International studies have demonstrated associations between exposure to air pollutants and deaths and hospitalizations due to stroke. However, the profile of these associations is not known in Brazil. This study aims to estimate the association between exposure to air pollutants and hospital admissions due to stroke in individuals who live in a medium-sized city, Sorocaba, Sao Paulo, Brazil. This was ecological time-series study using hospitalization data relating to the diagnosis of stroke (ICD-10 I.60-I.64) in persons 50 years of age or older who resided in the city of Sorocaba between January 1, 2007 to December 31, 2011. The pollutants studied were particulate matter, ozone, nitrogen dioxide and nitrogen oxide, controlled by apparent temperature. The generalized additive model using Poisson regression for the day of hospitalization and for up to five days of lag was used for the analysis. It was not possible to estimate the association between exposure to daily levels of particulate matter, ozone and nitrogen oxide and hospitalizations for strokes, but it was possible to identify an association between exposure to nitrogen dioxide and hospitalization for stroke (RR = 1.004, 95% CI 1.000-1.008) for the third one-day lag. An increase of 10 mg m-³ in concentrations of this pollutant represented an increase of 4 percentage points in the risk of hospitalization. Thus, it was established that the nitrogen dioxide is associated with hospitalization for stroke in a medium-sized city, i.e., Sorocaba.
air pollution; stroke; time series studies; nitrogen dioxide