Impacto del Material Particulado aéreo (MP 2, 5 ) sobre las hospitalizaciones por enfermedades respiratorias en niños: estudio caso-control alterno / Impact of Particulate Matter (PM 2, 5 ) and children's hospitalizations for respiratory diseases: a case cross-over study

INTRODUCCIÓN: Santiago de Chile con 7 millones de habitantes alcanza elevados niveles de contaminación atmosférica en invierno, el material particulado habitualmente excede los estándares de la OMS. OBJETIVO: Evaluar la influencia de la contaminación atmosférica por material particulado en las hospitalizaciones por enfermedades respiratorias en niños, entre 2001 y 2005 en la Región Metropolitana de Chile, independientemente de la presencia ambiental de virus sincicial respiratorio (VRS). MATERIAL Y MÉTODO: 72.479 hospitalizaciones públicas y privadas por enfermedades respiratorias de niños menores de 15 años residentes en la región del estudio se analizaron con un diseño de caso control alternante, con estratificación temporal. Se evaluó principalmente: hospitalizaciones por enfermedades respiratorias (J00-J99), neumonía (J12-J18); asma (J21.0 - J21.9) y bronquiolitis (J45 - J46). Recopilándose diariamente temperatura, MP10, MP2,5, ozono, virus respiratorios (VRS) y humedad ambientales. RESULTADOS: Los promedios de MP10 y MP2,5 fueron 81,5 y 41,2 pg/m3 respectivamente. El promedio de temperatura fue 12,8 °C y de la humedad del aire 72,6 %. Un aumento de 10 pg/m3 de MP25 con 1 y 2 días de rezago se asoció con un incremento de las hospitalizaciones por enfermedades respiratorias cercano a 2%, este porcentaje aumentó a 5% cuando la exposición fue con 8 días de rezago, reflejando sinergismo entre material particulado y virus respiratorio (VRS). CONCLUSIÓN: La exposición breve a contaminación atmosférica puede provocar hospitalizaciones por enfermedades respiratorias en niños.

INTRODUCTION: With seven million inhabitants, Santiago de Chile reaches high levels of air pollution in winter, the particulate matter usually exceeds WHO standards. OBJECTIVE: To assess the influence of air pollution caused by particulate matter on children's hospitalizations due to respiratory diseases between 2001 and 2005 in the Metropolitan Region of Chile, independently from the environmental presence of respiratory syncytial virus (RSV). MATERIAL AND METHOD: 72,479 public and private hospitalizations due to respiratory diseases of children under 15 years of age residing in the study region were analyzed using a time-stratified alternating case-control design. The main evaluations were: hospitalizations due to respiratory diseases (J00-J99), pneumonia (J12-J18); asthma (J21.0 - J21.9), and bronchiolitis (J45 - J46). Daily compilation of temperature data, PM10, PM2,5, ozone, respiratory virus (RSV), and environmental humidity. RESULTS: Mean values of PM10 and PM2.5 were 81.5 and 41.2 pg/m3 respec tively. The average temperature was 12.8 °C and air humidity 72.6%. An increase of 10 pg/m3 of PM25 with one and two days of lag was associated with an hospitalizations increase due to respiratory diseases close to 2%, this percentage increased to 5% when the exposure was with eight days of lag, reflecting synergism between particulate matter and respiratory viruses (RSV). CONCLUSION: Short air pollution exposure can lead to children's hospitalizations due to respiratory diseases.

Tabaquismo activo y cancer pulmonar: determinación de fracciones atribuibles por sexo / Smoking and Lung Cancer: attributable risks according to gender

Background: The association between Lung Cancer and smoking is well documented. However there is less information about the estimation of its attributable fraction and population burden. Aim: To estímate the attributable risk and population attributable risk of smoking among Lung Cancer patients attended in Public Health Services at Santiago. Material and methods: A case control study matched by age was carried out. Crude and adjusted attributable and population attributable risks were estimated, controlling for potential confounders and interaction variables. Results: Mean age for cases was 63 years for women and 67 years for men. Lung Cancer patients had a higher smoking prevalence than controls (64.5 percent and 39.7 percent respectively among women; 95.8 and 67.1 respectively among men p <0.01). Heavy smoker proportion was 4 times higher among patients that smoked 5 to 10 years more (women and men respectively, p <0.01) and 3 times more cigarettes per day (p <0.01). Attributable risk for women was 64.4 percent and 90.4 percent for men. Population attributable fraction was 41.9 percent and 86.3 percent for women and men, respectively. Projecting these estimates to the Chilean population, approximately 1975 new cases per year of Lung Cancer caused by smoking will be diagnosed. Conclusions: Attributable risks of smoking for Lung Cancer are high and significant, even when they are adjusted by confounding variables.

Tabaquismo y enfermedad pulmonar obstructiva crónica: determinación de fracciones atribuibles / Smoking and chronic obstructive pulmonary disease: attributable risk determination

Background: Smoking is the main risk factor for Chronic Obstructive Pulmonary Disease (COPD), an important cause of morbidity and mortality. Aim: To estimate smoking attributable risk and population attributable risk in COPD patients attended in Public Health Services of Santiago. Materials and methods: A case control study matched by sex and age was carried out. Crude and adjusted attributable risks as well as population attributable risk were estimated, controlled by potential confounders and by interaction variables. Results: Mean ages for cases and controls were 68 and 67 years respectively. When compared to the control group, COPD patients had a higher smoking prevalence (at least 100 cigarettes in their life span: 89.7 percent vs 60.3 percent; p <0.01). Among COPD patients, heavy smokers proportion was 4 times higher than in controls, they smoked for more years (43 vs 31; p <0.01) and more cigarettes per day (18 vs 5; p <0.01). Adjusted attributable risk was 87 percent (95 percent Confidence Interval (CI): 63.7-94.8). If a patient smoked at least 100 cigarettes in his/her life span and this risk was 92.7 percent (CI: 82.4-96.9) for heavy smokers. Projecting this index to Santiago inhabitants, about 87,000 individuals older than 40 years would be suffering COPD due to smoking. Conclusions: This article confirms the strong association between smoking and COPD. Attributable risks are high and significant, even when they are adjusted by confounding variables. Women had a higher risk than men, at lower levels of tobacco consumption.

Contaminación aérea intradomiciliaria en el área sur-oriente de Santiago / Indoor air pollution in south east Santiago

Background: Indoor air pollution could play an important role in the susceptibility to respiratory diseases of vulnerable individuals, such as elders and infants. Aim: To evaluate indoor air pollution in a low income population of South East Santiago. Subjects and methods: A domiciliary survey of contaminant sources was carried out in the houses of a cohort of 522 children less than one year old. Using a case-control design, 121 children consulting for respiratory diseases were considered as cases and 131 healthy infants of the same age and sex were considered as controls. In the houses of both groups, active monitors for particulate matter (PM10) and passive monitors for NO2 were installed. Results: Forty two percent of fathers and 30 percent of mothers were smokers, and in two thirds of the families there was at least one smoker. Eighty five percent used portable heaters in winter. Of these, 77 percent used kerosene as fuel. Only 27 percent had water heating appliances. The rest heated water on the kitchen stove or on bonfires. Most kitchen stoves used liquid gas as fuel. Twenty four hour PM10 was 109 ñ 3.2 µg/m3. Mean indoor and outdoor NO2 in 24 h was 108 ñ 76.3 and 84 ñ 53.6 µg/m3 respectively. Indoor NO2 levels were related to the use of heating devices and smoking. No differences in PM10 and NO2 levels were observed between cases and controls. Conclusions: There is a clear relationship between indoor pollution and contaminating sources. Indoor NO2 levels are higher than outdoors