A Meta-analysis on the relations between short-term exposure to PM2.5 and both mortality and related emergency visits in China / 中华流行病学杂志

ABSTRACT

Objective To carry out a quantitative estimate that related to the effects of shortterm exposure to PM2.5 on all-cause mortality and emergency visits in China by using the systematic review and Meta-analysis.Methods We selected all the studies published before March 2018 from China National Knowledge Infrastructure,Wanfang database,PubMed and EMBASE and data on relative risk (RR),excess risk (ER) and their 95％CIsappeared in these papers were extracted.According to the differences in the size or direction (heterogeneity) of the results,we computed summary estimates of the effect values using a random-effect or fixed effect model.We also conducted the subgroup analysis and Meta-analysis to have assessed the selected studies for the evidence of study bias.Results A total of 33 original studies,indexed in databases,were identified.Among those studies,39 sets of data on mortality and 4 sets of data on emergency were valid to show that within the daily concentration range from 47.7 to 176.7 pg/m3,for 10 μg/m3 increases in PM2.5 concentrations,it would increase the daily numbers of deaths by 0.49％ (95％CI0.39％-0.59％) and 0.30％ (95％CI0.10％-0.51％) for all-cause deaths and all-cause emergency-room visits,respectively.For subgroup analysis,the combined effect of PM2.5 in causing short-term all-cause deaths in the northern areas (ER=0.42％,95％CI0.30％-0.54％) seemed lower than that in the southern areas (ER=0.63％,95％CI0.44％-0.82％).The combined effect of PM2.5 concentration below 75 μg/m3 (ER=0.50％,95％CI0.37％-0.62％) was higher than that of PM25 concentration ≥75 μ g/m3 (ER=0.39％,95％ CI0.26％-0.52％).Conclusion Within the concentration range from 47.7 to 176.7 μg/m3,short-term exposure to current level of PM2.5 might increase both the all-cause daily mortality and daily emergency visits in China.