摘要：Background Although the association between long-term exposure to PM 2.5 and mortality has been evaluated intensively, little is known about the socioeconomic disparity in the association. Methods We collected data on annual all-cause mortality, PM 2.5 concentration, socioeconomic and demographic characteristics of 2640 counties from the two most recent Chinese censuses in 2000 and 2010. We applied the difference-in-differences (DID) method to estimate PM 2.5 -mortality association for counties at different quartiles of literacy rate, college rate, urbanization rate and GDP per capita, respectively. Results Overall, every 10 µg/m 3 increase in annual average PM 2.5 was associated with 3.8% (95% confidence interval [CI]: 3.0–5.0) increase of all-cause mortality. The stratified analysis suggested higher health impact of exposure in counties with lower socioeconomic status. For counties of the lowest quartile (Q 1 ) of literacy rate, college rate, urbanization rate and GDP per capita, the effect estimates were 6.0% (95% CI: 4.2–7.7), 4.4% (95% CI: 2.8–6.0), 3.5% (95% CI: 2.0–5.1) and 4.9% (95% CI: 2.7–7.1), respectively. There was strong evidence for elevated risk in mortality associated with PM 2.5 of all socioeconomic factors in the lowest quartile (Q 1 ) compared with the highest quartile counties (Q 4 ) ( p -value for difference < 0.05). Conclusions There was socioeconomic disparity in the PM 2.5 -mortality association in China. Dwellers living in less developed counties are more vulnerable to long-term exposure to ambient PM 2.5 than those living in developed counties.
关键词：PM 2.5 -mortality association ; Socioeconomic status ; Difference-in-differences
