVP use and substitution, NVP use will translate into 1.8 million premature smoking- and vaping-attributable deaths avoided and 38.9 million life-years gained between 2013 and 2060. When the NVP relative risk is set to 5%, the results are sensitive to the level of switching and smoking cessation rates and to a lesser extent smoking initiation rates. When the NVP relative risk is raised to 40%, the public health gains in terms of averted deaths and LYL are reduced by 42% in the base case, and the results become much more sensitive to variations in the base case parameters.

Discussion

Policymakers, researchers, and other public health stakeholders can apply the SAVM to estimate the potential public health impact of NVPs in their country or region using their own data sources. In developing new simulation models involving NVPs, it will be important to conduct extensive sensitivity analysis and continually update and validate with new data.

Conclusion

The SAVM indicates the potential benefits of NVP use. However, given the uncertainty surrounding model parameters, extensive sensitivity analysis becomes particularly important.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12963-021-00250-7.

Exclusive, Dual, and Polytobacco Use Among US Adults by Sociodemographic Factors: Results From 3 Nationally Representative Surveys

PURPOSE

To provide tobacco product use patterns for US adults by sociodemographic group.

DESIGN

A secondary analysis of Tobacco Use Supplement to the Current Population Survey (2014-15), National Health Interview Survey (2015), and Population Assessment of Tobacco and Health (2015-16).

SETTING

United States.

SAMPLE

Three nationally representative samples of adults (N = 28,070-155,067).

MEASURES

All possible combinations of cigarette, Electronic Nicotine Delivery Systems (ENDS), other combustible product, and smokeless tobacco use, defined as current use every day or some days.

ANALYSIS

Weighted population prevalence and proportion among tobacco users of exclusive, dual, and polyuse patterns by sex, race/ethnicity, education, income, and age.

RESULTS

Exclusive cigarette use was the most prevalent pattern (10.9-12.8% of US population). Dual and polyuse were less prevalent at the population level (2.6-5.2% and 0.3-1.3%, respectively) but represented 16.7-25.5% of product use among tobacco users. Cigarette plus ENDS use was similar by sex, but men were more likely to be dual users of cigarettes plus other combustibles or smokeless tobacco. Among race/ethnic subgroups, non-Hispanic (NH) Whites were most likely to use cigarettes plus ENDS, while NH Blacks were most likely to use cigarettes plus other combustibles. Dual and polyuse were generally less common among adults with higher education, income, and age.

CONCLUSION

Differences in product use patterns by sociodemographic group likely represent different risk profiles with important implications for resulting health disparities.

Trends in Tobacco Use Among Adolescents by Grade, Sex, and Race, 1991-2019

IMPORTANCE

Use of e-cigarettes increased among adolescents between 2011 and 2019. However, whether these changes are affecting patterns of use of other tobacco products, especially cigarettes, remains unclear.

OBJECTIVE

To examine the long-term and recent trends in cigarette smoking and smokeless tobacco product use among US adolescents by grade (8th, 10th, and 12th), sex (male and female), and race (White and Black).

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional study, joinpoint regression analyses were performed to characterize trends in tobacco product use for key sociodemographic groups, identifying change of trend years (joinpoints). Students in the 8th, 10th, and 12th grades at US secondary schools and high schools who participated in the nationally representative Monitoring the Future survey from January 7, 1991, to June 3, 2019, were evaluated.

EXPOSURES

Cigarette smoking and smokeless tobacco product use during the past 30 days.

MAIN OUTCOMES AND MEASURES

Past 30-day and daily prevalence of cigarette smoking and smokeless tobacco product use by year, grade, sex, and race. The prevalence trend segments, change of trend years (joinpoints), and annual percentage change (APC) in prevalence within each trend segment were estimated using joinpoint regression.

RESULTS

Since 1991, 487 335 8th-grade, 447 310 10th-grade, and 424 236 12th-grade students have completed the Monitoring the Future survey (including 663 663 girls and 632 698 boys [those who did not respond to the sex question in the survey were excluded from the sex analyses]). Past 30-day and daily smoking prevalence increased in all groups analyzed from 1991 until 1996 and 1997 and has been decreasing ever since, with more rapid reductions in recent years. For example, daily smoking among 12th-grade boys increased at an APC of 4.9% (95% CI, 3.5%-6.3%) from 1991 to 1998, decreased at an APC of -8.0% (95% CI, -9.3% to -6.7%) from 1998 to 2006, decreased at an APC of -1.6% (95% CI, -4.6% to 1.5%) from 2006 to 2012, and decreased at an APC of -17.4% (95% CI, -19.4% to -15.4%) from 2012 to 2019. Similar results were observed for boys in the 8th grade (5.0% [95% CI, 0.1%-10.2%] for 1991-1996, -8.8% [95% CI, -10.0% to -7.6%] for 1996-2011, and -17.3% [95% CI, -22.2% to -12.0%] for 2011-2019) and 10th grade (7.1% [95% CI, 3.7%-10.7%] for 1991-1997, -11.1% [95% CI, -13.9% to -8.2%] for 1997-2005,-0.7% [95% CI, -5.9% to 4.9%] for 2005-2011, and -17.9 [95%, -21.7% to -13.9%] for 2011-2019), for girls in 8th grade (10.9% [95% CI, 5.0%-17.2%] for 1991-1996 and -10.8% [95% CI, -11.7% to -10.0% for 1996-2019), 10th grade (7.2% [95% CI, 3.9%-10.7%] for 1991-1997, -9.5% [95% CI, -10.5% to -8.6%] for 1997-2012, and -16.3% [95% CI, -21.8% to -10.4%] for 2012-2019), and 12th grade (6.5% [95% CI, 3.6%-9.5%] for 1991-1997, -7.2% [95% CI, -8.1% to -6.3%] for 1997-2012, and -17.5% [95% CI, -21.2% to -13.6%] for 2012-2019). Results were similar, too, for Black adolescents (2015-2019 average annual percentage change: -8.6% [95% CI, -10.3% to -6.8%] for 8th graders; -17.7% [95% CI, -26.3% to -8.2%] for 10th graders; and -18.3% [95% CI, -23.9% to -12.2%] for 12th graders) and White adolescents (2015-2019 average annual percentage change: -17.3% [95% CI, -20.6% to -13.7%] for 8th graders; -16.9% [95% CI, -20.5% to -13.2%] for 10th graders; and -17.0% [95% CI, -20.5% to -13.2%] for 12th graders). Smokeless tobacco was used more variably through 2012, followed by consistent decreases in the past 5 years. For instance, smokeless tobacco use in the past 30 days in 10th-grade boys decreased at an APC of -6.5% (95% CI, -7.5% to -5.4%) from 1991 to 2004, increased at an APC of 3.1% (95% CI, -0.8% to 7.1%) from 2004 to 2012, and decreased at an APC of -11.6% (95% CI, -15.7% to -7.4%) from 2012 to 2019. Similarly, daily smokeless tobacco use in 12th-grade boys decreased at an APC of -3.8% (95% CI, -5.4% to -2.1%) from 1992 to 2005, increased at an APC of 3.1% (95% CI, -0.2% to 6.5%) from 2005 to 2015, and decreased at an APC of -23.0% (95% CI, -33.3% to -11.0%) from 2015 to 2019.

CONCLUSIONS AND RELEVANCE

This cross-sectional study suggests that, despite the increase in the prevalence of e-cigarette use among adolescents between 2011 and 2019, the prevalence of cigarette and smokeless tobacco use has decreased more rapidly during the same period compared with earlier years.

Effects of tobacco cigarettes, e-cigarettes, and waterpipe smoking on endothelial function and clinical outcomes

Tobacco smoking is a leading cause of non-communicable disease globally and is a major risk factor for cardiovascular disease (CVD) and lung disease. Importantly, recent data by the World Health Organizations (WHO) indicate that in the last two decades global tobacco use has significantly dropped, which was largely driven by decreased numbers of female smokers. Despite such advances, the use of e-cigarettes and waterpipes (shisha, hookah, narghile) is an emerging trend, especially among younger generations. There is growing body of evidence that e-cigarettes are not a harm-free alternative to tobacco cigarettes and there is considerable debate as to whether e-cigarettes are saving smokers or generating new addicts. Here, we provide an updated overview of the impact of tobacco/waterpipe (shisha) smoking and e-cigarette vaping on endothelial function, a biomarker for early, subclinical, atherosclerosis from human and animal studies. Also their emerging adverse effects on the proteome, transcriptome, epigenome, microbiome, and the circadian clock are summarized. We briefly discuss heat-not-burn tobacco products and their cardiovascular health effects. We discuss the impact of the toxic constituents of these products on endothelial function and subsequent CVD and we also provide an update on current recommendations, regulation and advertising with focus on the USA and Europe. As outlined by the WHO, tobacco cigarette, waterpipe, and e-cigarette smoking/vaping may contribute to an increased burden of symptoms due to coronavirus disease 2019 (COVID-19) and to severe health consequences.

Unboxed: US Young Adult Tobacco Users' Responses to a New Heated Tobacco Product

The heated tobacco product (HTP) IQOS was authorized for sale in the US in 2019. We investigated how young adults with experience using multiple tobacco products reacted to, perceived, and developed interest in IQOS, informing policies that might prevent HTPs from becoming ubiquitous. We used a novel qualitative method in which 33 young adult tobacco users in California (fall 2019) "unboxed" an IQOS device, tobacco sticks, and marketing materials and narrated their impressions and opinions. We conducted content and thematic analyses of participants' reactions, sensory experiences, and interest. Multiple attributes influenced appeal for participants, including sleek electronic design, novel technology, perceived harmfulness, complexity, and high cost. The "no smoke" claim and heating technology suggested that smoking IQOS was safer than smoking cigarettes. Public health programs should closely monitor HTP marketing and uptake, particularly as "reduced exposure" claims were authorized in July 2020. Evidence-based regulations (e.g., requiring plain packaging for tobacco sticks), actions addressing IQOS' unique attributes (e.g., regulating device packaging to reduce high-tech appeal), and public education might help to counter the appeal generated by potentially misleading IQOS marketing tactics.

Could E-cigarette vaping contribute to heart disease?

INTRODUCTION

E-cigarettes have become a controversial topic. While their benefits are questioned by the scientific community, a part of the medical profession is still supporting them as an effective harm reduction tool for smoking cessation. The impact of E-cigarettes on the cardiovascular system is still elusive.

AREAS COVERED

We assessed results from animal, pre(clinical), and epidemiological studies to critically evaluate and synthesize evidence relevant to the cardiovascular effects of E-cigarettes. Animal studies have demonstrated that E-cigarette vapor exposure can cause endothelial and cardiac dysfunction. However, there have also been reports on the less harmful effects of E-cigarette vapor exposure in comparison to classical tobacco cigarettes. Measurements of flow-mediated dilation in acute human exposure settings have mostly demonstrated that E-cigarettes cause vascular endothelial dysfunction. Epidemiological studies have shown that E-cigarette use is associated with an increased risk for cardiovascular disease, although switching from classical tobacco cigarettes to E-cigarettes can have beneficial cardiovascular effects. Misinterpretation of scientific data by activists on either side is another problem.

EXPERT OPINION

In conclusion, we need more and better (pre)clinical data comparing the health effects of E-cigarette vaping as compared with tobacco cigarette smoking, in order to counsel the legislation for better health policies.

The rise of electronic nicotine delivery systems and the emergence of electronic-cigarette-driven disease

In 2019, the United States experienced the emergence of the vaping-associated lung injury (VALI) epidemic. Vaping is now known to result in the development and progression of severe lung disease in the young and healthy. Lack of regulation on electronic cigarettes in the United States has resulted in over 2,000 patients and 68 deaths. We examine the clinical representation of VALI and the delve into the scientific evidence of how deadly exposure to electronic cigarettes can be. E-cigarette vapor is shown to affect numerous cellular processes, cellular metabolism, and cause DNA damage (which has implications for cancer). E-cigarette use is associated with a higher risk of developing crippling lung conditions such as chronic obstructive pulmonary disease (COPD), which would develop several years from now, increasing the already existent smoking-related burden. The role of vaping and virus susceptibility is yet to be determined; however, vaping can increase the virulence and inflammatory potential of several lung pathogens and is also linked to an increased risk of pneumonia. As it has emerged for cigarette smoking, great caution should also be given to vaping in relation to SARS-CoV-2 infection and the COVID-19 pandemic. Sadly, e-cigarettes are continually promoted and perceived as a safer alternative to cigarette smoking. E-cigarettes and their modifiable nature are harmful, as the lungs are not designed for the chronic inhalation of e-cigarette vapor. It is of interest that e-cigarettes have been shown to be of no help with smoking cessation. A true danger lies in vaping, which, if ignored, will lead to disastrous future costs.

Youth vaping and smoking and parental vaping: a panel survey

BACKGROUND

Concerns remain about potential negative impacts of e-cigarettes including possibilities that: youth e-cigarette use (vaping) increases risk of youth smoking; and vaping by parents may have impacts on their children's vaping and smoking behaviour.

METHODS

With panel data from 3291 youth aged 10-15 years from the 7th wave of the UK Understanding Society Survey (2015-2017), we estimated effects of youth vaping on youth smoking (ever, current and past year initiation), and of parental vaping on youth smoking and vaping, and examined whether the latter differed by parental smoking status. Propensity weighting was used to adjust for measured confounders and estimate average effects of vaping for all youth, and among youth who vaped. E-values were calculated to assess the strength of unmeasured confounding influences needed to negate our estimates.

RESULTS

Associations between youth vaping and youth smoking were attenuated considerably by adjustment for measured confounders. Estimated average effects of youth vaping on youth smoking were stronger for all youth (e.g. OR for smoking initiation: 32.5; 95% CI: 9.8-107.1) than among youth who vaped (OR: 4.4; 0.6-30.9). Relatively strong unmeasured confounding would be needed to explain these effects. Associations between parental vaping and youth vaping were explained by measured confounders. Estimates indicated effects of parental vaping on youth smoking, especially for youth with ex-smoking parents (e.g. OR for smoking initiation: 11.3; 2.7-46.4) rather than youth with currently smoking parents (OR: 1.0; 0.2-6.4), but these could be explained by relatively weak unmeasured confounding.

CONCLUSIONS

While measured confounding accounted for much of the associations between youth vaping and youth smoking, indicating support for underlying propensities, our estimates suggested residual effects that could only be explained away by considerable unmeasured confounding or by smoking leading to vaping. Estimated effects of youth vaping on youth smoking were stronger among the general youth population than among the small group of youth who actually vaped. Associations of parental vaping with youth smoking and vaping were either explained by measured confounding or could be relatively easily explained by unmeasured confounding.

E-cigarettes, nicotine, the lung and the brain: multi-level cascading pathophysiology

Tobacco smoking is highly addictive and causes respiratory disease, cardiovascular disease and multiple types of cancer. Electronic-cigarettes (e-cigarettes) are non-combustible tobacco alternatives that aerosolize nicotine and flavouring agents in a propylene glycol-vegetable glycerine vehicle. They were originally envisaged as a tobacco cessation aid, but whether or not they help people to quit tobacco use is controversial. In this review, we have compared and contrasted what is known regarding the effects of nicotine on the lungs vs. the effects of nicotine in the brain in the context of addiction. Critically, both combustible tobacco products and e-cigarettes contain nicotine, a highly addictive, plant-derived alkaloid that binds to nicotinic acetylcholine receptors (nAChRs). Nicotine's reinforcing properties are primarily mediated by activation of the brain's mesolimbic reward circuitry and release of the neurotransmitter dopamine that contribute to the development of addiction. Moreover, nicotine addiction drives repeated intake that results in chronic pulmonary exposure to either tobacco smoke or e-cigarettes despite negative respiratory symptoms. Beyond the brain, nAChRs are also highly expressed in peripheral neurons, epithelia and immune cells, where their activation may cause harmful effects. Thus, nicotine, a key ingredient of both conventional and electronic cigarettes, produces neurological effects that drive addiction and may damage the lungs in the process, producing a complex, multilevel pathological state. We conclude that vaping needs to be studied by multi-disciplinary teams that include pulmonary and neurophysiologists as well as behaviourists and addiction specialists to fully understand their impact on human physiology.