Smokeless tobacco use and public health in countries of South-East Asia region

Smokeless tobacco consumption among women of reproductive age: a systematic review and meta-analysis

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.

From cultivation to cancer: formation of N-nitrosamines and other carcinogens in smokeless tobacco and their mutagenic implications

Tobacco use is a major cause of preventable morbidity and mortality globally. Tobacco products, including smokeless tobacco (ST), generally contain tobacco-specific N-nitrosamines (TSNAs), such as N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-butanone (NNK), which are potent carcinogens that cause mutations in critical genes in human DNA. This review covers the series of biochemical and chemical transformations, related to TSNAs, leading from tobacco cultivation to cancer initiation. A key aim of this review is to provide a greater understanding of TSNAs: their precursors, the microbial and chemical mechanisms that contribute to their formation in ST, their mutagenicity leading to cancer due to ST use, and potential means of lowering TSNA levels in tobacco products. TSNAs are not present in harvested tobacco but can form due to nitrosating agents reacting with tobacco alkaloids present in tobacco during certain types of curing. TSNAs can also form during or following ST production when certain microorganisms perform nitrate metabolism, with dissimilatory nitrate reductases converting nitrate to nitrite that is then released into tobacco and reacts chemically with tobacco alkaloids. When ST usage occurs, TSNAs are absorbed and metabolized to reactive compounds that form DNA adducts leading to mutations in critical target genes, including the RAS oncogenes and the p53 tumor suppressor gene. DNA repair mechanisms remove most adducts induced by carcinogens, thus preventing many but not all mutations. Lastly, because TSNAs and other agents cause cancer, previously documented strategies for lowering their levels in ST products are discussed, including using tobacco with lower nornicotine levels, pasteurization and other means of eliminating microorganisms, omitting fermentation and fire-curing, refrigerating ST products, and including nitrite scavenging chemicals as ST ingredients.

Smokeless Tobacco as a Risk Factor for Type 2 Diabetes Mellitus in South East Asia Region: Systematic Review and Meta-Analysis

Background

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder of which prevalence has been increasing steadily all over the world. There is a need of understanding the role of tobacco products in diabetes mellitus, especially smokeless tobacco (ST) products.

Objective

To analyze if ST is a determinant for T2DM among patients in South East Asia Region (SEAR) and secondly to obtain the pooled prevalence of use of ST in T2DM patients/participants from these studies.

Materials and Methods

PubMed, Google Scholar, EBSCO, and Scopus are the databases that were searched to find desired manuscripts, which fulfilled the inclusion criteria to undertake this systematic review and meta-analysis (SRMA). Meta-analysis was carried out to determine the pooled effect size for the odds ratio of ST use in T2DM with 95% CI. MedCalc statistical software was used followed by the DerSimonian and Laird method under the random effect model.

Results

A total of 8 manuscripts were involved in the systematic review and 7 in the meta-analysis. Odds of 1.39 indicating increased frequency of using ST among T2DM patients or survey participants was observed, which was not significant with C.I. 95% (0.843-2.288) and P < 0.001 with high heterogeneity. The pooled prevalence of use of ST in T2DM is 24.08% (CI 15.67 to 33.64) under random effect model with I2 inconsistency of 97.16% in 8 studies from India and Bangladesh.

Conclusion

This pooled analysis shows that ST use is not a risk factor for T2DM. The number of studies included in the SRMA from SEAR is limited having no representation from Myanmar, Bhutan, Timor Leste, and Sri Lanka.

The global impact of tobacco control policies on smokeless tobacco use: a systematic review

BACKGROUND

Smokeless tobacco, used by more than 300 million people globally, results in substantial morbidity and mortality. For smokeless tobacco control, many countries have adopted policies beyond the WHO Framework Convention on Tobacco Control, which has been instrumental in reducing smoking prevalence. The impact of these policies (within and outside the Framework Convention on Tobacco Control) on smokeless tobacco use remains unclear. We aimed to systematically review policies that are relevant to smokeless tobacco and its context and investigate their impact on smokeless tobacco use.

METHODS

In this systematic review, we searched 11 electronic databases and grey literature between Jan 1, 2005, and Sept 20, 2021, in English and key south Asian languages, to summarise smokeless tobacco policies and their impact. Inclusion criteria were all types of studies on smokeless tobacco users that mentioned any smokeless tobacco relevant policies since 2005, except systematic reviews. Policies issued by organisations or private institutions were excluded as well as studies on e-cigarettes and Electronic Nicotine Delivery System except where harm reduction or switching were evaluated as a tobacco cessation strategy. Two reviewers independently screened articles, and data were extracted after standardisation. Quality of studies was appraised using the Effective Public Health Practice Project's Quality Assessment Tool. Outcomes for impact assessment included smokeless tobacco prevalence, uptake, cessation, and health effects. Due to substantial heterogeneity in the descriptions of policies and outcomes, data were descriptively and narratively synthesised. This systematic review was registered in PROSPERO (CRD42020191946).

FINDINGS

14 317 records were identified, of which 252 eligible studies were included as describing smokeless tobacco policies. 57 countries had policies targeting smokeless tobacco, of which 17 had policies outside the Framework Convention on Tobacco Control for smokeless tobacco (eg, spitting bans). 18 studies evaluated the impact, which were of variable quality (six strong, seven moderate, and five weak) and reported mainly on prevalence of smokeless tobacco use. The body of work evaluating policy initiatives based on the Framework Convention on Tobacco Control found that these initiatives were associated with reductions in smokeless tobacco prevalence of between 4·4% and 30·3% for taxation and 22·2% and 70·9% for multifaceted policies. Two studies evaluating the non-Framework policy of sales bans reported significant reductions in smokeless tobacco sale (6·4%) and use (combined sex 17·6%); one study, however, reported an increased trend in smokeless tobacco use in the youth after a total sales ban, likely due to cross-border smuggling. The one study reporting on cessation found a 13·3% increase in quit attempts in individuals exposed (47·5%) to Framework Convention on Tobacco Control policy: education, communication, training, and public awareness, compared with non-exposed (34·2%).

INTERPRETATION

Many countries have implemented smokeless tobacco control policies, including those that extend beyond the Framework Convention on Tobacco Control. The available evidence suggests that taxation and multifaceted policy initiatives are associated with meaningful reductions in smokeless tobacco use.

FUNDING

UK National Institute for Health Research.

Perceptions and reasons for quitting and transitioning between smoking and smokeless tobacco products: Findings from four waves of the ITC Bangladesh survey

INTRODUCTION

Transitions between different tobacco products are frequent among tobacco users in Bangladesh; however, the reasons leading to such transitions and why they quit are not well researched. The aim of the study is to examine perceptions and reasons reported by tobacco users in Bangladesh to transition to other products or quit.

METHODS

Data from four waves (2009-2015) of the International Tobacco Control (ITC) Bangladesh Survey were used. Repeated data on perceptions and reasons for exclusive cigarette (n=520), bidi (n=130), and SLT users (n=308) to either start using other products or quit were analyzed with sampling weights. The percentages of responses across waves were used to calculate the pooled proportion data using a meta-analysis approach.

RESULTS

Common reasonsig for respondents switching to other tobacco products were influence of friends/family (73.8-86.0%), and curiosity (44.4-71.3%). The perceived calming effect of smoking cigarettes and bidis (43.2-56.9%), and the impression that bidis were less harmful (52.3%) and taste better (71.2%) were major reasons for exclusive SLT users to switch products. Health concerns (16.5-62.7%) and disapproval from friends/family (29.8-56.4%) were generally the main reasons for quitting. For smoked tobacco users, doctor's advice (41.6%), package warning labels (32.3%), and price (32.4%) seemed to be the major driving factors to quit.

CONCLUSIONS

Results highlight that the reasons for switching between tobacco products and quitting include social factors (e.g. friends/family) and (mis) perceptions regarding the products. Tobacco control policy could emphasize cessation support, increased price and education campaigns as key policies to reduce overall tobacco use in Bangladesh. Data from four waves (2009-2015) of the International Tobacco Control (ITC) Bangladesh Survey were used. Repeated data on perceptions and reasons for exclusive cigarette (n=520), bidi (n=130), and SLT users (n=308) to either start using other products or quit were analyzed with sampling weights. The percentages of responses across waves were used to calculate the pooled proportion data using a meta-analysis approach.

Smokeless Tobacco Use in Iran: A Systematic Review

Background

Smokeless tobacco (ST) use is one of the most important public health problems in Southeast Asia. The use of these substances increases the incidence of some cancers and other diseases. The purpose of this review study was to investigate on ST use in Iran.

Methods

A literature search was conducted on PubMed, Google Scholar, and three national databases [Scientific Information Database (SID), IranMedex, and IranDoc] based on the standard search strategy.

Findings

Most consumer people lived in Sistan and Baluchestan Province (Zahedan and Chabahar Cities) and Golestan Province, Iran. ST use rates ranged from 11.0% to 45.7% among college students in Sistan and Baluchestan (Zahedan and Chabahar) and Golestan. There are various types of ST consumed in Iran that have been mentioned in various articles, including Pan, Gutka, Nass, Naswar, Biti, and Supari.

Conclusion

Most studies on ST have been conducted in Sistan and Baluchestan and Golestan Provinces and we need more research for other provinces. Consumption by women is a warning and a threat to women's health in the future. Further studies will be needed to find out more precisely the prevalence of consumption in Iran.

Smokeless tobacco cessation interventions: A systematic review

Background & objectives:

Smokeless tobacco (SLT) consumption is a global health issue with about 350 million users and numerous adverse health consequences like oral cancer and myocardial disorders. Hence, cessation of SLT use is as essential as smoking cessation. An update on the available literature on SLT cessation intervention studies is provided here.

Methods:

Through an extensive literature search on SLT cessation intervention studies, using keywords such as smokeless tobacco, cessation, interventions, quitlines, brief advice, nicotine replacement therapy, nicotine gum, nicotine lozenge, nicotine patch, bupropion, varenicline, mHealth, etc., 59 eligible studies were selected. Furthermore, efficacy of the interventions was assessed from the reported risk ratios (RRs) [confidence intervals (CIs)] and quit rates.

Results:

Studies were conducted in Scandinavia, India, United Kingdom, Pakistan and the United States of America, with variable follow up periods of one month to 10 years. Behavioural interventions alone showed high efficacy in SLT cessation; most studies were conducted among adults and showed positive effects, i.e. RR [CI] 0.87 [0.7, 1.09] to 3.84 [2.33, 6.33], quit rate between 9-51.5 per cent, at six months. Regular telephone support/quitlines also proved beneficial. Among pharmacological modalities, nicotine lozenges and varenicline proved efficacious in SLT cessation.

Interpretation & conclusions:

Globally, there is limited information available on SLT cessation intervention trials, research on which must be encouraged, especially in the low-resource, high SLT burden countries; behavioural interventions are most suitable for such settings. Appropriate training/sensitization of healthcare professionals, and school-based SLT use prevention and cessation programmes need to be encouraged.