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Naswar is a smokeless tobacco product, commonly consumed in Pashtun population of Pakistan and Afghanistan. Despite being an established risk factor for oral cancer, not much is known about microbiological constituents of Naswar. Objectives: The objective of the study was to explore bacterial diversity in Naswar using shotgun metagenomic sequencing. Methodology: DNA was extracted from twelve (n = 12) famous brands of Naswar samples using an enzymatic and mechanical lysis method followed by next generation sequencing on Illumina Miseq platform. Results: Naswar samples exhibits differential abundance profile at all taxonomic levels with Khamar brand having the highest species richness and diversity indices. Of the total 22 phyla identified, phylum Proteobacteria was the most abundant (88.4%) followed by Bacteroidetes (4.71%) and Firmicutes (3.73%). At genus level, 234 genera (range: 32 - 132) were identified. Metagenomic sequencing also revealed presence of 455 (range: 44 - 210) different bacterial species in Naswar samples. The most common species were Pesudomonas aurgenosa, Yersinia enterocolitica, Salmonella enterica, Xanthomonas campestris, and E. coli. Some of the species are of concern due their ability to cause infections in humans. Conclusions: Naswar products harbor diverse bacterial microbiota with differential abundance at phylum, genus and species level. These findings may have several implications in terms of further research to explore microbiological associated health risks and provide scientific evidence to inform potential regulations regarding manufacturing and testing of Naswar in Pakistan. [ABSTRACT FROM AUTHOR]

Background/aim: Smokeless tobacco has been associated with oral cavity cancer for several decades. The incidence of oral cavity cancer is higher in some parts of the world especially South and South-East Asia including Pakistan. The aim of current study was to evaluate the risk of oral cavity cancer among smokeless tobacco users in our country. Materials and methods: A case-control study was conducted between November 2016 and September 2017. Patients diagnosed with oral cavity cancer receiving treatment were included as cases and the attendants of various cancer patients visiting the hospital during the study period were included in the study as controls. Odds ratios (OR) and 95% confidence intervals (CI) were calculated and all reported P-values were considered significant at < 0.05. Results: The crude OR for the "ever smokeless tobacco users" among cases and controls came out to be 4.98 (95%CI; 2.76-9.01). The OR for snuff users among cases and controls was 4.82 (95%CI; 2.37-9.80) and that for betel leaf users was 4.42 (95%CI; 1.66-11.91) after adjusting for smoking and age. Conclusion: Our study provided strong evidence for snuff and betel leaf to be independent risk factors for oral cavity cancer. [ABSTRACT FROM AUTHOR]

The extent to which smokeless tobacco endangers human health is an ongoing subject of debate. In this study, concentrations of toxic metals, cadmium (Cd), lead (Pb), and nickel (Ni), were measured in different snuff products (dry brown and black and moist green and brown), available and consumed in Pakistan. Concentrations of Cd, Pb, and Ni were determined in 23 samples of various brands of snuff by electrothermal atomic absorption spectrometry, after microwave-assisted acid digestion. The reliability of methodology was assured by analyzing certified reference material. The resulted data of toxic metals in different snuff products are comparable to the existing information with limited exceptions. It was estimated that 10 g intake of different types of snuff could contribute 14-68, 17-47, and 20-73 % of the provisional maximum tolerable daily intake for Cd, Ni, and Pb, respectively. [ABSTRACT FROM AUTHOR]