Altered executive control network and default model network topology are linked to acute electronic cigarette use: A resting-state fNIRS study.

In recent years, electronic cigarettes (e-cigs) have gained popularity as stylish, safe, and effective smoking cessation aids, leading to widespread consumer acceptance. Although previous research has explored the acute effects of combustible cigarettes or nicotine replacement therapy on brain functional activities, studies on e-cigs have been limited. Using fNIRS, we conducted graph theory analysis on the resting-state functional connectivity of 61 male abstinent smokers both before and after vaping e-cigs. And we performed Pearson correlation analysis to investigate the relationship between alterations in network metrics and changes in craving. E-cig use resulted in increased degree centrality, nodal efficiency, and local efficiency within the executive control network (ECN), while causing a decrease in these properties within the default model network (DMN). These alterations were found to be correlated with reductions in craving, indicating a relationship between differing network topologies in the ECN and DMN and decreased craving. These findings suggest that the impact of e-cig usage on network topologies observed in male smokers resembles the effects observed with traditional cigarettes and other forms of nicotine delivery, providing valuable insights into their addictive potential and effectiveness as aids for smoking cessation.

A pilot study on oral microbiome in electronic cigarettes consumers versus traditional cigarettes smokers.

Oral microorganisms are closely related to oral health, the occurrence of some oral diseases is associated with changes in the oral microbiota, and many studies have demonstrated that traditional smoking can affect the oral microbial community. However, due to the short time since the emergence of e-cigarettes, fewer studies are comparing oral microorganisms for users of e-cigarettes versus cigarettes. We collected saliva from 40 non-smokers (NS), 46 traditional cigarette smokers (TS), and 27 e-cigarette consumers (EC), aged between 18 and 35 years. We performed 16S rRNA gene sequencing on the saliva samples collected to study the effects of e-cigarettes versus traditional cigarettes on the oral microbiome. The results showed that compared with the NS group, the alpha diversity of oral flora in saliva was altered in the TS group, with no significant change in the e-cigarette group. Compared with the NS and EC groups, the relative abundance of Actinomyces and Prevotella was increased in the TS group. However, compared with the NS and TS groups, the relative abundance of Veillonella was increased, and the relative abundance of Porphyromonas and Peptostreptococcus was decreased in the EC group. These results showed that both e-cigarettes and traditional cigarettes could alter the structure and composition of oral microbiota. The use of traditional cigarettes promotes the growth of some anaerobic bacteria, which may contribute to dental decay and bad breath over time. E-cigarettes have a different effect on the structure and composition of the oral microbial community compared to conventional cigarettes. In order to better understand the effects of e-cigarettes and traditional cigarettes on users' mouths, future studies will investigate the relationship between diseases such as dental caries and periodontitis and changes in oral microbial species levels.

Spontaneous Pneumomediastinum Induced by a Combination of Flu-A Infection and E-cigarettes: A Case Report.

Pneumomediastinum (PM) and subcutaneous emphysema are characterized by extra-alveolar air within the mediastinum and subcutaneous tissue. PM may occur spontaneously or due to trauma or an underlying airway disease. Spontaneous pneumomediastinum (SPM) may be caused by intractable vomiting, forceful coughing, child birthing, or performing a Valsalva maneuver. However, there are limited studies or case reports that present a combination of influenza A infection and electronic cigarette (e-cigarette)-induced SPM. This case report presents SPM in a previously healthy 20-year-old female with untreated influenza A infection and a history of e-cigarette use who presented to the emergency department with fever, cough, chest pain, dyspnea, and vomiting. Her physical examination was significant for neck tenderness, subcutaneous neck crepitus, and increased respiratory effort. Diagnostic evaluation included a chest X-ray and chest computed tomography that revealed PM with subcutaneous emphysema extending into the neck, as well as a negative Gastrografin study. She was treated conservatively and discharged after two days, with a follow-up scheduled at a pulmonary clinic. This case report highlights the need for a detailed substance use history, particularly e-cigarette use, when determining the etiology of SPM in a previously healthy patient. Management for SPM is conservative and should include addressing underlying etiologies with special attention to cessation and education of e-cigarettes and illicit substances.

Thermal Pharyngeal Injury Resulting From Vaping: A Case Report.

Thermal injury to the pharyngeal structures is uncommon, and clinicians generally attribute these injuries to consuming hot foods or liquids. While thermal injuries have been reported with the ingestion of hot substances, thermal injuries from vape pens have not been widely described in the literature. We present a case of a 35-year-old male who presented to the emergency department (ED) with oropharyngeal burns after utilizing a vape pen that malfunctioned. The patient had visible burns on his uvula, as well as on the soft and hard palate. Additionally, he had symptoms of difficulty swallowing and a hoarse voice, which raised concerns about a possible deeper airway or lung injury. The patient required a flexible nasopharyngolaryngoscopy by a head and neck surgeon, which revealed mild edema and erythema of the epiglottis and the arytenoids. The patient was admitted to the hospital overnight for observation and treatment with analgesia and dexamethasone. The following morning, the patient's symptoms had improved. The repeat nasopharyngolaryngoscopy showed improvement in the swelling of the epiglottis and arytenoids, and the patient was deemed stable for discharge. This case brings attention to the variety of injuries possible from e-cigarette use and the importance of prompt management of oropharyngeal thermal injuries.

Effectiveness of e-cigarettes as a stop smoking intervention in adults: a systematic review.

BACKGROUND: This systematic review aims to identify the benefits and harms of electronic cigarettes (e-cigarettes) as a smoking cessation aid in adults (aged ≥ 18 years) and to inform the development of the Canadian Task Force on Preventive Health Care's (CTFPHC) clinical practice guidelines on e-cigarettes. METHODS: We searched Ovid MEDLINE®, Ovid MEDLINE® Epub Ahead of Print, In-Process & Other Non-Indexed Citations, PsycINFO, Embase Classic + Embase, and the Cochrane Library on Wiley. Searches were conducted from January 2016 to July 2019 and updated on 24 September 2020 and 25 January 2024. Two reviewers independently performed title-abstract and full-text screening according to the pre-determined inclusion criteria. Data extraction, quality assessments, and the application of Grading of Recommendations Assessment, Development and Evaluation (GRADE) were performed by one independent reviewer and verified by another. RESULTS: We identified 18 studies on 17 randomized controlled trials that compared e-cigarettes with nicotine to e-cigarettes without nicotine and e-cigarettes (with or without nicotine) to other interventions (i.e., no intervention, waitlist, standard/usual care, quit advice, or behavioral support). Considering the benefits of e-cigarettes in terms of smoking abstinence and smoking frequency reduction, 14 studies showed small or moderate benefits of e-cigarettes with or without nicotine compared to other interventions; although, with low, very low or moderate evidence certainty. With a focus on e-cigarettes with nicotine specifically, 12 studies showed benefits in terms of smoking abstinence when compared with usual care or non-nicotine e-cigarettes. In terms of harms following nicotine or non-nicotine e-cigarette use, 15 studies reported mild adverse events with little to no difference between groups and low to very low evidence certainty. CONCLUSION: The evidence synthesis on the e-cigarette's effectiveness shows data surrounding benefits having low to moderate evidence certainty for some comparisons and very low certainty for others, indicating that e-cigarettes may or probably increase smoking cessation, whereas, for harms, there is low to very low evidence certainty. Since the duration for outcome measurement varied among different studies, it may not be long-term enough for Adverse Events (AEs) to emerge, and there is a need for more research to understand the long-term benefits and potential harms of e-cigarettes. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42018099692.

The potential of new nicotine and tobacco products as tools for people who smoke to quit combustible cigarettes - a systematic review of common practices and guidance towards a robust study protocol to measure cessation efficacy.

New types of nicotine and tobacco products like electronic cigarettes (ECs), heated tobacco products or nicotine pouches have been discussed as less harmful alternatives to combustible cigarettes and other toxic forms of tobacco products. Their harm reduction potential lay in the efficient transition away from smoking to those new products. Numerous studies addressing the cessation efficacy of ECs have been published with contradictory outcomes. Yet, a comprehensive Cochrane review concluded with high certainty on the cessation efficacy of ECs. This prompted us to perform a review to identify weaknesses in common study designs and to summarize best practices for the study design on the potential of new nicotine products as cessation aids. 120 articles retrieved from Medline were found to be eligible. Most of the studies in the field were interventional trials while observational studies played a minor role in the evaluation of smoking cessation. Efficacy was predominantly assessed for ECs in 77% of the reports while heated tobacco (17%) and non-combustible products (11%) were less frequently investigated up to now. Measures to determine the efficacy were questionnaire-based assessments as well as use documentation/prevalence and abstinence rates. Studies varied largely in their duration and sample size with medians of 3 months and 156.5 participants, respectively.With the help of this review, we identified several weaknesses in the common study designs. One major limitation in longitudinal trials was the lack of compliance measures suited to verify the use status over longer time periods, relying solely on self-reports. Moreover, the motivation of the participants to quit was rarely defined and a profound familiarization period was not taken into account for the majority of the studies. To what extent such weaknesses influence the outcome of the studies was beyond the scope of this review. We encourage researchers to consider the recommendations which resulted from this review in order to determine the abuse liability and cessation efficacy of the products in a more robust manner. Finally, we like to call attention to the missing data for low- and middle-income countries which would require quitting strategies most urgently to combat the tobacco smoking epidemic.

Perceptions and usage of traditional cigarettes, electronic cigarettes, and waterpipes among young and middle-aged adults in Iraq: A descriptive study.

Tobacco use poses significant public health concerns, linked to various mental and physical health outcomes. Iraq has a high prevalence of smoking, predominantly with traditional cigarettes, but there is also growing popularity of electronic cigarettes and waterpipes among younger and middle-aged adults. This study aims to explore the perceptions and usage of traditional cigarettes, electronic cigarettes, and waterpipes among this population in Iraq. A descriptive study was conducted among 402 young and middle-aged adults (50.25% females), aged between 18 and 45 years, with a mean age of 25.88 (SD = 7.27). For the data collection, an online questionnaire was developed utilizing distribution channels on common social networking platforms. The results showed that 41.79% of respondents have used traditional cigarettes, while 31.1% of participants reported that they use electronic cigarettes. Ninety-four per cent of respondents acknowledged that they use waterpipes. The results also indicated that a significant proportion believe that using electronic cigarettes is either much more harmful or more harmful than traditional cigarettes. Participants commonly perceived all three types of tobacco products as highly harmful, including secondhand smoke, addictive qualities, and popularity among peers. Additionally, significant differences in perceptions emerged between smokers and nonsmokers regarding electronic cigarettes and traditional cigarettes, although no such differences were observed for waterpipes. These findings contribute to understanding the attitudes toward different forms of tobacco use among respondents, highlighting the need for targeted interventions to address the perceived harm associated with tobacco products.

Combining app-based behavioral therapy with electronic cigarettes for smoking cessation: a study protocol for a single-arm mixed-methods pilot trial.

BACKGROUND: Cigarette smoking remains a leading cause of preventable illness and death, underscoring the need for effective evidence-based smoking cessation interventions. Nuumi, a novel smoking cessation program integrating a digital behavioral therapy and an electronic cigarette, may provide a solution. OBJECTIVE: To investigate the initial efficacy, acceptability and psychological outcomes of an evidence-based smoking cessation intervention comprised of a mobile phone app and an electronic cigarette among adults who smoke and who are motivated to quit. METHODS: A prospective 6-month single-arm mixed-methods pilot study will be conducted. Seventy adults who smoke and who are motivated to quit will be recruited via web-based advertisements and flyers. Participants receive access to an app and an electronic cigarette with pods containing nicotine for temporary use of at least 3 months. The electronic cigarette is coupled with the app via Bluetooth, allowing for tracking of patterns of use. The behavioral therapy leverages evidence-based content informed by cognitive behavioral therapy and mindfulness-informed principles. Web-based self-report surveys will be conducted at baseline, at 4 weeks, at 8 weeks, at 12 weeks, and at 24 weeks post-baseline. Semi-structured interviews will be conducted at baseline and at 12 weeks post-baseline. Primary outcomes will be self-reported 7-day point prevalence abstinence from smoking at 12 weeks and 24 weeks. Secondary outcomes will include other smoking cessation-related outcomes, psychological outcomes, and acceptability of the nuumi intervention. Descriptive analyses and within-group comparisons will be performed on the quantitative data, and content analyses will be performed on the qualitative data. Recruitment for this study started in October 2023. DISCUSSION: As tobacco smoking is a leading cause of preventable morbidity and mortality, this research addresses one of the largest health burdens of our time. The results will provide insights into the initial efficacy, acceptability, and psychological outcomes of a novel mobile health intervention for smoking cessation. If successful, this pilot may generate an effective intervention supporting adults who smoke to quit smoking. The results will inform feasibility of a future randomized controlled trial. Trial Registration German Clinical Trials Register DRKS00032652, registered 09/15/2023, https://drks.de/search/de/trial/DRKS00032652 .

Multi-centre Study of Vaping Effects on COVID-19 Presentations in Western Sydney Australia.

Aim: This preliminary pilot study aimed to explore a correlation between COVID-19 presentation with e-cigarette vapers in the Western Sydney region of Australia. METHOD: Extracted data from questionnaires completed by 100 Australians residing in the Western Sydney region who were infected with COVID-19 during the pandemic from March 2020 to March 2022 were analyzed. Data collected included patient age, biological gender, years of vaping, if vaping began prior to COVID-19, weekly vaping frequency, the year that COVID-19 was contracted, and the category of COVID-19 symptoms. The symptoms are scaled into four categories for this study, from lowest severity to high severity based on the World Health Organization's classifications. RESULTS: Vapers in Western Sydney Australia experienced higher severity COVID-19 presentations compared to non-vapers. Biological males were found to be more susceptible than biological females for experiencing the highest severity. Vapers with higher years of vaping had severe COVID-19 presentations compared to lesser years of vaping. CONCLUSION: Among adults in Western Sydney Australia aged 18 years and above, the collected data showed a correlation between e-cigarette vapers reporting higher severity of COVID-19 presentations compared to non-vapers of the same demographic when they contracted COVID-19.

How Did COVID-19 Impact Smoking Habits in the Saudi Community?

Background/aims Most countries have gone through lockdowns to varying degrees during the COVID-19 pandemic to reduce the spread of the disease. The successive pandemic waves have impacted the health system, imposing restrictions set by the government. This changed people's daily life routines and they felt more socially isolated, which in turn had an impact on their mental health. Some factors were linked to the severity and outcome of COVID-19 on patients. One of these factors was smoking. This study was carried out to investigate the prevalence and impact of lockdown on smoking habits, as well as the changes in attitudes, behavior, and the rate of consumption before and after the government restrictions in the general population of Saudi Arabia. Materials and methods The present cross-sectional study was conducted on a sample of 921 participants from the general population of Saudi Arabia. Data were collected via an online questionnaire. A structured self-response questionnaire was given to the participants after institutional research ethical approval was obtained for the study. Results A total of 921 participants from the smoker population of Saudi Arabia were included in the study. The majority of participants were male (72.9%), and more than half were aged between 18 and 34 years (53.7%). Single individuals had a higher prevalence of increased smoking and a lower rate of quitting compared to married individuals. Participants with higher education levels were more likely to continue smoking at the same rate. While 40.5% of participants reported no change in their smoking rate during the pandemic, 15.4% reported a decrease, 39.0% reported an increase, and 5.1% reported quitting smoking. Participants who reported feeling more stressed during the pandemic had a higher prevalence of increased smoking. The majority of participants believed that smoking increased the risk of COVID-19 infection. Conclusion The study highlights the need for targeted smoking cessation interventions and support services during the pandemic, considering demographic factors, living arrangements, and psychological impact. Efforts should be made to raise awareness about the negative health consequences of smoking during the pandemic and provide resources for stress management and alternative coping strategies. These findings have important implications for public health interventions and policies in Saudi Arabia.

Reduced nicotine in cigarettes in a marketplace with alternative nicotine systems: randomized clinical trial.

Background: Reducing cigarette addictiveness has the potential to avert millions of yearly tobacco-related deaths worldwide. Substantially reducing nicotine in cigarettes decreases cigarette consumption, but no large clinical trial has determined the effects of reduced-nicotine cigarettes when other nicotine-containing products are available. The aim of this study was to examine the effects of reduced-nicotine cigarettes in the context of the availability of alternative nicotine delivery systems. Methods: In a U.S. six-site, open-label, parallel-arm study, smokers were randomized for twelve weeks to an experimental marketplace containing cigarettes with either 0.4 mg or 15.8 mg nicotine per gram of tobacco; all had access to non-combusted alternative nicotine delivery systems (e.g., e-cigarettes; medicinal nicotine). Group differences in the primary outcomes (cigarettes per day, number of smoke-free days) were examined using linear and negative binomial regression, respectively (Trial Registration: NCT03272685). Findings: Among 438 randomized participants (mean [standard deviation (SD), range] age, 44.5 [11.9, 20-73] years, 225 [51.4%] women, 282 [64.4%] White and 339 [77.4%] trial completers), those in the 0.4 mg vs. 15.8 mg nicotine cigarette condition experienced significantly lower cigarettes per day at the end of intervention (mean [SD], 7.05 [7.88] vs. 12.95 [9.07], adjusted mean difference, -6.21 [95% CI, -7.66 to -4.75], P < 0.0001) and greater smoke-free days during intervention (mean [SD], 18.59 [27.97] vs. 5.06 [13.77], adjusted rate ratio, 4.25 [95% CI, 2.58-6.98], P < 0.0001). Interpretation: A reduced-nicotine cigarette standard in the context of access to other non-combusted nicotine products has the potential to benefit public health. Funding: U.S. NIH/FDA U54DA03165.

Assessing the association between e-cigarette use and cardiovascular disease: A meta-analysis of exclusive and dual use with combustible cigarettes.

BACKGROUND: Growing evidence highlights the impact of e-cigarette use on cardiovascular health, prompting a crucial examination of its association with cardiovascular disease (CVD) in both exclusive e-cigarette and dual use scenarios with combustible cigarettes. This meta-analysis assessed the association between e-cigarette use and CVD by synthesizing the existing literature. METHODS: Pertinent observational studies were identified using multiple electronic databases, from August 22nd, 2006, to April 10th, 2024. A meta-analysis was conducted using random-effect models. Risk of bias was assessed using the National Institutes of Health (NIH) Study Quality Assessment Tools. FINDINGS: A total of 20 observational studies involving 8,499,444 participants were included in the meta-analysis. Dual use (e-cigarettes and combustible cigarette) increased the odds of CVD by 2.56 times (95 % CI: 2.11, 3.11) compared to never use of both. Current e-cigarette use combined with former combustible cigarette increased the odds of CVD by 2.02 times (95 % CI: 1.58, 2.58) compared to never use of either. Exclusive current e-cigarette use did not show a statistically significant association with CVD odds compared to never use of either (OR = 1.24, 95 % CI: 0.93, 1.67). CONCLUSIONS: Dual use of e-cigarettes and combustible cigarettes was significantly associated with CVD, but results failed to show a significant association between exclusive e-cigarette use and CVD. Robust and longitudinal studies are needed to understand the long-term implications of e-cigarette use and CVD. Public health efforts should focus on awareness, smoking cessation, and regulating both e-cigarettes and combustible cigarettes.

Investigative analysis of blood-brain barrier penetrating potential of electronic nicotine delivery systems (e-cigarettes) chemicals using predictive computational models.

INTRODUCTION: Seizures are known potential side effects of nicotine toxicity and have been reported in electronic nicotine delivery systems (ENDS, e-cigarettes) users, with the majority involving youth or young adults. AREAS COVERED: Using chemoinformatic computational models, chemicals (including flavors) documented to be present in ENDS were compared to known neuroactive compounds to predict the blood-brain barrier (BBB) penetration potential, central nervous system (CNS) activity, and their structural similarities. The literature search used PubMed/Google Scholar, through September 2023, to identify individual chemicals in ENDS and neuroactive compounds.The results show that ENDS chemicals in this study contain >60% structural similarity to neuroactive compounds based on chemical fingerprint similarity analyses. The majority of ENDS chemicals we studied were predicted to cross the BBB, with approximately 60% confidence, and were also predicted to have CNS activity; those not predicted to passively diffuse through the BBB may be actively transported through the BBB to elicit CNS impacts, although it is currently unknown. EXPERT OPINION: In lieu of in vitro and in vivo testing, this study screens ENDS chemicals for potential CNS activity and predicts BBB penetration potential using computer-based models, allowing for prioritization for further study and potential early identification of CNS toxicity.

Vaping during pregnancy: a systematic review of health outcomes.

INTRODUCTION: Smoking during pregnancy is harmful to maternal and child health. Vaping is used for smoking cessation but evidence on health effects during pregnancy is scarce. We conducted a systematic review of health outcomes of vaping during pregnancy. METHODS: We searched six databases for maternal/fetal/infant outcomes and vaping, including quantitative, English language, human studies of vaping during pregnancy, to November 10th, 2023. We assessed study quality with the Mixed-Methods Appraisal Tool. We focused on comparisons of exclusive-vaping with non-use of nicotine and tobacco products and with smoking. Presentation is narrative as the studies were of insufficient quality to conduct meta-analysis. RESULTS: We included 26 studies, with 765,527 women, with one randomised controlled trial (RCT) comparing vaping and nicotine replacement therapy for smoking cessation, 23 cohort studies and two case-control studies. While the RCT met 4/5 quality criteria, the quality of the cohort studies and case-control studies was poor; none adequately assessed exposure to smoking and vaping. For studies comparing exclusive-vaping with 'non-use', more reported no increased risk for vaping (three studies) than reported increased risk for maternal pregnancy/postpartum outcomes (one study) and for fetal and infant outcomes (20 studies no increased risk, four increased risk), except for birth-weight and neurological outcomes where two studies each observed increased and no increased risk. When the RCT compared non-users with those not smoking but vaping or using NRT, irrespective of randomisation, they reported no evidence of risk for vaping/NRT. For studies comparing exclusive-vaping and exclusive-smoking, most studies provided evidence for a comparable risk for different outcomes. One maternal biomarker study revealed a lower risk for vaping. For small-for-gestational-age/mean-birth-centile equal numbers of studies found lower risk for vaping than for smoking as found similar risk for the two groups (two each). CONCLUSIONS: While more studies found no evidence of increased risk of exclusive-vaping compared with non-use and evidence of comparable risk for exclusive-vaping and exclusive-smoking, the quality of the evidence limits conclusions. Without adequate assessment of exposure to vaping and smoking, findings cannot be attributed to behaviour as many who vape will have smoked and many who vape may do so at low levels. STUDY REGISTRATION: https://osf.io/rfx4q/ .

In vitro toxicity and chemical analysis of e-cigarette aerosol produced amid dry hitting.

Dry hitting, a phenomenon produced by e-cigarettes with refillable cartridges when the liquid in the coil is low, is a common occurrence among regular vapers despite being an unintended consequence of the device. This phenomenon's hazard to public health is still unknown and needs further investigation. Lung cells cultured at the air-liquid interface were exposed to vaped aerosol consisting of 3 % w/v ethyl maltol in propylene glycol for three-second puffs every 30 seconds for 80 total puffs with either dry hit or saturated conditions. Cytotoxicity was measured colorimetrically. The thermal degradation of the heating coils and wicks was visualized using scanning electron microscopy. The chemical byproducts in the aerosol were analyzed using proton nuclear magnetic resonance and inductively coupled plasma mass spectrometry. The results revealed a highly significant increase in cytotoxicity from dry hit treatments. Imaging showed thermal decomposition of the cotton wick after dry hitting, which was confirmed by energy dispersive x-ray spectroscopy with less oxygen in the dry hit cotton. Chemical byproducts were found via unique peaks in the dry hit condensate in the aromatic and alkene regions. Saturated condensate showed higher concentrations of detected metal species than dry-hit condensate. E-cigarette users should avoid dry hitting by refilling tanks or cartridges preemptively or by using disposable coils to avoid increased toxicity during vaping.

Level and timing of product substitution in a trial of e-cigarettes for smokers not interested in quitting.

INTRODUCTION: The e-cigarette market is large and diverse. Traditional smoking cessation trials involving a control group and a 6-month observation period are an inefficient methodology for testing the multiple treatment options e-cigarettes provide for harm reduction in cigarette smokers. We determined when product substitution occurred in the e-cigarette provision arm of an e-cigarette substitution trial for cigarette smokers who were not interested in quitting. METHODS: We conducted a secondary analysis of 120 cigarette smokers with severe mental illness (recruitment 2017-2020) who were given disposable e-cigarettes for 8 weeks and assessed at weeks 0 (t0), 2, 4, 6, and 8. We explored product substitution through visit-to-visit correlations in change in product use, then developed a dual process growth model for cigarette and e-cigarette use to test the association between increases in e-cigarette use and concurrent decreases in cigarettes smoked. RESULTS: Mean age of the participants was 45.9 years, and 42.7% smoked ≥20 cigarettes per day. Almost all product substitution occurred between t0 and t2. For the average smoker (18 cigarettes per day), t2 cigarette frequency decreased by 0.39 (95% CI: -0.56 - -0.22) cigarettes for each additional e-cigarette session. There was effect modification (p=0.033), such that baseline light smokers (<10 cigarettes/day) had no significant decrease in t2 cigarette frequency, regardless of their initial increase in e-cigarette use, while heavy smokers (38 cigarettes/day) switched products nearly on a one-to-one basis. CONCLUSIONS: In this study, most product substitution occurred early, and heavier smokers had larger t2 decreases in cigarettes/day with increased e-cigarette use. If confirmed with replication studies, the findings could suggest establishment of a novel outcome for e-cigarette studies - early product substitution - and support the value of short-term comparative effectiveness trials that compare multiple potentially lower harm tobacco products. CLINICAL TRIAL REGISTRATION: The study was registered on the official website of ClinicalTrials.gov. IDENTIFIER: ID NCT03050853.

Electronic cigarettes and subsequent use of cigarettes in young people: An evidence and gap map.

BACKGROUND AND AIMS: The use of e-cigarettes may influence later smoking uptake in young people. Evidence and gap maps (EGMs) are interactive on-line tools that display the evidence and gaps in a specific area of policy or research. The aim of this study was to map clusters and gaps in evidence exploring the relationship between e-cigarette use or availability and subsequent combustible tobacco use in people aged < 30 years. METHODS: We conducted an EGM of primary studies and systematic reviews. A framework and an interactive EGM was developed in consultation with an expert advisory group. A systematic search of five databases retrieved 9057 records, from which 134 studies were included. Systematic reviews were appraised using AMSTAR-2, and all included studies were coded into the EGM framework resulting in the interactive web-based EGM. A descriptive analysis of key characteristics of the identified evidence clusters and gaps resulted in this report. RESULTS: Studies were completed between 2015 and 2023, with the first systematic reviews being published in 2017. Most studies were conducted in western high-income countries, predominantly the United States. Cohort studies were the most frequently used study design. The evidence is clustered on e-cigarette use as an exposure, with an absolute gap identified for evidence looking into the availability of e-cigarettes and subsequent cessation of cigarette smoking. We also found little evidence analysing equity factors, and little exploring characteristics of e-cigarette devices. CONCLUSIONS: This evidence and gap map (EGM) offers a tool to explore the available evidence regarding the e-cigarette use/availability and later cigarette smoking in people under the age of 30 years at the time of the search. The majority of the 134 reports is from high-income countries, with an uneven geographic distribution. Most of the systematic reviews are of lower quality, suggesting the need for higher-quality reviews. The evidence is clustered around e-cigarette use as an exposure and subsequent frequency/intensity of current combustible tobacco use. Gaps in evidence focusing on e-cigarette availability, as well as on the influence of equity factors may warrant further research. This EGM can support funders and researchers in identifying future research priorities, while guiding practitioners and policymakers to the current evidence base.

Metal in biological samples from electronic cigarette users and those exposed to their second-hand aerosol: a narrative review.

Introduction: Electronic nicotine delivery systems (ENDS) are gradually becoming more popular, particularly, among today's youth. Despite being marketed as safe by the tobacco industry, the notable absence of regulation in their composition is evident. Both the generated fluids and aerosol exhibit a wide variety of substances that are not yet fully identified. In addition to additives, the aerosol contains metals, the presence of which can be attributed to the excessive heating of metallic filaments used in vaporizing the liquid. Objective: This review aimed to identify and describe studies that have assessed metal levels in biological samples obtained from electronic cigarette users and those exposed to their second-hand aerosol. This involved detailing the types and concentrations of metals identified and the biological samples in which the metals were detected. Methods: Two independent researchers conducted searches in the MEDLINE and EMBASE databases to identify studies that measured the metal levels in human non-invasive biological samples from electronic cigarette users and second-hand exposure. Data were presented as a narrative review. Results: In total, 18 articles were included in this review. Overall active and passive exposure to ENDS was related to higher levels of many metals, including lead and cadmium, in biological samples. ENDS users, in general, have lower metal concentrations in biological samples compared to the users of combustible cigarettes. Conclusion: The exposure to primary and second-hand e-cigarette aerosol is related to higher metal concentrations in the biological samples. The adverse effects of this exposure on long-term users are yet to be determined.

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

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

Knowledge, Perception, and Associated Factors of Electronic Cigarette Consumption Among the Saudi Population in Jeddah City.

Introduction Electronic cigarettes (e-cigarettes) are rising in popularity among young adults and teenagers. Previous studies have shown that among high and middle schoolers, the percentage of e-cigarette smokers was noticeably higher than tobacco cigarette smokers. Various research papers focusing on different communities have reported a low-to-moderate level of knowledge and awareness of e-cigarette's effects on health. E-cigarettes were initially advertised as devices to help people quit smoking, but the use of e-cigarettes in modern days has changed considerably. A big chunk of the population perceived that e-cigarettes have no harmful effects because they are nicotine-free and thus are used as a replacement for regular cigarettes rather than as a way to quit smoking. Objectives The study aimed to assess the perception of e-cigarette consumption and associated factors among the Saudi population in Jeddah city. Methodology A cross-sectional study was conducted on the Saudi population in Jeddah, Saudi Arabia, during the year 2023. The study assessed the participant's perceptions of e-cigarette consumption and its risk factors. A pre-existing online questionnaire created by Google Forms was distributed among the population through social media applications to collect data after obtaining their informed consent. Results A total of 515 participants were included in this study. Relatives and friends were the most common sources (54%) for information about e-cigarettes. Of the sample, 17.5% thought that e-cigarettes were safer than conventional cigarettes, 13.4% used e-cigarettes on a regular basis, and 65% had not smoked electronically before. Vaping pushed only 17.2% to try traditional tobacco cigarettes, and 25% stopped using traditional tobacco products after starting to smoke e-cigarettes. Gender, age group, and total family salary were the associated factors with the use of e-cigarettes. In addition, an association between the perception of e-smoking and its use was noticed, as well as a significant association between gender and withdrawal symptoms. Conclusion A minority of the participants perceived that e-cigarette smoking is safer than conventional methods of smoking. The majority did not practice e-smoking at all. Furthermore, results showed that relatives and friends were the most common sources of information. The findings from the correlation testing underscore several noteworthy associations within the studied population. Notably, gender, age, total family salary, and occupation exhibited statistically significant correlations with e-cigarette usage.