Use of biomass fuel in households is not a risk factor for pulmonary tuberculosis in South Ethiopia

SETTING: Rural settings of Sidama Zone in southern Ethiopia.

OBJECTIVE: To investigate the association between exposure to biomass fuel smoke and tuberculosis (TB).

DESIGN: A matched case control study in which cases were adult smear-positive pulmonary tuberculosis (PTB) patients on DOTS-based treatment at rural health institutions. Age-matched controls were recruited from the community.

RESULTS: Of 355 cases, 350 (98.6%) use biomass fuel for cooking, compared to 801/804 (99.6%) controls. PTB was not associated with exposure to the biomass fuel smoke. None of the factors such as heating the house, type of stove, presence of kitchen, presence of adequate cooking room ventilation, light source and number of rooms in the house was associated with the presence of TB. However, TB determinants such as sex, household contact with TB, history of TB treatment, smoking and presence of a smoker in the household have previously shown an association with TB.

CONCLUSION: We found no evidence of an association between the use of biomass fuel and TB. Low statistical power due to the selection of neighbourhood controls might have contributed to this negative finding. We would advise that future protocols should not use neighbourhood controls and that they should include measurements of indoor air pollution and of exposure duration.