Biomass fuel and risk of tuberculosis: a case-control study from Northern India.
BACKGROUND
Although a known risk factor for several respiratory diseases, the relationship between cooking smoke and tuberculosis has not been conclusively established. Hence, a case-control study was conducted among adult women of Chandigarh Union Territory in India.


METHODS
Physician-diagnosed cases of sputum positive pulmonary tuberculosis (n=126) and age- and residence area-matched controls (n=252) were enrolled from clinics in urban, rural and slum areas. Interviews were conducted in the clinic using a pretested questionnaire to collect information on type of cooking fuel, education, occupation, socio-economic status, smoking, overcrowding and type of kitchen, etc. The conditional logistic regression model was used for control of confounding.


RESULTS
The study population was predominantly in the 20-29-year-old age group (58%) and lived in urban areas (67%). The majority were illiterate (52%) and housewives (93%), and nearly half (46%) had an income of no more than Rs 25 000. Among the cases, 20.6%, 27% and 52.4% used biomass fuel, kerosene and liquid petroleum gas (LPG), respectively, whereas among controls, the respective figures were: 12.3%, 26.2% and 61.5%. The unadjusted OR for biomass fuel compared with LPG was 2.33 (95% CI 1.18 to 4.59, p 0.01). Adjustment for confounding factors (education, type of kitchen, smoking tobacco and TB in a family member) and interaction between cooking fuel and smoker in family revealed an OR of 3.14 (95% CI 1.15 to 8.56, p=0.02) for biomass fuel in comparison with LPG.


CONCLUSIONS
Cooking with biomass fuel increases the risk for pulmonary tuberculosis.
School of Public Health, Post Graduate Institute of Medical Education and Research, Chandigarh, India. dr.rajeshkumar@gmail.com
P V M
PV
Lakshmi
Navkiran Kaur
NK
Virdi
J S
JS
Thakur
Kirk R
KR
Smith
Michael N
MN
Bates
Rajesh
R
Kumar
D000328:Adult; D016902:Air Pollution, Indoor / Q000009:adverse effects*; D016022:Case-Control Studies; D003296:Cooking; D005260:Female; D005579:Fossil Fuels; D006801:Humans; D007194:India; D008875:Middle Aged; D012307:Risk Factors; D012959:Socioeconomic Factors; D014397:Tuberculosis, Pulmonary / Q000209:etiology*
D005579:Fossil Fuels