OBJECTIVE:Electronic nicotine delivery systems (ENDS) have seen a global surge in their usage. However, their role in smoking initiation, particularly among non-smokers, remains a critical concern. This umbrella review evaluated the risk of tobacco-smoking initiation following ENDS use, focusing on non-smokers, by synthesising evidence using Bayesian meta-analysis. STUDY DESIGN:Systematic review and Bayesian meta-analysis. METHODS:We searched databases including PubMed, EMBASE and Cochrane Library up to 1 May 2025. We included systematic reviews assessing tobacco-smoking initiation after ENDS use among non-smokers. Quality was evaluated using the AMSTAR-2 (A Measurement Tool to Assess Systematic Reviews - version 2). A Bayesian hierarchical meta-analysis was conducted to estimate pooled ORs with 95% credibility intervals (CrIs), using non-informative priors to model heterogeneity and uncertainty. This study was registered with PROSPERO (CRD42023464207). RESULTS:From 5055 records, 13 systematic reviews were included. Of them, five were rated as 'high quality', one as 'moderate', four as 'low' and 'three' as critically low, as per AMSTAR-2 quality assessment. The meta-analysis revealed a pooled median OR of 3.1 (95% CrI 2.56 to 3.72) for smoking initiation among non-smoking ENDS users, with moderate heterogeneity (τ mean: 1.23). Among adolescents, the OR was 2.7 (95% CrI 2.27 to 3.21), with moderate heterogeneity (τ mean: 0.63). The risk of relapse in former tobacco smokers who used ENDS was doubled (RR: 2.03, 95% CI 1.39 to 2.96). Individuals who had never smoked but engaged with ENDS had more than twice the odds of developing an intention to smoke, with an OR of 2.21 (95% CI 1.86 to 2.61). The overall certainty of the evidence was rated very low due to the risk of bias in the studies and evidence of publication bias across the studies. CONCLUSIONS:ENDS use is significantly associated with increased risk of tobacco smoking initiation among non-smokers, particularly adolescents, supporting the gateway hypothesis. These findings indicate the need for stringent regulatory and public health strategies to protect people from nicotine addiction. PROSPERO REGISTRATION NUMBER:CRD42023464207.

Tuberculosis (TB) and tobacco use are two intertwined public health challenges that significantly impact low- and middle-income countries, particularly India, which bears the highest global TB burden. Tobacco use exacerbates TB risk, progression, and treatment outcomes. Despite the established association, research on the prevalence of smoking and smokeless tobacco (SLT) use among pulmonary TB (PTB) patients in India remains limited. This systematic review and meta-analysis aim to estimate the prevalence of smoking and SLT use among PTB patients in India and evaluate the association between tobacco consumption and TB incidence and treatment outcomes. A systematic search was conducted across four databases (PubMed, Embase, Web of Science, and Scopus) for studies published up to September 30, 2024, adhering to PRISMA guidelines. Pooled prevalence estimates were calculated using random-effects models, and subgroup analyses examined variations by gender and treatment stage. Odds ratios (ORs) were used to assess the association between smoking and PTB. Sensitivity analyses and Egger’s test were conducted to evaluate heterogeneity and publication bias. A total of 27 studies (n=9593 subjects) were included. The pooled prevalence of smoking among PTB patients was 31% [95% confidence interval (CI): 25-36%], while SLT use was 19% (95% CI: 13-26%). PTB patients were 2.5 times more likely to be smokers than non-TB controls (OR=2.51, 95% CI: 1.36-4.62). Smoking prevalence was highest among newly diagnosed patients (42%) and predominantly observed among males (38%). High heterogeneity (I²>98%) was observed across studies. To conclude, tobacco use is highly prevalent among Indian PTB patients, significantly contributing to disease burden. Integrating tobacco cessation strategies into India’s National TB Elimination Program is critical to improving TB outcomes, reducing transmission, and addressing the dual burden of tobacco and TB.

BACKGROUND:The rise of electronic nicotine delivery systems (ENDS) has introduced new challenges to tobacco control and regulation, particularly among young adults, raising questions about their safety. This umbrella review aimed to synthesise existing systematic reviews with or without meta-analyses to evaluate the health impacts of ENDS. METHODS:We conducted a systematic literature search via the PICO strategy across multiple databases, focusing on e-cigarettes, ENDS and e-liquids, while excluding non-nicotine e-cigarette and nicotine replacement therapies (NRTs). Health outcomes include a range of clinical diseases and physiological changes. Quality assessment was performed via assessing the methodoligcal quality of systematic reviews 2 (AMSTAR-2), and the findings were synthesised narratively and in tables, prioritising the highest-rated reviews. The meta-analyses used R software (V.4.3) random effects models, and evidence quality was assessed via the Grading of Recommendations, Assessment, Development and Evaluation criteria. RESULTS:Of the 5055 records, 69 systematic reviews were included. Systematic reviews have indicated increased risks of cardiovascular and respiratory diseases, mental health issues and substance abuse with ENDS use, especially among adolescents. Cardiovascular risk factors included increased heart rate (mean difference (MD) 1.41, 95% CI 0.81 to 2.01, I2=91%) from 25 studies; increased blood pressure (MD for systolic blood pressure=0.51 mm Hg, 95% CI 0.26 to 0.75, I2=89%; MD for diastolic blood pressure=0.59 mm Hg, 95% CI 0.35 to 0.83, I2=82%) from 23 studies; endothelial dysfunction and increased platelet activity. Respiratory risk factors included reduced lung function and a higher incidence of asthma in nine studies (OR 1.30, 95% CI 1.1 to 1.55; I2=43%) and chronic obstructive pulmonary disease. Mental health concerns, such as depression and suicidality, were also prevalent among adolescent ENDS users. Nine studies reported a negative effect of ENDS on periodontal health. Evidence of carcinogens has been found in the urinary examinations of ENDS users in some studies. The adverse events reported in seven randomised controlled trials with 2611 participants were similar between ENDS and NRT (RR 1.13, 95% CI 0.83 to 1.54, I2=12%). CONCLUSIONS:Exposure to ENDS is harmful to various organ systems, especially cardiovascular and respiratory systems. Comprehensive regulatory measures and public health strategies are necessary to curb the use of ENDS, particularly among young people.

BackgroundElectronic nicotine delivery systems (ENDS), commonly known as e-cigarettes or vapes, have witnessed a rise in popularity, particularly among the youth. Although they were initially introduced as an alternative to traditional smoking, the design and function of ENDS vary. The potential health effects of ENDS, especially in comparison to traditional cigarettes, are a matter of ongoing debate. Given the increasing number of clinical studies and systematic reviews on this topic, there exists a demand for an umbrella review that offers a comprehensive assessment. The goal of this study is to perform an umbrella review of systematic reviews and meta-analyses to assess the safety, efficacy, health implications and potential gateway effect associated with ENDS.Methods and analysisThis umbrella review will adhere to the Joanna Briggs Institute (JBI) framework and the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. A planned literature search will be executed across databases such as OVID, PubMed/MEDLINE, EMBASE, Cochrane Library and Web of Science. The inclusion criteria are systematic reviews that discuss ENDS and e-liquids in the context of safety, efficacy and health outcomes. The exclusion criteria include narrative reviews, non-systematic reviews and studies not in English. Quality of the selected studies will be evaluated using the AMSTAR V.2 Scale. An overlap assessment will be done using the Corrected Covered Area, and data synthesis will be presented both narratively and in tabulated formsEthics and disseminationEthics approval is not required for this study, as it does not involve the collection of original data. The results will be disseminated through peer-reviewed publication. The findings will offer crucial insights for stakeholders, policy-makers and the general public, underlining the health implications and the role of ENDS in tobacco cessation.

1. Tata Institute of Social Sciences, Mumbai and Ministry of Health and Family Welfare, Government of India. Global Adult Tobacco Survey GATS 2 India 2016-17. Accessed March 30, 2023. https://ntcp.mohfw.gov.in/asse... document/surveys-reports-publications/Global-Adult- Tobacco-Survey-Second-Round-India-2016-2017.pdf WWW Google Scholar

The rapid proliferation of smokeless tobacco (SLT) in India has occurred without adequate information on the possible dangers and toxicity of these products. Tobacco flavors as well as nicotine (both protonated and un-protonated) are responsible for health dangers and addiction. The study aimed to offer information on the physical characteristics of commonly used smokeless tobacco products (including microscopic analysis), along with nicotine content (both total and un-protonated), pH, moisture, and flavors. The Standard Operating Procedures (SOPs) validated by the World Health Organization (WHO) recognized Tobacco Testing Laboratory TobLabNet) were applied for the analysis of various constituents of the SLTs. The microscopic analysis indicated that some of the SLT products like khaini were finely processed and available in filter pouches for users’ convenience and prolonged use leading to prolonged retention and addiction potential. Nicotine absorption and availability (both protonated and un-protonated) are affected by moisture and pH. Essences provide a pleasant aroma and flavor, with an increased risk of misuse and other health problems. Few chewing tobacco and Zarda had the lowest levels of un-protonated nicotine (0.10–0.52% and 0.15–0.21%, respectively), whereas Gul, Gudhaku, and Khaini had the highest levels, ranging from 95.33 to 99.12%. Moisture and pH ranged from 4.54 to 50.19% and 5.25–10.07 respectively. Menthol (630.74–9681.42 µg/g) was the most popular flavour, followed by Eucalyptol (118.16–247.77 µg/g) and camphor (148.67 and 219.317 µg/g). SLT’s health concerns and addiction dangers are exacerbated by the high proportion of bioavailable nicotine coupled with flavors. The findings of this study have important implications for the regulation and use of SLT in countries where use of SLT is prevalent.

Tobacco kills more than 8 million people worldwide every year. Over 80% of the world's 1.3 billion tobacco users live in low- and middle-income countries (LMICs), where the future burden is projected to grow. At the same time, progress in tobacco control has not advanced as far as in many LMICs. In particular, the implementation of tobacco-cessation programs and interventions remains limited. The bulk of the evidence for tobacco-cessation interventions comes from high-income countries and may not reflect the context in LMICs, particularly as resources and training for tobacco cessation are limited. This paper summarizes the current evidence for tobacco-cessation interventions in LMICs and highlights some key challenges and research gaps. Overall, there is a need to build capacity for locally relevant research and implementation science to support tailored cessation interventions and strategies for LMICs.

Tobacco use and socioeconomic status are related with each other and important determinants of disparities and inequalities to access to care. There is overall reduction in number of smokers but still most number of smokers is represented by people from low socioeconomic status, with less number of these people having an access to the treatment centers. Patients who are tobacco users have shown to be less likely to receive any form of treatment for lung cancer, whether that be chemotherapy, radiotherapy, or surgery. As there is less awareness about signs and symptoms of lung cancer, lower socioeconomic patients are likely to report to hospitals at advanced stages or many times as a medical emergency. We are well aware that patients with advanced lung cancer have lower chances of survival in view of incomplete response to treatment. As there is an intersection between tobacco use, health disparities, and inequalities and lung cancer treatment and survival, this issue needs better focus and attention to minimize disparities and inequalities in access to care and outcomes.