Tobacco-specific nitrosamines in smokeless tobacco products marketed in India

Human Urinary Metabolomics as Biomarkers in Tobacco Users: A Systematic Review

Aim

Urine as a biofluid has been rarely used as a diagnostic fluid in oral diseases. The article aims to systematically review the utility of human urinary carcinogen metabolites as an approach for obtaining important information about tobacco and cancer.

Materials and Methods

The following article reviews the use of urine and its metabolites as biomarkers in various lesions of the oral cavity including oral squamous cell carcinoma and as a screening method in evaluating tobacco and its components. A bibliographic comprehensive search was carried out in the main databases: PUBMED, SciELO, Google Scholar, VHL, and LILACS for articles that were published from 1985 to 2020. The inclusion criteria were "urinary metabolites," "oral cancer/HNSCC," "body fluids," "tobacco," and "metabolomics." A total of 55 articles were collected which included laboratory studies, systematic reviews, and literature of urinary metabolites in tobacco users.

Results

Most of the studies carried out show accurate results with high sensitivity of urinary metabolite biomarkers in individuals with tobacco-based habits and lesions caused by them.

Conclusion

The review indicates that urinary metabolite analysis demonstrates its applicability for the diagnosis and prognosis of disease. Urine is a remarkable and useful biofluid for routine testing and provides an excellent resource for the discovery of novel biomarkers, with an advantage over tissue biopsy samples due to the ease and less invasive nature of collection.

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.

Comparative Analysis of Dentition and Periodontal Status in Patients With Unilateral Smokeless Tobacco Pouch Keratosis

INTRODUCTION

The consumption of smokeless tobacco (SLT) and related products has become an epidemic worldwide, especially among young people, as they come into direct contact with the tissues of the oral cavity. Therefore, the present cross-sectional study was conducted to compare the status of dentition and periodontal health of teeth associated with the unilateral SLT pouch keratosis with the unaffected contralateral side.

MATERIALS AND METHODS

In this study, 96 SLT users from north Maharashtra, India, with unilateral SLT pouch keratosis were studied. Demographic data, past and present SLT use history, features of SLT pouch keratosis, modified community periodontal index, dentition status index, and loss of tooth attachment were recorded. Data were collected and subjected to statistical analysis using the unpaired t-test and chi-square test.

RESULTS

The results of the present study showed a significant difference (p≤0.05) in gingival bleeding, pocket depth, and attachment loss in teeth associated with smokeless tobacco keratosis (STK) compared to teeth at the contralateral sides of the arch. The duration of tobacco use had a significant effect on the severity of loss of attachment at SLT pouch keratosis sides. There was a significant difference (p≤0.05) in the mean scores of the sound crown, carious crown, and coronal caries status between the SLT pouch keratosis side and the contralateral side.

CONCLUSION

The results of the study revealed that significant gingival bleeding, gingival recession, and attachment loss in the teeth are associated with SLT pouch keratosis compared with the teeth on the contralateral side without the lesion.

Chemical analysis of selected harmful and potentially harmful constituents and in vitro toxicological evaluation of leading flavoured e-cigarette aerosols in the Chinese market

Use of electronic cigarettes (e-cigarettes) has increased significantly over the past decade due to consumer perception that these products represent a less risky alternative to combustible cigarettes. E-liquids generally contain a simple mix of vegetable glycerin, propylene glycerol, nicotine, organic acids, and flavourings. Regulators require that harmful and potentially harmful constituents (HPHCs) that might cause harm to the consumer must be monitored in the aerosol generated by e-cigarettes and in cigarette smoke (CS). To quantify HPHCs in aerosols from commercial flavoured e-cigarettes in Chinese market, this study has systematically compared levels of HPHCs, including eight carbonyls, five volatile organic compounds, four tobacco-specific nitrosamines, 16 polycyclic aromatic hydrocarbons, and seven heavy metals, in the aerosols of four market-leading flavoured e-cigarettes and mainstream CS, alongside in vitro cytotoxicity and mutagenicity assays. The vast majority of HPHCs were either undetected or significantly lower in the e-cigarette aerosols than in commercial CS or reference CS (3R4F). Where HPHCs were detected, there were small variations among the different flavoured e-cigarettes. In the neutral red uptake and Ames assays, aqueous extracts of the e-cigarette aerosols did not induce obvious cytotoxicity or mutagenicity, whereas CS aqueous extract showed dose-related cytotoxicity and mutagenicity. Collectively, these results indicate that use of e-cigarettes might potentially lead to a significant reduction in exposure to harmful substances, with fewer cytotoxic and mutagenic effects, as compared with conventional smoking. Further studies based on human puffing conditions and longer evaluation periods will be needed to substantiate this potential.

Physical and chemical characterization of smokeless tobacco products in India

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.

Risk factors for head and neck cancer in more and less developed countries: Analysis from the INHANCE consortium

OBJECTIVE

We analyzed the pooled case-control data from the International Head and Neck Cancer Epidemiology (INHANCE) consortium to compare cigarette smoking and alcohol consumption risk factors for head and neck cancer between less developed and more developed countries.

SUBJECTS AND METHODS

The location of each study was categorized as either a less developed or more developed country. We compared the risk of overall head and neck cancer and cancer of specific anatomic subsites associated with cigarette smoking and alcohol consumption. Additionally, age and sex distribution between categories was compared.

RESULTS

The odds ratios for head and neck cancer sites associated with smoking duration differed between less developed and more developed countries. Smoking greater than 20 years conferred a higher risk for oral cavity and laryngeal cancer in more developed countries, whereas the risk was greater for oropharynx and hypopharynx cancer in less developed countries. Alcohol consumed for more than 20 years conferred a higher risk for oropharynx, hypopharynx, and larynx cancer in less developed countries. The proportion of cases that were young (<45 years) or female differed by country type for some HNC subsites.

CONCLUSION

These findings suggest the degree of industrialization and economic development affects the relationship between smoking and alcohol with head and neck cancer.

Genetic and epigenetic instability induced by betel quid associated chemicals

Over the years, betel quid chewing and tobacco use have attracted considerable interest as they are implicated as the most likely causative risk factors of oral and esophageal cancers. Although areca nut use and betel quid chewing may lead to apoptosis, chronic exposure to areca nut and slaked lime may promote pre-malignant and malignant transformation of oral cells. The putative mutagenic and carcinogenic mechanisms may involve endogenous nitrosation of areca and tobacco alkaloids as well as the presence of direct alkylating agents in betel quid and smokeless tobacco. Metabolic activation of carcinogenic N-nitrosamines by phase-I enzymes is required not only to elicit the genotoxicity via the reactive intermediates but also to potentiate the mutagenicity with the sporadic alkylations of nucleotide bases, resulting in the formation of diverse DNA adducts. Persistent DNA adducts provides the impetus for genetic and epigenetic lesions. The genetic and epigenetic factors cumulatively influence the development and progression of disorders such as cancer. Accumulation of numerous genetic and epigenetic aberrations due to long-term betel quid (with or without tobacco) chewing and tobacco use culminates into the development of head and neck cancers. We review recent evidence that supports putative mechanisms for mutagenicity and carcinogenicity of betel quid chewing along with tobacco (smoking and smokeless) use. The detailed molecular mechanisms of the extent of accumulation and patterns of genetic alterations, indicative of the prior exposure to carcinogens and alkylating agents because of BQ chewing and tobacco use, have not yet been elucidated.

A chemometric experimental design with three-step stacking capillary electrophoresis for analysis of five tobacco-specific nitrosamines in cigarette products

Tobacco-specific nitrosamines (TSNAs) as carcinogens endanger our health and life from cigarette products. However, the safe range of TSNAs levels in commercial cigarette products has not yet been established. For the purpose of safety and supervision, a three-step stacking approach including field amplified sample injection (FASI), sweeping, and analyte focusing by micelle collapse (AFMC), was developed for the simultaneous determination of five TSNAs levels in cigarette products. This approach also involved aspects of chemometric experimental design, including fractional factorial design and central composite design. After the multilevel optimization of the experimental design, the five TSNAs were well separated. The LOD (S/N = 3) values of the N´-nitrosonornicotine (NNN), N´-nitrosoanatabine (NAT), N´-nitrosoanabasine (NAB), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in the FASI-sweeping-AFMC CE approach were 1.000 ng/mL, 0.500 ng/mL, 0.125 ng/mL, 1.000 ng/mL, and 0.500 ng/mL respectively. The results of relative standard deviation (RSD) and relative error (RE) were all less than 3.35%, demonstrating good precision and accuracy. Finally, this novel approach was further applied to monitor three commercial cigarette products, and a range of 250.1-336.6 ng/g for NNN, 481.6-526.7 ng/g for NAT, 82.2-247.6 ng/g for NAB, 167.7-473.7 ng/g for NNAL, and 39.4-246.7 ng/g for NNK could be observed among these. Based on these results, the novel CE stacking strategy was successfully applied for the analysis of five TSNAs levels in cigarette products and could serve as a tool for assays of quality control of nitrosamines.

Structure-based study to identify alkaloids as promising cytochrome P450 (CYP1A1) inhibitors: An in silico approach using virtual screening, molecular dynamic simulations, and binding free energy calculation

Carcinogens present in smokeless tobacco (SLT) like tobacco-specific nitrosamines can be metabolized by the cytochrome P450 (CYP450) enzyme. Functionally, the CYP450 enzyme resides in a heme pigment to perform the catalytic activity. The CYP1A1 is one of the main extrahepatic CYP450 enzymes known to detoxify toxic substances and activate carcinogens. The CYP1A1 inhibition by potential inhibitors reduce the chance of oral cancer. The current study aimed to explore more about the inhibitor binding site and identification of lead alkaloids, that could work as putative inhibitors against target CYP1A1. In respect, we have performed docking studies, virtual screening of alkaloids, and natural product libraries against CYP1A1 followed by molecular dynamic simulations and binding free energy calculations. Docking studies of tobacco-specific nitrosamine (TSNA) products and their similar carcinogen analogs revealed that the heme group is bound to the floor of the bowl-shaped cavity whereas carcinogens are bound to the roof of the rounded shape cavity. Furthermore, virtual screening and binding free energy calculations revealed Tomatidine as a putative inhibitor against CYP1A1. On the basis of altogether outcomes of the current study, we have concluded that the addition of lead-hit alkaloid Tomatidine and others in SLT products may be working as a supplement that could be able to reduce the expression of human CYP1A1 and suppresses carcinogenic by-products formations.

Delineating the Bacteriome of Packaged and Loose Smokeless Tobacco Products Available in North India

Smokeless tobacco product (STP) consumption is a significant public health threat across the globe. STPs are not only a storehouse of carcinogens and toxicants but also harbor microbes that aid in the conversion of tobacco alkaloids to carcinogenic tobacco-specific nitrosamines (TSNAs), thereby posing a further threat to the health of its consumers. The present study analyzed the bacterial diversity of popular dry and loose STPs by 16S rRNA gene sequencing. This NGS-based investigation revealed four dominant phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria and identified 549 genera, Prevotella, Bacteroides, and Lactobacillus constituting the core bacteriome of these STPs. The most significantly diverse bacteriome profile was displayed by the loose STP Mainpuri kapoori. The study further predicted the functional attributes of the prevalent genera by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) algorithm. Genes encoding for nitrate and nitrite reduction and transport enzymes, antibiotic resistance, multi-drug transporters and efflux pumps, secretion of endo- and exotoxin, and other pro-inflammatory molecules were identified. The loose STPs showed the highest level of nitrogen metabolism genes which can contribute to the synthesis of TSNAs. This study reveals the bacteriome of Indian domestic loose STPs that stagger behind in manufacturing and storage stringencies. Our results raise an alarm that the consumption of STPs harboring pathogenic genera can potentially lead to the onset of several oral and systemic diseases. Nevertheless, an in-depth correlation analysis of the microbial diversity of STPs and their elicit impact on consumer health is warranted. KEY POINTS: • Smokeless tobacco harbors bacteria that aid in synthesis of carcinogenic nitrosamines. • Most diverse bacteriome profile was displayed by loose smokeless tobacco products. • Pathogenic genera in these products can harm the oral and systemic health of users.

Assessment of the Exposure to Tobacco-Specific Nitrosamines and Minor Tobacco Alkaloids in Users of Various Tobacco/Nicotine Products

Tobacco-specific nitrosamines (TSNAs), in particular, the human carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN), are important toxicants in tobacco and also (as contaminants) in nicotine products. In a clinical study comprising a period of 74 h under confinement, we investigated the exposure to NNK, NNN, N'-nitrosoanabasine (NAB), and N'-nitrosoanatabine (NAT) as well as to the minor tobacco alkaloids anabasine (AB) and anatabine (AT) by measuring suitable biomarkers in habitual users of combustible cigarettes (CCs), electronic cigarettes (ECs), heated tobacco products (HTPs), oral tobacco (OT), and nicotine replacement therapy products (NRTs). Non-users (NU) of any tobacco/nicotine products served as the (negative) control group. Smokers exhibited the highest levels for all biomarkers measured, except for AB in urine, which was found to be highest in OT users. Somewhat elevated levels compared to NU, EC, and NRT groups were also observed in the users of HTPs. In the users of tobacco-containing products (CC, HTP, and OT), most frequently the biomarkers significantly correlated with the dose markers such as daily consumption, urinary nicotine equivalents (Nequ), and plasma cotinine (CotP). In conclusion, except for smokers (CC) and OT users, exposure of users of ECs, HTPs, and NRTs to TSNAs as well as the minor tobacco alkaloids AB and AT is marginal and statistically not distinguishable from that of NU. Finally, our results for NNN in the saliva provide preliminary evidence for the formation of NNN from the precursor nornicotine in the presence of thiocyanate as a catalyst. The latter hypothesis requires experimental verification.

Simultaneous analysis of urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, N'-nitrosonornicotine, and cotinine by liquid chromatography-tandem mass-spectrometry

Biomarkers of exposure to harmful tobacco constituents are key tools for identifying individuals at risk and developing interventions and tobacco control measures. However, tobacco biomarker studies are scarce in many parts of the world with high prevalence of tobacco use. Our goal was to establish a robust method for simultaneous analysis of urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), N'-nitrosonornicotine (NNN), and cotinine at the Advanced Centre for Treatment, Research and Education in Cancer (ACTREC) in Mumbai, India. These biomarkers are validated measures of exposure to the carcinogenic tobacco nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and NNN and the addictive alkaloid nicotine, respectively. The established method is characterized by excellent accuracy, linearity, and precision, and was successfully applied to the analysis of 15 smokeless tobacco (SLT) users and 15 non-users of tobacco recruited in Mumbai. This is the first report of establishment of such procedure in a laboratory in India, which offers the first in-country capacity for research on tobacco carcinogenesis in Indian SLT users.

Tobacco, Cigarettes, and the Liver: The Smoking Gun

The association between alcohol and liver disease, including alcoholic hepatitis, cirrhosis, acute-on-chronic liver failure, and hepatocellular carcinoma, has been well described, but the same cannot be said for the association between smoking, water pipe or tobacco chewing. A review of cumulative evidence suggests that smoking is independently a risk factor for liver fibrosis and contributes to carcinogenesis in HCC. Smoking-related fibrosis has been reported in patients with nonalcoholic fatty liver disease, primary biliary cholangitis, alcoholic liver disease and chronic viral hepatitis. Heavy smoking leads to systemic inflammation, oxidative stress, insulin resistance, and results in tissue hypoxia, as well as free radical damage. Other than damaging the liver, patients also suffer from the systemic effects of the 4000 chemicals associated with tobacco, which include nitrosamines, aromatic hydrocarbons, nicotine, nornicotine, and other alkaloids. These include respiratory ailments, cancer of the lungs, oral cavity, esophagus, pancreas and colon, atherosclerotic vascular disease, and stroke.

Aqueous extract of tobacco induces mitochondrial potential dependent cell death and epithelial-mesenchymal transition in gingival epithelial cells

Smokeless tobacco habits are detrimental to oral health. A correlation between tobacco use and local epithelial tissue damage exists. Yet, the underlying cellular mechanism is not precisely characterized. This study assessed the dose-dependent action of Smokeless tobacco extract on gingival epithelial cells. Gingival tissue was taken from 5 healthy donors. Gingival epithelial cells were isolated by an enzymatic method and cultured up to passage 2. The cultured cells were treated with smokeless tobacco extract at 10%, 25%, 50%, and 75% volume concentration. After 48 h of incubation, MTT assay, Annexin V/PI assay, and DiIC1(5) assay were used to evaluate viability, apoptosis, and mitochondrial potential of the cells. RT-qPCR was used to determine the expression of BAX, BCL2, ECAD, NCAD, and TWIST. The Smokeless tobacco extract reduced cell viability by disrupting the mitochondrial potential and inducing apoptosis. Further, the Smokeless tobacco extract induced a dose-dependent epithelial-mesenchymal-transition in gingival epithelial cells. Apoptotic cellular death caused by tobacco extract on the gingival epithelial system was dependant on the mitochondrial potential of the cell. The results demonstrate that smokeless tobacco causes detrimental metabolic alterations of the periodontium.

Featured application

This study elucidates the mechanism by which Smokeless tobacco products cause cellular damage to the gingival epithelium. The use of Smokeless tobacco products can lead to major cellular and surface changes in the gingiva and its appearance. The consequences of these changes are not limited to oral cancer but also increases a person's risk for dental and periodontal disease.

Consumption pattern and genotoxic potential of various smokeless tobacco products in Assam, India: A public health concern

Smokeless tobacco (SLT) consumption is presumed to be one of the major causes of high incidence of oral cancer in India. The present study aimed to document various types of SLT products consumed and their potential impact on the genome instability on the population from Assam state in Northeast India. A cross-sectional study (n = 5000) showed that 60.56 % of the study population consumed at least one of the three forms (sadagura, zarda and khaini) of SLT of which 52.0 % were only sadagura users. Genotoxicity assessment using buccal cytome assay in 240 age and sex matched volunteers revealed that except for zarda, other forms of SLT induced significantly higher incidence micronuclei in the buccal epithelial cells compared to the control individuals. Similar effects were also observed in other cytome parameters related to cell proliferation, cytokinesis defects and cell death. Significantly higher incidence of micronucleus was observed among sadagura and khaini users in lymphocyte cytokinesis-blocked micronucleus assay. The addition of lime in sadagura increased the pH and anion levels which possibly result in higher absorption and may lead to the development of cellular anomalies.

Comparison of tobacco-specific nitrosamine levels in smokeless tobacco products: High levels in products from Bangladesh

Bangladesh exhibits the second highest rate of smokeless tobacco (SLT) product usage in the world, and this has been associated with the high upper aerodigestive tract cancer incidence in this country. The goal of the present study was to examine the levels of the highly carcinogenic tobacco-specific nitrosamines (TSNAs) in Bangladeshi SLT products and compare these levels to that observed in SLT brands from southeast Asia and the USA. The levels of TSNAs and nicotine were determined by LC-MS/MS in twenty-eight SLT brands and several tobacco additives from Bangladesh, as well as several SLT brands from India, Pakistan and the USA. The levels of N-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N-nitrosoanatabine (NAT) and N-nitrosoanabasine (NAB) in Bangladeshi SLT brands ranged from 1.1-59, 0.15-34, 0.79-45, and 0.037-13 μg/g SLT powder, respectively. The mean levels of the highly carcinogenic TSNAs (NNN+NNK) were 7.4-, 2.4-, and 63-fold higher in Bangladeshi SLT products as compared to SLT brands from the USA, India and Pakistan, respectively; these trends were also observed for NAT and NAB. Similar mean levels of nicotine were observed in the Bangladeshi brands (31 mg/g powder) versus brands from the USA (25 mg/g powder) and India (20 mg/g powder); they were 3-fold higher than brands from Pakistan (10 mg/g powder). Gul SLT brands exhibited the highest pH and the highest levels of unprotonated nicotine. The high levels of TSNAs in Bangladeshi SLT brands may be an important factor contributing to the high rates of upper aerodigestive tract cancer in Bangladesh.

Comprehensive Chemical Characterization of Natural American Spirit Cigarettes

OBJECTIVES

Marketing of the Natural American Spirit (NAS) cigarettes implies reduced risk of toxic exposures. We aimed to provide a comprehensive chemical characterization of these cigarettes.

METHODS

We analyzed 13 varieties of NAS for a range of tobacco- and combustion-derived constituents. Cigarettes were smoked by 2 standard regimens and analyzed using our routine analytical procedures. We also analyzed tobacco filler and physical cigarette characteristics.

RESULTS

Under intense smoking conditions, nicotine in smoke of NAS cigarettes averaged 3.3(±0.7) mg/cigarette, compared to 2.4(±0.4) in other brands. The levels of carcinogenic nitrosamines NNN and NNK varied extensively across NAS varieties, their sum ranging from 71 to 443 ng/cigarette. Levels of volatile toxicants were generally similar to, or higher than those found in other commercial US cigarettes.

CONCLUSIONS

High nicotine content suggests that NAS cigarettes may be more addictive than many other brands. Similarly low TSNA levels were measured in some NAS varieties, independent of whether or not they were labeled as organic. Levels of other toxicants were similar to other brands. Consumer education and additional regulatory measures are needed to address the misperceptions that NAS cigarettes are safer than other commercial cigarette brands.

Improving Utility of Data on Cancer Mortality Risk Associated with Smokeless Tobacco: Recommendations for Future Research

Background:

We analyzed in detail the studies utilized in most recent global systematic review of risk of cancer mortality with smokeless tobacco (SLT) use to report challenges in the available data that limit the understanding of association between SLT use and cancer mortality.

Methods:

For each study, we documented study design, reporting of mortality risk by type of SLT variant, SLT use frequency, and sex of SLT user for oral, oesophageal, pharyngeal, laryngeal and orolaryngeal cancers. These findings are discussed within the context of prevalence of SLT use by geographic regions and sex.

Results:

Majority of studies reported mortality risk for oral (70.6%) followed by oesophageal cancer (38.2%). The availability of population-based evidence was low (35.3%). The geographic distribution of studies did not reflect the geographic distribution of countries with high SLT consumption; 61.8% of the studies were from India followed by Sweden (20.6%). Hospital-based (84.2%) studies reported risk with chewing tobacco and the population-based studies (61.5%) with non-chewing tobacco. Hardly any study reported on a particular type of SLT. Definition of SLT use as current, ever or former was limited without consideration of the wide variations in frequency and duration of use within these patterns. Mortality risk reporting for males dominated all cancers other than oral (50% males).

Conclusions:

Unless the methodological and generalizability challenges identified in this review are addressed in future research to develop a stronger scientific basis of the association of SLT use and cancer mortality, we would continue to face significant challenges in monitoring the health effects of SLT.

Lifestyle chemical carcinogens associated with mutations in cell cycle regulatory genes increases the susceptibility to gastric cancer risk

In the present study, we correlated the various lifestyle habits and their associated mutations in cell cycle (P21 and MDM2) and DNA damage repair (MLH1) genes to investigate their role in gastric cancer (GC). Multifactor dimensionality reduction (MDR) analysis revealed the two-factor model of oral snuff and smoked meat as the significant model for GC risk. The interaction analysis between identified mutations and the significant demographic factors predicted that oral snuff is significantly associated with P21 3'UTR mutations. A total of five mutations in P21 gene, including three novel mutations in intron 2 (36651738G > A, 36651804A > T, 36651825G > T), were identified. In MLH1 gene, two variants were identified viz. one in exon 8 (37053568A > G; 219I > V) and a novel 37088831C > G in intron 16. Flow cytometric analysis predicted DNA aneuploidy in 07 (17.5%) and diploidy in 33 (82.5%) tumor samples. The G2/M phase was significantly arrested in aneuploid gastric tumor samples whereas high S-phase fraction was observed in all the gastric tumor samples. This study demonstrated that environmental chemical carcinogens along with alteration in cell cycle regulatory (P21) and mismatch repair (MLH1) genes may be stimulating the susceptibility of GC by altering the DNA content level abnormally in tumors in the Mizo ethic population.

Ecological Analysis to Study Association between Prevalence of Smokeless Tobacco Type and Head-and-Neck Cancer

Context: Head-and-neck cancers (HNCs) are most common cancer in Indian cancer registries. However, there is a huge variation and heterogeneity in use of different types of smokeless tobacco (SLT) consumption across India. Aims: The aims and objectives of this study were to investigate how different types of SLT use are distributed across Indian states and examined its association with different subsites of HNC incidence rates. Settings and Design: Ecological analysis of correlation between SLT prevalence and incidence rates from population-based cancer registries. Methods: Incidence data was extracted from population-based cancer registries report from the National Cancer Registry Programme database 2012–2014. The current SLT uses the prevalence of all Indian States and Union territories from Global Adult Tobacco Survey 2009–2010. Statistical Analysis Used: Pearson’s correlation coefficient was used to estimate an ecological correlation between the prevalence of types of SLT uses in different region of India and age-adjusted incidence rate of different subsites of HNC. Results: In our brief analysis, we found a significant correlation between certain types of SLT use and subsite of HNC. Betel quid and tobacco use are correlated (r = 0.53) with oropharynx cancer incidence. Khaini use is correlated with hypopharynx cancer incidence (r = 0.48). Gutka use is correlated with mouth cancer incidence (r = 0.54). Oral tobacco is correlated with mouth cancer incidence (r = 0.46). Other SLT use is correlated for hypopharynx cancer incidence (r = 0.47). Conclusions: The variations in SLT use across Indian states account for differences in incidence rates of HNC subsites across the states. The inferences from this brief analysis can be used as a base to modify and design observational epidemiological studies in the future.

Self-perceived oral symptoms and periodontal inflammatory conditions in habitual naswar dippers

Objectives:

To compare self-perceived oral symptoms and clinical (plaque index [PI], bleeding on probing [BOP], clinical attachment loss [CAL]) and radiographic (marginal bone loss [MBL]) periodontal parameters among naswar (NW) and non-naswar dippers (NNW).

Methods:

One hundred and forty-two individuals (72 patients consuming naswar and 70 controls) were included. All participants completed a baseline questionnaire that included information regarding demographic characteristics and self-perceived oral symptoms. Clinical periodontal parameters (PI, BOP, PD and CAL) were recorded. MBL was measured on digital panoramic radiographs.

Results:

Pain in teeth, pain on chewing, bleeding gums and burning sensation in the mouth was significantly worse among NW than NNW (p<0.01). Clinical periodontal parameters and MBL were significantly high in NW than NNW (p<0.001). There was statistically significant influence of daily use and mean duration of naswar consumption on the severity of PI, BOP, PD (4 to 6 and >6 mm) and MBL among NW group.

Conclusions:

Self-perceived oral symptoms and periodontal parameters were worse among naswar dippers. It is highly recommended that naswar dipping should be considered a potential threat that could have major effects on periodontal tissues.

Oral health consequences of smokeless tobacco use

Smokeless tobacco (SLT) use has many oral effects including oral cancer, leukoplakia and erythroplakia, oral submucous fibrosis (if mixed with areca nut), loss of periodontal support (recession) and staining of teeth and composite restorations. This review was aimed to provide information to identify oral lesions that occur due to the use of smokeless tobacco so that effective interventions can be undertaken to reduce morbidity and mortality from the use of SLT.

Regulation of toxic contents of smokeless tobacco products

Effective regulation of contents of tobacco products is one of the primary milestones to reduce negative health effects associated with the use of smokeless tobacco (SLT) products. As per the available sources, testing of some SLT products has been done on ad hoc basis, but there is a lack of comprehensive and periodic analysis of these products. In addition, the available results indicate huge variations among the levels of pH, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, N-nitrosonornicotine, benzo[a]pyrene, heavy metals and nicotine within different products as well as within different brands of the same product. This review was aimed to throw light on the variations and gaps in testing of SLT products and emphasize the need for strong policy regulation for monitoring the chemical constituents of these products.

Reviewing smokeless tobacco epidemiology, carcinogenesis, and cessation strategy for otolaryngologists

OBJECTIVES/OBJECTIVES

We aimed to provide an otolaryngologist-targeted summary regarding the epidemiology, carcinogenesis, and cessation strategies for smokeless tobacco usage.

STUDY DESIGN

Evidence-based literature review.

METHODS

We reviewed the current evidence-based literature concerning trends in smokeless tobacco use, associations with neoplastic change, and therapeutic interventions to assist with sustained abstinence. In complement, we present an actual case of laryngeal squamous cell carcinoma in the setting of chronic tobacco-dentifrice usage in a lifelong nonsmoker.

RESULTS

This report provides a synopsis of epidemiological data and evidence-based recommendations for general, pharmaceutical, and behavioral cessation strategies.

CONCLUSIONS

Smokeless tobacco use continues to be prevalent among patients seen by otolaryngologists, particularly of various Indian and Southeast Asian descent. The data presented in this article will aid in the identification of at risk patients. The provided recommended cessation strategies will tool otolaryngologists for patient counseling and management, ultimately aimed at improving health outcomes. Laryngoscope, 128:2067-2071, 2018.

Global burden of all-cause and cause-specific mortality due to smokeless tobacco use: systematic review and meta-analysis

OBJECTIVES

To systematically review and meta-analyse the studies investigating the association between smokeless tobacco (SLT) use and all-cause mortality and cause-specific mortality outcomes among adult users of SLT and estimate the number of attributable deaths worldwide.

METHODS

Random-effects meta-analysis was used to estimate the pooled risk of death due to SLT use. Population attributable fractions were derived and used to calculate the number of attributable deaths. Observational studies published upto 2015 were identified through MEDLINE, IndMED, Google Scholar and other databases. Data on the prevalence of SLT use was obtained from latest reports or national surveys. Data on the disease burden were obtained from the Global Burden of Disease Study. Hospital-based or community-based case-control and cohort studies that adjusted for the smoking status were included.

RESULTS

16 studies that provided estimates for mortality due to all cause, all cancer, upper aerodigestive tract (UADT) cancer, stomach cancer, cervical cancer, ischaemic heart disease (IHD) and stroke were included. A significant association was found for mortality due to all cause (1.22; 1.11-1.34), all cancer (1.31; 1.16-1.47), UADT cancer (2.17; 1.47-3.22), stomach cancer (1.33; 1.12-1.59), cervical cancer (2.07; 1.64-2.61), IHD (1.10; 1.04-1.17) and stroke (1.37; 1.24-1.51). Subgroup analysis showed major regional differences. Globally, the number of attributable deaths from all-cause mortality was 652 494 (234 008-1 081 437), of which 88% was borne by the South-East Asian region.

CONCLUSIONS

SLT is responsible for a large number of deaths worldwide with the South-East Asian region bearing a substantial share of the burden.

Tobacco-specific N-nitrosamines and polycyclic aromatic hydrocarbons in cigarettes smoked by the participants of the Shanghai Cohort Study

Our recent studies on tobacco smoke carcinogen and toxicant biomarkers and cancer risk among male smokers in the Shanghai Cohort Study showed that exposure to tobacco-specific nitrosamines (TSNA) and polycyclic aromatic hydrocarbons (PAH) is prospectively associated with the risk of cancer. These findings support the hypothesis that the smokers' cancer risk is a function of the dose of select tobacco carcinogens and highlight the importance of understanding the factors that affect the intake of these carcinogens by smokers. Given that tobacco constituent exposures are driven, at least in part, by the levels of these constituents in cigarette smoke, we measured mainstream smoke TSNA and PAH levels in 43 Chinese cigarette brands that participants of the Shanghai Cohort Study reported to smoke. In all brands analyzed here, mainstream smoke levels of NNN and NNK, the two carcinogenic TSNA, were generally relatively low, averaging (±SD) 16.8(±25.1) and 14.2(±9.5) ng/cigarette, respectively. The levels of PAH were comparable to those found in U.S. cigarettes, averaging 15(±9) ng/cigarette for benzo[a]pyrene, 119(±66) ng/cigarette for phenanthrene and 37(±19) ng/cigarette for pyrene. Our findings indicate that the generally low levels of NNN and NNK are most likely responsible for the relatively low levels of the corresponding biomarkers in the urine of the Shanghai Cohort Study participants as compared to those found in the U.S. smokers, supporting the role of the levels of these constituents in cigarette smoke in smokers' exposures. Our findings also suggest that, in addition to smoking, other sources contribute to Chinese smokers' exposure to PAH.

Analysis of Tobacco-Specific Nitrosamines in the Common Smokeless Tobacco Afzal in Oman

OBJECTIVES

There is a lack of awareness regarding the carcinogenicity of Afzal, an illegal smokeless tobacco product (STP) widely used among the Omani youth. Previous research has shown that certain types of tobacco-specific nitrosamines (TSNAs) are associated with oral and lung cancers. This study therefore aimed to assess levels of four common TSNAs in a randomly selected sample of Afzal.

METHODS

This study was carried out at Sultan Qaboos University in Muscat, Oman, between April and September 2013. A random sample of Afzal was analysed for four types of TSNAs using high-performance liquid chromatography-tandem mass spectrometry. The four types of TSNAs analysed were 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK), N-nitrosonornicotine (NNN), N-nitrosoanatabine (NAT) and N-nitrosoanabasine (NAB). As a reference product, a sample of laboratory-manufactured American moist snuff (Centers for Disease Control and Prevention, Atlanta, Georgia, USA) was also used to confirm the accuracy and precision of the analysis.

RESULTS

The analysis revealed total TSNA levels of 3.573 μg/g in the Afzal sample. Mean levels of NNN, NNK, NAT and NAB were 1.205, 1.015, 0.809 and 0.545 μg/g, respectively.

CONCLUSION

Levels of the two most abundant TSNAs (NNN and NNK) found in the Afzal sample exceeded international regulatory limits. Afzal users therefore need to be educated regarding the potential health risks associated with their STP use. Stricter implementation of current legislation is recommended to reduce the availability and usage of Afzal in Oman.

Patterns of Use and Perceptions of Harm of Smokeless Tobacco in Navi Mumbai, India and Dhaka, Bangladesh

Background:

Globally, smokeless tobacco use is disproportionately concentrated in low-income and middle-income countries like India and Bangladesh.

Objectives:

The current study examined comparative patterns of use and perceptions of harm for different smokeless tobacco products among adults and youth in Navi Mumbai, India, and Dhaka, Bangladesh.

Methods:

Face-to-face interviews were conducted on tablets with adult (19 years and older) smokeless tobacco users and youth (16–18 years) users and non-users in Navi Mumbai (n = 1002), and Dhaka (n = 1081).

Results:

A majority (88.9%) of smokeless tobacco users reported daily use. Approximately one-fifth (20.4%) of the sample were mixed-users (used both smoked and smokeless tobacco), of which about half (54.4%) reported that they primarily used smokeless over smoked forms like cigarettes or bidis. The proportion of users planning to quit was higher in India than in Bangladesh (75.7% vs. 49.8%, p < 0.001). Gutkha was the most commonly used smokeless product in India, and pan masala in Bangladesh. Among users in Bangladesh, the most commonly reported reason for using their usual product was the belief that it was “less harmful” than other types. Perceptions of harm also differed with respect to a respondent's usual product. Bangladeshi respondents reported more negative attitudes toward smokeless tobacco compared to Indian respondents.

Conclusions:

The findings highlight the high daily use of smokeless tobacco, and the high prevalence of false beliefs about its harms. This set of findings reinforces the need to implement effective tobacco control strategies in low and middle-income countries like India and Bangladesh.

High levels of tobacco-specific N-nitrosamines and nicotine in Chaini Khaini, a product marketed as snus

INTRODUCTION

Recently, a tobacco product, Chaini Khaini, identified as snus appeared in India. The product marketing emphasises its discreet nature and explicitly claims safety by referring to the existing evidence on Swedish snus. We analysed tobacco-specific nitrosamines and nicotine in 12 samples of Chaini Khaini purchased in 2013 at open markets in India.

METHODS

Samples were purchased twice: in March 2013 from Mumbai and in November 2013 from Mumbai and Ahmedabad. Chemical constituents were measured by our routine validated methods.

RESULTS

Levels of carcinogenic nitrosamines NNN, NNK and NNAL averaged 22.9 (±4.9), 2.6 (±1.0) and 3.1 (±1.5) µg/g tobacco (wet weight), respectively. The levels of NAB, which is normally present in trace levels in tobacco products, ranged from 3.9 to 12.9 µg/g tobacco. Total nicotine levels in all samples averaged 10.0 mg/g tobacco and unprotonated nicotine accounted for an average 95.4% of the total nicotine content.

CONCLUSIONS

Chaini Khaini, which is labelled as snus and is marketed as a safe alternative to other tobacco products contains very high levels of carcinogenic nitrosamines and biologically available nicotine. Interventions are urgently needed to educate current and potential consumers of this product.

Smokeless tobacco-associated cancers: A systematic review and meta-analysis of Indian studies

The International Agency for Research on Cancer (IARC) has concluded that there is sufficient evidence in humans for the carcinogenicity of smokeless tobacco (SLT) for mouth, oesophagus and pancreas, based largely on Western studies. We wanted to confirm this by conducting a systematic review using Indian studies because India faces the biggest brunt of SLT-attributable health effects. A systematic search was conducted for published and unpublished studies. Two authors independently reviewed the studies and extracted data. Summary odds ratio (OR) for each cancer type was calculated using fixed and random effects model. The population attributable fraction (PAF) method was used to calculate the attributable burden of incident cases. A significant association was found for oral-5.55 (5.07, 6.07), pharyngeal-2.69 (2.28, 3.17), laryngeal-2.84 (2.18, 3.70), oesophageal-3.17 (2.76, 3.63) and stomach-1.26 (1.00, 1.60) cancers. But in random effects model, laryngeal-1.79 (0.70, 4.54) and stomach-1.31 (0.92, 1.87) cancers became non-significantly associated. Gender-wise analysis revealed that women had a higher risk (OR = 12.0 vs. 5.16) of oral but a lower risk (1.9 vs. 4.5) of oesophageal cancer compared with men. For oral cancer, studies that adjusted for smoking, alcohol and other factors reported a significantly lower OR compared with studies that adjusted for smoking only or smoking and alcohol only (3.9 vs. 8.4). The annual number of attributable cases was calculated as 49,192 (PAF = 60%) for mouth, 14,747 (51%) for pharynx, 11,825 (40%) for larynx, 14,780 (35%) for oesophagus and 3,101 (8%) for stomach.

Evidence supporting product standards for carcinogens in smokeless tobacco products

Smokeless tobacco products sold in the United States vary significantly in yields of nicotine and tobacco-specific nitrosamines (TSNA). With the passage of the Family Smoking Prevention and Tobacco Control Act, the Food and Drug Administration now has the authority to establish product standards. However, limited data exist determining the relative roles of pattern of smokeless tobacco use versus constituent levels in the smokeless tobacco product in exposure of users to carcinogens. In this study, smokeless tobacco users of brands varying in nicotine and TSNA content were recruited from three different regions in the U.S. Participants underwent two assessment sessions. During these sessions, demographic and smokeless tobacco use history information along with urine samples to assess biomarkers of exposure and effect were collected. During the time between data collection, smokeless tobacco users recorded the amount and duration of smokeless tobacco use on a daily basis using their diary cards. Results showed that independent of pattern of smokeless tobacco use and nicotine yields, levels of TSNA in smokeless tobacco products played a significant role in carcinogen exposure levels. Product standards for reducing levels of TSNA in smokeless tobacco products are necessary to decrease exposure to these toxicants and potentially to reduce risk for cancer.

An analytical study on the common type of smokeless tobacco available in the Iranian market

Background:

The use of smokeless tobacco is considered as a risk factor for oral cancer.

Objectives:

The current study aimed to chemically analyze, separate and measure the existing substances in a type of chewing tobacco.

Materials and Methods:

In the current descriptive study, the investigated sample was a type of smokeless tobacco, known as BT, manufactured in India. First steam distillation method and Clevenger machine were used to separate and extract the essential oil of the sample. The presence of the desired compounds was evaluated in the essential oil, using gas chromatography (GC) and then gas chromatography coupled to mass spectrometry (GC/MS) analysis.

Results:

Based on the results obtained by the applied technique, the presence of carcinogenic compounds, N-nitrosomethyl-vinylamine (162 µg/g), N-nitrosonornicotine (6.3 µg/g), and Acetaldehyde (117 µg/g) was confirmed in the sample.

Conclusions:

Chemical analysis of the sample confirmed the existence of carcinogenic compounds.

Non-cigarette tobacco and the lung

Cigarette smoking is known to cause a wide range of damaging health outcomes; however, the effects of non-cigarette tobacco products are either unknown or perceived as less harmful than cigarettes. Smokeless tobacco, cigar smoking, and waterpipe smoking have increased in usage over the past few decades. Some experts believe that their use is reaching epidemic proportions. Factors such as a perception of harm reduction, targeted advertising, and unrecognized addiction may drive the increased consumption of non-cigarette tobacco products. In particular, the need for social acceptance, enjoyment of communal smoking activities, and exotic nature of waterpipe smoking fuels, in part, its popularity. The public is looking for "safer" alternatives to smoking cigarettes, and some groups advertise products such as smokeless tobacco and electronic cigarettes as the alternatives they seek. Though it is clear that cigar and waterpipe tobacco smoking are probably as dangerous to health as cigarette smoking, there is an opinion among users that the health risks are less compared to cigarette smoking. This is particularly true in younger age groups. In the cases of smokeless tobacco and electronic cigarettes, the risks to health are less clear and there may be evidence of a harm reduction compared to cigarettes. In this article, we discuss commonly used forms of non-cigarette tobacco products, their impacts on lung health, and relevant controversies surrounding their use.

Combusted but not smokeless tobacco products cause DNA damage in oral cavity cells

The aim of this work was to investigate genomic DNA damage in human oral cavity cells after exposure to different tobacco product preparations (TPPs). The oral carcinoma cell line 101A, gingival epithelial cells HGEC, and gingival fibroblasts HGF were exposed to TPM (total particulate matter from 3R4F cigarettes), ST/CAS (2S3 smokeless tobacco extract in complete artificial saliva), and NIC (nicotine). Treatments were for 24 h using TPM at its EC-50 doses, ST/CAS and NIC at doses with equi-nicotine units, and high doses for ST/CAS and NIC. Comet assays showed that TPM, but not ST/CAS or NIC, caused substantial DNA breaks in cells; only the high ST/CAS dose caused weak DNA damage. These results were confirmed by immunofluorescence for γ-H2AX protein. These data revealed that the combusted TPP caused substantial DNA damage in all cell types, whereas the two non-combusted TPPs exerted no or only minimal DNA damage. They support epidemiologic evidence on the relative risk associated with consumption of non-combusted versus combusted tobacco products, and help to understand potential genotoxic effects of such products on oral cavity cells.

Tropical Oral Health

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Oral health poses a major health burden for many countries, and some forms of oral disease are specific to tropical countries.

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Oral diseases are the most common non-communicable diseases and share risk factors with many other non-communicable diseases.

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Some 90% of the world's population is affected by tooth decay.

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A high proportion suffer from periodontal disease.

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Oral cancer rates are high among smokers and tobacco users.

Local responses to the Maharashtra gutka and pan masala ban: a report from Mumbai

BACKGROUND

The Maharashtra government has banned the production, sale, distribution and storage of gutka, and pan masala in the Maharashtra State due to the increasing burden of cancer and reproductive health problems attributable to the use of these products. In view of this, it is important to understand the way producers', sellers' and users' are adapting to the ban.

OBJECTIVE

During the two months following the ban (July 19 th through Sept 30, 2012), a research team studying smokeless tobacco use and promotion in a low income community of Mumbai conducted rapid surveillance to assess the impact of the ban in the study community.

MATERIALS AND METHODS

Assessment involved documenting new points of sale, informal observations of tobacco use, and interviews with thirteen shop owners and eight gutka users'. Overall changes in accessibility, availability, patterns of use of tobacco products, perception of ban, social norms and surveillance activities were assessed.

RESULTS

Tobacco companies were marketing new products that resembled gutka, under similar brand logos. Surveillance, financial and social cost of selling gutka or using it in public have had an immediate effect on reducing local supply, demand and use and increasing stigma associated with its use. There was an increased recognition of ill-effects of gutka on cancer among sellers' but not overall.

CONCLUSIONS

To reduce the overall consumption of tobacco in the community, it is critical to include programs that create awareness about effects of smokeless tobacco on health and sustain surveillance levels. This would maintain requirements of the ban, and sustain limits on accessibility, availability and use of these products in the community and other similar communities.

Comparison of the Carcinogenic Potential of Smokeless Tobacco and Smoked Tobacco by Quantifying the Excretion of Nicotine Metabolite NNAL in Patients with Oral Leukoplakia

The case control study was conducted to quantify the amount of the carcinogenic tobacco specific nitrosamine in smokeless tobacco users and smokers in patients with oral leukoplakia and also to emphasize the role of tobacco-specific nitrosamine in the incidence of oral leukoplakia. The study was conducted on 30 patients. The urine samples were obtained from smokeless tobacco users with oral leukoplakia, smokers with oral leukoplakia and non-tobacco users (i.e. people who do not use tobacco in any form). The collected samples were processed by gas chromatography-mass spectrometry. A highly significant difference of NNAL[4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol] in smokeless tobacco users than tobacco smokers P = 0.0002 (Table 1) was obtained. This significant difference shows smokeless tobacco is more carcinogenic than smoked tobacco. This study confirmed that NNAL is a potent biomarker for calculating the risk of occurrence of carcinoma in smokeless tobacco users and smokers, and that smokeless tobacco is more harmful than smoked tobacco.

Levels of (S)-N'-nitrosonornicotine in U.S. tobacco products

INTRODUCTION

N'-nitrosonornicotine (NNN), an esophageal and oral carcinogen present in tobacco products, has a chiral center in its structure. Of its two enantiomers, (S)-NNN exhibits higher tumorigenic potency than (R)-NNN. There is no information available on the levels of (S)-NNN in various tobacco products currently marketed in the United States.

METHODS

We used chiral gas chromatography analysis to determine (S)-NNN levels in a convenience sample of 37 tobacco products currently marketed in the United States: conventional smokeless tobacco, novel smokeless tobacco products, and cigarette tobacco filler.

RESULTS

Among all products analyzed here, (S)-NNN averaged 62.9 ± 6.3% (SD) of NNN. The absolute amount of (S)-NNN in conventional moist snuff averaged 1.26 ± 0.5 µg/g tobacco; in novel smokeless products 0.70 ± 0.2 µg/g tobacco; and in cigarette filler 1.36 ± 0.6 µg/g tobacco (all values are per wet weight). For each cigarette brand, the enantiomeric composition of NNN in cigarette smoke was similar to that of the corresponding tobacco filler.

CONCLUSIONS

Our results demonstrate that (S)-NNN is the predominant NNN enantiomer in moist snuff, novel smokeless tobacco products, and cigarettes currently marketed in the United States. Efforts toward the reduction of NNN in U.S. tobacco products should take into account its enantiomeric composition, with particular focus on (S)-NNN as a causative agent for esophageal and oral cancers associated with tobacco use.

Chemical characterization of domestic oral tobacco products: total nicotine, pH, unprotonated nicotine and tobacco-specific N-nitrosamines

In the United States, moist snuff has been studied more widely than other distinct categories of oral tobacco. In this study, we measured pH, moisture, nicotine (total and unprotonated), and tobacco-specific N-nitrosamines (TSNAs) for other established (twist, loose leaf, plug, and dry snuff without pouch) and emerging oral tobacco products (dry snuff pouch, US-made snus, and dissolvable tobacco). Among the seven product categories, product pH ranged from 4.7 to 7.9, and total nicotine concentration spanned from 3.9 to 40.1 mg/g. The most readily absorbable form of nicotine (unprotonated nicotine) varied more than 350-fold, ranging from 0.01 to 3.7 mg/g. While the highest total nicotine concentrations were observed in twist products, snus and dissolvable tobacco had the highest unprotonated nicotine levels. Among all products, total TSNA concentrations ranged from 313 to 76,500 ng/g with dry snuff having the highest total TSNA concentrations. This study demonstrates the diversity among oral tobacco products and highlights the potential of these products to deliver a wide range of nicotine and carcinogenic TSNAs. Characterizing the chemical content of these products may be helpful in further understanding the risk of marketing these products to oral tobacco users and smokers as an alternative and discrete form of tobacco.

The chemical composition of smokeless tobacco: a survey of products sold in the United States in 2006 and 2007

Selected toxicant concentrations and other chemical measures have been determined for 43 U.S. smokeless tobacco products sold in 2006 and 2007. Products evaluated included moist snuff, dry snuff, loose leaf, plug, dissolvable and snus tobacco brands. Reference products available for scientific research purposes and eleven Swedish products were also evaluated and compared to the commercial products studied. Chemical endpoints determined included benzo[a]pyrene (B[a]P), N'-nitrosonornicotine (NNN), N'-nitrosoanatabine (NAT), N'-nitrosoanabasine (NAB), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N-Nitrosodimethylamine (NDMA), nitrite, cadmium, lead, arsenic, nickel, chromium, chloride, water, pH and nicotine. Different toxicant profiles were observed for the products studied, with snus tobacco brands generally containing relatively low concentrations of B[a]P and tobacco specific nitrosamines (TSNAs) compared to other moist snuffs. Smokeless tobacco reference product toxicant profiles were similar to corresponding commercial products, with the exception of the TSNA content of the dry snuff reference material. TSNA concentrations observed for all commercial products were lower than historically reported values, likely reflecting changes in product shelf life, tobacco curing practices and, possibly, product blend formulations during the last 20-30 years. The survey results summarized provide a temporal point of comparison with future data anticipated from FDA "harmful and potentially harmful constituents in tobacco products" reporting.

O(6)-methylguanine-DNA methyltransferase (MGMT): impact on cancer risk in response to tobacco smoke

Tobacco, smoked, snuffed and chewed, contains powerful mutagens and carcinogens. At least three of them, N-dimethylnitrosamine, N'-nitrosonornicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, attack DNA at the O(6)-position of guanine. The resulting O(6)-alkylguanine adducts are repaired by the suicide enzyme O(6)-methylguanine-DNA methyltransferase (MGMT), which is known to protect against the mutagenic, genotoxic and carcinogenic effects of monofunctional alkylating agents. While in rat liver MGMT was shown to be subject to regulation by genotoxic stress leading to adaptive changes in its activity, in humans evidence of adaptive modulation of MGMT levels is still lacking. Several polymorphisms are known, which are suspected to impact on the risk of developing cancer. In this review we focus on three questions: (a) Has tobacco consumption by smoking or chewing an impact on MGMT expression and MGMT promoter methylation in normal and tumor tissue? (b) Is there an association between MGMT polymorphisms and cancer risk and is this risk related to smoking? (c) Does MGMT protect against tobacco-associated cancer? There are several lines of evidence for an increase of MGMT activity in the normal tissue of smokers compared to non-smokers. Furthermore, in tumors developed in smokers a tendency towards an increase of MGMT expression was found. The data points to the possibility that agents in tobacco smoke are able to trigger upregulation of MGMT in normal and tumor tissue. For MGMT promoter methylation data is conflicting. There is some evidence for an association between MGMT polymorphisms and smoking-induced cancer risk. The key question whether or not MGMT protects against tobacco smoke-induced cancer is difficult to answer since prospective studies on smokers versus non-smokers are lacking and appropriate animal studies with MGMT transgenic mice exposed to the complex mixture of tobacco smoke have not been performed, which indicates the need for further explorations.

Delivery of nicotine in an extract of a smokeless tobacco product reduces its reinforcement-attenuating and discriminative stimulus effects in rats

RATIONALE

Animal models of tobacco addiction rely on administration of nicotine alone or nicotine combined with isolated constituents. Models using tobacco extracts derived from tobacco products and containing a range of tobacco constituents might more accurately simulate tobacco exposure in humans.

OBJECTIVE

To compare the effects of nicotine alone and an aqueous smokeless tobacco extract in several addiction-related animal behavioral models.

METHODS

Nicotine alone and nicotine dose-equivalent concentrations of extract were compared in terms of their acute effects on intracranial self-stimulation (ICSS) thresholds, discriminative stimulus effects, and effects on locomotor activity.

RESULTS

Similar levels of nicotine and minor alkaloids were achieved using either artificial saliva or saline for extraction, supporting the clinical relevance of the saline extracts used in these studies. Extract produced reinforcement-enhancing (ICSS threshold-decreasing) effects similar to those of nicotine alone at low to moderate nicotine doses, but reduced reinforcement-attenuating (ICSS threshold-increasing) effects at a high nicotine dose. In rats trained to discriminate nicotine alone from saline, intermediate extract doses did not substitute for the training dose as well as nicotine alone. Locomotor stimulant effects and nicotine distribution to brain were similar following administration of extract or nicotine alone.

CONCLUSIONS

The reinforcement-attenuating and discriminative stimulus effects of nicotine delivered in an extract of a commercial smokeless tobacco product differed from those of nicotine alone. Extracts of tobacco products may be useful for evaluating the abuse liability of those products and understanding the role of non-nicotine constituents in tobacco addiction.

Non-cigarette tobacco products: what have we learnt and where are we headed?

A wide variety of non-cigarette forms of tobacco and nicotine exist, and their use varies regionally and globally. Smoked forms of tobacco such as cigars, bidis, kreteks and waterpipes have high popularity and are often perceived erroneously as less hazardous than cigarettes, when in fact their health burden is similar. Smokeless tobacco products vary widely around the world in form and the health hazards they present, with some clearly toxic forms (eg, in South Asia) and some forms with far fewer hazards (eg, in Sweden). Nicotine delivery systems not directly reliant on tobacco are also emerging (eg, electronic nicotine delivery systems). The presence of such products presents challenges and opportunities for public health. Future regulatory actions such as expansion of smoke-free environments, product health warnings and taxation may serve to increase or decrease the use of non-cigarette forms of tobacco. These regulations may also bring about changes in non-cigarette tobacco products themselves that could impact public health by affecting attractiveness and/or toxicity.

Monitoring tobacco-specific N-nitrosamines and nicotine in novel Marlboro and Camel smokeless tobacco products: findings from Round 1 of the New Product Watch

INTRODUCTION

Information on chemical composition of the new oral "spitless" smokeless tobacco products is scarce, and it is not clear whether there is some variability as a function of purchase place or time due to either unintended or intended manufacturing variations or other conditions.

METHODS

We analyzed tobacco-specific N-nitrosamines (TSNA) and nicotine in Marlboro Snus, Camel Snus, and dissolvable Camel products Orbs, Sticks, and Strips that were purchased in various regions of the country during the summer of 2010.

RESULTS

A total of 117 samples were received from different states representing six regions of the country. Levels of unprotonated nicotine in Marlboro Snus and Camel Snus varied significantly by regions, with the differences between the highest and the lowest average regional levels being relatively small in Marlboro Snus (∼1.3-fold) and large in Camel Snus (∼3-fold). Some regional variations in TSNA levels were also observed. Overall, Camel Snus had significantly higher TSNA levels than Marlboro Snus, and Camel Strips had the lowest TSNA levels among all novel products analyzed here. The amount of unprotonated nicotine in the dissolvable Camel products was comparable to the levels found in Marlboro Snus.

CONCLUSIONS

Our study demonstrates some regional variations in the levels of nicotine and TSNA in Marlboro and Camel novel smokeless tobacco products. Continued monitoring of this category of products is needed as the existing products are being test marketed and modified, and new products are being introduced. This information is particularly important given its relevance to Food and Drug Administration regulation of tobacco products.

Is there any association between use of smokeless tobacco products and coronary heart disease in Bangladesh?

BACKGROUND

Most epidemiological studies exploring the association between smokeless tobacco (SLT) use and coronary heart disease (CHD) have been in Western populations, and have focused on SLT products used in those countries. Few studies come from South Asian countries. Our objective was to determine the association between SLT use and CHD among non-smoking adults in Bangladesh.

METHODS

A matched case-control study of non-smoking Bangladeshi adults aged 40-75 years was conducted in 2010. Incident cases of CHD were selected from two cardiac hospitals. Community controls, matched to CHD cases, were selected from neighbourhoods, and hospital controls were selected from outpatient departments of the same hospitals. The Rose Angina Questionnaire (RAQ) was also used to re-classify cases and controls.

RESULTS

The study enrolled 302 cases, 1,208 community controls and 302 hospital controls. Current use was higher among community controls (38%) compared to cases (33%) and hospital controls (32%). Current use of SLT was not significantly associated with an increased risk of CHD when community controls were used (adjusted OR 0.87, 95% CI 0.63-1.19), or when hospital controls were used (adjusted OR 1.00, 95% CI 0.63-1.60), or when both control groups were combined (adjusted OR 1.00, 95% CI 0.74-1.34). Risk of CHD did not increase with use of individual types except gul, frequency, duration, past use of SLT products, or using the RAQ to re-classify cases and controls. There was a significant association between gul use and CHD when both controls were combined (adjusted OR 2.93, 95% CI 1.28-6.70).

CONCLUSIONS

There was no statistically significant association between SLT use in general and CHD among non-smoking adults in Bangladesh. Further research on the association between gul use and CHD in Bangladesh along with SLT use and CHD in other parts of the subcontinent will guide public health policy and interventions that focus on SLT-related diseases.