Environmental and domestic risk factors for respiratory symptoms in Nicaraguan children

Abstract: Background Respiratory diseases are the most common cause for seeing a doctor in Nicaragua, and the second most common cause of death in children. An air monitoring program in the capital city, Managua, has shown high levels of air pollution, especially small particles. Important sources for this pollution are road traffic, smoke from cooking with wood, from burning of sugar cane fields before harvest, and open burning of solid waste due to an insufficient waste-collection system. The population is young in the country, in Managua there were in 2003 (the time for the last national survey) 163,568 boys and 161,465 girls who were five to 14 years old. Many of the live under difficult conditions, and due to the poverty many children work, some of them under extreme conditions, including constant exposure to dust and fumes, as in waste-picking. Also non-working children may have high exposures to air pollution, through general contamination of the air or exposures in the home. Studies of how these conditions affect the children’s respiratory health are important as a basis for preventive actions. Aim: To evaluate associations between environmental exposures (road traffic, tobacco smoke, cooking, burning of waste, mattress materials, pets, parasites), allergy, respiratory symptoms, and lung volumes, among working and non-working children in Managua. Materials and Methods: In a cross-sectional approach we included: i) 103 waste-picking children and 103 not waste-picking children from the same area, to study the respiratory effects of the work, and ii) 401 children from a district of low-medium socioeconomic status, stratified with regard to wheezing status in a population-based study conducted in 2002, to study the influence of general and domestic air pollution. We measured exposure to particulate matter, NO2, and in the second study also black smoke. Questionnaire and interview information was used to classify the children with regard to exposure, respiratory symptoms, and socio-economic conditions. We obtained information on allergy and nutritional status from a clinical examination, which also included measurement of lung volumes. Associations between indoor and outdoor exposures, and allergy on the one hand, and effects on prevalence of wheeze during the last 12 months and on FEV1 (the volume exhaled during the first second of a forced expiration) on the other hand, were evaluated with multivariate regression analysis. Results Exposure to airborne particles was generally high, exceeding national and international guide-line values. Wheeze was more common among waste-picking than non waste-picking children, and associated with exposure status (p<0.008) so that wheeze during the last 12 months was most common among the ever highly exposed children (42%, (Odds Ratio OR=3.3, 95% Confidence Interval CI 1.6 to 7.0), as compared to non-exposed children. Among children with wheeze, an effect on FEV1 was observed with a trend with exposure (p=0.04), with a 13% lower FEV1 (CI -15 to -1%) among the ever highly exposed children with wheeze. In the study of domestic exposures, cooking with wood indoors (OR=4.4, CI 0.94 to 21), or outdoors (OR=3.7, CI 0.98 to 14) was associated with wheeze during the last 12 months. Cooking with wood indoors was also associated with a lower FEV1 (-9.1%, CI -15 to -2.5%), as was domestic burning of waste (-2.5%, CI-4.6 to -0.2%). Sensitization to aeroallergens was common (55% among children with wheeze and 45% among children without wheeze), with mites, house dust, and cockroach as the most common allergens. Sensitization to D pteronyssinus was associated with having wheeze also at the screening two years earlier (OR=4.1, CI 2.0 to 8.5). Conclusions and comments Exposures associated with high peaks of particulate matter (waste-collecting, cooking with wood, and burning of waste) were associated with wheeze during the last 12 months and lower FEV1 among children in Managua. Also sensitization to mites was common, and associated to persistent wheeze.