Summary

The study of altitude-related illnesses is an important field of investigation relevant to the 140 million people worldwide who live at altitudes > 2500 meters above sea level. The most commonly fatal altitude-related illnesses are chronic mountain sickness (CMS) and pulmonary hypertension (PH). Previous reports estimate that 5–15% of high-altitude residents may develop CMS; however, the prevalence of altitude-related cardiopulmonary illnesses is not well characterized in large population-based studies and the influence of other risk factors such as exposure to biomass fuels are not well understood. In rural populations of the Peruvian Andes, the use of biomass fuels for cooking is highly prevalent if not exclusive. Biomass fuel exposure has been shown to increase the risk of pulmonary and cardiovascular diseases, but its effect on the risk of altitude-related illnesses has not been previously investigated. Since 90% of rural households worldwide use biomass fuels as the main source of domestic energy, the population attributable risk may be of public health significance. We hypothesize that the prevalences of CMS and PH and the average carotid intima-media thickness is greater in high-altitude populations exposed to daily use of biomass fuels than in those who are not. To test this hypothesis we will conduct a cross-sectional study of 644 high-altitude dwellers in Puno, Peru (3825 meters above sea level): 322 subjects who live in rural households where biomass fuels are used exclusively for cooking and 322 subjects who live in urban households where propane or electricity are used exclusively for cooking. We will assess the prevalence of CMS and related symptoms via pulse oximetry, hemoglobin levels and a validated symptoms questionnaire. We will assess for PH and right ventricular remodeling via echocardiography, electrocardiography and serum markers such as pro-brain natriuretic peptide. Finally, we will assess carotid-intima media thickness and carotid plaque by ultrasonography of the carotid artery. This award will help to support pilot studies on the effects of biomass fuels on altitude-related illnesses in Puno.