Effect of household air pollution due to solid fuel combustion on childhood respiratory diseases in a semi urban population in Sri Lanka

BACKGROUND: Household air pollution from combustion of solid fuels for cooking and space heating is one of the most important risk factors of the global burden of disease. This study was aimed to determine the association between household air pollution due to combustion of biomass fuel in Sri Lankan households and self-reported respiratory symptoms in children under 5 years. METHODS: A prospective study was conducted in the Ragama Medical Officer of Health area in Sri Lanka. Children under 5 years were followed up for 12 months. Data on respiratory symptoms were extracted from a symptom diary. Socioeconomic data and the main fuel type used for cooking were recorded. Air quality measurements were taken during the preparation of the lunch meal over a 2-h period in a subsample of households. RESULTS: Two hundred and sixty two children were followed up. The incidence of infection induced asthma (RR = 1.77, 95%CI;1.098–2.949) was significantly higher among children resident in households using biomass fuel and kerosene (considered as the high exposure group) as compared to children resident in households using Liquefied Petroleum Gas (LPG) or electricity for cooking (considered as the low exposure group), after adjusting for confounders. Maternal education was significantly associated with the incidence of infection induced asthma after controlling for other factors including exposure status. The incidence of asthma among male children was significantly higher than in female children (RR = 1.17; 95% CI 1.01–1.37). Having an industry causing air pollution near the home and cooking inside the living area were significant risk factors of rhinitis (RR = 1.39 and 2.67, respectively) while spending less time on cooking was a protective factor (RR = 0.81). Houses which used biomass fuel had significantly higher concentrations of carbon monoxide (CO) (mean 2.77 ppm vs 1.44 ppm) and particulate matter(2.5) (PM(2.5)) (mean 1.09 mg/m(3) vs 0.30 mg/m(3)) as compared to houses using LPG or electricity for cooking. CONCLUSION: The CO and PM(2.5) concentrations were significantly higher in households using biomass fuel for cooking. There was a 1.6 times higher risk of infection induced asthma (IIA) among children of the high exposure group as compared to children of the low exposure group, after controlling for other factors. Maternal education was significantly associated with the incidence of IIA after controlling for exposure status and other variables.