Associations between ambient air pollution and prevalence of stroke and cardiovascular diseases in 33 Chinese communities

Inconsistent results have been reported that long-term exposure to ambient air pollution contributes to the increased prevalence of stroke and cardiovascular diseases (CVDs). In order to examine whether the exposure to ambient air pollution was associated with the prevalence of stroke and CVDs among people living in a heavy industrial province of northeast China, we conducted a cross-sectional study of 24,845 Chinese adults, ages 18-74 years old, from 33 communities in the 11 districts of the three Northeastern Chinese Cities during 2009. Three-year (2006-2008) average concentrations of particles with an aerodynamic diameter ≤10μm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxides (NO₂), and Ozone (O₃) were calculated from monitoring stations in each of the 11 districts. We used two-level logistic regressions models to examine the effects of yearly variations in exposure to each pollutant, controlling for important covariates. We found significant associations between PM₁₀ and SO₂ levels and stroke prevalence after accounting for important covariates: the adjusted odds ratio for stroke increased by 1.16 (95% confidence interval [CI], 1.03-1.30) per 19μgm^-3 increase in PM₁₀, and 1.14 (95%CI, 1.01-1.29) per 20μgm^-3 increase in SO₂, respectively. When stratified analysis by gender, these associations were significant only in men, but not in women. In conclusion, this study shows the association between long-term exposure to PM₁₀ and SO₂ and increased stroke prevalence, and the associations were more apparent in men than in women.