Relationship between hemorrhagic stroke hospitalization and exposure to fine particulate air pollution in Taipei, Taiwan.

This study was undertaken to determine whether there was a correlation between fine particle (PM2.5) levels and hospital admissions for hemorrhagic stroke (HS) in Taipei, Taiwan. Hospital admissions for HS and ambient air pollution data for Taipei were obtained for the period 2006-2010. The relative risk of hospital admissions was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased HS admissions were significantly associated with PM2.5 levels both on warm days (>23°C) and cool days (<23°C), with an interquartile range rise associated with a 12% (95% CI = 7-18%) and 4% (95% CI = 0-8%) elevation in admissions for HS, respectively. In the two-pollutant models, PM2.5 remained significantly high after inclusion of SO2 or O3 on both warm and cool days. This study provides evidence that higher levels of PM2.5 increase the risk of hospital admissions for HS.