Background: Electronic cigarette adoption has transformed nicotine delivery patterns globally, with 15% prevalence among youth aged 13-15 years. The cardiovascular implications of combined electronic cigarette and combustible tobacco use remain incompletely characterized. We examined the associations of combined smoking and/or vaping versus no nicotine exposure with elevated blood pressure (BP) and hypertension prevalence using nationally representative United States data from 2021-2023. Methods: Data from the US National Health and Nutrition Examination Survey (NHANES) 2021-2023 cycle, which included 6,262 individuals aged ≥12 years old with complete smoking/vaping status: any smoking and/or vaping (n=1,190) versus no smoking or vaping (n=5,072) were used. Elevated BP was classified as ≥120/70mmHg and hypertension as ≥140/90mmHg, and history of smoking and/or vaping were collected with questionnaire. Multivariable logistic regression and mediation path analysis were conducted. Results: Among 6,262 participants (mean age 42.2 years [SD 21], 63.3% female), smokers/vapers had significantly higher prevalence of elevated BP compared to non-smokers/non-vapers (54.4% vs 39.2%, p<0.001) and hypertension (15.4% vs 11.8%, p<0.001). In fully adjusted models, smoking/vaping was associated with increased odds of elevated BP (aOR: 1.34, 95%CI: 1.12-1.60, p=0.001) and hypertension (aOR: 1.46, 95% CI: 1.06-1.99, p<0.001). Smoking/vaping was associated with a 1.05 mmHg higher diastolic BP (p<0.001) but had no association with systolic BP. Mediation analysis revealed that higher total cholesterol partly mediated (6.7% mediation effect) the relationship between smoking/vaping and diastolic BP. Conclusions: Combined smoking and/or vaping exposure was associated with higher odds of elevated BP and hypertension compared to no nicotine use. The selective diastolic BP elevation suggests an increased peripheral vascular resistance as the primary mechanism; however, longitudinal studies examining these direct vascular mechanisms are warranted.

Hydroxyacetone was previously detected at high concentrations (up to ∼12 mg/mL) in electronic cigarette (EC) aerosols, including those derived from products associated with adverse health effects. Given the limited understanding of its inhalation toxicology, we investigated hydroxyacetone's impact on human airway epithelial cells. Acute exposures at the air-liquid interface (ALI) using 3D EpiAirway tissues─a surrogate for human tracheobronchial epithelium─were analyzed via proteomics. Differential expression analysis identified numerous affected proteins, with enrichment pointing to alterations in mitochondrial function and actin cytoskeletal disruption as major targets. Ingenuity Pathway Analysis (IPA) highlighted "Mitochondrial Dysfunction" and "NRF2-Mediated Oxidative Stress" among top toxicological categories, and "Nuclear Cytoskeletal Signaling" as a key canonical pathway. To validate and extend these findings, submerged cultures of BEAS-2B cells were exposed to hydroxyacetone (0.01-10 mg/mL) and assessed for mitochondrial activity, oxidative stress, and F-actin integrity. At 1 mg/mL, mitochondrial membrane potential and reactive oxygen species (ROS) increased, with elevated hydrogen peroxide detected in the culture medium. At 10 mg/mL, mitochondrial activity declined significantly, accompanied by cell rounding and apoptotic blebbing within 2 h. F-actin destabilization occurred at 1, 3.33, and 10 mg/mL, with cytoplasmic and perinuclear filaments more affected than cortical actin. Findings from ALI and submerged models were concordant, supporting hydroxyacetone-induced mitochondrial stress, oxidative damage, and cytoskeletal disruption. These results suggest that hydroxyacetone concentrations found in EC aerosols may contribute to respiratory toxicity and warrant further investigation.

Emergency Psychiatric Effects of Nicotine Vaping Cessation: A Narrative Review

The increasing use of flavored electronic cigarettes (e-cigarettes) raises concerns about their potential impact on the emission of harmful chemicals, particularly carbonyl compounds. This study systematically examines the effects of eight representative flavoring chemicals from four major classes including esters (ethyl acetate, ethyl butyrate), alcohols (menthol, ethyl maltol), aromatic aldehydes (benzaldehyde, vanillin), and terpenes (limonene, linalool) under varying power outputs (50 and 90 W), base liquid composition [propylene glycol (PG)/vegetable glycerin (VG) ratios (80:20, 50:50, and 20:80)], and flavor concentrations (1 and 5 mg/mL). Across all conditions, flavored e-liquids tend to produce carbonyl emissions that are higher than those of unflavored controls. Terpene-based flavors showed the strongest effects, with formaldehyde emissions being up to 2-fold higher and acrolein emissions up to 8-fold higher, frequently exceeding short-term exposure limits. Aromatic aldehydes and alcohols also increased emissions, though to a lesser extent, while esters showed smaller or inconsistent effects. The influence of flavors was further modulated by their concentration, PG/VG ratio, and device power, with higher concentration, VG content, and power amplifying emissions. These results highlight the complex interactions among e-liquid composition, flavor class, and vaping conditions, demonstrating that certain flavorings substantially elevate toxicant emissions. These findings underscore the importance of considering flavor composition, device power, and base material in evaluating the potential health risks associated with e-cigarette use.

Combustible cigarettes remain the dominant tobacco product in China, although use of emerging tobacco/nicotine products such as electronic cigarettes (ECs), heated tobacco products (HTPs), smokeless tobacco and nicotine pouches (NPs) is increasing. However, their addictive potential is not well understood. We conducted an online survey (June-September 2025) among 5,901 adult tobacco/nicotine users in China, assessing dependence using the Autonomy Over Tobacco Scale (AUTOS) and the Fagerström Test for Nicotine Dependence (FTND). General linear regression indicated that EC-only users had the lower AUTOS scores (18.32 ± 6.84), while poly-users, especially cigarette + EC users, showed the higher AUTOS (21.61 ± 6.46) and FTND scores (4.06 ± 2.10), compared with cigarette-only users (AUTOS: 20.41 ± 7.02, FTND: 3.63 ± 2.26). Similarly, individuals using ECs plus HTPs (4.79 ± 2.39), cigarettes plus ECs plus HTPs (4.77 ± 1.70), or other combinations (4.76 ± 2.02) exhibited higher FTND scores than cigarette-only users. Familiarity with tobacco/nicotine products and perceived social facilitation were positively associated with both AUTOS and FTND, while perceptions of addictiveness, quitting difficulty, and health risk were positively related to AUTOS. These findings highlight multidimensional dependence, encompassing psychological and physiological dimensions, and reflect influences of diverse product use and cognitive perceptions.

E-cigarette switching, smoking cessation, and the risk of hepatocellular carcinoma in patients with chronic hepatitis B: A nationwide cohort study in South Korea.

E-cigarettes can help smokers quit, but how e-cigarettes used for tobacco smoking cessation impact sleep is still unclear. The primary objective was to evaluate the effect of e-cigarettes for smoking abstinence on sleep quality. Secondary objectives included subscales of sleep quality. We conducted a secondary analysis of the Efficacy, Safety, and Toxicology of electronic nicotine delivery systems for smoking cessation (ESTxENDS) randomized controlled trial, which included adult smokers in Switzerland (5 sites, 7.2018-6.2021). The intervention group received free e-cigarettes and e-liquids over 6 months plus standard-of-care smoking-cessation counseling (SOC); the control group received SOC alone. The primary outcome was overall self-reported sleep quality at 6 months, measured by the Pittsburgh Sleep Quality Index (PSQI). We considered a minimal clinically important difference (MCID) of 2.5-5. Secondary outcomes included PSQI subscales. We used adjusted linear regressions with inverse probability of attrition weights (IPAW). ESTxENDS included 1246 participants. Of these, 831 participants completed the PSQI at follow-up. For the primary outcome, there was no significant difference in PSQI score between groups (b=-0.20, p=.256, adjusted analyses with IPAW). For PSQI subscales, only sleep efficiency was significantly better in the intervention group (b=1.87, p=.018), below MCID. E-cigarettes added to SOC for tobacco smoking abstinence did not significantly alter participant's self-reported sleep quality compared to SOC alone. Clinicians can inform patients willing to quit smoking with e-cigarettes that their use is not likely to disrupt their perceived sleep quality on average.

Electronic cigarettes (e-cigs) have rapidly gained popularity in the past 20 years. However, the health impacts of their use remain unclear. E-cigs generate aerosols by heating e-liquids containing solvent vehicles, nicotine, additives, and flavorant chemicals. This process not only aerosolizes the liquid ingredients but also generates a complex mixture of by-products, many of which are harmful. Recent studies have demonstrated that inhaling e-cig aerosols can disrupt cardiac electrophysiology and rhythm as well as autonomic regulation of the heart. Furthermore, recent and historical observations indicate that many individual e-cig constituents, such as nicotine, aldehydes, flavorants, polycyclic aromatic hydrocarbons, metals, and carbon monoxide, can impair cardiac electrophysiology and rhythmicity. Although it remains largely unclear which constituents pose the greatest harm, a growing body of in vivo animal experiments, in vitro studies, and clinical studies collectively indicate that e-cigs adversely alter electrophysiology and thus may increase risk for severe and fatal arrhythmias. Nonetheless, more studies are needed to determine how these effects translate to e-cig users and relate to specific constituent compounds. Here, we summarize the existing science detailing how e-cig aerosols and their individual constituents disturb cardiac electrophysiology and promote arrhythmia. Although direct evidence that e-cigs cause arrhythmias in humans remains elusive, research continues to advance the biological plausibility of a causal relationship between e-cig use and life-threatening disruptions in cardiac electrophysiology.

The laryngeal epithelium contains a basal cell (BC) layer. The BC layer is a reservoir of progenitor cells necessary for the formation and regeneration of the epithelium. The epithelium is susceptible to the deposition of inhaled irritants such as cigarette smoke (CS) and electronic cigarette (E-Cig) aerosol. The objective of this study was to quantify BC, proliferating cells, and epithelial histologic architecture in the larynx following a 6-week exposure to CS or E-Cig aerosol. Mice (N = 12) were assigned to a room-air control, CS-exposed, or an E-Cig-exposed group. Exposures were conducted for 2 h per day, 5 days a week for a total of 6 weeks. Mice were then euthanized and the larynx was evaluated using immunofluorescence and histology. We assessed p63-positive BCs, Ki67-positive proliferating cells, p63 and Ki67 colocalized cells, overall cellularity, and epithelial thickness across the supraglottic, vocal fold, and subglottic regions of the larynx. Following E-Cig exposure, there was a significant reduction in p63-positive BC in the vocal folds as compared to the CS-exposed and control group and epithelial thickness compared to the CS-exposed group. No significant changes were observed in the numbers of BCs, proliferating cells, colocalized cells, or overall cellularity in any of the other laryngeal regions examined. An E-Cig-induced reduction in BCs within the vocal fold epithelium may have implications for decreased regenerative capacity. Overall, our findings highlight distinct epithelial responses to CS and E-Cig exposures and underscore the regional heterogeneity of the laryngeal response to these common inhaled challenges.

Introduction Cigarette consumption among university students remains a complex public health issue, encompassing both conventional and electronic products. This study investigates the multidimensional aspects of cigarette use among young adults, with a particular focus on psychosocial, perceptual, and behavioral determinants influencing nicotine consumption. Methods A quantitative, cross-sectional design was employed. Data were collected through a standardized online questionnaire administered to 267 students enrolled in higher education institutions in Brașov, Romania. Descriptive statistics, correlation analyses, and ANOVA were used to identify consumption patterns, differentiate user types (current smokers, former smokers, and non-smokers), and examine emotional and motivational factors associated with tobacco and e-cigarette use. Results Findings indicate that traditional cigarette smoking is most frequently initiated under social influence, whereas electronic cigarette use is primarily associated with aesthetic appeal and flavor variety. Psychological motivations, particularly stress relief and social comfort, show significant correlations with continued nicotine use, especially among current smokers. Analysis informed by the Theory of Planned Behavior and Social Cognitive Theory highlights the role of behavioral intention and self-efficacy in sustaining smoking behaviors. Discussion The results underscore the multifaceted nature of smoking behavior among youth populations, revealing a dynamic interplay between cognitive, emotional, and environmental variables. These findings provide empirical support for the development of targeted intervention strategies and emphasize the need for integrated public health policies that address both product regulation and psychosocial education.

Despite the growing public health threat of electronic cigarettes (e-cigs), the cell-specific immune responses to differently flavored e-cig exposure remain poorly understood. To bridge this gap, we characterized the lung immune landscape following acute nose-only exposure to flavored e-cig aerosols in vivo using single-cell RNA sequencing (scRNA seq) in mice. Metal analysis of daily generated aerosols revealed flavor-dependent, day-to-day variation in metal (Ni, Cu, K, and Zn) leaching. scRNA seq profiling of 71,725 lung cells from control and exposed mice revealed pronounced dysregulation of myeloid cell function in menthol (324 differentially expressed genes, DEGs) and tobacco (553 DEGs) flavors, and lymphoid cell dysregulation in fruit-flavor (112 DEGs) e-cig aerosol exposed mouse lung, compared to air controls. Flow cytometry corroborated these findings, showing increased neutrophil frequencies and reduced eosinophil counts in menthol- and tobacco-exposed lungs. Flavored e-cig exposure also increased CD8+ T-cell proportions, upregulated inflammatory gene expression (Stat4, Il1b, Il1bos, Il1ra, and Cxcl3), and enriched terms like 'Th1 cytokine signaling' and 'NK cell degranulation'. Notably, tobacco-flavored e-cig aerosol exposure increased immature (Ly6G⁻) neutrophils and reduced S100A8 expression, suggesting altered neutrophil activation in vivo. Overall, this study identifies flavor-dependent immune alterations in the lung following acute e-cig aerosol exposure and provides a foundation for future mechanistic studies.

Background/Objectives: Cigarette smoking is a well-established risk factor for periodontal tissue damage caused by oxidative stress and increased proteolytic activity. Electronic cigarettes (e-cigarettes), marketed as less harmful alternatives, deliver nicotine and reactive compounds that may similarly disrupt periodontal health. However, their molecular effects on clinically healthy periodontal tissues remain unclear. This study aimed to compare oxidative stress-related and matrix-degradative biomarkers in the gingival crevicular fluid (GCF) of cigarette smokers (CS), e-cigarette (EC) users, and non-smokers (NS), and to examine the relationships among these markers. Methods: Sixty individuals, who were systemically and periodontally healthy (20 CS, 20 EC, and 20 NS), were examined. Clinical parameters, including probing depth (PD), clinical attachment level (CAL), plaque index (PI), and bleeding on probing (BOP), were recorded. GCF samples were analyzed for reactive oxygen species (ROS), matrix metalloproteinase-9 (MMP-9), and forkhead box protein O-1 (FOXO-1) using ELISA. Initial group comparisons were descriptive, followed by analysis of covariance (ANCOVA) to adjust for age; PI and PD were included as covariates in separate models. Correlations were assessed using Spearman’s analysis. Results: PD was significantly higher in both EC users and CS compared with NS (p = 0.022). MMP-9 levels were significantly higher in CS than in EC users and NS (p &lt; 0.05), while FOXO-1 concentrations were significantly lower in CS compared with NS (p = 0.0227). ROS levels did not differ significantly among groups (p &gt; 0.05). After adjustment for age, PI, or PD, group differences in MMP-9 and FOXO-1 remained statistically significant, whereas ROS levels remained comparable. FOXO-1 demonstrated positive correlations with ROS and MMP-9 within exposure groups; these associations were considered exploratory. Conclusions: In this cross-sectional study, CS and EC use were associated with altered matrix-regulatory biomarker profiles in clinically healthy periodontal tissues, independent of age and periodontal indices. Causal or temporal inferences cannot be drawn, and longitudinal studies are needed to clarify the long-term periodontal implications of these findings.

The marketing of electronic nicotine delivery systems (ENDSs) has been prohibited in Brazil since 2009, and their regular use is less prevalent than in countries where these devices are not banned. To monitor the presence of ENDSs, it is important to prevent the development of a new generation of nicotine-dependent individuals. However, traditional surveys are costly for accessing rare populations. Therefore, to reach ENDS users aged ≥15 years, we used the online version of the respondent-driven sampling method (web-RDS), a peer chain recruitment method for contacting hard-to-reach groups. This paper aims to provide information on the implementation of the first web-RDS study in Brazil to recruit ENDS users. This study was conducted in Rio de Janeiro, the second largest city in Brazil. After a formative phase using qualitative in-depth interviews, we selected the first participants ("seeds") to complete an online quantitative questionnaire on the profile of their own ENDS use and the size of their contact network of ENDS users. Participants received 3 coupons to invite eligible peers. For participation and recruitment, each participant received a gift card worth approximately US $4. The target sample size was 300 ENDS users based on a conservative estimate and adjusted for design effect. From August 2022 to May 2023, of the 12 seeds included, 508 attempts at access were recorded in the data collection system, of which 330 (65%) were eligible. Duplicate or ineligible attempts were identified and removed through automated and manual checks. Recruitment was initially slow due to the low monetary incentive, but it improved after the amount was increased. We found that 43.1% (75/174) of recruiters recruited only 1 eligible participant, 34.5% (60/174) recruited 2 eligible participants, and 22.4% (39/174) recruited 3 participants. Web-RDS was able to reach individuals in different areas of the city. Convergence was reached for target variables (ie, age and age at first use of electronic cigarettes). The median time to complete the questionnaire was 12 (IQR 8-17) minutes. Half (154/324, 47.5%) of the respondents reported that they knew up to 5 other ENDS users. The web-RDS methodology proved to be a feasible approach for accessing the population of ENDS users in Brazil. Incentives for participation and recruitment emerged as a determining factor in the data collection process. However, researchers needed to be aware of individuals attempting to circumvent the system by participating without being eligible or participating multiple times. Implications for optimizing web-RDS are discussed. On the basis of the method's performance in this study, web-RDS shows potential to support future repeated data collection processes that could help monitor changes in the profiles of ENDS users over time, supporting the implementation of ongoing measures from Brazil's National Tobacco Control Policy.

INTRODUCTIONThis rise in vaping has become a significant public health concern. This mixed-methods study aims to assess the impact of vaping cessation infographics on different cessation motivation and gather feedback regarding how the infographic could be further improved.METHODSCurrent e-cigarette users completed an online cross-sectional survey in January 2022 through Prolific®. Participants evaluated a vaping cessation infographic. Eligible participants were adults aged 19–64 years, US residents, fluent in English, and current e-cigarette users. Participants completed a questionnaire with questions regarding demographics, e-cigarette use, and assessment of the liking of infographics. Poisson regressions were conducted to assess the associations between infographic liking and perceived vaping cessation importance, readiness, and commitment. The open-ended feedback provided in the online survey on the infographic was assessed using content analysis.RESULTSAmong 361 participants who were presented with the cessation infographic, 85.9% of them rated the infographic favorably. The liking of the cessation infographic (e.g. excellent vs fair/poor) was associated with greater perceived quit importance (incidence rate ratio, IRR=2.0, p<0001, quit commitment (IRR=1.6, p=0.005), and readiness to quit (IRR=1.9, p=0.001). The analysis of open-ended feedback resulted in several themes. Participants appreciated the detailed coping strategies, ease of understanding and accessibility, timelines and expectations, support and encouragement, comprehensive information, youth-focused content, and visual and structural appeals. Areas identified for improvement included health information and risks, design and presentation, target audience and content, support and resources, and user engagement.CONCLUSIONSThis study highlights the need for tailored vaping cessation interventions. The infographic presented in this study resonated more with African American and Hispanic participants, who reported higher favorability than White participants.

Background: Nicotine use among the youth has been on the rise, especially with the introduction of E-cigarettes. This has sparked concerns regarding E-cigarettes and traditional cigarettes in terms of patterns, dependence, and perceptions within the youth population, which are issues this study aimed to investigate. Methods: A cross-sectional survey was conducted among university students at Ajman University, which is in the Middle East and North Africa (MENA) region. Using the Cigarette Dependence Scale (CDS-12) and Penn State Electronic Cigarette Dependence Index (PS-ECDI), dependence on both cigarettes and E-cigarettes was quantified. Results: Out of 1713 respondents, 18.9% were currently using nicotine products, including E-cigarettes (12.7%) and traditional cigarettes (5.1%). Nicotine use was significantly associated more with males than females with an odds ratio of 4.14. However, there was no difference between genders in the dependence scores. In addition, dual nicotine use and an earlier onset of nicotine consumption were associated with significantly higher dependence scores than single users and a late onset of smoking. Participants overall attributed cigarettes and E-cigarettes as equally harmful. Conclusions: Both cigarette and e-cigarette use were prevalent and associated with notable dependence. Although E-cigarettes are often promoted as cessation aids, their use in our sample did not appear to facilitate quitting and may instead sustain nicotine dependence. Targeted youth-focused cessation programs and stricter marketing and sales regulations are essential to prevent further normalization. Longitudinal studies are needed to track evolving patterns and health impacts in the MENA region.

Abstract Introduction: Despite legal prohibitions, electronic cigarette (E-cigarette) use among Thai adolescents is increasing. While smoke-free school policies have shown promise in reducing youth tobacco use, longitudinal evidence of their effectiveness in Thailand remains limited. This study aimed to examine the impact of smoke-free school environments on cigarette and E-cigarette use among secondary school students in four regions of Thailand. Methods: A multicenter prospective cohort study was conducted from May 2023 to November 2024 across four points. A total of 5555 students in Grades 7 and 8 from smoke-free and nonsmoke-free schools were recruited via multistage sampling, with 1952 students completing all four data collection rounds. Data were collected via a validated self-administered online questionnaire. Descriptive statistics summarized participant characteristics and outcomes. Generalized estimating equations (GEEs) were used to assess differences in smoking-related behaviors, adjusting for potential confounders. Results: Students in smoke-free schools consistently reported a lower prevalence of current smoking (4.2%–4.5% vs. 4.9%–6.5%), lower smoking intention, and lower E-cigarette use intention over time. Multivariable GEE analysis revealed significantly reduced odds of smoking (adjusted odds ratio [AOR] = 0.60; 95% confidence interval [CI]: 0.43–0.86), smoking intention (AOR = 0.74; 95% CI: 0.62–0.90), and E-cigarette use intention (AOR = 0.67; 95% CI: 0.55–0.82) among students in smoke-free schools. However, they reported higher odds of witnessing vaping on campus (AOR = 1.36; 95% CI: 1.19–1.57). Conclusion: Smoke-free school policies effectively reduce adolescent smoking and E-cigarette use intentions, although additional strategies are needed to reduce vaping exposure in school settings.

Background and Objectives: E-cigarette use among middle and high school students steadily increased in the last decade, raising significant public health concerns. It is argued that e-cigarettes contain a lower level of toxicants than combustible tobacco cigarettes. This perception has contributed to the growing popularity of e-cigarettes among youth. However, lower level of toxicants does not mean addiction is less likely. In this study, we examine trends in the usage of electronic cigarettes among middle and high school students in the U.S. from 2018 to 2023, compare these patterns with traditional cigarette use over the same period and population, and explore the underlying reasons driving e-cigarette use within this demographic. Understanding patterns and motivations are essential for developing effective prevention and intervention strategies. Materials and Methods: Data were derived from the National Youth Tobacco Survey (NYTS), administered by the Centers for Disease Control and Prevention (CDC). Population-level estimates and standard errors were calculated to facilitate comparisons across subgroups and time points. Results: A declining trend in e-cigarette use was observed over the study period. The proportion of students who reported exclusive e-cigarette use was significantly higher than that of those who used combustible cigarettes exclusively. Among reported motivations, anxiety consistently ranked among the top three reasons for vaping for current users. Conclusions: The downward trend in youth e-cigarette experimentation is encouraging. However, the period from 2020 to 2023, which includes the COVID-19 pandemic (2020 and 2021) era, may have impacted usage patterns. Alarmingly, the number of students who vape exclusively is approximately five times greater than that of those who smoke only cigarettes. This finding contradicts claims by e-cigarette manufacturers that their products facilitate smoking cessation. Further rising e-cigarette smoking exclusively is of public health concern, which warrants targeted intervention.

Use of menthol-flavored (vs. tobacco-flavored) electronic nicotine delivery systems (ENDS) may be associated with higher rates of complete switching among adults who smoke (AWS). This paper evaluates the association over 2years, while considering robustness across different missing-data approaches. 22,905 US AWS and purchased JUUL ENDS were enrolled in a longitudinal cohort study and completed up to 10 follow-ups. To assess potential bias due to missingness, analyses: (a) compared participant characteristics by levels of missingness and (b) assessed whether tobacco or menthol JUUL was associated with missingness. The association of menthol (vs. tobacco) JUUL with switching (no past 30-day smoking) was evaluated using four missing-data treatments: (1) non-missing data-only; (2) imputing smoking for missing ('missing-as-smoking'); imputing outcome from participant characteristics and previous switching (3) one time, and (4) Multiple Imputations. Survey completion was minimally associated with participant characteristics (each explaining < 0.4% of variance) or flavor (< 2% between-flavor difference). In observed data, menthol was significantly associated with a higher switch rate than tobacco (adjusted risk ratio = 1.12 [95% CI = 1.09-1.16], model-based average switching probability: 51.6% vs. 45.9%). Effects were similar across all approaches, including Missing-as-Smoking (1.15 [1.11-1.18]; 44.1% vs. 38.4%), Single Imputation (1.12 [1.09-1.16]; 51.3% vs. 45.7%), and Multiple Imputation (1.11 [1.08-1.15]; 51.9% vs. 46.6%). The added benefit of menthol- (vs. tobacco-flavored) JUUL was concentrated among adults smoking non-mentholated cigarettes. AWS using menthol JUUL, especially those smoking non-menthol cigarettes, were more likely to switch completely than those using tobacco JUUL. Consistent results across several approaches suggested minimal bias due to missing data.

Introduction. The liquids of electronic nicotine delivery systems (ENDS), which have the multi-component composition, represent a major environmental hazard, as they contain extremely toxic substances. Although the popularity of this form of smoking grows, the data on the biological effects of long-term exposure of animals and humans to e-cigarette and vape components are insufficient. The aim of the present study is to investigate the morphofunctional state of the lungs and main organs of detoxification in Djungarian hamsters under long-term exposure to ENDS aerosol. Materials and Methods. The research was conducted in 2021 in the colony of laboratory Djungarian hamsters kept at the Institute of Systematics and Ecology of Animals SA RAS. Thirty-six hamsters were divided into two groups. During 80 days, animals in the experimental group (10 females and 10 males) were exposed to vapour from heating the X-3 Yoghurt Pear liquid. The procedure was performed twice a day for 10 minutes, with a 2-hour interval. Hamsters in the control group (8 males and 8 females) were placed in exposure chambers but were not exposed to vapour. At the end of the 80-day experiment, the animals were decapitated, and organs were collected for preparing thin histological sections. The specimens were stained with Boehmer’s hematoxylin and eosin. Collagen distribution was determined using the Mallory method. Histological specimens of organs were examined under transmission light microscope Results. In experimental animals exposed to toxic vapour, a homogeneous black substance was detected in bronchial epithelial cells and in the alveolar interstitium. In the lung parenchyma, signs of developing interstitial pneumonia, atelectasis, emphysema, and obstructive bronchitis were detected, indicating impaired ventilation-perfusion relationships in the lung tissue and gas exchange disorder. In the kidneys, the homogeneous substance was localized in the lumen of renal tubules. Light optical microscopy revealed the main signs of lethal damage in renal epithelial cells. Strongly expressed dilation of the renal glomerular capillaries, coupled with a nearly 2-fold reduction in the surface area of renal corpuscles compared to control samples, indicates impaired hemodynamics and disrupted renal reabsorption-filtration function. Regarding the liver, a high level of localization of evolutionarily adapted to detoxification dark hepatocytes dying by apoptosis in the centrilobular region of the lobule, indicates the involvement of toxic substances in this process, which enter the liver with the blood. Discussion and Conclusion. The experiment demonstrated the general pathogenic effects of ENDS aerosol on the lungs and organs of detoxification in animals after long-term exposure to it. Such studies are necessary in the context of the observed growth of consumption of the nicotine delivery systems at the global market.

Background The rise of electronic cigarettes (e-cigarettes) has attracted both former smokers and teenagers looking for an alternative nicotine source. This study aimed to assess the prevalence of e-cigarette use, the determinants associated with its use, dependence, and the impact of e-cigarette use on physical activity and mental health among the Saudi population. Methods A cross-sectional study was conducted from September 27, 2024, to October 21, 2024. We used Penn State Nicotine Dependence Index, the Kessler Psychological Distress Scale, and the Global Physical Activity Questionnaire. Convenience and snowball sampling methods were used to recruit participants using an electronic survey questionnaire and face-to-face interviews. Results Among 3092 participants, the prevalence of e-cigarette use was 9.8%.Nicotine dependence was notable among users, with 41.7% exhibiting medium dependence and 22.2% reporting high dependence. Physical activity levels varied: 22.3% engaged in high activity, 34.1% in moderate, and 24.3% in low activity. Regarding mental health, 42.2% experienced high psychological distress. Participants with high physical activity had significantly higher odds of e-cigarette use [crude odds ratio (cOR) = 1.79, 95% confidence interval (CI): 1.29–2.49], while those with high distress had lower odds [cOR = 0.27, 95% CI: 0.19–0.39]. Path analysis revealed that mental distress positively predicted e-cigarette dependence ( β = 0.118 ), whereas physical activity showed a small positive association with dependence ( β = 0.209 ). Conclusions E-cigarette use in this population is significantly influenced by socio-demographic factors, physical activity levels, and mental health status. The complex relationship observed, where high physical activity is associated with use and mental distress is protective against initiation but predictive of dependence, highlights the need for integrated public health strategies. Interventions should focus on high-risk groups and address the dual role of lifestyle and psychological factors in both prevention and dependence management.