Chronic Obstructive Pulmonary Disease and Smoking in India: A Meta-Analysis

Abstract

Introduction: WHO estimates show Chronic obstructive pulmonary disease [COPD] as a growing major global cause of morbidity as well as mortality. An estimated 90% of COPD- related deaths occur in low/middle income countries. India and China together constitutes about one third of the total humanpopulation, accounting for 66% of COPD mortality globally. In the south east Asia region, COPD associated mortality is projected to grow by 160% in the decades ahead. Much of this projection holds pansexual cigarette smoking, improved life expectancy, bulging geriatric population and high levels ofsmall particle pollution, as major causes behind increase in COPD case burden. Methods: The aim of the meta-analysis was to investigate association between COPD and risk factors by pooled and subgroup analysis. We searched for case control studies and studies which are meeting the inclusion criteria. The publications listed in the NCBI PubMed and Cochrane library were searched using the following combination of the key words “COPD”; “smokers”; “health”; “risk” or “factors”;“diagnostic”; “burden”; “exposure”; “disease” or “prevalence” or “morbidity ” or “mortality”; “tobacco”; “smoking”; “smoke”, “India”. Random effects meta-analysis was applied to generate pooled  SMD by using CMA software. Results: Data base search identified twenty-nine thousand two hundred twenty-two records and 14 articles made to the cut after implementing the inclusion and exclusion criteria. Main risk factors for COPD were higher age [SMD=0.53, CI= (0.0018-1.05)], total pack years of Smoking [SMD=13.83,CI (10.060-17.616)], FEV1 [SMD=-13.15, CI= (-16.234 to -10.085) and FEV/FVC ratio [SMD=0.915.CI= (0.767-1.063)]. Higher age, smoking, low values of FEV1 and FEV/FVC ratio is directly associated with high risk of COPD. Discussions: The findings of the study shows evidence of smoking history in terms of pack of years as a major risk factor for COPD prevalence. Further research is needed on COPD prevalence andincidence associated with other chemical exposure, to identify how to effectively reduce risks fromexposure to smoking.