Estimating the acute effects of fine and coarse particle pollution on stroke mortality of in six Chinese subtropical cities

While increasing evidence suggested that PM_2.5 is the most harmful fraction of the particle pollutants, the health effects of coarse particles (PM_10-2.5) have been inconclusive, especially on cerebrovascular diseases, we thus evaluated the effects of PM₁₀, PM_2.5, and PM_10-2.5 on stroke mortality in six Chinese subtropical cities using generalized additive models. We also conducted random-effects meta-analyses to estimate the overall effects across the six cities. We found that PM₁₀, PM_2.5, and PM_10-2.5 were significantly associated with stroke mortality. Each 10 μg/m³ increase of PM₁₀, PM_2.5 and PM_10-2.5 (lag03) was associated with an increase of 1.88% (95% CI: 1.37%, 2.39%), 3.07% (95% CI: 2.35%, 3.79%), and 5.72% (95% CI: 3.82%, 7.65%) in overall stroke mortality. Using the World Health Organization's guideline as reference concentration, we estimated that 3.21% (95% CI: 1.65%, 3.01%) of stroke mortality (corresponding to 1743 stroke mortalities, 95% CI: 896, 1633) were attributed to PM₁₀, 5.57% (95% CI: 0.50%, 1.23%) stroke mortality (3019, 95% CI: 2286, 3777) were attributed to PM_2.5, and 2.02% (95% CI: 1.85%, 3.08%) of stroke mortality (1097, 95% CI: 1005, 1673) could be attributed to PM_10-2.5. Our analysis indicates that both PM_2.5 and PM_10-2.5 are important risk factors of stroke mortality and should be considered in the prevention and control of stroke in the study area.