Health impact of E-cigarettes: a prospective 3.5-year study of regular daily users who have never smoked

Direct health implications of e-cigarette use: a systematic scoping review with evidence assessment

Background

E-cigarettes are often marketed as a less harmful alternative to traditional tobacco cigarettes. Despite their popularity, the evidence regarding their effects on human health remains unclear and is filled with complexities.

Objectives

This systematic review aims to elucidate the direct effects of electronic cigarette use on human health, carefully distinguishing between the specific characteristics of the populations studied.

Methodology

Adhering to the PRISMA guidelines, we conducted a comprehensive search in PubMed/Medline, Web of Science, Scopus, and Google Scholar databases without date restrictions, including articles in both Spanish and English. This approach enabled the identification and analysis of primary studies to understand the direct effect of electronic cigarettes on human health.

Results

A total of 33 studies were included that evaluated cardiovascular, pulmonary, renal, weight and fertility effects. Only five studies analyzed e-cigarettes in healthy populations and seven studies compared healthy individuals against smokers. The effects evaluated on smokers or former tobacco smokers were apparently positive, however, among healthy individuals, increased heart rate, mean arterial pressure, oxidative stress, alteration of respiratory epithelial cells and increased airflow resistance were found.

Conclusion

Smokers or former smokers who switch to e-cigarettes may reduce their exposure to carcinogens and lower their risk of developing severe health issues associated with conventional smoking. However, in healthy individuals who have never smoked traditional cigarettes, the use of e-cigarettes introduces several cardiovascular and respiratory adverse effects. These findings suggest that while e-cigarettes can be a strategic harm reduction tool for smokers, they are not a safe option for non-smokers.

A Global Health Survey of People Who Vape but Never Smoked: Protocol for the VERITAS (Vaping Effects: Real-World International Surveillance) Study

BACKGROUND

There is only limited information about the health effects of regular vaping. Research on the health status of people who used to smoke faces the challenge that previous smoking may have caused unknown health effects. Only studies of people who vape but have never smoked combustible cigarettes can enable the detection of harms attributable to vaping. Large prospective studies of well-characterized electronic cigarette users with and without a history of combustible cigarette smoking are warranted to establish the long-term effects of regular vaping on respiratory health.

OBJECTIVE

We will conduct a global cross-sectional survey of individuals from 6 world regions. Respiratory symptoms will be assessed using a validated questionnaire-the Respiratory Symptom Experience Scale (RSES). Current vapers who are nonusers of other tobacco or nicotine products will be compared with matched controls who are nonusers of vapes and other tobacco or nicotine products.

METHODS

This will be a multicountry, cross-sectional internet-based survey of 750 adults aged ≥18 years who satisfy the criteria for inclusion in either a cohort of people who exclusively vape and who are nonusers of other tobacco or nicotine products ("vapers cohort"; target N=500) or a cohort of nonvapers who are also nonusers of other tobacco or nicotine products ("controls cohort"; target N=250). The primary end point of the study is the RSES score. RSES scores of people in the "vapers cohort" will be compared with those of people in the "controls cohort." Additionally, the study will collect data to characterize patterns of vaping product use among the vapers cohort. Data collection will include information about the age initiation of using vape products, reasons for starting and continuing the use of vape products, specific types of products used, flavors and nicotine strengths of recently used products, as well as the frequency and intensity of product use in the past 30 days.

RESULTS

Participant recruitment started in April 2023, and enrollment was completed by November 2023 with 748 participants. Results will be reported in 2024.

CONCLUSIONS

This will be the first study providing key insights into respiratory health effects associated with using electronic cigarettes in people who vape with no established use of combustible cigarettes or other tobacco or nicotine products.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/54236.

Electronic cigarette use and respiratory symptoms in the French population-based Constances cohort

BACKGROUND

Knowledge about the consequences of electronic cigarette (EC) use on respiratory health is still limited. We aimed to assess whether EC use is associated with the occurrence of asthma symptoms and chronic bronchitis among the French adult population, with a specific focus on never combustible cigarettes (CC) smokers. We further investigated whether the association differed in men and women.

METHODS

Constances is a population-based cohort of adults aged 18-69 years at inception. We analyzed baseline data collected in 136,276 participants recruited in 2015-2019. Associations of current and former EC use with respiratory symptoms (asthma symptom score and chronic bronchitis) were assessed, controlling for CC smoking, cannabis use, demographics, education and body mass index (BMI).

RESULTS

Increased frequencies of respiratory symptoms were observed in both current and former EC users (for the asthma symptom score, adjusted mean score ratio (aMSR): 1.34 [95 % confidence interval: 1.28-1.41] and 1.39 [1.33-1.45], respectively; for chronic bronchitis, adjusted prevalence ratio (aPR): 1.27 [1.19-1.36] and 1.40 [1.32-1.48], respectively). Among never CC smokers, ever EC use was associated with an increased asthma symptom score in both men and women (aMSR = 1.44 [1.09-1.90] and 1.36 [1.01-1.83], respectively), and with a higher prevalence of chronic bronchitis only in women (aPR = 1.97 [1.27-3.05]).

CONCLUSION

EC use is associated with symptoms of asthma and chronic bronchitis, independently of CC smoking and cannabis use. The fact that these associations are observed among individuals who have never smoked tobacco adds further evidence of the deleterious effects of EC on respiratory health.

Impact of e-cigarette liquid on porcine lung tissue-Ex vivo confocal Raman micro-spectroscopy study

Ex vivo porcine lung immersed in e-liquid was investigated in-depth using confocal Raman micro-spectroscopy to assess the e-liquid influence on the lung. It was found that lung-related Raman band intensities at 1002, 1548, 1618 and 1655 cm-1 increased after first and second treatments except the surface, which was attributed to the well-known optical clearing (OC) effect due to alveoli filling with e-liquid resulting in light scattering reduction. The autofluorescence enhancement was explained by oxidative stress induced in lung during exposure to e-liquid. Moreover, e-liquid induced collagen dehydration was revealed by the I937 /I926 Raman band intensity ratio change. The effect was enhanced after the second treatment of the same lung tissue that indicates the possibility of multi-step OC treatment. We hypothesize that the nicotine-flavour-free e-liquids containing glycerol and propylene glycol could potentially be used in clinical protocols as OC agent for enhanced in-depth Raman-guided bronchoscopy.

Associations between e-cigarette use or dual use of e-cigarette and combustible cigarette and metabolic syndrome: results from the National Health and Nutrition Examination Survey (NHANES)

PURPOSE

Examine associations between e-cigarette use or dual use of e-cigarette and combustible cigarette and metabolic syndrome (MetS).

METHODS

Cross-sectional data of 5121 U.S. adults from the National Health and Nutrition Examination Survey were analyzed. Weighted multivariable Poisson regression models were used to examine associations between e-cigarette use or dual use and MetS and its components. Prevalence ratios (PRs) with 95% confidence intervals (95% CI) were estimated.

RESULTS

Current and former e-cigarette users were 30% (95% CI: 1.13, 1.50) and 15% (95% CI: 1.03, 1.28) more likely to have MetS than never e-cigarette users. Current or former e-cigarette use was also associated with elevated triglycerides, reduced high-density lipoprotein (HDL) cholesterol, and elevated blood pressure (AOR ranged from 1.15 to 1.42, all P < 0.05). The prevalence of MetS for dual users was 1.35-fold (95% CI: 1.15, 1.58) higher than that for never smokers and 1.21-fold (95% CI: 1.00, 1.46) higher than that for combustible cigarette-only users. Dual users were also more likely to report elevated triglycerides and reduced HDL cholesterol than never smokers or combustible cigarette-only users (all P < 0.05).

CONCLUSIONS

E-cigarette use or dual use is associated with MetS. Our findings may inform tobacco control policies regarding regulations of e-cigarette use.

A Quick Method for the Determination of the Fraction of Freebase Nicotine in Electronic Cigarettes

Recently, many electronic cigarettes (ECIGs) manufacturers have begun offering e-liquids, known as "nicotine salts". These salts that have started gaining big popularity among users can be formed by adding weak acid to e-liquid mixtures consisting of propylene glycol (PG), vegetable glycerin (VG), flavors, and nicotine. The latter can exist in two forms: monoprotonated (mp) and freebase (fb) based on the pH of the matrix. Over the years, the determination of the fraction of fb was found important to policymakers as the prevalence of this form in ECIGs has been associated with the harshness sensory of inhalable aerosols. Liquid-liquid extraction (LLE), ¹H NMR, and Henderson-Hasselback have been developed to deduce the fraction of fb; however, these methods were found to be time-consuming and have shown some challenges mainly due to the presence of a non-aqueous matrix consisting of PG and VG. This paper presents a quick non-aqueous pH measurement-based method that allows a quick determination of the fraction fb by just measuring the pH and the dielectric constant of the e-liquid. Then, by inputting these values into an established mathematical relationship, the fraction fb can be deduced. The relationship between pH, dielectric constant, and fb relies on knowing the values of the acidity dissociation constants of nicotine, which were determined for the first time in various PG/VG mixtures using a non-aqueous potentiometric titration. To validate the proposed method, the fraction fb was determined for commercials and lab-made nicotine salts utilizing the pH and LLE methods. The variation between the two methods was (<8.0%) for commercial e-liquids and lab-made nicotine salts containing lactic acid and salicylic acid. A larger discrepancy of up to 22% was observed for lab-made nicotine salts containing benzoic acid, which can be attributed to the stronger affinity of benzoic acid to toluene in the LLE method.

The cardiovascular consequences of electronic cigarette smoking: a narrative review

INTRODUCTION

E-cigarettes have emerged as a popular alternative to traditional tobacco smoking in recent years. Despite their growing popularity, concerns have arisen regarding the cardiovascular implications of e-cigarette use.

AREAS COVERED

This narrative review aims to highlight the latest evidence on the impact of e-cigarettes on cardiovascular health.

EXPERT OPINION

Numerous studies have demonstrated that e-cigarette use can lead to acute adverse cardiovascular effects. Inhalation of e-cigarette aerosols exposes users to a wide range of potentially harmful substances that have been implicated in critical pathophysiologic pathways of cardiovascular disease, namely endothelial dysfunction, oxidative stress, inflammation, sympathetic overdrive, and arterial stiffness. While long-term epidemiological studies specifically focusing on the cardiovascular effects of e-cigarettes are still relatively scarce, early evidence suggests a potential association between e-cigarette use and an increased risk of adverse cardiovascular events. However, it is essential to recognize that e-cigarettes are relatively new products, and the full extent of their long-term cardiovascular impact has not been fully elucidated. In the meantime, promoting tobacco cessation strategies that are evidence-based and regulated, along with rigorous monitoring of e-cigarette use patterns and associated health outcomes, are essential steps in safeguarding cardiovascular health in the face of this emerging public health challenge.

Nicotine promotes e-cigarette vapour-induced lung inflammation and structural alterations

BACKGROUND

Electronic cigarette (e-cigarette) vapour is gaining popularity as an alternative to tobacco smoking and can induce acute lung injury. However, the specific role of nicotine in e-cigarette vapour and its long-term effects on the airways, lung parenchyma and vasculature remain unclear.

RESULTS

In vitro exposure to nicotine-containing e-cigarette vapour extract (ECVE) or to nicotine-free e-cigarette vapour extract (NF ECVE) induced changes in gene expression of epithelial cells and pulmonary arterial smooth muscle cells (PASMCs), but ECVE in particular caused functional alterations (e.g. a decrease in human and mouse PASMC proliferation by 29.3±5.3% and 44.3±8.4%, respectively). Additionally, acute inhalation of nicotine-containing e-cigarette vapour (ECV) but not nicotine-free e-cigarette vapour (NF ECV) increased pulmonary endothelial permeability in isolated lungs. Long-term in vivo exposure of mice to ECV for 8 months significantly increased the number of inflammatory cells, in particular lymphocytes, compared to control and NF ECV in the bronchoalveolar fluid (BALF) (ECV: 853.4±150.8 cells·mL-1; control: 37.0±21.1 cells·mL-1; NF ECV: 198.6±94.9 cells·mL-1) and in lung tissue (ECV: 25.7±3.3 cells·mm-3; control: 4.8±1.1 cells·mm-3; NF ECV: 14.1±2.2 cells·mm-3). BALF cytokines were predominantly increased by ECV. Moreover, ECV caused significant changes in lung structure and function (e.g. increase in airspace by 17.5±1.4% compared to control), similar to mild tobacco smoke-induced alterations, which also could be detected in the NF ECV group, albeit to a lesser degree. In contrast, the pulmonary vasculature was not significantly affected by ECV or NF ECV.

CONCLUSIONS

NF ECV components induce cell type-specific effects and mild pulmonary alterations, while inclusion of nicotine induces significant endothelial damage, inflammation and parenchymal alterations.

Genotoxicity and hypomethylation of LINE-1 induced by electronic cigarettes

Currently, the marketing of electronic cigarettes as a safe alternative to smoking has increased, which is associated with greater use of these devices, especially among young people and smokers interested in quitting tobacco cigarettes. Given the growing use of this type of product, there is a need to determine the consequences of electronic cigarettes on human health, especially since many of the compounds contained in the aerosol and liquid of these devices have a high potential to be carcinogenic and genotoxic. Additionally, many of these compounds' aerosol concentrations exceed the safe limits. We have evaluated the levels of genotoxicity and changes in DNA methylation patterns associated with vaping. We analyzed a total of 90 peripheral blood samples from a population of vapers (n = 32), smokers (n = 18), and controls (n = 32), in which the frequencies of genotoxicity were determined by the cytokinesis-blocking micronuclei (CBMN) assay and the patterns of methylation of the repetitive elements of LINE-1 through the Quantitative Methylation Specific PCR (qMSP) assay. Here we show an increase in genotoxicity levels associated with vaping habits. Additionally, the group of vapers showed changes at the epigenetic level specifically associated with the loss of methylation of the LINE-1 elements. These changes in LINE-1 methylation patterns were reflected in its representative RNA expression detected in vapers.

Actual Use Behavior Assessment of a Novel Puff Recording Electronic Nicotine Delivery System: Observation Study

BACKGROUND

Compared with combustible cigarettes, electronic cigarettes (e-cigarettes) can deliver a sufficient amount of nicotine with a significantly reduced emission of toxicants, which renders them as potential harm reduction candidates for tobacco and smoking replacement. However, the use of e-cigarettes is not harm free and the long-term health effect of using e-cigarettes is yet to be established. Given the high prevalence of e-cigarette use across the globe and its potential health concerns, it is imperative to conduct actual use behavior assessments to better understand how e-cigarettes are being consumed in real-world conditions. However, with the currently available technologies, there is still a lack of noninvasive, noninterventional, and convenient instruments for the real-time and real-world use behavior monitoring of e-cigarette product use. Novel technology-based systems that do not primarily rely on self-report or intrusive measurements to monitor e-cigarette use behaviors are therefore highly desired.

OBJECTIVE

The primary goal of this study is to investigate the e-cigarette actual use behaviors in the real world via a novel puff recording electronic nicotine delivery system (PR-ENDS). Specifically, we aim to analyze and summarize the survey and PR-ENDS use data and to study the relationships and effects of different factors on these variables.

METHODS

In real-world conditions, 61 enrolled UK e-cigarette users were instructed to use PR-ENDS as the primary source of nicotine with their selected e-liquids for at least 3 weeks (21 days). A baseline survey was conducted to collect information about participants' demographics and nicotine use history (cigarette and ENDS). The puff data (ie, puff number, puff duration for each puff, device power, e-liquid nicotine concentrations) were directly recorded by PR-ENDS and uploaded to the cloud for further analyses. The nicotine emission and nicotine consumption were estimated based on recorded puff data.

RESULTS

Middle-aged adults with a nicotine history represented the major user profile during the PR-ENDS trial. A wide range of device power and e-liquid nicotine concentrations was applied and their combinations during actual use were found to be rather complex. Various puff parameters (ie, puff duration, puff number, nicotine emission) were assessed with contributing factors from device, e-liquid, and user nicotine history in different effect sizes. The real-time observation revealed substantial intra- and interindividual variabilities in PR-ENDS use behaviors. The use pattern of a quick adaptation followed by consistent product use was recognized for at least 3 weeks during actual use.

CONCLUSIONS

The actual use behavior assessment of PR-ENDS was conducted as a proof-of-concept application. The complex interactions of product attributes and significant intra- and interindividual variabilities in e-cigarette use behaviors provided new insights of compensatory behavior, which can inspire future studies in the field of nicotine addiction and abuse liability behavior assessment.

Association between electronic cigarettes use and whole blood cell among adults in the USA-a cross-sectional study of National Health and Nutrition Examination Survey analysis

Electronic cigarettes (E-cigarettes) use is an emerging public health problem. Trying to assess the independent associations between E-cigarettes use and whole blood cell in a nationally representative sample of the US adults is very important for the smoking population. Using E-cigarettes data from NHANES (National Health and Nutrition Examination Survey) 2013-2018, 17,180 adults were included in this cross-sectional analysis. All participants were stratified into four different groups (non-smoke group N=10087, E-cigarettes group N=52, dual-smoke group N=249, cigarettes group N=6792) based on questions SMQ020 (smoked at least 100 cigarettes in life) and SMQ690H (used last 5 days E-cigarettes). Whole blood cell tests included white blood cell (WBC) with differentials, red blood cell (RBC) with characteristics, and platelet variables. With adjusted by age, gender, and race ethnicity, multivariate logistic regression analyses were used to assess independent associations between E-cigarettes group and other groups for different whole blood cell variables. A total of 17,180 participants were included in the study; 47.9% were males, with a mean age of 46.99 (±0.29). In WBC-related variables, non-smoke group had the lowest value in WBC counts (7.15±0.05), lymphocyte (2.15±0.02), and monocyte (0.57±0.01), among the four different groups. In RBC-related variables, non-smoke group had the lowest value in mean cell volume (MCV, 88.46±0.14, p<0.05) and mean cell hemoglobin (MCH, 29.73±0.06, p<0.05), among the four different groups. In adjusted analysis, WBC (OR = 0.97, 95% CI: 0.96-0.98, p<0.001), especially lymphocyte (OR = 0.97, 95% CI: 0.96-0.98, p<0.001) and monocyte (OR = 0.11, 95% CI: 0.02-0.66, p<0.001) of non-smoke group, showed negative significant effect for E-cigarettes group. Meanwhile, lower odds of MCV (OR = 0.91, 95% CI: 0.81-1.04, p<0.05) and MCH (OR = 0.81, 95% CI: 0.65-1.00, p<0.05) in non-smoke group were observed compared to E-cigarettes group. Conversely, for dual-smoke group and cigarette group, there was no significant results in all whole blood cell variables compared to E-cigarettes group. E-cigarettes use might be associated with a systemic response that could lead to an increase in WBC, especially lymphocytes and monocytes, in the US adults. Meanwhile, the properties of RBC might also be influenced simultaneously; MCV and MCH in E-cigarettes population were bigger than the non-smoke population.

Electronic Cigarette Use, Misuse, and Harm

Electronic cigarettes (e-cigarettes) are battery-powered devices that use heat to aerosolize a liquid containing a variety of substances (usually nicotine and/or cannabinoids, flavorings, and glycerol or propylene glycol base) that is then inhaled. E-cigarettes are rapidly evolving over time, so the true health effects of e-cigarettes are difficult to study and remain largely unknown. We review the effects of e-cigarettes on nicotine addiction and on pulmonary disease including the effects of dual use and switching from combustible cigarettes to e-cigarettes. Studies show that e-cigarette use can increase the risk to nicotine dependence and combustible tobacco use. Studies show an association between e-cigarette use and pulmonary disease. Some studies suggest reduced harm from e-cigarette use compared with smoking, but this requires further study. Most adults who use e-cigarettes also smoke cigarettes; epidemiologic studies suggest that the combination of e-cigarettes and cigarettes is more harmful than using either product alone.

A Close Look at Vaping in Adolescents and Young Adults in the United States

Vaping by adolescents and young adults is a legitimate concern as there is a risk that some may start smoking and that electronic cigarette (EC) use may have adverse effects in the developing lungs of adolescents. This commentary provides updated information on vaping patterns among adolescents and young adults in the United States, as well as the impact of EC usage on respiratory health. EC use has surged greatly among high school students and young adults over the last decade but fortunately has declined significantly since its peak in 2019. During the same time period, smoking rates have constantly fallen to new low record levels. These trends argue against EC use as a gateway to smoking. Most EC usage is infrequent and unlikely to increase a person's risk of negative health consequences. Furthermore, the majority of EC usage has happened among those who have previously smoked. There is a dearth of data on the long-term health implications of EC usage in adolescents and young adults. We do not know whether short-term or intermittent use of EC in youth can lead to negative health outcomes in adulthood, and long-term high-quality studies in well-defined groups are needed. Although vaping has been linked to respiratory symptoms, they tend to be transient and of uncertain significance. This commentary provides up-to-date information so health care providers can give objective and responsible medical advice on EC usage.

Update on new forms of tobacco use

Smoking remains the leading cause of morbidity and mortality worldwide. Because of its clear influence on cardiovascular and respiratory diseases, it is an important factor in internal medicine consultations. Although the rate of smoking cessation has been increasing in recent years, there is a percentage of patients who continue to smoke because they are unable or unwilling to quit, despite having tried existing pharmacological and non-pharmacological therapies. For this group of patients there are strategies based on interventions aimed at reducing the negative effects of smoking without the need for complete cessation. In this review it is shown that due to the absence of combustion of organic matter in conventional cigarettes, snus, e-cigarettes and heated tobacco products generate significantly lower levels of toxic substances.

A systematic review of the effects of e-cigarette use on lung function

Given the increasing use of e-cigarettes and uncertainty surrounding their safety, we conducted a systematic review to determine the effects of e-cigarettes on measures of lung function. We systematically searched EMBASE, MEDLINE, and PsycINFO databases via Ovid, the Cochrane CENTRAL database, and the Web of Science Core from 2004 until July 2021, identifying 8856 potentially eligible studies. A total of eight studies (seven studying immediate effects and one long-term effects, 273 total participants) were included. The risk of bias was assessed using the Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I) and Cochrane risk of bias tools. These studies suggest that vaping increases airway resistance but does not appear to impact forced expiratory volume in one second (FEV₁₎, forced vital capacity (FVC), or FEV₁/FVC ratio. However, given the limited size and follow-up duration of these studies, larger, long-term studies are required to further determine the effects of e-cigarettes on lung function.

Chronic health effects associated with electronic cigarette use: A systematic review

Introduction

Over the last decade, e-cigarette use has been on the rise but with growing health concerns. The objective of this systematic review was to update findings for chronic health outcomes associated with e-cigarette use from the 2018 National Academies of Sciences, Engineering, and Medicine (NASEM) report.

Methods

Three bibliographic databases were searched to identify studies comparing the chronic health effects of e-cigarette users (ECU) to non-smokers (NS), smokers, and/or dual users indexed between 31 August 2017 and 29 January 2021. Two independent reviewers screened abstracts and full texts. Data were extracted by one reviewer and verified by a second one. Outcomes were synthesized in a narrative manner using counts and based on statistical significance and direction of the association stratified by study design and exposure type. Risk of bias and certainty of evidence was assessed. The protocol was prospectively registered on Open Science Framework https://osf.io/u9btp.

Results

A total of 180 articles were eligible. This review focused on 93 studies for the 11 most frequently reported outcomes and from which 59 reported on daily e-cigarette use. The certainty of evidence for all outcomes was very low because of study design (84% cross-sectional) and exposure type (27% reported on exclusive ECU, i.e., never smoked traditional cigarettes). Overall, the summary of results for nearly all outcomes, including inflammation, immune response, periodontal and peri-implant clinical parameters, lung function, respiratory symptoms, and cardiovascular disease, suggested either non-significant or mixed results when daily ECU was compared to NS. This was also observed when comparing exclusive ECU to NS. The only notable exception was related to oral health where most (11/14) studies reported significantly higher inflammation among daily ECU vs. NS. Compared to the smokers, the exclusive-ECUs had no statistically significant differences in inflammation orperiodontal clinical parameters but had mixed findings for peri-implant clinical parameters.

Conclusions

This review provides an update to the 2018 NASEM report on chronic health effects of e-cigarette use. While the number of studies has grown, the certainty of evidence remains very low largely because of cross-sectional designs and lack of reporting on exclusive e-cigarette exposure. There remains a need for higher quality intervention and prospective studies to assess causality, with a focus on exclusive e-cigarette use.

A systematic review examining the pulmonary effects of electronic vapor delivery systems

STUDY OBJECTIVE

Despite the popularity of vaping and electronic vapor delivery systems (EVDS), the healthcare community remains largely unfamiliar with their potential to induce harm. The purpose of this systematic review is to identify how EVDS use affects the pulmonary system in order to support future anesthetic guidelines for patients who vape.

DESIGN

Systematic Review. An electronic search of databases CINAHL and PubMed was performed in October 2020.

STUDY ELIGIBILITY CRITERIA

Studies were included if they were deemed original research published in English, if they were performed exclusively in humans or on human tissue, if they examined the effects of EVDS on pulmonary function or tissue, and/or if they produced quantitative data. Studies were excluded if they utilized animal samples, studied subjects under the age of 18, presented expert opinions or reviews, offered qualitative data, reported case studies, or only evaluated EVDS' efficacy as a smoking cessation tool.

MAIN RESULTS

This review identified six EVDS-induced pulmonary implications warranting anesthetic consideration: alterations in pulmonary function tests, disrupted ventilation, impaired mucociliary clearance, tissue destruction, a disrupted immune response, and oxidative stress with DNA fragmentation.

CONCLUSION

A total of 38 studies described the effects of EVDS on pulmonary function, airway epithelial tissue, and inflammatory mechanisms that may lead to chronic pulmonary disease. Anesthesia providers are encouraged to assess patients for EVDS use during the preoperative period and use the information generated by this systematic review to drive subsequent care.

On the toxicity of e-cigarettes consumption: Focus on pathological cellular mechanisms

Tobacco smoking remains without a doubt one of the leading causes of premature death worldwide. In combination with conventional protocols for smoking cessation, e-cigarettes have been proposed as a useful tool to quit smoking. Advertised as almost free of toxic effects, e-cigarettes have rapidly increased their popularity, becoming a sought-after device, especially among young people. Recently some health concerns about e-cigarette consumption are being raised. It is well known that they can release several toxic compounds, some of which are carcinogenic to humans, and emerging results are now outlining the risks related to the onset of respiratory and cardiovascular diseases and even cancer. The present review shows the emerging evidence about the role of technical components of the devices, the e-liquid composition as well as customization by consumers. The primary topics we discuss are the main toxicological aspects associated with e-cigarette consumption, focusing on the molecular pathways involved. Here it will be shown how exposure to e-cigarette aerosol induces stress/mitochondrial toxicity, DNA breaks/fragmentation following the same pathological pathways triggered by tobacco smoke, including the deregulation of molecular signalling axis associated with cancer progression and cell migration. Risk to fertility and pregnancy, as well as cardiovascular risk associated with e-cigarette use, have also been reported.

Impact of vaping on respiratory health

Widespread uptake of vaping has signaled a sea change in the future of nicotine consumption. Vaping has grown in popularity over the past decade, in part propelled by innovations in vape pen design and nicotine flavoring. Teens and young adults have seen the biggest uptake in use of vape pens, which have superseded conventional cigarettes as the preferred modality of nicotine consumption. Relatively little is known, however, about the potential effects of chronic vaping on the respiratory system. Further, the role of vaping as a tool of smoking cessation and tobacco harm reduction remains controversial. The 2019 E-cigarette or Vaping Use-Associated Lung Injury (EVALI) outbreak highlighted the potential harms of vaping, and the consequences of long term use remain unknown. Here, we review the growing body of literature investigating the impacts of vaping on respiratory health. We review the clinical manifestations of vaping related lung injury, including the EVALI outbreak, as well as the effects of chronic vaping on respiratory health and covid-19 outcomes. We conclude that vaping is not without risk, and that further investigation is required to establish clear public policy guidance and regulation.

TOBACCO USE DISORDER AND DUAL DISORDERS Joint statement by the Spanish Psychiatry Society and the Spanish Dual Disorders Society

Tobacco Use Disorder (TUD) is a health problem of the first order in the world population, affecting a vulnerable population, such as people with other mental disorders, whose morbidity and mortality are increased as a result.

Electronic Cigarette Use and the Risk of Cardiovascular Diseases

Electronic cigarettes or e-cigarettes are the most frequently used tobacco product among adolescents. Despite the widespread use of e-cigarettes and the known detrimental cardiac consequences of nicotine, the effects of e-cigarettes on the cardiovascular system are not well-known. Several in vitro and in vivo studies delineating the mechanisms of the impact of e-cigarettes on the cardiovascular system have been published. These include mechanisms associated with nicotine or other components of the aerosol or thermal degradation products of e-cigarettes. The increased hyperlipidemia, sympathetic dominance, endothelial dysfunction, DNA damage, and macrophage activation are prominent effects of e-cigarettes. Additionally, oxidative stress and inflammation are unifying mechanisms at many levels of the cardiovascular impairment induced by e-cigarette exposure. This review outlines the contribution of e-cigarettes in the development of cardiovascular diseases and their molecular underpinnings.

News events and their relationship with US vape sales: an interrupted time series analysis

OBJECTIVE

News coverage around vaping-related events may have furthered misconceptions regarding the relative harms of vapes. Such information may influence the decisions of individuals who smoke, around switching to vaping, potentially affecting the overall tobacco mortality burden. Thus, it is prudent to study how news events (e.g., 2019 vaping illness epidemic) are associated with vape sales in the United States, to possibly reduce the tobacco mortality burden.

METHODS

We used weekly retail sales data for e-cigarettes (30 December 2018 - 28 December 2019) from the US retail scanner data compiled by the Nielsen Company. We used an interrupted time series design with segmented regression analysis to determine immediate and longer-term impacts of individual news events (e.g. Trump administration's planned ban on some flavored vaping products) on vape sales, controlling for pre-existing trends.

RESULTS

Unexpectedly, we noted a statistically significant positive relationship between vape sales and the CDC announcing an investigation into vaping-related illnesses (Change: 6.59%, Estimate: 0.066; 95% CI: 0.036, 0.092; P < 0.001). We also observed a similar positive association between vape sales and the CDC's announcement on the link between Vitamin E acetate and EVALI (Change: 2.93%, Estimate: 0.029; 95% CI: 0.003, 0.055; P < 0.05). There was a steep decline in sales after these events.

CONCLUSIONS

News events may be associated with US vape sales. Findings have implications for the management of risk perceptions around vaping to improve health outcomes of tobacco users. Information-based policy instruments can be applied to balance the effects of news events that may influence vape sales.

Electronic Cigarette Exposure Causes Vascular Endothelial Dysfunction Due to NADPH Oxidase Activation and eNOS Uncoupling

We recently reported a mouse model of chronic electronic cigarette (e-cig) exposure-induced cardiovascular pathology, where long-term exposure to e-cig vape (ECV) induces cardiac abnormalities, impairment of endothelial function, and systemic hypertension. Here, we delineate the underlying mechanisms of ECV-induced vascular endothelial dysfunction (VED), a central trigger of cardiovascular disease. C57/BL6 male mice were exposed to ECV generated from e-cig liquid containing 0, 6, or 24 mg/ml nicotine for 16 and 60 weeks. Time-dependent elevation in blood pressure and systemic vascular resistance were observed, along with an impairment of acetylcholine-induced aortic relaxation in ECV-exposed mice, compared to air-exposed control. Decreased intravascular nitric oxide (NO) levels and increased superoxide generation with elevated 3-nitrotyrosine levels in the aorta of ECV-exposed mice were observed, indicating that ECV-induced superoxide reacts with NO to generate cytotoxic peroxynitrite. Exposure increased NADPH oxidase expression, supporting its role in ECV-induced superoxide generation. Downregulation of endothelial nitric oxide synthase (eNOS) expression and Akt-dependent eNOS phosphorylation occurred in the aorta of ECV-exposed mice, indicating that exposure inhibited de novo NO synthesis. Following ECV exposure, the critical NOS cofactor tetrahydrobiopterin was decreased, with a concomitant loss of its salvage enzyme, dihydrofolate reductase. NADPH oxidase and NOS inhibitors abrogated ECV-induced superoxide generation in the aorta of ECV exposed mice. Together, our data demonstrate that ECV exposure activates NADPH oxidase and uncouples eNOS, causing a vicious cycle of superoxide generation and vascular oxidant stress that triggers VED and hypertension with predisposition to other cardiovascular disease.

E-Cigarettes and Cardiopulmonary Health: Review for Clinicians

Electronic cigarettes (e-cigarettes) are battery powered electronic nicotine delivery systems that use a propylene glycol/vegetable glycerin base to deliver vaporized nicotine and flavorings to the body. E-cigarettes became commercially available without evidence regarding their risks, long-term safety, or utility in smoking cessation. Recent clinical trials suggest that e-cigarette use with counseling may be effective in reducing cigarette use but not nicotine dependence. However, meta-analyses of observational studies demonstrate that e-cigarette use is not associated with smoking cessation. Cardiovascular studies reported sympathetic activation, vascular stiffening, and endothelial dysfunction, which are associated with adverse cardiovascular events. The majority of pulmonary clinical trials in e-cigarette users included standard spirometry as the primary outcome measure, reporting no change in lung function. However, studies reported increased biomarkers of pulmonary disease in e-cigarette users. These studies were conducted in adults, but >30% of high school-age adolescents reported e-cigarette use. The effects of e-cigarette use on cardiopulmonary endpoints in adolescents and young adults remain unstudied. Because of adverse clinical findings and associations between e-cigarette use and increased incidence of respiratory diseases in people who have never smoked, large longitudinal studies are needed to understand the risk profile of e-cigarettes. Consistent with the Centers for Disease Control and Prevention recommendations, clinicians should monitor the health risks of e-cigarette use, discourage nonsmokers and adolescents from using e-cigarettes, and discourage smokers from engaging in dual use without cigarette reduction or cessation.

E-Cigarette Toxicology

Since the spread of tobacco from the Americas hundreds of years ago, tobacco cigarettes and, more recently, alternative tobacco products have become global products of nicotine addiction. Within the evolving alternative tobacco product space, electronic cigarette (e-cigarette) vaping has surpassed conventional cigarette smoking among adolescents and young adults in the United States and beyond. This review describes the experimental and clinical evidence of e-cigarette toxicity and deleterious health effects. Adverse health effects related to e-cigarette aerosols are influenced by several factors, including e-liquid components, physical device factors, chemical changes related to heating, and health of the e-cigarette user (e.g., asthmatic). Federal, state, and local regulations have attempted to govern e-cigarette flavors, manufacturing, distribution, and availability, particularly to underaged youths. However, the evolving e-cigarette landscape continues to impede timely toxicological studies and hinder progress made toward our understanding of the long-term health consequence of e-cigarettes.

The chemistry and toxicology of vaping

Vaping is the process of inhaling and exhaling an aerosol produced by an e-cigarette, vape pen, or personal aerosolizer. When the device contains nicotine, the Food and Drug Administration (FDA) lists the product as an electronic nicotine delivery system or ENDS device. Similar electronic devices can be used to vape cannabis extracts. Over the past decade, the vaping market has increased exponentially, raising health concerns over the number of people exposed and a nationwide outbreak of cases of severe, sometimes fatal, lung dysfunction that arose suddenly in otherwise healthy individuals. In this review, we discuss the various vaping technologies, which are remarkably diverse, and summarize the use prevalence in the U.S. over time by youths and adults. We examine the complex chemistry of vape carrier solvents, flavoring chemicals, and transformation products. We review the health effects from epidemiological and laboratory studies and, finally, discuss the proposed mechanisms underlying some of these health effects. We conclude that since much of the research in this area is recent and vaping technologies are dynamic, our understanding of the health effects is insufficient. With the rapid growth of ENDS use, consumers and regulatory bodies need a better understanding of constituent-dependent toxicity to guide product use and regulatory decisions.

Use of a rapid human primary cell-based disease screening model, to compare next generation products to combustible cigarettes

A growing number of public health bodies, regulators and governments around the world consider electronic vapor products a lower risk alternative to conventional cigarettes. Of critical importance are rapid new approach methodologies to enable the screening of next generation products (NGPs) also known as next generation tobacco and nicotine products. In this study, the activity of conventional cigarette (3R4F) smoke and a range of NGP aerosols (heated tobacco product, hybrid product and electronic vapor product) captured in phosphate buffered saline, were screened by exposing a panel of human cell-based model systems using Biologically Multiplexed Activity Profiling (BioMAP® Diversity PLUS® Panel, Eurofins Discovery). Following exposure, the biological activity for a wide range of biomarkers in the BioMAP panel were compared to determine the presence of toxicity signatures that are associated with specific clinical findings. NGP aerosols were found to be weakly active in the BioMAP Diversity PLUS Panel (≤3/148 biomarkers) whereas significant activity was observed for 3R4F (22/148 biomarkers). Toxicity associated biomarker signatures for 3R4F included immunosuppression, skin irritation and thrombosis, with no toxicity signatures seen for the NGPs. BioMAP profiling could effectively be used to differentiate between complex mixtures of cigarette smoke or NGP aerosol extracts in a panel of human primary cell-based assays. Clinical validation of these results will be critical for confirming the utility of BioMAP for screening NGPs for potential adverse human effects.

Impact of tobacco and/or nicotine products on health and functioning: a scoping review and findings from the preparatory phase of the development of a new self-report measure

BACKGROUND

Measuring self-reported experience of health and functioning is important for understanding the changes in the health status of individuals switching from cigarettes to less harmful tobacco and/or nicotine products (TNP) or reduced-risk products (RRP) and for supporting tobacco harm reduction strategies.

METHODS

This paper presents insights from three research activities from the preparatory phase of the development of a new self-report health and functioning measure. A scoping literature review was conducted to identify the positive and negative impact of TNP use on health and functioning. Focus groups (n = 29) on risk perception and individual interviews (n = 40) on perceived dependence in people who use TNPs were reanalyzed in the context of health and functioning, and expert opinion was gathered from five key opinion leaders and five technical consultants.

RESULTS

Triangulating the findings of the review of 97 articles, qualitative input from people who use TNPs, and expert feedback helped generate a preliminary conceptual framework including health and functioning and conceptually-related domains impacted by TNP use. Domains related to the future health and functioning measurement model include physical health signs and symptoms, general physical appearance, functioning (physical, sexual, cognitive, emotional, and social), and general health perceptions.

CONCLUSIONS

This preliminary conceptual framework can inform future research on development and validation of new measures for assessment of overall health and functioning impact of TNPs from the consumers' perspective.

Nicotine and energy balance: A review examining the effect of nicotine on hormonal appetite regulation and energy expenditure

Nicotine has been shown to decrease appetite, food intake (FI) and body weight, but the mechanisms are unclear. The purpose of this review was to examine research on the effects of nicotine on energy balance by exploring physiological mechanisms and hormone regulation related to FI, subjective appetite and energy expenditure (EE). We searched PubMed and MEDLINE, and included articles investigating the effects of nicotine on central appetite regulation, FI, leptin, peptide-YY (PYY), ghrelin, glucagon-like peptide-1 (GLP-1), adiponectin, cholecystokinin (CCK), orexin, and EE. A total of 65 studies were included in the qualitative synthesis and review. Our findings suggest that the decrease in appetite and FI may be attributed to nicotinic alterations of neuropeptide Y (NPY) and pro-opiomelanocortin (POMC) but the effect of nicotine on FI remains unclear. Furthermore, nicotine increases resting EE (REE) and physical activity EE (PAEE) in both smokers and non-smokers; and these increases may be a result of the catecholaminergic effect of nicotine. Decreases in body weight and appetite experienced by nicotine users results from increased EE and changes in the central hypothalamic regulation of appetite. There is not enough evidence to implicate a relationship between peripheral hormones and changes in appetite or FI after nicotine use. Although nicotine increases REE and PAEE, the effect of nicotine on other components of EE warrants further research. We conclude that further research evaluating the effect of nicotine on appetite hormones, FI and EE in humans is warranted.

Vaping and E-Cigarette Use in Children and Adolescents: Implications on Perioperative Care From the American Society of Anesthesiologists Committee on Pediatric Anesthesia, Society for Pediatric Anesthesia, and American Academy of Pediatrics Section on Anesthesiology and Pain Medicine

Electronic cigarettes (e-cigarettes) or vaping use in adolescents has emerged as a public health crisis that impacts the perioperative care of this vulnerable population. E-cigarettes have become the most commonly used tobacco products among youth in the United States. Fruit and mint flavors and additives such as marijuana have enticed children and adolescents. E-cigarette, or vaping, product use-associated lung injury (EVALI) is a newly identified lung disease linked to vaping. Clinical presentation of EVALI can be varied, but most commonly includes the respiratory system, gastrointestinal (GI) tract, and constitutional symptoms. Clinical management of EVALI has consisted of vaping cessation and supportive therapy, including supplemental oxygen, noninvasive ventilation, mechanical ventilation, glucocorticoids, and empiric antibiotics, until infectious causes are eliminated, and in the most severe cases, extracorporeal membrane oxygenation (ECMO). Currently, although there is an insufficient evidence to determine the safety and the efficacy of e-cigarettes for perioperative smoking cessation, EVALI clearly places these patients at an increased risk of perioperative morbidity. Given the relatively recent introduction of e-cigarettes, the long-term impact on adolescent health is unknown. As a result, the paucity of postoperative outcomes in this potentially vulnerable population does not support evidence-based recommendations for the management of these patients. Clinicians should identify "at-risk" individuals during preanesthetic evaluations and adjust the risk stratification accordingly. Our societies encourage continued education of the public and health care providers of the risks associated with vaping and nicotine use and encourage regular preoperative screening and postoperative outcome studies of patients with regard to smoking and vaping use.

Critical appraisal of the European Union Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) Preliminary Opinion on electronic cigarettes

BACKGROUND

In preparation for the 2021 revision of the European Union Tobacco Products Directive, the Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) has posted its Preliminary Opinion on Electronic Cigarettes. They concluded that e-cigarettes only achieve a sub-optimal level of protection of human health. In this paper, we provide evidence that the Opinion's conclusions are not adequately backed up by scientific evidence and did not discuss the potential health benefits of using alternative combustion-free nicotine-containing products as substitute for tobacco cigarettes.

METHODS

Searches for articles were conducted in PubMed and by citation chasing in Google Scholar. Articles were also retrieved with a review of references in major publications. Primary data from World Health Organization surveys, the conclusions of reviews, and peer-reviewed non-industry studies were cited to address errors and omissions identified in the Opinion.

RESULTS

The Opinion omitted reporting on the individual and population health benefits of the substitution of e-cigarettes (ENDS) for cigarette smoking. Alternative hypotheses to the gateway theory were not evaluated. Its assessment of cardiovascular risk is contradicted by numerous reviews. It cites ever-use data that do not represent current patterns of use. It did not report non-nicotine use. It presented erroneous statements on trends in ENDS prevalence. It over-emphasized the role of flavours in youth ENDS initiation. It did not discuss cessation in sufficient length.

CONCLUSIONS

For the delivery of a robust and comprehensive final report, the members of the Working Group of the Scientific Committee on Health, Environmental and Emerging Risks will need to consider (1) the potential health benefits of ENDS substitution for cigarette smoking, (2) alternative hypotheses and contradictory studies on the gateway effect, (3) its assessment of cardiovascular risk, (4) the measurements of frequency of use, (5) non-nicotine use, (6) the role of flavours, and (7) a fulsome discussion of cessation.

Cardiorespiratory and Immunologic Effects of Electronic Cigarettes

PURPOSE OF REVIEW

Although e-cigarettes have become popular, especially among youth, the health effects associated with e-cigarette use remain unclear. This review discusses current evidence relating to the cardiovascular, pulmonary, and immunological effects of e-cigarettes.

RECENT FINDINGS

The use of e-cigarettes by healthy adults has been shown to increase blood pressure, heart rate, and arterial stiffness, as well as resistance to air flow in lungs. Inhalation of e-cigarette aerosol has been shown to elicit immune responses and increase the production of immunomodulatory cytokines in young tobacco-naïve individuals. In animal models, long-term exposure to e-cigarettes leads to marked changes in lung architecture, dysregulation of immune genes, and low-grade inflammation. Exposure to e-cigarette aerosols in mice has been shown to induce DNA damage, inhibit DNA repair, and promote carcinogenesis. Chronic exposure to e-cigarettes has also been reported to result in the accumulation of lipid-laden macrophages in the lung and dysregulation of lipid metabolism and transport in mice. Although, the genotoxic and inflammatory effects of e-cigarettes are milder than those of combustible cigarettes, some of the cardiorespiratory effects of the two insults are comparable. The toxicity of e-cigarettes has been variably linked to nicotine, as well as other e-cigarette constituents, operating conditions, and use patterns.

SUMMARY

The use of e-cigarettes in humans is associated with significant adverse cardiorespiratory and immunological changes. Data from animal models and in vitro studies support the notion that long-term use of e-cigarettes may pose significant health risks.

Pulmonary Health Effects of Electronic Cigarettes: A Scoping Review

BACKGROUND

There is global concern regarding the public health impact of electronic cigarettes (ECs). ECs are commonly promoted as safer than conventional cigarettes (CCs), however there is limited knowledge of the long-term health effects. This scoping review examined the pulmonary health effects of ECs reported in the literature from 2009 to 2019.

METHOD

PubMed, CINAHL, and Science Direct databases were used. Search terms included "vaping, electronic nicotine delivery systems, electronic cigarettes, lung diseases, respiratory diseases, and pulmonary." Original research articles in English that used human subjects between January 1, 2009 and January 31, 2020 and reported pulmonary outcomes were included.

RESULTS

Forty-five studies met the inclusion criteria. There were 14 (31.1%) randomized experimental, 7 (15.6%) nonrandomized experimental, 6 (13.3%) cohort, and 18 (40.0%) cross-sectional studies. Sixteen (35.6%) studies were conducted in the United States; the rest were conducted across 11 other countries. The total number of subjects was 1,465,292 and ages ranged from 12 to 99 years across studies. Eligible studies demonstrated an association between EC use and pulmonary symptoms, asthma and chronic obstructive pulmonary disease diagnosis and exacerbations. The degree of this association varied based on the use of additional tobacco products. EC use resulted in worse outcomes than nonsmoking, but resulted in improved outcomes when compared with CC use or dual use of CC and EC.

CONCLUSION

Evidence indicates that EC use, especially dual use, leads to negative pulmonary effects and adverse outcomes. Education on the potential risks and publishing of EC ingredients on labels could help improve public health safety communication and reduce EC use.

Social Learning, Social Bonds, Self-Control and Adolescent Nicotine Vaping

The aim of this study was to examine whether three theories of adolescent substance use-social learning, social bonding, and self-control-were useful for predicting adolescent nicotine vaping. Methods: The analysis utilized data on U.S. 8th and 10th grade students from the 2017 and 2018 Monitoring the Future (MTF) studies, repeated cross-sectional surveys that included 11,624 youth who responded to questions about past 12-month nicotine vaping. Measures from each of the three theories were used to predict the outcome using a zero-inflated negative binomial model. Results: The results demonstrated that variables from social learning and self-control theories were key predictors of nicotine vaping. Friends' substance use appeared as the most consequential predictor, followed by low self-control or higher risk-taking propensities. An interaction effect also suggested that friends' substance use had a stronger association with nicotine vaping among youth who reported higher self-control. Conclusions/Importance: The findings suggested that adolescent nicotine vaping is a consequence of social learning influences and low self-control. Future research should explore these and similar factors in more detail.

Well-being and harm reduction, the consolidated reality of electronic cigarettes ten years later from this emerging phenomenon: A narrative review

Tobacco use is the greatest threat to public health worldwide, killing more than seven million people annually. This paper, about 10 years after the first review on electronic cigarettes, analyses the evolution that this tool has had in these years. It concludes with comments on the significance of the research and why it constitutes an original contribution. We searched PubMed (National Library of Medicine), and PsycINFO (Ovid) (2006-2020) for studies on e-cigarettes (harms and benefits, e-cigarette use, craving and smoking cessation) and smoking cessation treatment (smoking cessation treatment or varenicline or tobacco cessation or reduction or bupropion or NRT or behavioral treatment or ecigarette) and evidence suggests that they may effective as smoking cessation tool and may be less harmful alternatives to combustible cigarette smoking. Consequently, e-cigarettes could be considered as an applicable instrument for Tobacco Harm Reduction (THR) and smoking cessation.

E-cigarette use among Asian Americans: a systematic review

The use of electronic cigarettes (e-cigarettes) has been rising among adolescents and adults in the United States, including among Asian Americans. However, despite being one of the largest racial/ethnic minority groups, the specific trends and patterns of e-cigarette use among Asian Americans are understudied and unclear. This review aimed to summarize relevant information in the last two decades. This systematic review followed the a priori guide outlined by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Articles were gathered from PsycINFO, PubMed, Sage Journals Online, ScienceDirect, and SpringerLink. Forty articles were reviewed and analyzed. Most articles reviewed only reported on the prevalence rate of e-cigarettes among Asian Americans and indicated regional differences. Results noted between- and within-group differences among racial/ethnic groups that warrant further examination. There is a dearth of information regarding health outcomes and correlates or predictors of e-cigarette use among Asian Americans. Despite its popularity and prevalence among Asian Americans, the use of e-cigarettes and related factors or outcomes deserves more nuanced studies and analyses. It is important to delineate subgroup differences by adjusting study designs and data analytic methods to glean meaningful information regarding Asian American's e-cigarette use in the future.

Electronic Cigarette Use and Blood Pressure Endpoints: a Systematic Review

PURPOSE OF REVIEW

E-cigarettes (e-cigs) release toxic chemicals known to increase blood pressure (BP) levels. The effects of e-cigs on BP, however, remain unknown. Studying BP may help characterize potential cardiovascular risks of short- and long-term e-cig use. We summarized published studies on the association of e-cig use with BP endpoints.

RECENT FINDINGS

Thirteen e-cig trials (12 cross-over designs) and 1 observational study evaluated systolic and diastolic blood pressure (SBP and DBP). All trials included at least one e-cig arm with nicotine, 6 a no-nicotine e-cig arm, and 3 a placebo arm. SBP/DBP increased in most nicotine e-cig arms, in some non-nicotine e-cig arms, and in none of the placebo arms. The observational study followed e-cig users and nonsmokers for 3.5 years with inconsistent findings. The use of e-cigs with and without nicotine may result in short-term elevations of both SBP and DBP. Prospective studies that investigate the long-term cardiovascular impact of e-cig use are needed.

Acute e-cig inhalation impacts vascular health: a study in smoking naïve subjects

This study was designed to investigate the acute effects of nonnicotinized e-cigarette (e-cig) aerosol inhalation in nonsmokers both in terms of blood-based markers of inflammation and oxidative stress and evaluate their association with hemodynamic-metabolic MRI parameters quantifying peripheral vascular reactivity, cerebrovascular reactivity, and aortic stiffness. Thirty-one healthy nonsmokers were subjected to two blood draws and two identical MRI protocols, each one before and after a standardized e-cig vaping session. After vaping, the serum levels of C-reactive protein, soluble intercellular adhesion molecule, and the danger signal machinery high-mobility group box 1 (HMGB1) and its downstream effector and the NLR family pyrin domain containing 3 (NLRP3) inflammasome (as monitored by its adaptor protein ASC) increased significantly relative to the respective baseline (prevaping) values. Moreover, nitric oxide metabolites and reactive oxygen species production decreased and increased, respectively. These observations were paralleled by impaired peripheral vascular reactivity (with reduced flow-mediated dilation and attenuated hyperemic response after a cuff-occlusion test) and metabolic alterations expressed by decreased venous oxygen saturation, postvaping. The current results suggest propagation of inflammation signaling via activation of the danger signaling axis (HMGB1-NLRP3). The findings indicate that a single episode of vaping has adverse impacts on vascular inflammation and function.NEW & NOTWORTHY Endothelial cell signaling and blood biomarkers were found to correlate with functional vascular changes in a single episode e-cigarettes inhalation in healthy adults. This is indicative of the potential of e-cigarettes (even when inhaled acutely) to lead of vascular dysfunction.

Use of Electronic Cigarettes and Self-Reported Chronic Obstructive Pulmonary Disease Diagnosis in Adults

INTRODUCTION

Electronic cigarette (e-cigarette) use (vaping) has increased in recent years. Chronic obstructive pulmonary disease (COPD) is the third leading cause of death associated with smoking.

AIMS AND METHODS

Based on 2016 and 2017 Behavioral Risk Factor Surveillance System national survey data on 891 242 adult participants who indicated their smoking and vaping status, the cross-sectional association of vaping with self-reported COPD diagnosis was investigated, using univariable and multivariable weighted logistic regression models.

RESULTS

Compared to never users, while dual users showed the highest association with self-reported COPD diagnosis (adjusted odds ratio [aOR] = 4.39; 95% confidence interval [CI] = 3.98 to 4.85), current vapers who were either ex-smokers or never smoked showed significantly higher association with self-reported COPD diagnosis (aOR = 3.24; 95% CI = 2.78 to 3.78 and aOR = 1.47; 95% CI = 1.01 to 2.12, respectively). Current vapers who were ex-smokers showed higher association with self-reported COPD diagnosis than ex-smokers who do not vape (aOR = 1.27; 95% CI = 1.09 to 1.48). Dual users showed higher association with self-reported COPD diagnosis than current smokers who do not vape (aOR = 1.16; 95% CI = 1.05 to 1.27). Ex-smokers showed significantly less association with self-reported COPD diagnosis (aOR = 0.67; 95% CI = 0.64 to 0.71) than current smokers. Current vapers who were either ex-smokers or never smoked had less association with self-reported COPD diagnosis compared to current smokers, with aOR = 0.85 (95% CI = 0.73 to 0.99) and aOR = 0.39 (95% CI = 0.27 to 0.56).

CONCLUSIONS

Vaping is significantly associated with self-reported COPD diagnosis in adults, even among vapers who never smoked. Whether there is a benefit for COPD of switching from smoking to vaping requires study of the long-term effects of vaping.

IMPLICATIONS

With the increase of e-cigarette use in recent years, the health effects of e-cigarettes need to be investigated. While several studies have examined the association of vaping with respiratory symptoms among adolescents, little is known about the association of vaping with susceptibility to COPD among US adults. Using cross-sectional national survey data in adults, our study showed that vaping was significantly associated with self-reported COPD diagnosis. Although our data did not establish the causal relationship between vaping and self-reported COPD diagnosis, this study raises concerns about the observed association between vaping and self-reported COPD diagnosis.

Electronic Cigarette Use and Metabolic Syndrome Development: A Critical Review

The metabolic syndrome is a combination of several metabolic disorders, such as cardiovascular disease, atherosclerosis, and type 2 diabetes. Lifestyle modifications, including quitting smoking, are recommended to reduce the risk of metabolic syndrome and its associated complications. Not much research has been conducted in the field of e-cigarettes and the risk of metabolic syndrome. Furthermore, taking into account the influence of e-cigarettes vaping on the individual components of metabolic syndrome, i.e, abdominal obesity, insulin resistance, dyslipidemia and elevated arterial blood pressure, the results are also ambiguous. This article is a review and summary of existing reports on the impact of e-cigarettes on the development of metabolic syndrome as well as its individual components. A critical review for English language articles published until 30 June 2020 was made, using a PubMed (including MEDLINE), Cochrane, CINAHL Plus, and Web of Science data. The current research indicated that e-cigarettes use does not affect the development of insulin resistance, but could influence the level of glucose and pre-diabetic state development. The lipid of profile an increase in the TG level was reported, while the influence on the level of concentration of total cholesterol, LDL fraction, and HDL fraction differed. In most cases, e-cigarettes use increased the risk of developing abdominal obesity or higher arterial blood pressure. Further research is required to provide more evidence on this topic.

E-cigarettes use in the United States: reasons for use, perceptions, and effects on health

BACKGROUND

Many researchers claim electronic cigarettes (e-cigarettes) to be a breakthrough invention for tobacco users that aspires to curb their addiction to conventional cigarettes. Claimed to be safer by their promoters, these smokeless devices have become increasingly popular since their arrival on the market among users of all ages, especially adolescents. This paper investigated the trends in e-cigarette usage since the time it arrived in the United States, highlighting the highest surge that has occurred in adolescent e-cigarette use. It also aimed to understand the reasons and perceptions behind the ever-increasing use of e-cigarettes by adolescents.

MAIN BODY

With the advent of e-cigarettes and common positive perceptions regarding their use, we are at risk of reversing the years of efforts regarding tobacco control and instead advance towards a new addiction with currently unknown long-term health hazards. There is substantial data showing a significant increase of e-cigarette users in the United States, especially among adolescents. The aim of this review was to explore the reasons behind this widespread increase in the use of e-cigarettes among the teenage population in the US and also to uncover the common perceptions about these new electronic delivery systems. In addition, this review attempted to summarize health benefits and hazards associated with e-cigarette use as it crucial to have the right information among its users regarding the health effects of e-cigarette use.

CONCLUSION

E-cigarettes are more appealing than c-cigarettes for a variety of reasons, including cost, choice of different flavors, ease of accessibility, and use and impact of social media. There are also different perceptions among e-cigarette users, including both adolescents and adults. The former group may use them because of the sense of fashion associated with this novel device, and the latter might intend to quit conventional/combustible cigarettes (c-cigarettes) by switching to e-cigarettes. However, it is important to note that e-cigarettes are a recent phenomenon; therefore, there is a lack of many long-term studies that can identify future health risks associated with e-cigarette use. We need more detailed studies that focus on the long-term health effects of e-cigarette use. Moreover, with the ever-increasing usage of e-cigarettes by adolescents (10 and 19 years), it is very important that e-cigarettes be incorporated into the current tobacco-free laws and ordinances. We conclude by stating that e-cigarettes need stronger regulations to prevent youth access and use.

Exposure to nicotine-free and flavor-free e-cigarette vapors modifies the pulmonary response to tobacco cigarette smoke in female mice

Most of electronic cigarette (e-cigarette) users are also smoking tobacco cigarettes. Because of the relative novelty of this habit, very little is known on the impact of vaping on pulmonary health, even less on the potential interactions of dual e-cigarette and tobacco cigarette use. Therefore, we used well-established mouse models to investigate the impact of dual exposure to e-cigarette vapors and tobacco cigarette smoke on lung homeostasis. Groups of female BALB/c mice were exposed to room air, tobacco smoke only, nicotine-free flavor-free e-cigarette vapors only or both tobacco smoke and e-cigarette vapors. Moreover, since tobacco smoke and electronic cigarette vapors both affect circadian processes in the lungs, groups of mice were euthanized at two different time points during the day. We found that dual-exposed mice had altered lung circadian gene expression compared with mice exposed to tobacco smoke alone. Dual-exposed mice also had different frequencies of dendritic cells, macrophages, and neutrophils in the lung tissue compared with mice exposed to tobacco smoke alone, an observation also valid for B-lymphocytes and CD4+ and CD8+ T lymphocytes. Exposure to e-cigarette vapors also impacted the levels of immunoglobulins in the bronchoalveolar lavage and serum. Finally, e-cigarette and dual exposures increased airway resistance compared with mice exposed to room air or tobacco smoke alone, respectively. Taken together, these data suggest that e-cigarette vapors, even without nicotine or flavors, could affect how the lungs react to tobacco cigarette smoke exposure in dual users, potentially altering the pathological course triggered by smoking.

Chronic electronic cigarette use elicits molecular changes related to pulmonary pathogenesis

The relative safety of chronic exposure to electronic cigarette (e-cig) aerosol remains unclear in terms of lung pathogenesis. Therefore, this study aims to evaluate gene/protein biomarkers, which are associated with cigarette-induced pulmonary injury in animals chronically exposed to nicotine containing e-cig aerosol. C57BL/6 J mice were randomly assigned to three exposure groups: e-cig, tobacco cigarette smoke, and filtered air. Lung tissues and/or paraffin embedded slides were used to evaluate gene and/or protein expressions of the CYP450 metabolism (CYP1A1, CYP2A5, and CYP3A11), oxidative stress (Nrf2, SOD1), epithelial-mesenchymal transition (E-cadherin and vimentin), lung pathogenesis (AhR), and survival/apoptotic pathways (p-AKT, BCL-XL, p53, p21, and CRM1). Expressions of E-cadherin and CRM1 were significantly decreased, while CYP1A1, AhR, SOD1 and BCL-XL were significantly upregulated in the e-cig group compared to the control (p < 0.05). Nuclear sub-cellular localization of p53, evaluated by immunohistochemistry staining, in bronchiolar tissues was higher in the e-cig group (25.3 ± 2.7%) as compared to controls (12.1 ± 1.8%) (p < 0.01). Although the biomarkers responses were not identical, in general, the responses had similar qualitative trends between the e-cig and cigarette groups. As these related molecular changes are involved in the pathogenesis of cigarette-induced lung injury, the possibility exists that e-cigs can produce a similar outcome. Although further investigation is warranted, e-cigs are unlikely to be considered as safe in terms of pulmonary health.