SHORT-TERM EFFECTS OF URBAN AIR POLLUTION ON MORTALITY IN SPAIN

Abstract

ISEE-108 Introduction: The EMECAS multicenter study aims to evaluate the short-term effects of air pollution on mortality and hospital admissions in 16 Spanish cities. In this paper we present the combined results for total, respiratory and cardiovascular mortality. Methods: Daily mortality for all causes (ICD-9: 001–799), respiratory diseases (ICD-9: 460–519) and cardiovascular diseases (ICD-9: 390–459) was obtained for each city (1995–1999). Data for 24 hours daily levels of black smoke, total suspended particles (TSP), particles less than 10 mg (PM10), SO2 and NO2; 8 hours maximum moving average of CO and ozone; and 1 hour maximum of SO2, NO2, CO and ozone were collected from local Air Pollution Networks. Magnitude of association in each city was estimated using Generalized Additive Models (GAM) of Poisson, controlling for confusion and overdispersion. Covariables included were trend, temperature, humidity, barometric pressure, influenza, day of the week and unusual events. For each cause, lagged effects, up to three days, of each pollutant were examined. Data were analyzed using S-Plus GAM function with more stringent convergence criteria. Combined estimates were obtained under ’fixed effects’ model and, if heterogeneity, under ’random effects’ ones. For ozone the analyses were restricted to the warm period (May to October). Lastly, two-pollutants models are currently being performed to explore potential confounding for the other pollutants. Results: Average levels of pollutants were, in general, low to moderate (i.e., SO2: 15–73 mg/m3, PM10: 33–43 mg/m3, NO2: 23–79 mg/m3, ozone: 41–79 mg/m3). The more consistent lags were 0 (concurrent day) and 1. The combined estimates showed a significant association with total mortality for black smoke, TSP, SO2, CO and ozone. An increase of 10 mg/m3 in PM10 levels was associated with a 1.3% (95% CI: 0.2–2.5%) increase in respiratory mortality. The same increase in NO2 levels was associated with a 1.03% (95% CI: 0.4–1.7%), increase in respiratory mortality. Lastly, the combined estimates showed a significant increase of cardiovascular mortality associated with an increase of 10 mg/m3 in TSP levels (0.7%, 95% CI: 0.1–1.2%), black smoke levels (0.6%, 95% CI: 0.02–1.1%) and NO2 levels (0.6%, 95% CI: 0.2–0.9%). Results after performing the two-pollutants models will be presented as well, as modifications of the associations are expected. Discussion: A short-term association between increases in daily levels of urban air pollutants and daily mortality for all causes and respiratory and cardiovascular diseases has been found, with greater estimates for respiratory mortality.