Association between concentrations of air pollutants and mean time of hospitalization due to pneumonia in children

Abstract

A time-series ecological study was developed to estimate the role of air pollutants in the mean daily duration of hospitalization for pneumonia in children under one year old and living in São José dos Campos, SP, between January 1, 2009 and December 31, 2009. Air pollutants PM10, SO2 and O3, and climatic variables were measured by the Environmental Company of the State of São Paulo (Cetesb). The duration of each hospitalization was obtained from the Datasus site. The values of air pollutants and climatic variables were analyzed using multiple linear regression in lags of zero to five days; the dependent variable was the mean duration of hospitalization and the independent variables were the pollutants. We obtained R2 and alpha = 0.05 was the significance level of the model. There were 559 children under one year of age admitted during the study period; the mean hospital stay was 3.81 days (SD = 4.06). The PM10 was associated with length of stay in concurrent days and lags four and five (P <0.001, R2 = 0.08); a 15 μg.m-3 increase in concentration of this pollutant implies an increase of approximately one day of mean time of hospitalization for lags of 0, 4 and 5 days. It was therefore possible to identify the role of particulate matter in the duration of pneumonia hospitalizations in children.