Urban air pollution and emergency admissions for cerebrovascular diseases in Taipei, Taiwan

Aims: This study was designed to evaluate the association between urban air pollutants and emergency admissions for cerebrovascular diseases. Methods and results: Daily emergency admissions for cerebrovascular diseases (ICD-9-CM, 430-437) to the National Taiwan University Hospital were regressed against daily concentrations of carbon monoxide (CO), nitrogen dioxide (NO₂), sulphur dioxide (SO₂), ozone (O₃), and particulate matters with aerodynamic diameter <2.5 (PM_2.5) and 10 μm (PM ₁₀) from 12 April 1997 to 31 December 2002 in Taipei metropolitan areas by the Poisson regression models adjusting for meteorological conditions and temporal trends. Single-pollutant models showed O₃ lagged 0 day, CO lagged 2 days, and PM_2.5 and PM₁₀ lagged 3 days were significantly associated with increasing emergency admissions for cerebrovascular diseases and CO lagged 2 days was significantly associated with increasing emergency admissions for strokes (ICD-9-CM, 430-434). Such association remained significant for O₃, CO, and cerebrovascular admissions after adjusting for PM_2.5 and PM₁₀ in two-pollutant models. The odds ratios were 1.021-1.022 per 31.3 ppb O ₃ and 1.023-1.031 per 0.8 ppm CO, respectively. However, only CO was significantly associated with emergency admissions for stroke in the three-pollutant models with CO, O₃, and PM_2.5 or PM ₁₀. Conclusion: Emergency admissions for cerebrovascular diseases among adults were positively associated with increasing urban air pollution levels of O₃ lagged 0 day and CO lagged 2 days in Taipei.