Exposure to combustion of solid fuel and tuberculosis: a matched case-control study

The present study was conducted in Benin to ascertain the association between exposure to combustion of solid fuel (coal and biomass) and tuberculosis. Cases were consecutive, sputum smear-positive tuberculosis patients never previously treated for tuberculosis for as long as 1 month. Two controls were selected from the neighbourhood of each case, matched by age and sex by a predefined procedure. A total of 200 new smear-positive cases and 400 neighbourhood controls were enrolled. In univariate analysis, using solid fuel for cooking (OR 1.7, 95% CI 1.1-2.8), ever smoking (OR 5.5, 95% CI 3.1-9.8), male sex (OR 10.5, 95% CI 1.6-71.1), daily use of alcoholic beverages (OR 2.3, 95% CI 1.2-4.2) and having a family member with tuberculosis in the previous 5 yrs (OR 30.5, 95% CI 10.8-85.8) were all significantly associated with tuberculosis cases. When all significant variables were entered into a multivariate conditional logistic regression model, the association between using solid fuel for cooking and tuberculosis cases was no longer statistically significant (adjusted OR 1.4, 95% CI 0.7-2.7). In conclusion, the association between exposure to combustion of solid fuel and tuberculosis was relatively weak and not statistically significant.