The effect of biomass burning on respiratory symptoms and lung function in rural Mexican women

Background: The use of biomass as a cooking fuel is commonplace in developing countries and has been associated with chronic bronchitis and obstructive airway disease. Methods: A cross-sectional survey was done in the village of Solis, close to Mexico City. Lifelong nonsmoking women 38 yr of age or older (n = 841) completed a questionnaire on respiratory symptoms and illnesses and on cooking fuel use, and performed spirometry in their homes. Particulate matter concentration was measured with a nephelometer in the kitchen for 1 h, while the subject was cooking. Results: The peak indoor concentration of particulate matter (PM10, particles with a diameter of 10 mu m or less) often exceeded 2 mg/m(3). Compared with those cooking with gas, current use of a stove burning biomass fuel was associated with increased reporting of phlegm (27 vs. 9%) and reduced FEV1/FVC (79.9 vs. 82.8%). Levels of FEV1 were 81 ml lower and cough was more common (odds ratio, 1.7; 95% confidence interval, 1.0-2.8) in women from homes with higher PM10 concentrations. All women found with moderate airflow obstruction (Global Initiative for Chronic Obstructive Lung Disease stage II and above) were cooking with biomass stoves. Conclusion: Women cooking with biomass fuels have increased respiratory symptoms and a slight average reduction in lung function compared with those cooking with gas.