Indoor air pollution exposure effects on lung and cardiovascular health in the High Himalayas, Nepal: An observational study

Background: Exposure to indoor biomass fuel smoke is associated with increased morbidity and mortality. The aim of this study is to evaluate the association between exposure to indoor biomass burning and early pulmonary and cardiovascular damage. Methods: The indoor levels of particulate matter (PM) [PM10, PM2.5] and black carbon (BC) were monitored in 32 houses in a Himalayan village. Seventy-eight subjects were submitted to spirometry and cardiovascular evaluation [carotid to femoral pulse wave velocity (PWV) and echocardiography]. Results: Peak indoor BC concentration up to 100 μg m−3 and PM10 - PM2.5 up to 1945–592 μg m−3 were measured. We found a non-reversible bronchial obstruction in 18% of subjects ≥40 yr; mean forced expiratory flow between 25% and 75% of the forced vital capacity (FEF25–75) <80% in 54% of subjects, suggestive of early respiratory impairment, significantly and inversely related to age. Average BC was correlated with right ventricular-right atrium gradient (R = 0.449,p =.002), total peripheral resistances (TPR) (R = 0.313,p =.029) and PWV (R = 0.589,p <.0001) especially in subjects >30 yr. In multiple variable analysis, BC remained an independent predictor of PWV (β = 0.556,p =.001), and TPR (β = 0.366;p =.018). Conclusions: Indoor pollution exposure is associated to early pulmonary and cardiovascular damages, more evident for longer duration and higher intensity exposure.