Acute Effect of Fine Particulate Matters on Daily Cardiovascular Disease Mortality in Seven Cities of China

Objective: To explore the effect of fine particulate matters with an aerodynamic diameter less than 2.5 μm (PM(2.5)) on daily cardiovascular disease mortality in seven cities of China. Methods: Daily average concentrations of PM(2.5), cardiovascular disease mortality data and environmental data were collected from January 1, 2013 to December 31, 2015 in seven cities of China, including Shijiazhuang, Haerbin, Shanghai, Wuhan, Guangzhou, Chengdu and Xi' an. We linked generalized additive model with Quasi-Poisson distribution to evaluate the association between daily concentrations of PM(2.5) and cardiovascular disease mortality at single-city level and multi-city level, after adjusting for the long-term and seasonal trend, as well as meteorological factors and the effect of " days of week" . Results: The single-pollutant model indicated that there were marked differences in association strength in these cities, among which the effect in Guangzhou was strongest. At multi-city level, a 10 μg/m(3) increase of PM(2.5) was associated with an increase of 0.315% (95%CI: 0.133%-0.497%) of daily cardiovascular disease mortality. From lag0 to lag2, the effect of PM(2.5) on cardiovascular disease mortality decreased, while it was strongest on lag01. In the two-pollutant model, the estimated effect decreased in all the cities with the adjustments of SO(2) or NO(2). The insignificant combined results suggested that PM(2.5) might have combined effect with other pollutants. Each 10 μg/m(3) increase of PM(2.5) was associated with increases of 0.371% (95%CI: 0.141%-0.600%) and 0.199% (95% CI: 0.077%-0.321%) of cardiovascular disease mortality in males and females, respectively. The effect of PM(2.5) on cardiovascular disease mortality increased with age and decreased with educational level, although the differences between different subgroups were insignificant. The dose-response relationship between PM(2.5) and cardiovascular disease mortality was non-linear and non-threshold, with a steeper curve at lower concentrations. Conclusion: The increases of PM(2.5) concentration can result in the increase of daily cardiovascular mortality.