BACKGROUND: Scientific evidence clearly demonstrates that inhaling the smoke from the combustion of cigarettes is responsible for most of the harm caused by smoking, and not the nicotine. However, a majority of U.S. adults who smoke inaccurately believe that nicotine causes cancer which may be a significant barrier, preventing switching to potentially reduced risk, non-combustible products like electronic nicotine delivery systems (ENDS) and smokeless tobacco (ST). We assessed the population health impact associated with nicotine perceptions.
METHODS: Using a previously validated agent-based model to the U.S. population, we analyzed nationally representative data from the Population Assessment of Tobacco and Health (PATH) study to estimate base case rates of sustained (maintained over four waves) cessation and switching to non-combustible product use, by sex. Nicotine perception scenarios were determined from PATH data. The overall switch rate from smoking in Wave 4 to non-combustible product use in Wave 5 (3.94%) was stratified based on responses to the nicotine perception question \"Do you believe nicotine is the chemical that causes most of the cancer caused by smoking cigarettes?\", (four-item scale from \"Definitely not\" to \"Definitely yes\"). The relative percent change between the overall and stratified rates, corresponding to each item, was used to adjust the base case rates of switching, to determine the impact, if all adults who smoke exhibited switching behaviors based on responses to the nicotine perceptions question. The public health impact of nicotine perceptions was estimated as the difference in all-cause mortality between the base case and the four nicotine perception scenarios.
RESULTS: Switch rates associated with those who responded, \"Definitely not\" (8.39%) resulted in a net benefit of preventing nearly 800,000 premature deaths over an 85-year period. Conversely switch rates reflective of those who responded, \"Definitely yes\" (2.59%) resulted in a net harm of nearly 300,000 additional premature deaths over the same period.
CONCLUSIONS: Accurate knowledge regarding the role of nicotine is associated with higher switch rates and prevention of premature deaths. Our findings suggest that promoting public education to correct perceptions of harm from nicotine has the potential to benefit public health.

OBJECTIVE: To investigate the association of early snus use initiation (≤15 years of age) with asthma and asthma symptoms.
METHODS: Cross-sectional analysis of a population-based cohort.
METHODS: Study centres in Norway, Sweden, Iceland, Denmark and Estonia, from 2016 to 2019.
METHODS: 9002 male and female participants above 15 years of age of the Respiratory Health in Northern Europe, Spain and Australia study.
METHODS: Current asthma and asthma symptoms.
RESULTS: The median age of study participants was 28 years (range 15-53) and 58% were women. 20% had used snus, 29% men and 14% women. Overall, 26% of males and 14% of females using snus started ≤15 years of age. Early snus use initiation was associated with having three or more asthma symptoms (OR 2.70; 95% CI 1.46 to 5.00) and a higher asthma symptom score (β-coefficient (β) 0.35; 95% CI 0.07 to 0.63) in women. These associations were weak in men (OR 1.23; 95% CI 0.78 to 1.94; β 0.16; 95% CI -0.06 to 0.38, respectively). There was evidence for an association of early snus initiation with current asthma (OR 1.72; 95% CI 0.88 to 3.37 in women; OR 1.31; 95% CI 0.84 to 2.06 in men). A sensitivity analysis among participants without smoking history showed stronger estimates for all three outcomes, in both men and women, statistically significant for three or more asthma symptoms in women (OR 3.28; 95% CI 1.18 to 9.10). Finally, no consistent associations with asthma outcomes were found for starting snus after age 15 years.
CONCLUSIONS: Snus initiation in puberty was associated with higher likelihood of asthma and asthma symptoms, with the highest estimates in females and those without smoking history. These results raise concerns about the health adversities of early snus initiation and emphasise the need for public health initiatives to protect young people from this tobacco product.

BACKGROUND: This study delves into the intricate landscape of oral cancer, a global concern with a high incidence in Asian countries. We focus on oral squamous cell carcinoma (OSCC), primarily driven by the consumption of betel nut and its derivatives. OSCC often arises from premalignant lesions like oral submucous fibrosis (OSF). In Pakistan, OSCC is prevalent among men due to various addictive substances, including smokeless tobacco and chewing materials. Mutations in tumor suppressor genes, such as TP53 and p21, play crucial roles in this malignancy\'s development. We also explore the involvement of TUSC3 gene deletion in OSCC and OSF.
METHODS: In this study we investigated demographics, TUSC3 gene expression, deletion analysis, and TP53 and p21 genetic alterations in OSCC and OSF patients (blood and tissue of 50 samples in each condition) who had tobacco derivates usage history. The association analysis was carried out mainly through PCR based genotyping.
RESULTS: The study\'s patient cohort (OSCC and OSF) displayed a wide age range from 13 to 65 years (Mean = 32.96 years). Both conditions were more prevalent in males, with a male-female ratio of approximately 2.5:1. Chewing habits analysis revealed high frequencies of gutka use in both OSF and OSCC patients. TUSC3 expression analysis in OSCC cell lines indicated significant downregulation. Genotyping showed no TUSC3 deletion in OSF cases, but a deletion rate of over 22% in OSCC tissue samples. Analysis supported a significant association of TUSC3 deletion with OSCC development but not with OSF. Polymorphism in p53 exon 4 and p21 (rs1801270) were significantly associated with both OSCC and OSF, adding to their pathogenesis. Our findings further revealed a strong correlation between TUSC3 deletion and the excessive use of tobacco and related products, shedding light on the genetic underpinnings of OSCC development.
CONCLUSIONS: Notably, our study provides a crucial insight into genetic aspects underlying OSCC and OSF in response of addictive consumption of areca nut, betel quid, and tobacco derivatives. A significant association between TUSC3 deletion and OSCC development, along with polymorphisms in TP53 and p21, underscores the importance of further research into the molecular mechanisms driving oral cancer progression for improved diagnosis and treatment outcomes.

Smokeless tobacco products (STPs) are attributed to oral cancer and oral pathologies in their users. STP-associated cancer induction is driven by carcinogenic compounds including tobacco-specific nitrosamines (TSNAs). The TSNAs synthesis could enhanced due to the metabolic activity (nitrate metabolism) of the microbial populations residing in STPs, but identifying microbial functions linked to the TSNAs synthesis remains unexplored. Here, we rendered the first report of shotgun metagenomic sequencing to comprehensively determine the genes of all microorganisms residing in the Indian STPs belonging to two commercial (Moist-snuff and Qiwam) and three loose (Mainpuri Kapoori, Dohra, and Gudakhu) STPs, specifically consumed in India. Further, the level of nicotine, TSNAs, mycotoxins, and toxic metals were determined to relate their presence with microbial activity. The microbial population majorly belongs to bacteria with three dominant phyla including Actinobacteria, Proteobacteria, and Firmicutes. Furthermore, the STP-linked microbiome displayed several functional genes associated with nitrogen metabolism and antibiotic resistance. The chemical analysis revealed that the Mainpuri Kapoori product contained a high concentration of ochratoxins-A whereas TSNAs and Zink (Zn) quantities were high in the Moist-snuff, Mainpuri Kapoori, and Gudakhu products. Hence, our observations will help in attributing the functional potential of STP-associated microbiome and in the implementation of cessation strategies against STPs. KEY POINTS: •Smokeless tobacco contains microbes that can assist TSNA synthesis. •Antibiotic resistance genes present in smokeless tobacco-associated bacteria. •Pathogens in STPs can cause infections in smokeless tobacco users.

BACKGROUND: Tobacco use is widely recognised as a significant risk factor for oral cancer and periodontal diseases. However, the relationship between various types of tobacco use and dental caries has been inconsistent. This study aimed to determine the association between smoking and smokeless tobacco and dental caries among patients in a tertiary care hospital in Quetta, Pakistan.
METHODS: This cross-sectional study was conducted from November 2020 to March 2021 among patients in a tertiary care hospital in Quetta, Pakistan. Oral examinations and interviews were performed according to the WHO Oral Health Survey basic methods (5th edition) to determine dental caries status, tobacco use, and oral health behaviours. The odds ratio and binary logistic regression were analysed to assess the association between the types (smoking tobacco, smokeless tobacco, and use of both types), duration, and frequency of tobacco use and high caries level (DMFT ≥ 5).
RESULTS: Four hundred participants aged 18-65 were included, and 67.8% were tobacco users. Use of both smoking and smokeless tobacco (aOR = 14.7, 95%CI = 1.87-115.96, p = 0.011), smokeless tobacco only (aOR = 5.90, 95%CI = 1.89-18.37, p = 0.002), and smoking only (aOR = 2.18, 95%CI = 1.23-3.88, p = 0.008) were associated with significantly increased risk of high caries. Using tobacco for longer periods and more frequently daily also significantly increases the risk of high caries.
CONCLUSIONS: Smoking and smokeless tobacco are significantly associated with high dental caries after adjusting for other factors. Due to the high severity of dental caries and the high prevalence of tobacco use among Pakistani patients in this study, it is highly recommended to strengthen policies aimed at reducing tobacco usage, including smokeless forms.

BACKGROUND: E-cigarette use has increased considerably among US adolescents. While many studies have described cross-sectional prevalence trends of youth e-cigarette use, less is known about cohort or generational initiation and use patterns.
METHODS: We used data from the US National Youth Tobacco Survey (NYTS) from 2014 to 2022 and age-period-cohort models to analyze age-specific patterns of e-cigarette use initiation and prevalence by cohort and calendar. For comparison, we also examined initiation and prevalence for cigarettes, cigars, and smokeless tobacco, using NYTS data from 1999 to 2022.
RESULTS: Age-specific e-cigarette initiation and prevalence varied considerably by calendar year and birth cohort. There was a rapid increase in e-cigarette initiation and prevalence starting with the 1995 birth cohort, peaking with the 2005 birth cohort, and showing signs of decline with more recent cohorts. In contrast, there were substantial continuous reductions in cigarette, cigar, and smokeless use initiation and prevalence by birth cohort. While the reductions in cigarette smoking started with the 1980s birth cohorts, cigar and smokeless initiation and prevalence did not decrease until the 1990-1995 cohorts.
CONCLUSIONS: Despite their recent emergence, e-cigarette use has varied considerably across US adolescent cohorts. After early increases, e-cigarette use and initiation peaked with the 2005 birth cohort. These patterns are in contrast with the continuous decreases by cohort in cigarette, cigar, and smokeless use and initiation. As the tobacco product landscape continues to evolve, it will be essential to monitor patterns of use of adolescent and young adult cohorts as they age into adulthood.

UNASSIGNED: The adequacy of biomarkers of potential harm (BOPH) for assessing tobacco products was explored based on their ability to distinguish tobacco use from non-use, change with cessation, and to show biological gradient.
UNASSIGNED: The sample included individuals with biomarker data in wave 1 of the Population Assessment of Tobacco Health study who never used tobacco, currently smoke cigarettes exclusively, used to smoke cigarettes exclusively (quit in past 12 months), currently use smokeless tobacco exclusively, and currently use e-cigarettes exclusively. We compared BOPH levels between groups and assessed the relationships between log-transformed biomarkers of exposure [BOE; total nicotine equivalents including seven nicotine metabolites (TNE-7), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanonol (NNAL), N-acetyl-S-(2-cyanoethyl)-L-cysteine, 1-hydroxypyrene, cadmium, and serum cotinine (SCOT)], and BOPH [high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), fibrinogen, soluble intercellular adhesion molecule-1 (sICAM-1), and 8-isoprostane].
UNASSIGNED: Among people who smoke, both sICAM-1 and 8-isoprostane distinguished smoking from non-use and were associated with all six BOE. Among people who use smokeless tobacco, 8-isoprostane was associated with TNE-7 and NNAL whereas hs-CRP was associated with SCOT. Among people who use e-cigarettes, no associations between BOPH and BOE were observed.
UNASSIGNED: Both sICAM-1 and 8-isoprostane may be useful for assessing the use or changes in use of some tobacco products. Studies examining their predictive validity could further strengthen our understanding of these two biomarkers.
UNASSIGNED: We found that two biomarkers of potential harm, soluble intercellular adhesion molecule-1 and 8-isoprostane, may have utility in studies assessing the potential harm of tobacco use in absence of long-term epidemiological studies.

Smokeless tobacco (SLT) poses many negative health impacts. Despite its longstanding presence in societies across the world, the health implications of SLT have only been rigorously studied in recent decades. This systematic review and meta-analysis aimed to consolidate existing research to provide a comprehensive understanding of the global prevalence of SLT use among women of reproductive age. Relevant articles were extracted from databases such as PubMed, EMBASE, Web of Science, and Scopus from their inception until November 11, 2023. Observational studies reporting the number of SLT users among women of reproductive age were included. The quality of the studies was assessed using the Joanna Briggs Institute (JBI) tool. The meta-analysis used a random-effects model to determine SLT prevalence, supported by statistical tools like forest plots, I2 statistics, and sensitivity analyses to ensure the accuracy and comprehensiveness of the results. All statistical analyses were performed in R version 4.3. From 10 studies involving 2,053,667 participants, a pooled prevalence for SLT use among women of reproductive age was found to be 9.3% (95% CI: 0.038 to 0.21), with significant heterogeneity among studies (I2 = 100%). Publication bias was suspected among the studies. Sensitivity analysis and subgroup analysis couldn\'t resolve the heterogeneity. Our analysis shows a significant prevalence of SLT use in women of reproductive age, especially in low socioeconomic and developing countries like India, Pakistan, and Nepal. For women of reproductive age, the use of smokeless tobacco (SLT) can lead to infertility, pregnancy complications, and adverse fetal outcomes, including low birth weight and preterm birth. The results highlight the necessity for specific public health measures and policy changes to decrease SLT consumption among reproductive-age women. Further studies are needed to investigate the reasons behind SLT usage in this group and to assess the impact of intervention strategies, to guide more effective public health initiatives and policies.

BACKGROUND: Article 14 of the WHO \'Framework Convention on Tobacco Control\' recommends, that all oral healthcare providers provide support for tobacco cessation, to all patients. Despite evidence on the effectiveness of tobacco cessation interventions in dental settings, implementation remains low in most high-burden countries like Pakistan. A pragmatic pilot trial of a dentist-delivered behavioural support intervention for smokeless tobacco (ST) cessation, was conducted in dental hospitals in Pakistan. This paper presents the findings of the process evaluation of the trial.
METHODS: A mixed-method process evaluation of a multi-centre randomised control pilot trial of dentist-delivered behavioural support intervention ST cessation was conducted. The intervention included three sessions namely: pre-quit, quit and post-quit sessions. The process evaluation involved: semi-structured interviews with trial participants (n = 26, of which dental patients were n = 13 and participating dentists were n = 13 conducted from June-August 2022); and fidelity assessment of audio recordings of the intervention sessions (n = 29). The framework approach was used to thematically analyse the interview data.
RESULTS: Overall the trial procedures were well accepted, however, young patients expressed uneasiness over revealing their ST use status. The intervention was received positively by dentists and patients. Dentists identified some challenges in delivering behavioural support to their patients. Of these, some were related to the contents of the intervention whereas, others were related to the logistics of delivering the intervention in a clinical setting (such as workload and space). Acceptability of the intervention resources was overall low amongst young patients as they did not take the intervention resources home due to fear of their family members finding out about their ST use. The intervention was successful in achieving the intended impact (in those who engaged with the intervention), i.e., change in the patients\' ST use behaviour. Giving up ST with the aid of behavioural support also had an unintended negative effect i.e., the use of harmful substances (cannabis, cigarettes) to give up ST use. Patients\' satisfaction with their dental treatment seemed to influence the intervention outcome.
CONCLUSIONS: While there are many variables to consider, but for the participants of this study, behavioural support for abstinence delivered through dentists during routine dental care, appears to be an acceptable and practical approach in helping patients give up ST use, in a country like Pakistan, where negligible support is offered to ST users.

Tobacco use significantly influences the oral microbiome. However, less is known about how different tobacco products specifically impact the oral microbiome over time. To address this knowledge gap, we characterized the oral microbiome of cigarette users, smokeless tobacco users, and non-users over 4 months (four time points). Buccal swab and saliva samples (n = 611) were collected from 85 participants. DNA was extracted from all samples and sequencing was carried out on an Illumina MiSeq, targeting the V3-V4 region of the 16S rRNA gene. Cigarette and smokeless tobacco users had more diverse oral bacterial communities, including a higher relative abundance of Firmicutes and a lower relative abundance of Proteobacteria, when compared to non-users. Non-users had a higher relative abundance of Actinomyces, Granulicatella, Haemophilus, Neisseria, Oribacterium, Prevotella, Pseudomonas, Rothia, and Veillonella in buccal swab samples, compared to tobacco users. While the most abundant bacterial genera were relatively constant over time, some species demonstrated significant shifts in relative abundance between the first and last time points. In addition, some opportunistic pathogens were detected among tobacco users including Neisseria subflava, Bulleidia moorei and Porphyromonas endodontalis. Overall, our results provide a more holistic understanding of the structure of oral bacterial communities in tobacco users compared to non-users.