Efficiency and adverse events of electronic cigarettes: A systematic review and meta-analysis (PRISMA-compliant article)

The potential health effects associated with electronic-cigarette

A good old gateway theory that electronic-cigarettes (e-cigarettes) are widely recognized as safer tobacco substitutes. In actuality, demographics also show that vaping cannibalizes smoking, the best explanation of the data is the "common liability". However, the utilization of e-cigarette products remains a controversial topic at present. Currently, there has been a widespread and substantial growth in e-cigarette use worldwide owing to their endless new flavors and customizable characteristics. Furthermore, e-cigarette has grown widespread among smokers as well as non-smokers, including adolescents and young adults. And some studies have shown that e-cigarette users are at greater risk to start using combustible cigarettes while e-cigarettes use was also observed the potential benefits to people who want to quit smoking or not. Although it is true that e-cigarettes generally contain fewer toxic substances than combustible cigarettes, this does not mean that the chemical composition in e-cigarettes aerosols poses absolutely no risks. While concerns about toxic substances in e-cigarettes and their widespread use in the population are reasonable, it is also crucial to consider that e-cigarettes have been associated with the potential for promoting smoking cessation and the clinically relevant improvements in users with smoking-related pathologies. Meanwhile, there is still short of understanding of the health impacts associated with e-cigarette use. Therefore, in this review, we discussed the health impacts of e-cigarette exposure on oral, nasal, pulmonary, cardiovascular systems and brain. We aspire for this review to change people's previous perceptions of e-cigarettes and provide them with a more balanced perspective. Additionally, we suggest appropriate adjustments on regulation and policy for e-cigarette to gain greater public health benefits.

Association of e-Cigarette Use and Postpartum Depression: Pregnancy Risk Assessment Monitoring System 2016-2019

Background: Postpartum depression (PPD) is a prevalent public health concern. Combustible cigarette use is associated with increased risk of PPD. While electronic cigarette (e-cigarette) use during pregnancy is linked to increased risk of depressive symptoms during pregnancy, the relationship between e-cigarette use and PPD is not well understood. We sought to examine the association of e-cigarette use with PPD. Materials and Methods: Using Pregnancy Risk Assessment Monitoring System 2016-2019 data, unadjusted and adjusted logistic regression analyses for PPD were conducted via three analyses where e-cigarette use (any vs. none) was retrospectively self-reported (1) in past 2-year, (2) prepregnancy (i.e., 3 months before pregnancy), and (3) during pregnancy (i.e., last 3 months of pregnancy). We conducted an additional past 2-year e-cigarette use analysis excluding those who used combustible cigarette and/or hookah. Covariates included age, race, ethnicity, combustible cigarette, and/or hookah use, prenatal care during the last trimester, health insurance coverage during pregnancy, physical abuse during pregnancy, income, and survey type. Results: Only unadjusted odds ratios from past 2-year e-cigarette use (1.63, 95% confidence interval [CI]: 1.42-1.87) and past 2-year e-cigarette use excluding individuals with cigarette and/or hookah use (1.78, 95% CI: 1.30-2.38) were statistically associated with PPD. No adjusted analyses were statistically significant. Conclusion: Any e-cigarette use, as compared to no use, does not appear to be an independent risk factor of PPD, though it may be a useful clinical marker of increased risk of PPD. Future studies are warranted to advance our knowledge of impact of e-cigarette use on PPD.

Non-pharmacological interventions for smoking cessation: analysis of systematic reviews and meta-analyses

BACKGROUND

Although non-pharmacological smoking cessation measures have been widely used among smokers, current research evidence on the effects of smoking cessation is inconsistent and of mixed quality. Moreover, there is a lack of comprehensive evidence synthesis. This study seeks to systematically identify, describe, and evaluate the available evidence for non-pharmacological interventions in smoking populations through evidence mapping (EM), and to search for best-practice smoking cessation programs.

METHODS

A comprehensive search for relevant studies published from the establishment of the library to January 8, 2023, was conducted in PubMed, Web of Science, Embase, the Cochrane Library, CNKI, CBM, Wan Fang, and VIP. Two authors independently assessed eligibility and extracted data. The PRISMA statement and AMSTAR 2 tool were used to evaluate the report quality and methodology quality of systematic reviews/meta-analyses (SRs/MAs), respectively. Bubble plots were utilized to display information, such as the study population, intervention type, evidence quality, and original study sample size.

RESULTS

A total of 145 SRs/MAs regarding non-pharmacological interventions for smoking cessation were investigated, with 20 types of interventions identified. The most commonly used interventions were cognitive behaviour education (n = 32, 22.07%), professional counselling (n = 20, 13.79%), and non-nicotine electronic cigarettes (e-cigarettes) (n = 13, 8.97%). Among them, counselling and behavioural support can improve smoking cessation rates, but the effect varies depending on the characteristics of the support provided. These findings are consistent with previous SRs/MAs. The general population (n = 108, 74.48%) was the main cohort included in the SRs/MAs. The total score of PRISMA for the quality of the reports ranged from 8 to 27, and 13 studies (8.97%) were rated as high confidence, and nine studies (6.21%) as moderate confidence, in the AMSTAR 2 confidence rating.

CONCLUSIONS

The abstinence effect of cognitive behaviour education and money incentive intervention has advantages, and non-nicotine e-cigarettes appear to help some smokers transition to less harmful replacement tools. However, the methodological shortcomings of SRs/MAs should be considered. Therefore, to better guide future practice in the field of non-pharmacological smoking cessation, it is essential to improve the methodological quality of SRs and carry out high-quality randomized controlled trials (RCTs).

E-cigarette, cannabis and combustible tobacco use: associations with xerostomia among California adolescents

OBJECTIVE

Xerostomia (subjective experience of dry mouth), while less common in younger populations, can contribute to caries and oral discomfort. Use of e-cigarettes and cannabis among adolescents is increasing and may be a xerostomia risk factor. This study evaluates xerostomia prevalence in an adolescent population, overall and by e-cigarette, cannabis and combustible tobacco use.

METHODS

Cross-sectional analyses of 12-month follow-up data (N=976; collected 2020-2021) from a cohort of adolescents recruited from public high schools in Northern California (USA) compared self-reported past 30-day e-cigarette, cannabis and other tobacco use and dry mouth (overall dry mouth experience; shortened xerostomia inventory, SXI). Dry mouth experience (never, occasionally, frequently/always) was modelled using ordered logistic regression with school-level clustering and adjustment for gender, race/ethnicity, alcohol use, asthma, physical activity and mutually for e-cigarette, cannabis and tobacco use.

RESULTS

Past 30-day use prevalence was 12% for e-cigarettes, 16% for cannabis and 3% for combustible tobacco. Occasional dry mouth experience (54%) was more common than frequent/always experience (5%). Frequent/always dry mouth was more prevalent among frequent (>5 days/month) e-cigarette (14%) and cannabis (19%) users and combustible tobacco users (19%) than non-users of those respective products (all comparisons p < 0.001). In covariable-adjusted models, frequent e-cigarette use was no longer significantly associated with dry mouth experience (OR: 1.40; 95% CI: 0.69, 2.84), while frequent cannabis use (OR: 3.17; 95% CI: 1.47, 6.82) and combustible tobacco use (OR: 1.92; 95% CI: 1.38, 2.68) were associated with greater odds of reporting more frequent dry mouth. Findings were qualitatively similar using the SXI.

CONCLUSIONS

In this study, xerostomia was not independently associated with e-cigarette use but was one potential health concern of adolescent cannabis and combustible tobacco use.

[Smoking Cessation in Patients with COPD]

Tobacco dependence is a common comorbidity in patients with COPD (Chronic Obstructive Pulmonary Disease) that negatively affects the course of the disease. However, clinically relevant improvement in COPD can only be achieved by complete and permanent abstinence. Therefore, abstinence from tobacco use is a central therapeutic concept in smoking patients with COPD and requires specific and targeted treatment.After detailed documentation of smoking behaviour and motivational counseling outlining the risks of smoking, all such patients shall be offered a structured therapy for tobacco cessation. There is high-quality evidence for the effectiveness of a combination therapy of behavioral therapy and medication (to treat the withdrawal syndrome). Due to insufficient data, there is currently no recommendation for the use of e-cigarettes as a primary option for a cessation attempt.Smoking is the most important cause of COPD. Smoking cessation is the most effective and cost-efficient single intervention to reduce the risk of developing and progressing COPD.

Vaping among Norwegians who smoke or formerly smoked: reasons, patterns of use, and smoking cessation activity

BACKGROUND

The majority of Norwegians who use e-cigarettes are adults who have smoked. Little is known about vaping reasons and -patterns in this group. The aim of this paper was to study vaping prevalence, patterns, and motivations among adults who smoke. Furthermore, to investigate smoking intensity and smoking cessation behaviour differences between those who vape and those who do not.

METHODS

This study was based on two separate Norwegian samples: People who had ever smoked, from 2017 (N = 2099), and people who currently smoked and recent quitters, from 2018/2019 (N = 1336). Measures of vape frequencies, vape motives, and smoking cessation behaviours were utilised in descriptive analyses of relationships between vaping and smoking behaviour.

RESULTS

Less than 1 in 10 in the ever-smoked group, 1 in 5 of the currently smoked or recently quit group, were currently vaping. Ever trial rates for vaping were much higher at 1 in 3 in the ever-smoked group, and 1 in 2 in the currently smoked or recently quit group. Dual use with combustible cigarettes was common, but people who smoked tended to use e-cigarettes less frequently while those who formerly smoked tended to use them more frequently. Both quitting attempts and smoking intensity reduction were positively associated with vaping, and the most common reasons for e-cigarette use were reported to be desires to reduce harm, to stop smoking, or to reduce smoking intensity.

CONCLUSION

The results indicate that Norwegians who smoke tend to see e-cigarettes as a tool to reduce or completely stop smoking. The predominance of use-motivations related to reducing harm points at the importance of conveying correct information about relative harmfulness of tobacco- and nicotine products.

A Systematic Review Investigating Associations Between E-Cigarette Use Among Former Cigarette Smokers and Relapse to Smoking Cigarettes

As e-cigarette use has steadily increased over the recent years, the public health interest in the potential implications of e-cigarette use on cigarette smoking has grown in parallel. With strict adherence to PRISMA guidelines, this systematic review examined the potential associations between e-cigarette use and relapse to cigarette smoking among former cigarette smokers. The protocol was registered on November 06, 2018 (PROSPERO 2018 CRD42018115674). Literature searches were executed from January 01, 2007 to August 20, 2022 and search results were screened according to the PICOS review method. One RCT and 10 adjusted studies examined relapse to cigarette smoking (evidence grade "moderate") among regular e-cigarette users, reporting mixed and inconsistent findings according to varying definitions of e-cigarette use and relapse. Findings were similarly inconsistent among the 8 adjusted studies examining relapse to cigarette smoking among non-regular e-cigarette users. The inconsistency in findings among studies evaluating regular measures of e-cigarette use, combined with the numerous methodological flaws in the overall body of literature, limit the generalizability of results associated with a causal association between e-cigarette use and relapse to cigarette smoking. Based on findings from this review, more robust studies are required to determine whether a causal association exists between e-cigarette use and relapse to cigarette smoking. Future studies should apply consistent measures of regular e-cigarette use to examine causality with future use patterns, and sufficiently account for known or suspected confounding variables to support inform determinations related to e-cigarette use and cigarette smoking behaviors.

Content and trend analysis of user-generated nicotine sickness tweets: A retrospective infoveillance study

INTRODUCTION

Exposure to pro-tobacco and electronic nicotine delivery system (ENDS) social media content can lead to overconsumption, increasing the likelihood of nicotine poisoning. This study aims to examine trends and characteristics of nicotine sickness content on Twitter between 2018–2020.

METHODS

Tweets were collected retrospectively from the Twitter Academic Research Application Programming Interface (API) stream filtered for keywords: ‘nic sick’, ‘nicsick’, ‘vape sick’, ‘vapesick’ between 2018–2020. Collected tweets were manually annotated to identify suspected user-generated reports of nicotine sickness and related themes using an inductive coding approach. The Augmented Dickey-Fuller (ADF) test was used to assess stationarity in the monthly variation of the volume of tweets between 2018–2020.

RESULTS

A total of 5651 tweets contained nicotine sickness-related keywords and 18.29% (n=1034) tweets reported one or more suspected nicotine sickness symptoms of varied severity. These tweets were also grouped into five related categories including firsthand and secondhand reports of symptoms, intentional overconsumption of nicotine products, users expressing intention to quit after ‘nic sick’ symptoms, mention of nicotine product type/brand name that they consumed while ‘nic sick’, and users discussing symptoms associated with nicotine withdrawal following cessation attempts. The volume of tweets reporting suspected nicotine sickness appeared to increase throughout the study period, except between February and April 2020. Stationarity in the volume of ‘nicsick’ tweets between 2018–2020 was not statistically significant (ADF= -0.32, p=0.98) indicating a change in the volume of tweets.

CONCLUSIONS

Results point to the need for alternative forms of adverse event surveillance and reporting, to appropriately capture the growing health burden of vaping. Infoveillance approaches on social media platforms can help to assess the volume and characteristics of user-generated content discussing suspected nicotine poisoning, which may not be reported to poison control centers. Increasing volume of user-reported nicotine sickness and intentional overconsumption of nicotine in twitter posts represent a concerning trend associated with ENDS-related adverse events and poisoning.

Reporting system of suspected adverse effects from electronic cigarettes and refill liquids in Europe

In line with Article 20 (9) of the Tobacco Products Directive (TPD) 2014/40/EU, a guidance document outlining a reporting system of suspected adverse effects from electronic cigarettes and their refill liquids was produced by Work Package 4 entitled 'Integration into national policies and sustainability' of the Joint Action on Tobacco Control (JATC). The JATC was a European project that lasted three years (2017-2020), with the general objective of providing support for the implementation of the TPD throughout the 27 European Union Member States (EU MS). The reporting system described in the guidance document includes a short reporting template for the reporting of adverse effects on human health from electronic cigarettes and refill liquids, both by Economic Operators (EO) and by National Competent Authorities (NCA). The present guidance document aims at providing the necessary steps and modalities that each MS should follow if involved in the development of a system for the reporting of suspected adverse effects on human health from electronic cigarettes and refill liquids.

Reporting and methodological quality of systematic literature reviews evaluating the associations between e-cigarette use and cigarette smoking behaviors: a systematic quality review

Introduction

Several published systematic reviews have examined the potential associations between e-cigarette use and cigarette smoking, but their methodological and/or reporting quality have not yet been assessed. This systematic quality review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and AMSTAR (A MeaSurement Tool to Assess systematic Reviews) 2 to evaluate the quality of systematic reviews investigating potential associations between e-cigarette use and cigarette smoking.

Materials and methods

PubMed/MEDLINE, Embase, and PsycINFO were searched from 01 January 2007 to 24 June 2020. Methodological quality was assessed using AMSTAR 2, and reporting quality was assessed using PRISMA guidelines.

Results

Of 331 potentially relevant systematic reviews, 20 met predefined inclusion criteria. Most reviews (n = 15; 75%) reported on e-cigarette use and cigarette smoking cessation, while three reported on e-cigarette use and cigarette smoking initiation (15%); and two reported on cigarette smoking initiation and cessation (10%). According to AMSTAR 2 guidelines, 18 of the 20 reviews (90%) were “critically low” in overall confidence of the results, while two were ranked “low.” Additionally, reporting quality varied across the reviews, with only 60% reporting at least half of the PRISMA items.

Discussion

Methodological limitations were identified across reviews examining potential associations between e-cigarette use and cigarette smoking behaviors, indicating that findings from these reviews should be interpreted with caution.

Conclusions

Future systematic reviews in this field should strive to adhere to AMSTAR 2 and PRISMA guidelines, to provide high quality syntheses of the available data with transparent and complete reporting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12954-021-00570-9.

Vaping-Related Adverse Events and Perceived Health Improvements: A Cross-Sectional Survey among Daily E-Cigarette Users

Web-based samples of e-cigarette users commonly report significant vaping-related health improvements (HIs) and mild adverse events (AEs). This cross-sectional study with in-person interviewing data collection examined self-reported AEs and perceived HIs among Hungarian adult current daily exclusive e-cigarette (n = 65) and dual users (n = 127), and former daily e-cigarette users (n = 91) in 2018. Logistic regression was used to evaluate associations between reporting any AEs/HIs, vaping status, and covariates. More former users (52.7%) reported AEs than current users (39.6%; p = 0.038). Exclusive and dual daily users reported similar rates of AEs (44.6% and 37.0%, respectively; p = 0.308). More current users (46.9%) experienced HIs than former users (35.2%; p = 0.064). Exclusive daily users were more likely to report HIs than dual users (63.1% versus 38.6%; p = 0.001). Former user status and smoking cessation/reduction reasons increased the odds of reporting AEs, whereas nicotine-containing e-liquid use and older age decreased the odds of reporting AEs. Exclusive vaper status, using advanced generation devices, and smoking cessation/reduction reasons increased the odds of experiencing HIs. This study, which used a traditional data collection methodology, found a higher rate of AEs and a lower rate of HIs compared to web-based surveys. Our results highlight that experiencing AEs and HIs is affected by users’ characteristics, in addition to the device and e-liquid type.

European adult smokers' perceptions of the harmfulness of e-cigarettes relative to combustible cigarettes: cohort findings from the 2016 and 2018 EUREST-PLUS ITC Europe Surveys

Background

This study presents perceptions of the harmfulness of electronic cigarettes (e-cigarettes) relative to combustible cigarettes among smokers from six European Union (EU) countries, prior to the implementation of the EU Tobacco Products Directive (TPD), and 2 years post-TPD.

Methods

Data were drawn from the EUREST-PLUS ITC Europe Surveys, a cohort study of adult smokers (≥18 years) from Germany, Greece, Hungary, Poland, Romania and Spain. Data were collected in 2016 (pre-TPD: N = 6011) and 2018 (post-TPD: N = 6027). Weighted generalized estimating equations were used to estimate perceptions of the harmfulness of e-cigarettes compared to combustible cigarettes (less harmful, equally harmful, more harmful or ‘don’t know’).

Results

In 2016, among respondents who were aware of e-cigarettes (72.2%), 28.6% reported that they perceived e-cigarettes to be less harmful than cigarettes (range 22.0% in Spain to 34.1% in Hungary). In 2018, 72.2% of respondents were aware of e-cigarettes, of whom 28.4% reported perceiving that e-cigarettes are less harmful. The majority of respondents perceived e-cigarettes to be equally or more harmful than cigarettes in both 2016 (58.5%) and 2018 (61.8%, P > 0.05). Overall, there were no significant changes in the perceptions that e-cigarettes are less, equally or more harmful than cigarettes, but ‘don’t know’ responses significantly decreased from 12.9% to 9.8% (P = 0.036). The only significant change within countries was a decrease in ‘don’t know’ responses in Spain (19.3–9.4%, P = .001).

Conclusions

The majority of respondents in these six EU countries perceived e-cigarettes to be equally or more harmful than combustible cigarettes.

Effects of electronic cigarette aerosol exposure on oral and systemic health

Conventional cigarette smoke harms nearly every organ of the body and is the leading cause of death in the United States and in the world. Decades of research have associated conventional cigarette smoke with several diseases and death. Heavily marketed, electronic nicotine delivery systems such as electronic cigarettes (e-cigarettes) are available in a variety of flavors and high nicotine concentrations. In 2019, a severe lung disease outbreak linked to e-cigarette use led to several deaths, which was called electronic-cigarette or vaping product use-associated lung injury (EVALI). Even though the trend of e-cigarette use among teens continues to increase, information on the effects of e-cigarette smoke on oral and overall health are still scarce. This review discusses the possible health effects due to unregulated e-cigarette use, as well as the health effects of second-hand smoke and third-hand smoke on non-smokers.

Adolescent Use and Perceptions of JUUL and Other Pod-Style e-Cigarettes: A Qualitative Study to Inform Prevention

JUUL, a discrete pod-style e-cigarette, popular among adolescents, delivers high levels of nicotine. Limited research has assessed social and environmental influences that contribute to use of JUUL and other pod-style devices. We examined how these factors, as well as individual characteristics, shape adolescent use. Twenty-nine middle and high school students participated in six focus groups in June 2019 (58.6% female, 65.5% White, 27.6% Hispanic). Groups were stratified by e-cigarette use status and grade to understand perceptions and experiences among groups. Transcripts were coded using thematic analysis for individual, social, and environmental factors contributing to use. Users (n = 13) described their first experience with JUUL as mostly negative, mentioning reactions such as burning in the throat, coughing, wheezing, and headaches. Despite a negative first experience, stress relief and addiction were mentioned as reasons for continued use. Users and non-users identified vaping as a source of disruption to their daily life. Social factors included peer and parental influences, lack of support for quitting, and accessibility. Environmental factors included contrasting messages about long- and short-term health effects of e-cigarettes, as well as a lack of school vaping policy enforcement, health education, medical screenings, and cessation resources. Findings highlight the complex social system that influences adolescent e-cigarette use and have important implications for school and community responses. Strategies to prevent or reduce use may include reviewing existing school tobacco policies, providing counseling and cessation resources, training staff, and increasing knowledge through public education campaigns.

Electronic Cigarettes and Oral Health

Novel nicotine products, particularly electronic cigarettes (e-cigarettes), have become increasingly popular over the past decade. E-cigarettes are sometimes regarded as a less harmful alternative to tobacco smoking, and there is some evidence of their potential role as a smoking cessation aid. However, there are concerns about their health consequences, particularly in users who are not tobacco smokers, and also when used long term. Given the mode of delivery of these products, there is potential for oral health consequences. Over the past few years, there have been an increasing number of studies conducted to explore their oral health effects. In vitro studies have reported a range of cellular effects, but these are much less pronounced than those resulting from exposure to tobacco smoke. Microbiological studies have indicated that e-cigarette users have a distinct microbiome, and there is some indication this may be more pathogenic compared to nonusers. Evidence of oral health effects from clinical trials is still limited, and most studies to date have been small in scale and usually cross-sectional in design. Epidemiological studies highlight concerns over oral dryness, irritation, and gingival diseases. Interpreting data from e-cigarette studies is challenging, given the different populations that have been investigated and the continual emergence of new products. Overall, studies reveal potential oral health harms, underscoring the importance of efforts to reduce use in nonsmokers. However, in smokers who are using e-cigarettes as an aid to help them quit, the benefits of quitting tobacco smoking may outweigh any negative oral health impacts of e-cigarette use, particularly in the short term. Future research is needed to understand the clinical significance of some of the biological changes observed by following different cohorts of users longitudinally in carefully designed clinical studies and pragmatic trials supported by high-quality in vitro studies.

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.

Association between e-cigarette use and sleep deprivation in U.S. Young adults: Results from the 2017 and 2018 Behavioral Risk Factor Surveillance System

BACKGROUND

Few studies have assessed the association between e-cigarette use and sleep deprivation. This is an important question given the rapid increase in e-cigarette use among young adults in recent years.

PURPOSE

To determine whether e-cigarette use is associated with sleep deprivation in a sample of young (18-24 years-old) American adults.

METHODS

We used pooled cross-sectional data from the 2017 and 2018 Behavioral Risk Factor Surveillance System (BRFSS), selecting respondents aged 18 to 24 from forty-one states and U.S. territories that included the e-cigarette and sleep modules in the interview (N = 19,701). Poisson regression models tested the relationship between e-cigarette use and sleep deprivation. We adjusted for sociodemographic variables, physical activity, mental health, BMI, smokeless tobacco products use, alcohol drinking, and smoking.

RESULTS

In the pooled dataset, the weighted prevalence of current or former e-cigarette use was 47% and 35% of participants self-reported sleep deprivation. After adjusting for confounders, former e-cigarette users were 1.17 times more likely to report sleep deprivation, compared to never users (95%CI: 1.06, 1.29). The prevalence ratio for self-reported sleep deprivation increased to 1.42 (95%CI: 1.23, 1.65) for everyday users, compared to never e-cigarette users.

CONCLUSIONS

These findings suggest that e-cigarette use might be related to sleep deprivation in young adults. Future longitudinal studies should assess the causal and dose-response nature of this relationship.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol formed by heating an e-liquid. People who smoke report using ECs to stop or reduce smoking, but some organisations, advocacy groups and policymakers have discouraged this, citing lack of evidence of efficacy and safety. People who smoke, healthcare providers and regulators want to know if ECs can help people quit and if they are safe to use for this purpose. This review is an update of a review first published in 2014.

OBJECTIVES

To evaluate the effect and safety of using electronic cigarettes (ECs) to help people who smoke achieve long-term smoking abstinence.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO for relevant records to January 2020, together with reference-checking and contact with study authors.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and randomized cross-over trials in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention. To be included, studies had to report abstinence from cigarettes at six months or longer and/or data on adverse events (AEs) or other markers of safety at one week or longer.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking after at least six months follow-up, AEs, and serious adverse events (SAEs). Secondary outcomes included changes in carbon monoxide, blood pressure, heart rate, blood oxygen saturation, lung function, and levels of known carcinogens/toxicants. We used a fixed-effect Mantel-Haenszel model to calculate the risk ratio (RR) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data from these studies in meta-analyses.

MAIN RESULTS

We include 50 completed studies, representing 12,430 participants, of which 26 are RCTs. Thirty-five of the 50 included studies are new to this review update. Of the included studies, we rated four (all which contribute to our main comparisons) at low risk of bias overall, 37 at high risk overall (including the 24 non-randomized studies), and the remainder at unclear risk. There was moderate-certainty evidence, limited by imprecision, that quit rates were higher in people randomized to nicotine EC than in those randomized to nicotine replacement therapy (NRT) (risk ratio (RR) 1.69, 95% confidence interval (CI) 1.25 to 2.27; I2 = 0%; 3 studies, 1498 participants). In absolute terms, this might translate to an additional four successful quitters per 100 (95% CI 2 to 8). There was low-certainty evidence (limited by very serious imprecision) of no difference in the rate of adverse events (AEs) (RR 0.98, 95% CI 0.80 to 1.19; I2 = 0%; 2 studies, 485 participants). SAEs occurred rarely, with no evidence that their frequency differed between nicotine EC and NRT, but very serious imprecision led to low certainty in this finding (RR 1.37, 95% CI 0.77 to 2.41: I2 = n/a; 2 studies, 727 participants). There was moderate-certainty evidence, again limited by imprecision, that quit rates were higher in people randomized to nicotine EC than to non-nicotine EC (RR 1.71, 95% CI 1.00 to 2.92; I2 = 0%; 3 studies, 802 participants). In absolute terms, this might again lead to an additional four successful quitters per 100 (95% CI 0 to 12). These trials used EC with relatively low nicotine delivery. There was low-certainty evidence, limited by very serious imprecision, that there was no difference in the rate of AEs between these groups (RR 1.00, 95% CI 0.73 to 1.36; I2 = 0%; 2 studies, 346 participants). There was insufficient evidence to determine whether rates of SAEs differed between groups, due to very serious imprecision (RR 0.25, 95% CI 0.03 to 2.19; I2 = n/a; 4 studies, 494 participants). Compared to behavioural support only/no support, quit rates were higher for participants randomized to nicotine EC (RR 2.50, 95% CI 1.24 to 5.04; I2 = 0%; 4 studies, 2312 participants). In absolute terms this represents an increase of six per 100 (95% CI 1 to 14). However, this finding was very low-certainty, due to issues with imprecision and risk of bias. There was no evidence that the rate of SAEs varied, but some evidence that non-serious AEs were more common in people randomized to nicotine EC (AEs: RR 1.17, 95% CI 1.04 to 1.31; I2 = 28%; 3 studies, 516 participants; SAEs: RR 1.33, 95% CI 0.25 to 6.96; I2 = 17%; 5 studies, 842 participants). Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate over time with continued use. Very few studies reported data on other outcomes or comparisons and hence evidence for these is limited, with confidence intervals often encompassing clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that ECs with nicotine increase quit rates compared to ECs without nicotine and compared to NRT. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain. More studies are needed to confirm the degree of effect, particularly when using modern EC products. Confidence intervals were wide for data on AEs, SAEs and other safety markers. Overall incidence of SAEs was low across all study arms. We did not detect any clear evidence of harm from nicotine EC, but longest follow-up was two years and the overall number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up-to-date information for decision-makers, this review is now a living systematic review. We will run searches monthly from December 2020, with the review updated as relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

The mortality of lung cancer attributable to smoking among adults in China and the United States during 1990-2017

Background

Statistical data on the burden and relevant risk factors of lung cancer are valuable for policy‐making. This study aimed to compare the mortality of lung cancer attributable to smoking stratified by sex and age among adults in China and the United States (US).

Methods

We extracted age‐standardized mortality rates of lung cancer during 1990‐2017 using the comparative risk assessment framework of the 2017 Global Burden of Disease study. We performed an age‐period‐cohort analysis to estimate time trend of lung cancer mortality attributable to smoking.

Results

During 1990‐2017, the age‐standardized mortality rate of lung cancer was increasing in China but decreasing in the US for both sexes. The mortality attributable to smoking in China showed a generally increasing trend, while a continuous decrease was observed in the US. The age‐period‐cohort analysis showed a similar trend of age effect among adults between China and the US: the mortality substantially increased from the 30‐34 to 80‐84 age group and subsequently decreased in the 90‐94 age group. However, the period effect rapidly increased in Chinese adults during 1990‐2017, while it tended to be stable in the US although it was still slightly increasing in women. The cohort effect generally peaked in the earlier cohort born in 1902‐1906 in the two countries.

Conclusions

During 1990‐2017, the lung cancer mortality attributable to smoking and the period effect are generally increasing in Chinese adults; the mortality attributable to smoking is decreasing in the US adults, but the period effect tends to be stable. The rapid aging and prevalence of smoking may intensify the increasing mortality of lung cancer in China.

Electronic cigarette survey characteristics

Introduction

Electronic cigarettes (EC) remain a controversial topic with uncertainty about harm reduction in current smokers, their efficacy in smoking cessation, their potential for addiction, the need for regulation, and the type of information needed to educate the public about the benefits and hazards of EC. Multiple medical institutions and organizations have conducted surveys to investigate the demographics and perceptions of EC consumers in adult and youth populations. However, it is unknown whether these surveys use consistent, reliable, or accurate measures for EC use.

Methods

We analyzed 13 survey articles identified during a review of the use of EC during smoking cessation programs to determine the characteristic features of the surveys and to determine how frequently they satisfied the measurement of important core items suggested by recent articles.

Results

Our analysis focused on 13 studies. These studies represented the work of 13 separate research groups and were published in 10 different biomedical journals with a median impact factor score of 4.1. The median number of participants in the studies was 2,624 (Q1-Q3: 662-6,356); the number of participants ranged from 179 to 19,414. The median number of e-cigarette users in the surveys was 840 (Q1-Q3: 256-3,849). All studies provided clear study goals in their introduction. Five surveys used on-line methods to collect information; four studies provided limited information about the reliability of their data. All studies reported study outcomes and considered limitations. Five studies had limited external validity. None of the surveys collected a complete set of core information recommended by recent authorities on survey methodology for EC.

Conclusions

The surveys reviewed in this project had significant variability in study design, survey population, and study goals. Consequently, comparisons across studies become difficult and limit the external validity of survey studies on EC.

The Role of Anxiety in Smoking Onset, Severity, and Cessation-Related Outcomes: a Review of Recent Literature

PURPOSE OF REVIEW

Anxiety is one of the most common mental health conditions globally and co-occurs with smoking at a markedly high rate. The present review offers a narrative overview of the most recent research on the role of anxiety in smoking onset, maintenance, and cessation-related outcomes. Additionally, given the rise in electronic cigarette use, we review the emerging literature on the influence of anxiety on e-cigarette use.

RECENT FINDINGS

Evidence across studies varied as to the role of anxiety or anxiety symptoms in smoking behavior. The most consistent findings suggested that those with anxiety are more likely to be a smoker, supporting a high rate of co-occurrence across these conditions. Less consistent evidence was observed for the association between anxiety and onset, indicators of severity, and cessation outcomes. Although there is robust evidence for an association between smoking and anxiety, there were considerable discrepancies for the precise role of anxiety in smoking onset, severity, and cessation outcomes. Future work utilizing more sophisticated methodologies is needed to identify causal relations as well as putative moderators and mediators of the anxiety-smoking relation.

Use of Electronic Nicotine Delivery Systems (ENDS) in China: Evidence from Citywide Representative Surveys from Five Chinese Cities in 2018

China is the largest cigarette consuming country in the world. The emergence of electronic nicotine delivery systems (ENDS) in China may have important implications for the Chinese tobacco market. Unfortunately, research on ENDS in China, while growing, is still limited. This study was designed to examine the awareness and use of ENDS among adult urban residents in China. Data from five citywide representative surveys conducted in 2017–2018 were used. Percentages of residents who had ever heard of, ever used, or used ENDS in the past 30 days among all residents and smokers were estimated, in total and by demographic characteristics. Multiple logistic regression models were used to estimate the adjusted associations between awareness and use of ENDS and individual-level demographic characteristics and socioeconomic status (SES). Overall, 51.3% had ever heard, 4.8% ever used, and 0.9% used ENDS in the past 30 days. Men, young adults, those with high levels of education, and current smokers were more likely to be aware of and use ENDS. Among smokers, 67.8% had ever heard, 17.1% ever used, and 3.9% used ENDS in the past 30 days, respectively. Young adult smokers and smokers with high levels of education were more likely to be aware of and use ENDS. Our study results on ENDS awareness and use patterns and associated factors in China provide important evidence to inform research and policies related to ENDS manufacture, marketing, and sales in China.

Electronic nicotine delivery systems and pregnancy: Recent research on perceptions, cessation, and toxicant delivery

Electronic nicotine delivery systems (ENDS), which includes e-cigarettes (ECIGs), are a rapidly-expanding class of products that heat a liquid (which may or may not contain nicotine) to produce an aerosol. The variation of ECIG components is extensive as are their effects on users. Epidemiological data show that while both adults and youth use ECIGs, use among youth has increased dramatically in recent years. Other epidemiological data show that women of reproductive age and some pregnant women are also using ECIGs. The goal of this article is to provide readers with background information about ECIGs, with a focus on recent findings about ECIG use in pregnancy and potential implications. Among pregnant women, correlates of ECIG use include current cigarette smoking, among other factors. Regarding pregnant women's perceptions of ECIG use in pregnancy, two themes emerge from the literature: many pregnant women perceive ECIGs to be safer than conventional cigarettes, and that ECIGs can aid with smoking cessation. In contrast to these perceptions, there is little concrete evidence that ECIGs help smokers quit. In addition, there are concerns about ECIG nicotine and other toxicant delivery. Nicotine is a toxicant of particular concern for pregnant women, as nicotine is known to harm a developing fetus. There are many limitations to existing research, and the literature is scant in this area. Further, new "pod mod"-style ECIGs such as JUUL present new challenges. Overall, with limited evidence of their effectiveness, and concerns about developmental toxicology, the authors do not recommend that pregnant women use ECIGs.

Evaluating smoking control policies in the e-cigarette era: a modelling study

Background

In jurisdictions in which electronic cigarettes are currently prohibited, policy makers must weigh the potentially lower risk compared with conventional cigarettes against the risk of initiation of e-cigarettes among non-smokers.

Methods

We simulated a synthetic population over a 50-year time horizon with an open cohort model using data from Singapore, a country where e-cigarettes are currently prohibited, and data from the USA, the UK and Japan. Using the smoking prevalence and the quality-adjusted life year gained calculated, we compared tobacco control policies without e-cigarettes—namely, raising the minimum legal age (MLA), introducing a smoke-free generation (SFG) and tax rises on tobacco consumption—with policies legalising e-cigarettes, either taking a laissez-faire approach or under some form of restriction. We also evaluated combinations of these policies.

Results

Regardless of the country informing the transition probabilities to and from e-cigarette use in Singapore, a laissez-faire e-cigarette policy could reduce the smoking prevalence in the short term, but it is not as effective as other policies in the long term. The most effective single policies evaluated were SFG and aggressive tax rises; the most effective combination of policies considered was MLA plus moderate tax rises and e-cigarettes on prescription.

Conclusion

Policy makers in jurisdictions in which e-cigarettes are not yet established may be advised not to prioritise e-cigarettes in their tobacco end-game strategy, unless their use can be restricted to current smokers seeking to quit.

E-cigarette use and sleep-related complaints among youth

INTRODUCTION

E-cigarette use is highly prevalent among adolescents. However, little research has examined the relationship between e-cigarette use and sleep-related complaints in this population. The objective of this study was to assess whether exclusive e-cigarette, exclusive combusted cigarette, and dual-product use are associated with sleep-related complaints among adolescents.

METHODS

Participants were 9,588 U.S. adolescents from the Population Assessment of Tobacco and Health Study, a nationally representative cohort, followed from 2013 through 2015. Using logistic regression, we examined the cross-sectional association between past-year e-cigarette, combusted cigarette, or dual-product use and past-year sleep-related complaints (bad dreams, sleeping restlessly, or falling asleep during the day), both measured at Wave 2. We controlled for Wave 1 demographic characteristics, emotional and behavioral health, and prior history of e-cigarette use, combusted cigarette use, and sleep-related complaints.

RESULTS

In unadjusted analyses, e-cigarette, combusted cigarette, and dual-product use were significantly associated with greater odds of sleep-related complaints, compared to use of neither product (e-cigarettes: OR = 1.61, 95% CI 1.34-1.94; combusted cigarettes: OR = 1.62, 95% CI 1.26-2.09; dual-product use: OR = 2.00, 95% CI 1.63-2.46). Associations between e-cigarette and dual-product use and sleep-related complaints remained significant in fully adjusted analyses (e-cigarettes: aOR = 1.29, 95% CI 1.05-1.59; dual-product use: aOR = 1.57, 95% CI 1.24-1.99), whereas associations with combusted cigarette use were significant in all models except the fully adjusted model (aOR = 1.30, 95% CI 0.98-1.71).

CONCLUSIONS

E-cigarette and dual-product use are significantly associated with greater odds of reporting sleep-related complaints among adolescents. Future research should evaluate whether this association may be causal.

Perception of Harms and Benefits of Electronic Cigarettes Among Adult Malaysian Men: A Comparison by Electronic Cigarette Use and Smoking Status

Little is known about the perceptions of harm and benefit associated with the use of e-cigarettes in Malaysia. This was a cross-sectional analysis of a nationally representative sample comprising 1987 males (≥18 years of age). Current, former, and never users of conventional cigarettes and/or e-cigarettes participated in a questionnaire study conducted via face-to-face interviews. The relationship between participant characteristics and perceptions of harm and benefit of e-cigarettes were determined with multivariable logistic regression. There were 950 current, 377 former, and 660 never users of e-cigarettes. Government employees (odds ratio [OR] = 1.85, 95% confidence interval [CI] = 1.29-2.66, P = .001), private sector employees (OR = 1.67, 95% CI = 1.27-2.18, P = .001), and the self-employed people (OR = 1.68, 95% CI = 1.31-2.17, P = .001) were more likely to perceive e-cigarettes as more harmful than conventional cigarettes compared with respondents who were not wage earners. All current users in the form of e-cigarette users (OR = 7.87, 95% CI = 3.23-19.18), conventional cigarette smokers (OR = 1.80, 95% CI = 1.39-2.33), and dual users (OR = 8.59, 95% CI = 4.76-15.52) were more likely to perceive e-cigarettes as useful in quitting conventional cigarette smoking compared with former and never users. Our findings constitute an important snapshot into the perceptions of e-cigarette harms and benefits, which could inform targeted public health messaging strategies.

In times of tobacco-free nicotine consumption: The influence of nicotine on vascular calcification

BACKGROUND

Smoking remains the most important avoidable cause of global mortality. Even though the number of cigarette smokers declines in first world countries, the uses of alternative nicotine delivery products increase and may even surpass the sells of cigarettes. In this light, the explicit role of nicotine in the development of cardiovascular diseases should be elucidated.

OBJECTIVES

This narrative review attempts to connect current literature about possible effects of nicotine on the environment of the vasculature to the pathogenesis of vascular calcification, focusing on the tunica media of the vessel wall.

METHODS

For this review, papers found on Pubmed and Medline until December 2018 by searching for the keywords nicotine, vascular calcification, oxidative stress, osteoblastic transdifferentiation and matrix degradation were considered.

RESULTS

Nicotine creates an environment that probably facilitates and maybe even induces osteogenic transdifferentiation of VSMC by inflammation, endothelial dysfunction and reactive oxygen species. This process is believed to be a key event in calcification of the tunica media of the vessel wall. Furthermore, nicotine could lead to the formation of nucleation sites for hydroxyapatite by facilitating matrix vesicles and extracellular matrix degradation.

CONCLUSIONS

There is a growing body of evidence implicating that nicotine alone could impair vascular function and lead to vascular calcification. Further research is necessary to elucidate the explicit influence of nicotine on arteriosclerosis.