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Adults who smoke (AWS) who switch completely to e-cigarettes reduce their exposures to many harmful chemicals in cigarette smoke. Those who believe e-cigarettes are less harmful than cigarettes are more likely to use e-cigarettes to switch away from smoking, yet most believe e-cigarettes are at least as harmful as cigarettes. This study assessed the effect on risk perceptions of communicating that switching can reduce exposure to harmful chemicals from cigarette smoke. In a randomized experiment, AWS (n = 3485), dual users (DU) of cigarettes and e-cigarettes (n = 1756), and nonusers (n = 7316) viewed an ad for JUUL with or without a reduced-exposure message, and completed assessments of perceived risk. Message exposure decreased perceived risk of JUUL among adults who smoke, while increasing perceived risk of smoking, thus increasing the perceived risk differential (PRD). Among DU, the message increased perceived risk of smoking, but did not change perceived risk of JUUL. Among nonusers, who rated the perceived risk of all assessed tobacco products higher than did AWS and DU, the message decreased perceived risk of JUUL, and did not affect perceived risk of smoking. Accurate modified exposure communications have potential public health benefit by shifting the PRD of smoking and e-cigarettes., (© The Author(s) 2025. Published by Oxford University Press. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

Background: Placental abruption (PA) is a critical obstetric complication, with maternal smoking recognized as a key risk factor. Despite the increased use of heated tobacco products (HTPs), the impact of HTPs remains unclear. This study investigated whether pregnant women using HTPs are at a higher risk of PA than non-users., Methods: We analyzed data from "the Japan COVID-19 and Society Internet Survey," a prospective, self-reported online survey cohort. Questionnaires were randomly distributed between July 28, 2021, and August 30, 2021. Pregnant respondents in 2021 were invited to complete an additional survey from February 14, 2022, to February 28, 2022. We set the outcome as the absolute risk difference (aRD) and relative risk ratio (rRR) of PA incidence due to smoking HTPs in the first trimester of pregnancy. The sample size included 12 836 participants. We calculated outcomes using a generalized linear model (GLM) and inverse probability of treatment weighting (IPTW). We also performed a Bayesian approach and multiple-bias analysis for sensitivity analysis., Results: We found the robust aRD of 0.07 (95% confidence interval (CI): 0.06, 0.09) and the rRR of 11.3 (95% CI: 7.5, 17.0). Multiple bias analyses showed that unmeasurable confounders would need to have at least an rRR = 14 relationship with both exposure and outcome to disprove the observed association. There has not been post hoc analysis or secondary use of data., Conclusion: Early pregnancy use of HTPs is associated with an increased risk of PA., Competing Interests: Declarations. Ethics Approval and Consent to Participate: This study was conducted according to the 2008 Declaration of Helsinki. The Research Ethics Committee of the Osaka International Cancer Institute reviewed and approved the study protocol (approval no.: 1412175183). Before answering the online questionnaire, all participants provided written informed consent. Consent for Publication: Consent to publish was not needed because the information was anonymized, and the submission does not include personally identifiable images. Competing Interests: The authors declare no competing interests., (© 2025. The Author(s).)

Tobacco smoking is prevalent across the world and causes numerous diseases. Cigarette smoke (CS) compromises immunity, yet little is known of the components of CS that impact T cell function. MR1 is a ubiquitous molecule that presents bacterial metabolites to MAIT cells, which are highly abundant in the lungs. Using in silico, cellular, and biochemical approaches, we identified components of CS that bind MR1 and impact MR1 cell surface expression. Compounds, including nicotinaldehyde, phenylpropanoid, and benzaldehyde-related scaffolds, bound within the A' pocket of MR1. CS inhibited MAIT cell activation, ex vivo, via TCR-dependent and TCR-independent mechanisms. Chronic CS exposure altered MAIT cell phenotype and function and attenuated MAIT cell responses to influenza A virus infection in vivo. MR1-deficient mice were partially protected from the development of chronic obstructive pulmonary disease (COPD) features that were associated with CS exposure. Thus, CS can impair MAIT cell function by diverse mechanisms, and potentially contribute to infection susceptibility and disease exacerbations., (© 2025 Awad et al.)

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., Competing Interests: Declarations. Consent to participate: All authors have their consent to participate in this research. Consent for publication: The authors approved the last version of the manuscript for publication. Competing interests: The authors declare no conflict of interests., (© 2024. Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i.)

Introduction: Adults who switch from smoking cigarettes to use of electronic nicotine delivery systems (ENDS) may reduce their exposure to harmful and potentially harmful constituents (HPHCs). This study assessed changes in exposure to HPHCs, assessed via biomarkers of exposure (BOEs), among adults who switched to a new ENDS product., Methods: Adults who smoke cigarettes ( N  = 89) were randomized to: (1) switch completely to using JUUL2 Virginia Tobacco ( N  = 24) or Polar Menthol ( N  = 24); (2) continue smoking usual brand (UB) cigarettes ( N  = 21); or (3) abstain from all tobacco/nicotine products ( N  = 20) for 6 d. Changes in exposure to nicotine and 11 other HPHCs from Baseline to Day 6 were compared among study groups., Results: Changes in nicotine exposure did not significantly differ between JUUL2 and UB Cigarette groups ( p s > 0.37). Among participants who switched completely to JUUL2 products, median percent reductions (Day 6-Baseline) in non-nicotine BOEs ranged from 65% to 94%, significantly greater than changes in the UB Cigarette group ( p s < 0.001). None of the non-nicotine BOEs significantly differed between the JUUL2 groups and the Abstinence group ( p s > 0.025)., Conclusions: This randomized study demonstrates that adults who switch completely from smoking cigarettes to use of JUUL2 ENDS products substantially reduce their exposure to HPHCs associated with smoking-related diseases., International Standard Registered Clinical Trial Number: ISRCTN27662176.

A "blunt" is a hollowed-out cigar/cigarillo from which much of the loose tobacco has been removed, and the remaining tobacco wrapper filled with cannabis. Although blunts contain significant levels of tobacco/nicotine, they are often treated as if they were exclusive cannabis products and omitted from surveys of tobacco products. Whereas the prevalence of virtually all other tobacco products is on the decline in the USA, available data suggest that the prevalence of blunt smoking is not - and in fact, it may be increasing. Blunts are most frequently used by people who self-identify as Black. As a result of misperceptions and perhaps biases, there is a dearth of scientific investigation, hence knowledge, surrounding the health effects associated with blunt smoking. Co-use of tobacco and cannabis has been reported to have additive and even synergistic adverse health effects. Lack of investigations into the health effects of tobacco products most frequently used by Black people may contribute to tobacco-related health disparities. We argue that the scientific and public health communities must treat blunts as the potentially lethal tobacco product that they are, studying their prevalence and use patterns, and investigating their adverse health effects, both short and long term., Competing Interests: DECLARATIONS:. Conflict of Interest:: The authors declare that they do not have a conflict of interest., (© 2024. The Author(s).)

Background: Tobacco smoking is a major worldwide health issue that contributes to millions of deaths annually. Electronic cigarettes (E-cigarettes) are also harmful. Smoke/vapor from E-cigarettes and tobacco products consists of free radicals and other toxic substances. Tissue damage in smokers, such as lungs, is highly observed and is linked to oxidative damage and inflammation., Methods: The inflammation and oxidative status of rat lung tissues was examined following whole-body smoke/vapor exposure via E-cigarette, cigarette, and waterpipe for 2 h daily, 5 days per week for 8 weeks., Results: Lung tissue damage was higher in cigarettes and waterpipe groups compared to the E-cigarette group. Collectively, there was a significant increase (p < 0.05) in the mRNA expression of pro-inflammatory mediators (TNF-α, NF-κB, IL-1β) with the exception of IL-1β in the E-cigarettes group. As for the anti-inflammatory mediators (Nrf2 and IL-10), a significant reduction (p < 0.05) of mRNA expression was observed with the exception of Nrf2 in the E-cigarette group. As for IL-6, there was a significant increase in its mRNA expression (p < 0.05) in the cigarette and waterpipe groups. There was also a significant decrease (p < 0.05) in the antioxidant activity of all antioxidants tested (GPx, SOD, and CAT) in all groups with the exception of SOD in the cigarette group., Conclusion: Smoke/vapor administered via E-cigarette, cigarette, and waterpipe elicits inflammation and oxidative stress in rat lungs that is accompanied by histopathological changes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Tobacco smoking remains a major global health concern, causing preventable deaths and economic strain. Although new tobacco products such as heat-not-burn (HnB) are safer alternatives to traditional cigarettes, research on their associated risks remains limited. This study aimed to investigate the effects of HnB smoke exposure on the lungs compared to those of traditional cigarettes and the combined use of HnB and cigarettes using experiments with a mouse model. We quantitatively analyzed changes in the levels of 92 blood plasma proteins using the proximity extension assay method and observed significant changes in their levels in mice exposed to different smoke conditions; specifically, the levels of certain proteins, including Ccl20, Cxcl1, and Pdgfb, increased in the HnB smoke-exposed group, suggesting activation of nicotine pathways. Comparative analysis with traditional cigarette smoke-exposed mice further highlighted similarities and differences in their protein expression profiles. This study contributes to an improved understanding of the biological mechanisms underlying the harmful effects of alternative nicotine delivery systems and identifies potential biomarkers associated with the harmful effects of HnB smoke exposure. However, the precise impact of nicotine on the immune system may be influenced by various factors, necessitating further research.

Background: People who smoke cigars often have misperceptions about the associated risks, contributing to rises in smoking rates. This study investigates the perceived warning effectiveness (PWE) of health warning labels (HWLs) on cigar packages. We tested the impact of warning type and warning size in the HWLs on PWE and other health outcomes., Data and Methods: In a between-subjects experimental design, participants (n=809) who used little cigars or cigarillos in the past 30 days were randomly assigned to one of four conditions: text-only at 30% size, pictorial+text warning at 30% size, text-only at 50% size and pictorial+text warning at 50% size. In each condition, participants rated six cigarillo HWLs on PWE, self-reported learning, thinking about risks, new knowledge, perceived enjoyment and negative affect. Reactance to the labels was also measured. Data were analysed with mixed-effects models., Results: Pictorial+text cigarillo HWLs were deemed more effective than text-only HWLs in PWE ( b =0.34, SE=0.08, p<0.001), self-reported learning ( b =0.20, SE=0.08, p=0.01), thinking about risks ( b =0.18, SE=0.08, p=0.03) and new knowledge ( b =0.34, SE=0.12, p<0.01). They also elicited more negative affect than text-only warnings ( b =0.39, SE=0.08, p<0.001). Warning size did not impact outcomes, and neither warning type nor size predicted perceived enjoyment of smoking cigarillos or reactance to the warnings., Conclusion: Including images with text warning statements for cigarillos can increase PWE. Our findings provide important insights for the US Food and Drug Administration and international regulatory agencies in designing new HWLs for cigars that can more effectively communicate smoking risks, address misinformation and potentially reduce cigar smoking., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.)

Purpose: Despite the advent of heated tobacco products (HTPs), their relationship to mental health remains unclear. This study aimed to determine associations between the use of combustible cigarettes (CCs) and HTPs with depressive symptoms., Methods: This descriptive-analytical cross-sectional study was conducted in March 2023. Using the 8th Korea National Health and Nutrition Examination Survey, 5,349 adults aged 19 years or older were classified into four groups: non-users, CC-only users, HTP-only users, and dual users. Relationships between exclusive or dual use of CCs and HTPs and depressive symptoms were analyzed using item scores and total scores of the Patient Health Questionnaire-9 (PHQ-9). To examine associations between exclusive or dual use of CCs and HTPs and depressive symptoms, a multinomial regression analysis was performed using the PHQ-9 total score., Results: HTP-only users had the highest proportion of those with anhedonia and depressed mood. CC-only users had the highest proportion of individuals with trouble sleeping, while dual users had a higher proportion of those with fatigue and appetite problems. After adjusting for general characteristics, compared to non-users, CC-only users were more likely to have mild and moderate to severe depressive symptoms. HTP-only users and dual users were also more likely to have moderate to severe depressive symptoms., Conclusions: All smokers have a higher risk of depression than non-smokers. Health care providers should closely monitor depressive symptoms, especially in HTP users and dual users of tobacco products., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2025 Lee et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Cigarette filter microplastics are composed of cellulose acetate that does not undergo biological or photo-degradation. These microplastics are readily dispersed and can be found abundantly in water, soil, and air. These fibers possess high absorption capabilities, allowing them to collect and retain pollutants such as toxic elements. As a result, they are regarded as potential dangers to living organisms. The purpose of this study was to analyze the immune response of human peripheral blood mononuclear cells (PBMCs) when exposed to cigarette filter microfibers, measuring the secretion of the inflammatory cytokines TNFα (tumor necrosis factor-alpha) and IL-6 (interleukin-6). In this study, we examined how used cigarette cellulose acetate microfibers affect the viability of peripheral blood mononuclear cells in an appropriate culture medium at three concentrations: 50, 100, and 200 µg/ml. In addition, this study investigated the release of inflammatory cytokines TNFα and IL6 from PBMCs exposed to 200 µg/ml cigarette filter cellulose acetate. The results showed that increasing the concentration of cellulose acetate fibers of one of the brands in the culture medium has a significant effect on reducing cell viability. The 200 µg/ml in DW is more effective than 50 and 100 µg/ml in reducing cell viability. Peripheral blood mononuclear cells showed an inflammatory immune response when exposed to 200 µg/ml cellulose acetate from cigarette filters. They produced inflammatory cytokines that showed a significant increase compared to the control sample. In general, it can be concluded that cellulose acetate fibers in contact with body cells stimulate them and cause an inflammatory response., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: A Delphi study was conducted to reach a consensus among international clinical and health care experts on the most important health and functioning self-reported concepts when evaluating a switch from smoking cigarettes to using smoke-free tobacco and/or nicotine products (sf-TNPs)., Objective: The aim of this research was to identify concepts considered important to measure when assessing the health and functioning status of users of tobacco and/or nicotine products., Methods: Experts (n=105), including health care professionals, researchers, and policy makers, from 26 countries with professional experience and knowledge of sf-TNPs completed a 3-round, adapted Delphi panel. Online surveys combining quantitative (MaxDiff best-worst scaling and latent class analysis) and qualitative assessments were used to rank and achieve alignment on the importance of 69 health and functioning concepts. All experts participating in round I completed round II, and 101 (95%) completed round III., Results: The round I analysis identified 36 (52%) out of 69 concepts that were refined for the round II assessment. The highest-ranked concepts reflected health-related impacts, while the lowest-ranked ranked concepts were related to aesthetics and social impacts. Round II ranking reinforced the importance of concepts relating to health impacts, and the analysis resulted in 20 concepts retained for round III assessment. In round III, the 4 highest-ranked concepts were cardiovascular symptoms, shortness of breath, chest pain, and worry about smoking-related diseases and impact on general health, and they made up 50% of the total score in the MaxDiff analysis. Experts reported likelihood of seeing measurable levels of change in the final 20 concepts with a switch to an sf-TNP. The majority of experts felt it was "likely" or "extremely likely" to observe changes in concepts such as gum problems (74/101, 73%), phlegm or mucus while coughing or not coughing (72/101, 71%), general perception of well-being (72/101, 71%), and throat irritation or sore throat (72/101, 71%). Latent class analysis revealed subgroups of experts with different perceptions of the relative importance of the concepts, which varied depending on professional specialty and geographic region. For example, 74% (14/19) of oncologists aligned with the subgroup prioritizing physical health symptoms, while 71% (12/17) of experts from Asia aligned with the subgroup considering both physical health and psychosocial aspects., Conclusions: This study identified key concepts to be considered in the development of a new measurement instrument to assess the self-reported health and functioning status of individuals using sf-TNPs. The findings contribute to the scientific evidence base for understanding and evaluating both the individual and public health impacts of sf-TNPs., (©Vivienne Law, Esther F Afolalu, Linda Abetz-Webb, Lee Andrew Wemyss, Andrew Turner, Christelle Chrea. Originally published in JMIR Formative Research (https://formative.jmir.org), 02.01.2025.)

Background: The use of electronic cigarettes (e-cigarettes) as a perceived safer alternative to traditional cigarettes has grown rapidly. However, the cardiovascular risks associated with e-cigarettes compared to regular cigarettes remain unclear., Objective: To systematically review and compare the cardiovascular outcomes of e-cigarette use versus traditional cigarette use, focusing on the risks of myocardial infarction, arrhythmias, and sudden death., Methods: A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Peer-reviewed studies published in English were included if they reported cardiovascular outcomes related to e-cigarette or traditional cigarette use. A total of 20 studies were included, covering observational and interventional studies focusing on heart rate variability, myocardial infarction, arrhythmias, and sudden cardiac events. The quality of the evidence was assessed using the GRADE criteria, and data were extracted and analyzed based on the PICOS (Population, Interventions, Comparisons, Outcomes, and Study designs) framework., Results: The systematic review found that both e-cigarettes and traditional cigarettes pose significant cardiovascular risks, with traditional cigarettes linked to a higher incidence of myocardial infarction, arrhythmias, and sudden cardiac death. E-cigarette users also face increased risks of arrhythmias and myocardial infarction compared to non-smokers, primarily due to the constituents of aerosolized e-liquid, including nicotine and flavorings, which contribute to adverse cardiac effects. Regular e-cigarette use, particularly in combination with traditional cigarette use, was associated with a heightened risk of myocardial infarction. Studies also reported heart function abnormalities, such as systolic and diastolic dysfunction, and reduced ejection fractions. Additionally, changes in heart rate variability, heart rate, and blood pressure were observed, indicating both acute and chronic effects of e-cigarettes on cardiovascular autonomic regulation., Conclusions: While e-cigarettes may present a lower cardiovascular risk compared to traditional cigarettes, they are not without harm. Both products are linked to increased risks of myocardial infarction and arrhythmias, though traditional cigarettes pose a higher overall threat. Given the limitations in the current evidence base, particularly concerning the long-term effects of e-cigarette use, further research is needed to clarify these cardiovascular risks and inform public health guidelines., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The advent of heated tobacco products (HTPs) has introduced new variables in the study of nicotine delivery systems and their health implications. Amidst concerns over cardiovascular effects, this study aims to elucidate the acute impact of HTP inhalation on extracellular vesicles (EV) levels in young, healthy individuals. In this controlled, acute exposure study, 23 young, healthy volunteers were subjected to HTP inhalation. EV levels of endothelial and platelet origin were quantified through flow cytometry before and after exposure. Data analysis was performed using multiple measures ANOVA to assess changes in EV concentrations. Our findings reveal a significant increase in EVs of endothelial and platelet origin following short-term HTP inhalation with nicotine. Notably, no significant change was observed in leukocyte- and neutrophil-derived EVs. This increase in EVs suggests acute vascular stress, with peak levels observed 4 h post-exposure. The rise in endothelial and platelet-derived EVs aligns with documented responses to acute vascular injury, paralleling the effects seen with traditional cigarette and e-cigarette use. Despite HTPs being marketed as safer alternatives, our results indicate that nicotine-containing HTPs may still pose significant vascular risks. These findings contribute to the growing body of evidence cautioning against the perceived safety of HTPs and reinforce the importance of regulatory oversight and public health initiatives targeting nicotine delivery technologies. Trial Registrations: ClinicalTrials.gov ID: NCT04824495, registered 2021-01-07., Competing Interests: Declarations. Conflict of interests: The authors declare no competing interests., (© 2024. The Author(s).)

Latinx individuals who smoke represent a tobacco health disparities group. Yet, limited research has focused on examining dual combustible and electronic cigarette use among Latinx populations. Importantly, Latinx persons who smoke also evince elevated rates of pain problems and symptoms and prior research has consistently linked pain problems and severity to smoking prevalence, maintenance, and behavior. Accordingly, the current study sought to build from the limited work that exists among dual combustible cigarette and electronic cigarette Latinx users comparing levels of pain severity and interference. The current sample consists of 196 adult Latinx daily cigarette smokers (35.48 years old; 39.4% female), of which 72 reported current daily dual use of an e-cigarette. Results indicated that Latinx dual users reported greater levels of pain severity ( η p 2  = .12) and pain interference ( η p 2  = .10) than exclusive combustible cigarette users. The study adds uniquely to the limited literature on the clinical importance of dual cigarette use in relation to pain severity and interference in that pain may serve as an important risk factor for the initiation and maintenance of dual use for increased analgesic nicotine effects.