Air pollution and hospitalizations in the largest Brazilian metropolis

Abstract

OBJECTIVE: To evaluate the impact of air pollution on hospitalizations for respiratory andcardiovascular diseases in the largest Brazilian metropolis.METHODS: This study was carried out at the Metropolitan Region of São Paulo, Brazil.Environmental data were obtained from the network of monitoring stations of nine municipalities.Air pollution exposure was measured by daily means of PM10 (particles with a nominal meanaerodynamic diameter ≤ 10 μm) per municipality, while daily counts of hospitalizations forrespiratory and cardiovascular diseases within the Brazilian Unified Health System were theoutcome. For each municipality a time series analysis was carried out in which a semiparametricPoisson regression model was the framework to explain the daily fluctuations on counts ofhospitalizations over time. The results were combined in a meta-analysis to estimate the overallrisk of PM10 in hospitalizations for respiratory and cardiovascular diseases at the MetropolitanRegion of São Paulo.RESULTS: Regarding hospitalizations for respiratory diseases, the effect estimates werestatistically significant (p < 0.05) for all municipalities, except Santo André and Taboão da Serra.The RR (Relative Risk) of this outcome for an increase of 10 µg/m3 in the levels of PM10 rangedfrom 1.011 (95%CI 1.009–1.013) for São Paulo to 1.032 (95%CI 1.024–1.040) in São Bernardo doCampo. The RR of hospitalization for respiratory diseases in children for an increase of 10 µg/m3of PM10 ranged from 1.009 (95%CI 1.001–1.017) in Santo André to 1.077 (95%CI 1.056–1.098) inMauá. Only São Paulo and São Bernardo do Campo presented positive and statistically significantresults for hospitalizations for cardiovascular diseases.CONCLUSIONS: This is the first study to estimate the risk of illness from air pollution in the setof municipalities of the Metropolitan Region of São Paulo, Brazil. Global estimates of the effectof exposure to pollution in the region indicated associations only with respiratory diseases. OnlySão Paulo and São Bernardo do Campo showed an association between the levels of PM10 andhospitalizations for cardiovascular diseases