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 I-2 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.