Respirology | 2019
Letter from Colombia
Abstract
Respiratory health in Colombia is highly influenced by the wide variation of its geographical, climatic and socioeconomic conditions. The country has a population of 48 million inhabitants and its area is approximately twice that of Spain or France. It is located in the tropical zone of South America (the equator crosses through the south of the country). There are no seasons, although there are usually rainy and drier periods, and the temperature is relatively stable throughout the year. The Andean Mountain range crosses the territory from south to north so, despite its tropical location, the climate depends largely on the altitude with many cities and villages located at high altitude with permanent cold weather. Around 20% of the country’s population, approximately 10 million people, lives at high altitude (>2500 m above sea level). Bogotá (2640 m), the capital of the country, is the most populated city in the world located at high altitude. Although the World Bank currently classifies Colombia as an upper middle income country, there are broad disparities of the socio-economic conditions (inequity) with a significant proportion of the country’s population living in poverty. Tuberculosis has not decreased in the last decade (approximated incidence of 30/100 000). Almost 60% of people in the rural areas continue using biomass fuels, mainly wood, for cooking or heating their homes. Three of the mentioned conditions, inequity, residency at high altitude and chronic indoor exposure to wood smoke, and its combination, have significant negative impact on morbidity and mortality from respiratory diseases in the country and have marked some of the more relevant research and contributions by Colombian pulmonologists to global knowledge. The PREPOCOL study was the first population-based research in showing that chronic exposure to wood smoke from cooking is an independent risk factor for chronic obstructive pulmonary disease (COPD) and for asthma in people older than 40 years. Some studies have not found an association between biomass smoke exposure and COPD probably because of the lack of standardization of questionnaires for evaluating long-term exposure to biomass fuels in cross-sectional studies. The location of the kitchen, the stove and fuel characteristics and the ventilation conditions are not always described. In Colombia, people living at high altitude cook inside their homes or in poorly ventilated spaces because of the cold weather (Fig. 1). On the contrary, those living at low altitude cook outside in open spaces. The variation of household indoor air pollution (HAP) level derived from the residency at different altitudes can partially explain the lack of association found in some studies. A recent study confirms that COPD prevalence and HAP (measured by PM2.5) were higher in highlander than in lowlander residents. The high frequency of wood smoke COPD (WS-COPD) in Colombia has allowed characterizing this kind of COPD and demonstrating that WS-COPD is significantly different from COPD caused by tobacco smoke (TS-COPD). The first emblematic study by Restrepo et al., published in 1983 in Acta Médica Colombiana (Fig. 1), a regionally indexed medical journal, posed that the respiratory disease caused by the inhalation of wood smoke could be considered as pneumoconiosis because of the finding of interstitial deposits of anthracotic and particulate matter. Our subsequent studies demonstrated that this is a predominantly obstructive disease that could be included under the definition of COPD. These studies, together with those of Mexican researchers, show that WS-COPD is a markedly predominant disease in women, with greater inflammatory airway involvement and significantly lower emphysema than TS-COPD. Anthracosis of the central bronchi is frequent and can cause atelectasis. Womenwith WS-COPD have greater bronchial hyperresponsiveness and manifest more frequently an asthmatic phenotype than TS-COPD, suggesting a more relevant role of inhaled corticosteroids in the treatment. All of the abovementioned findings have led Colombian researchers to state that WS-COPD, rather than a different phenotype of COPD, is a distinct and separable disease. Going back to the Restrepo et al.’s study, the disease derived from indoor chronic exposure to wood smoke could have a spectrumofmanifestations that frequently include chronic airflow obstruction.