ABSTRACT
Objective: This study was aimed at comparing cardiorespiratory fitness (CF), measured as VO2 max, amongst school children exposed to varying levels of particulate matter (PM10), and air pollution in Bogotá, Colombia. Methods: This was a cross-sectional study; it involved 1,045 children aged 7-12 attending four public schools served by different public transit routes and systems. Three schools were classified as being highly polluted (HP) and one slightly polluted (SP). The children and their parents were surveyed to collect data regarding their socio-demographic characteristics, physical activity habits and respiratory disease background. Objective measurements of weight and height were used to calculate the body mass index. VO2max was estimated using the 20-meter shuttle-run test, previously validated for Bogotá. Spirometry was performed on 435 children. Results: After adjustment for covariates, no difference was found in VO2max between children attending SP or HP schools (girls SP 45.8 ml/kg/min vs HP 44.6 ml/kg/min, p=0.11; boys SP 47.2 ml/kg/min cf HP 48.2 ml/kg/min, p=0.41). Conclusions: VO2max levels did not differ amongst children attending schools exposed to high compared to low levels of air pollution and PM. A longitudinal study assessing children’s VO2max levels in relation to exposure to highly-polluted areas is warranted.
Objetivo: Comparar el acondicionamiento cardiorespiratorio medido como VO2 máximo en niños escolarizados expuestos a diferentes niveles de PM10 en Bogotá. Métodos: Estudio de corte transversal. Se incluyeron 1045 niños de 7-12 años de 4 colegios públicos con diferentes corredores viales y sistemas de transporte público. Tres colegios tenían alta contaminación (AC) y uno baja contaminación (BC). Se aplicó una encuesta a niños y padres sobre características sociodemográficas, actividad física, antecedentes de enfermedades respiratorias y salud. Se midió objetivamente peso y talla para calcular el índice masa corporal. El VO2 máximo se estimó con la prueba de Leger validada para Bogotá. Se realizaron espirometrias en 435 niños. Resultados: Después de ajustar por covariables, no se encontraron diferencias significativas en el VO2 máximo de los niños en colegios con BC ò AC. (Niñas BC: 45,8ml/kg/min vs. AC: 44,6ml/kg/min; p=0,11, niños BC: 47,2ml/kg/min vs. AC: 48,2ml/kg/min; p=0,41). Conclusión: No se encontraron diferencias en el VO2 máximo de los niños que asistían a los colegios de AC ó BC. Se recomienda un estudio longitudinal que evalúe los niveles de VO2 máximo en los niños expuestos a áreas altamente contaminadas.
Subject(s)
Child , Female , Humans , Male , Air Pollution , Heart/physiology , Particulate Matter , Physical Fitness , Play and Playthings , Respiratory Physiological Phenomena , Colombia , Cross-Sectional Studies , Spirometry , Urban HealthABSTRACT
<p><b>OBJECTIVE</b>To investigate the relationship between silica or silicosis and lung cancer in a large cohort of silicotic workers in Hong Kong.</p><p><b>METHODS</b>All workers with silicosis in Hong Kong diagnosed between 1981 and 1998 were followed up till the end of 1999 to ascertain their vital status and causes of death, using the corresponding mortality rates of Hong Kong males of the same period as external comparison. Standardized mortality ratios (SMR) for lung cancer and other major causes of death were calculated. Person-year method was used. Axelson's indirect method was performed to adjust for the confounding effect of smoking. Penalized smoothing spline (p-spline) models were used to evaluate the exposure-response relationship between silica dust exposure and lung cancer mortality.</p><p><b>RESULTS</b>A total of 2789 newly diagnosed cases of silicosis were included in the cohort, with an overall 24 992.6 person-years of observations. The loss-to-follow-up rate was only 2.9%. Surface construction workers (51%) and underground caisson workers (37%) constituted the major part of the cohort. There were 853 silicotics observed with an average age at death of 63.8 years. The SMR for all causes and all cancers increased significantly. The leading cause of death was non-malignant respiratory diseases. About 86 deaths were from lung cancer, giving a SMR of 1.69 (95% CI: 1.35 approximately 2.09). The risk of lung cancer death among workers in surface construction, underground caisson, and entire cohort was reduced to 1.12 (95% CI: 0.89 approximately 1.38), 1.09 (95% CI: 0.82 approximately 1.42) and 1.56 (95% CI: 0.98 approximately 2.36) respectively, after indirectly adjusting for smoking.</p><p><b>RESULTS</b>from P-spline model did not show a clear exposure-response relationship between silica dust (CDE and MDC) and lung cancer mortality.</p><p><b>CONCLUSION</b>This cohort study did not show an increased risk of lung cancer mortality among silicotic workers. P-spline model does not support an exposure-response relationship between silica dust exposure and lung cancer mortality.</p>