Exposure to indoor air pollution induces endothelial dysfunction in nepalese high-altitude dwellers

Aim: Biomass fuels are widely used in developing countries for cooking and heating, representing a relevant cause of indoor air pollution (IAP). The role of IAP in cardiovascular disease is poorly studied. Aim of the study is to evaluate endothelial function, an early marker of atherosclerosis, in high-altitude dwellers in the Kumbu Valley (Nepal) in relationship to IAP. Design and methods: 82 subjects without established cardiovascular disease (age range 15-65 years, mean age 35.5±14 years, men 38%, hypertensives 13%, smokers 5%, obese 6%), living in 3 rural Nepalese villages at 2500-3850m, were enrolled. Endothelial function in the brachial artery was evaluated by flowmediated dilation (FMD) and response to glyceryl trinitrate (GTN). Results: In the study population, 91% use biomass fuels (dung /wood), 63% were housemaids/work in the kitchen, 43% had no chimney, 21% had reduced kitchen ventilation coefficient. FMD was not influenced by smoking, blood pressure, BMI, O2 saturation (p=ns for all). FMD tended to be higher in people not using biomass fuels (n=9, 6.4±1.1%vs 5.0±0.4). Among biomass fuels users, FMD was significantly reduced in those with no chimney in the kitchen (4.3±0.5 vs 5.7±0.5%, p<0.05). Age- and sex-adjusted logistic regression analysis showed that the absence of chimney (OR 3.4, CL95% 1.1-9.9) remained an independent predictor of reduced FMD (below the median 4.84%). Conclusions: In rural Nepalese high-altitude dwellers using biomass fuels, absence of chimney is associated with selective impairment of conduit-artery endothelial function. This study suggests that simple interventions can reduce the cardiovascular burden related to exposure to IAP.