Health Effects of Electronic Cigarettes: An Umbrella Review and Methodological Considerations

Exploring the Experiences, Perceptions and Social Dynamics of Electronic Cigarette Users: A Qualitative Study

INTRODUCTION

Electronic cigarettes, or e-cigarettes, are rapidly gaining popularity throughout the globe as safer alternatives to traditional cigarette smoking. There are significant public health concerns due to the uncertainty of long-term health consequences. This study aims to examine the experiences, attitudes and social dynamics of e-cigarette users to provide guidance for public health policies and interventions.

METHODS

In this qualitative descriptive study, semi-structured interviews were conducted. Fifteen e-cigarette users were recruited using a snowball sampling strategy, where initial participants referred other suitable users. All participants had at least 6 months of regular e-cigarette use. Data were collected through face-to-face interviews with open-ended questions. The interviews were transcribed verbatim and reviewed by the researchers. This review identified four main themes and eight sub-themes.

RESULTS

The four main themes identified as a result of the analysis are as follows: (1) initiation and usage experiences; (2) perceptions of health effects; (3) social and environmental factors and (4) addiction and future plans. Participants primarily began using e-cigarettes out of curiosity, due to the appealing fragrance and the belief that they were less harmful than traditional cigarettes. Usage patterns varied among participants, with some reporting minimal cravings in the early morning hours. Opinions on the long-term health effects of e-cigarettes were diverse, with many participants acknowledging uncertainty. Peers and family members perceived e-cigarettes as more socially acceptable than traditional smoking, resulting in fewer negative reactions. Finally, participants' levels of addiction and intentions to quit varied, with some expressing a desire to reduce or cease usage due to health concerns.

CONCLUSION

The findings of this study indicate that the adoption of e-cigarettes is influenced by a confluence of factors, including curiosity, the perception of reduced damage in comparison to conventional cigarettes and social acceptance. Notwithstanding these claimed advantages, users have a diverse array of beliefs and understandings concerning the enduring health consequences of e-cigarettes. The presence of varying levels of addiction and the corresponding aspirations to cease the behaviour highlight the necessity for focused public health interventions.

PATIENT OR PUBLIC CONTRIBUTION

E-cigarette users were actively involved in this study, providing essential insights and feedback throughout. Their first-hand experiences shaped the interview guide and contributed to the identification of key themes. Participants also reviewed and confirmed the accuracy of the interview transcripts, ensuring the reliability of the data.

E-Cigarette Use in Adults

This JAMA Insights explores the adverse effects and health outcomes of e-cigarettes vs combusted cigarettes and the effectiveness of using e-cigarettes as a smoking cessation aid among US adults.

Electronic Cigarettes vs Varenicline for Smoking Cessation in Adults: A Randomized Clinical Trial

Importance

Little is known about the relative effectiveness of nicotine-containing electronic cigarettes (ECs) compared with varenicline as smoking cessation aids.

Objective

To determine the relative effectiveness of ECs in smoking cessation.

Design, Setting, and Participants

This randomized placebo-controlled single-center trial was conducted in northern Finland. Participants aged 25 to 75 years who smoked daily and had volunteered to quit smoking were recruited from August 1, 2018, to February 20, 2020, via local media. The trial included 52 weeks of follow-up. All data analyses were conducted from September 1, 2022, to January 15, 2024. The participants, study nurses, and researchers were masked to group assignment.

Intervention

The participants were assigned by block randomization to receive 18 mg/mL of nicotine-containing ECs together with placebo tablets, varenicline with standard dosing together with nicotine-free ECs, or placebo tablets together with nicotine-free ECs, all combined with a motivational interview, with the intervention phase lasting for 12 weeks.

Main Outcome and Measure

The primary outcome was self-reported 7-day conventional cigarette smoking abstinence as confirmed by the exhaled carbon monoxide level on week 26. The analysis followed the intent-to-treat principle.

Results

Of the 561 recruited participants, 458 (81.6%) eligible participants (257 women [56%]; 201 men [44%]; mean [SD] age, 51 [11.6] years) were randomized. The primary outcome occurred in 61 of 152 participants (40.4%) in the EC group, 67 of 153 (43.8%) in the varenicline group, and 30 of 153 (19.7%) in the placebo group (P < .001). In the pairwise comparison, placebo differed statistically significantly from ECs (risk difference [RD], 20.7%; 95% CI, 10.4-30.4; P < .001) and varenicline (RD, 24.1%; 95% CI, 13.7-33.7; P < .001), but the difference was statistically insignificant between ECs and varenicline (RD, 3.4%; 95% CI, -7.6 to 14.3; P = .56). No serious adverse events were reported.

Conclusions

This randomized clinical trial found that varenicline and nicotine-containing ECs were both effective in helping individuals in quitting smoking conventional cigarettes for up to 6 months.

Trial Registration

ClinicalTrials.gov Identifier: NCT03235505.

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.

ENDS, Cigarettes, and Respiratory Illness: Longitudinal Associations Among U.S. Youth

INTRODUCTION

ENDS use is highly prevalent among U.S. youth, and there is concern about its respiratory health effects. However, evidence from nationally representative longitudinal data is limited.

METHODS

Using youth (aged 12-17 years) data from Waves 1-5 (2013-2019) of the Population Assessment of Tobacco and Health Study, multilevel Poisson regression models were estimated to examine the association between ENDS use; cigarettes; and diagnosed bronchitis, pneumonia, or chronic cough. Current product use was lagged by 1 wave and categorized as (1) never/noncurrent use, (2) exclusive cigarette use, (3) exclusive ENDS use, and (4) dual ENDS/cigarette use. Multivariable models adjusted for age, sex, race and ethnicity; parental education; asthma; BMI; cannabis use; secondhand smoke exposure; and household use of combustible products. Data analysis was conducted in 2022-2023.

RESULTS

A total of 7.4% of respondents were diagnosed with bronchitis, pneumonia, or chronic cough at follow-up. In the multivariable model, exclusive cigarette use (incident rate ratio=1.85, 95% CI=1.29, 2.65), exclusive ENDS use (incident rate ratio=1.49, 95% CI=1.06, 2.08), and dual use (incident rate ratio=2.70, 95% CI=1.61, 3.50) were associated with a higher risk of diagnosed bronchitis, pneumonia, or chronic cough than never/noncurrent use.

CONCLUSIONS

These results suggest that ENDS and cigarettes, used exclusively or jointly, increased the risk of diagnosed bronchitis, pneumonia, or chronic cough among U.S. youth. However, dual use was associated with the highest risk. Targeted policies aimed at continuing to reduce cigarette smoking and ENDS use among youth, especially among those with dual use, are needed.

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.

Comparative systematic review on the safety of e-cigarettes and conventional cigarettes

BACKGROUND

This systematic review evaluated the health risks of electronic cigarettes (e-cigarettes) compared to traditional cigarettes. It examines various studies and research on the subject to provide a comprehensive analysis of potential health risks associated with both smoking methods.

METHODS

The systematic review, incorporating searches in PubMed, Scopus, Web of Science, and the Cochrane Library up to July 2023, examines the results obtained in relevant studies, and provides a critical discussion of the results.

RESULTS

E-cigarettes exhibit reduced exposure to harmful toxins compared to traditional cigarettes.

CONCLUSION

However, concerns persist regarding respiratory irritation and potential health risks, especially among youth, emphasizing the need for comprehensive, long-term research and protective legislation.

A clinical overview of adolescent e-cigarette use (vaping)

E-cigarette use (also known as "vaping") has become increasingly popular among adolescents over the past decade and grown into a significant public health concern in North America, the United Kingdom, and other countries. Concerns about this new trend have generated numerous new research studies. This aim of this study was to summarize recent scientific findings, with a focus on their relevance to clinicians working with adolescents. The first half covers epidemiology, risk factors for e-cigarette use, characteristics of e-cigarette use, youth perceptions of e-cigarettes, physical health risks of e-cigarettes, evidence for "gateway effects" of e-cigarette exposure on subsequent substance use, and the relationship between e-cigarette use and mental health. The review concludes with a clinical focus on assessment of youth who vape, psychoeducation for youth and families, clinical management of vaping, and regulatory considerations.

Examining indirect effects of advertising exposure on young adults' cannabis and nicotine vaping

OBJECTIVE

To examine longitudinal associations between exposure to two types of advertisements (medical/recreational cannabis and e-cigarette retailers [vape shops]) and young adults' cannabis and nicotine vaping behavior. Positive and negative expectancies for cannabis and vaping nicotine were examined as mediators of these associations.

METHOD

Secondary analysis of observational data from a longitudinal cohort of young adults recruited from Southern California (Wave 13: N = 2,411, 56% female, Mage = 23.6). Participants completed web-based surveys annually, reporting on advertising exposure in 2018, expectancies in 2019, and cannabis and nicotine vaping in 2020. Two path models were specified: (a) of past-month cannabis vaping only, nicotine vaping only, and co-use (vs. no vaping) and (b) of single product vaping (vs. co-use). Path analyses modeled direct and indirect associations between variables.

RESULTS

Controlling for past-month cannabis and nicotine use and other covariates, there were no significant direct associations of advertising exposure with cannabis and/or nicotine vaping. However, the association between cannabis advertising exposure and vaping (cannabis only) was significantly mediated by positive cannabis expectancies (β = 0.02, SE = 0.01, p = .03). Among those who vaped cannabis and/or nicotine in the past month at Wave 13, expectancies did not significantly mediate associations between advertising exposure and single product use (vs. co-use).

CONCLUSIONS

Although exposure to cannabis advertisements may not be directly associated with young adults' cannabis vaping 2 years later, the effects of advertising exposure may be exerted indirectly by increasing positive beliefs about cannabis. Implications for public health policy are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Electronic cigarette use and cigarette smoking associated with inadequate sleep duration among U.S. young adults

OBJECTIVE

Nicotine use can influence inadequate sleep, but less is known about the associations of exclusive and dual use of electronic cigarettes (e-cigarettes) with combustible cigarettes in U.S. young adults. This study assessed the associations between current exclusive e-cigarette use, exclusive cigarette smoking, and dual e-cigarette and combustible cigarette use and inadequate sleep duration among U.S. young adults.

METHODS

We performed a secondary analysis of 2020 Behavioral Risk Factor Surveillance System (BRFSS) data including 13,978 U.S. young adults ages 18-24 years. Inadequate sleep duration was assessed categorically using the National Sleep Foundation's age-specific recommendations that define <7 h as inadequate sleep. Weighted logistic regression models were performed while adjusting for participants' sex, race/ethnicity, education level, annual household income level, body mass index, current physical activity, mental health status, disability status, current alcohol use, and current smokeless tobacco use.

RESULTS

Concerning use patterns, 11.8% of young adults were exclusive e-cigarette users, 4.7% were exclusive cigarette smokers, and 3.8% were dual e-cigarette and combustible cigarette users. Exclusive e-cigarette users (adjusted odds ratio [AOR] = 1.41, 95% confidence interval [CI] = 1.16-1.72), exclusive cigarette smokers (AOR = 1.63, 95%CI = 1.22-2.18), and dual product users (AOR = 2.03, 95%CI = 1.44-2.86) were at increased odds of having inadequate sleep duration compared to non-users, while adjusting for the covariates. Additionally, dual product users were at increased odds (AOR = 1.52, 95%CI = 1.06-2.19) of reporting inadequate sleep duration compared to exclusive e-cigarette users, while adjusting for the covariates.

CONCLUSIONS

Current e-cigarette and cigarette use may influence inadequate sleep among U.S. young adults. Tobacco cessation efforts may encourage increased sleep health.

Electronic Cigarette Harms: Aggregate Evidence Shows Damage to Biological Systems

Evidence of the harms of e-cigarettes has been unfolding slowly and has been documented in many reviews and reports worldwide. A narrative review of new evidence is presented since, as research has continued, newly aggregated evidence of the dangers of electronic cigarettes on the brain, heart, and lungs is vital to inform decisions on restricting the use of e-cigarettes. Several biomedical research databases were searched for electronic cigarette health effects, emphasizing reviews, systematic reviews, and meta-analyses. Over 50 review studies, primarily in 2022 and 2023, illustrate some of the latest information on e-cigarette harms. Results show studies of respiratory, neurological, and cardiovascular effects. Researchers call for expanding studies through new methods to elaborate on initial findings of multiple harms emerging in clinical investigations. Since the use of electronic cigarettes for adult cessation is not sanctioned in most countries, it is clear that health authorities see significant costs to the health of the general population if the promotion and use of electronic cigarettes occur worldwide. Regulatory action to control electronic cigarettes should consider the substantial evidence of electronic cigarette harm.

Tobacco products and electronic cigarettes' legislation violations - observational study in 31 European countries, 2005-2022

BACKGROUND

European Union (EU) law regulates the manufacture, presentation, and sale of tobacco and related products in all member states. This study examined whether legislation non-compliant tobacco products and electronic cigarettes were available for sale in the European market.

METHODS

We queried the EU Rapid Information System for dangerous non-food products, covering 28 current and former EU member states and 3 associated countries, also known as Rapex, for non-compliant tobacco and related products reported between 2005 and 2022.

FINDINGS

During the operation of the Rapex system, 183 violations were reported (six on tobacco, three on traditional cigarettes, and 174 on e-cigarettes). Insufficient product safety information was found in 86% of the reports on e-cigarettes and 74% of the refills. Violations regarding the volume of the liquid container were observed in 26% of the e-cigarette reports and 20% of the refill reports. Approximately 15% of the reported e-cigarettes and 17% of refill liquids exceeded permissible nicotine levels. More serious standard violations were recorded for refills than for e-cigarettes. Approximately one-third of Rapex system countries submitted no notifications.

INTERPRETATION

E-cigarettes were the most frequently reported items in the European market of tobacco and non-tobacco nicotine products. The most common concerns were inadequate product safety information, incorrect liquid container volume, and excessive nicotine concentration. Identifying the most recognized legal infringements did not require laboratory tests and was based only on packaging and the manufacturer's declaration analysis. Further studies are necessary to corroborate whether products available in countries where no violations have been reported meet EU safety standards.

Chemical Profiles and Toxicity of Electronic Cigarettes: An Umbrella Review and Methodological Considerations

BACKGROUND

Electronic cigarettes (ECs) are often marketed as a safer alternative to combustible tobacco products. The global EC market has rapidly expanded since their introduction, creating an urgent need for research describing the toxicity and chemical composition of ECs. We conducted an umbrella review to summarize the evidence from existing systematic reviews (SRs).

METHODS

The search for SRs was conducted across four electronic databases through 25 January 2022. Methodological quality was assessed using the AMSTAR-2 quality appraisal tool.

RESULTS

Twenty-five SRs were included in our umbrella review. Chemical profiles widely varied across studies included in the reviews, which was mainly attributed to the lack of standardized protocols investigating the constituents, and differences in EC devices and e-liquids tested. Metals were more abundant in some EC aerosols than cigarettes, while carbonyls were typically found at lower levels. There was consistent evidence of in vitro toxicity from EC aerosol and e-liquid exposure. AMSTAR-2 revealed important limitations across reviews.

CONCLUSIONS

While most reviews concluded that ECs were likely less harmful than cigarettes, there was hesitancy to draw clear conclusions due to variable analytical procedures and inconsistent findings among the included studies. Future SRs with improved methodology and reporting are needed to adequately inform tobacco regulatory actions.