Case-control study to evaluate the role of smoking, alcohol abuse, intravenous drug abuse, tobacco use and biomass fuel exposure as risk factor in pulmonary tuberculosis

Background: An association between smoking and tuberculosis disease has been shown in various studies, it is less clear to what extent smoking increases the risk of Mycobacterium tuberculosis infection. Therefore the aim of this study is to evaluate the role of smoking, alcohol abuse, intravenous drug abuse, tobacco use and biomass fuel exposure as a risk factor for the development of pulmonary tuberculosis. Methods: This is a case control study and total 200 subjects will be included with 100 sputum smear positive pulmonary tuberculosis cases and 100 age and sex matched healthy subjects as controls. Data collected from both cases and controls using a proforma by enquiring smoking habits, alcohol abuse, intravenous drug abuse, biomass fuel exposure and documenting chest X-ray features. Results: The study showed significant association between tuberculosis and smoking as a risk factor with beedi smoking, early age of starting smoking, increased duration and quantity of smoking increases risk for tuberculosis. There was significant association between intravenous drug abuse, biomass fuel exposure and risk of tuberculosis. There was no significant association in the study between alcohol abuse, tobacco chewing and tuberculosis, but heavy drinking and tuberculosis showed significant association. The study also showed significant association of cavitary lesion with smoking. Conclusions: There is significant association between smoking, intravenous drug abuse, biomass fuel exposure and tuberculosis, since these risk factors impairs host immune defences that allows the development of active tuberculosis.