Exposure to household air pollution and respiratory symptoms in Nepal: A cross-sectional study

Background: Exposure to household air pollution (HAP) is associated with respiratory health problems in low and middle income countries. The aim of this study was to assess the association between respiratory symptoms and exposure to wood smoke in rural area of Nepal.Methods: A cross-sectional study of adults (16+ years) in a rural population (n=846) exposed to wood smoke and a non-exposed urban population (n=802) in Nepal. Validated questionnaire including that of respiratory symptoms, spirometry data were acquired along with indoor air quality (PM2.5 and CO) and outdoor PM2.5 measurement.Results: Rural females were significantly more likely to complain of ever having wheezed (32.8 % vs. 23.8%; p<0.001) compared to their male counterparts with smoking being a major risk factor. Women exposed to HAP were more likely to complain of dyspnoea not induced by exercise (OR=3.3, 95% CI 1.46-7.57), dyspnoea with wheeze (4.91, 2.49-9.69), ever wheeze (4.62, 2.71-7.87) and chest tightness (3.18, 1.53-6.61) but were not more likely to complain of productive cough. 24-hour PM2.5 measurement was positively associated with breathlessness and wheeze in women. Urban males exposed to outdoor air pollution were more likely to report ever wheeze (3.06, 1.28-7.31) and wheeze on most days and night (3.30, 1.35-8.13). There was a high negative correlation between lung function indices (FEV1, FEF25-75 and FEV1/FVC) and the presence of respiratory symptoms in those exposed to HAP.Conclusion: The study suggests that women exposed to HAP reported more respiratory symptoms but males exposed to outdoor air pollution not HAP reported more symptoms.