Domestic biomass fuel combustion and chronic bronchitis in two rural Bolivian villages

Background-Chronic bronchitis is an important public health problem worldwi de. A study was undertaken to examine the association between exposure to a ir pollution from domestic biomass fuel combustion and chronic bronchitis i n two rural Bolivian highland villages: a village in which cooking is done exclusively indoors and a village in which cooking is done primarily outdoo rs. Apart from this difference, the villages were virtually identical in te rms of socioeconomic status, climate, altitude, access to health care, and other potential confounders. Methods-Pollution exposure was assessed by combining information on concent rations of particulate matter of <10 mu m diameter (PM10) in 12 randomly se lected households in each village in all potential microenvironments of exp osure with time allocation information. The prevalence of chronic bronchiti s was assessed using the British Medical Research Council's questionnaire o n individuals >20 years of age in both villages (n = 241). Results-Daily pollution exposure was significantly higher in the indoor coo king village (range for adults: 9840-15 120 mu g-h/m(3)) than in the outdoo r cooking village (range for adults: 5520-6240 mu g-h/m(3)) for both season s and for men and women. The overall prevalence of chronic bronchitis was 2 2% and 13% for the indoor and outdoor cooking villages, respectively. Logis tic regression analysis, which excluded the few smokers present in the popu lation, showed a 60% reduced risk of chronic bronchitis in the outdoor cook ing village compared with the indoor cooking village (OR 0.4; 95% CI 0.2 to 0.8; p = 0.0102) after adjusting for age and sex. Individuals aged >40 yea rs were 4.3 times more likely to have chronic bronchitis than the younger a ge group (OR = 4.3; 95% CI 2.0 to 9.3; p = 0.0002). There was no significan t difference in the prevalence of chronic bronchitis in men and women. Conclusions-The results of this study suggest an association between chroni c bronchitis and exposure to domestic biomass fuel combustion, but further large scale studies from other areas of the developing world are needed to confirm the association. Results from this and other studies will assist th e development of culturally acceptable and feasible alternatives to the hig h exposure cooking stoves currently being used by most people worldwide.