There are a number risk factors for tuberculosis infection; worldwide the most important of these is HIV. Co-infection with HIV is a particular problem in Sub-Saharan Africa, due to the high incidence of HIV in these countries.[1][2] Smoking more than 20 cigarettes a day increases the risk of TB by two to four times[3] while silicosis increases the risk about 30 fold.[4]Diabetes mellitus is also an important risk factor that is growing in importance in developing countries.[5] Other disease states that increase the risk of developing tuberculosis are Hodgkin lymphoma, end-stage renal disease, chronic lung disease, malnutrition, and alcoholism.[6] A person's genetics also play a role.[7]
^Davies PD, Yew WW, Ganguly D, Davidow AL, Reichman LB, Dheda K, Rook GA (April 2006). "Smoking and tuberculosis: the epidemiological association and immunopathogenesis". Transactions of the Royal Society of Tropical Medicine and Hygiene. 100 (4): 291–8. doi:10.1016/j.trstmh.2005.06.034. PMID16325875.