广州市氧化性污染物与气温对居民心脑血管疾病死亡风险的交互作用

Interaction between oxidant pollutants and ambient temperature on cardio-cerebrovascular mortality risks in Guangzhou, China

[背景]近年来我国大气污染及极端天气现象日益严重,但二者对人群心脑血管健康的影响尚不明确。[目的]探究大气氧化性污染物和气温对居民心脑血管疾病死亡风险的影响及其交互作用。[方法]收集2006年1月1日—2016年12月31日广州市逐日大气污染物质量浓度(浓度)、气象因素以及居民心脑血管疾病死亡个案数据。采用基于泊松分布的广义相加模型分析大气氧化性污染物和气温与居民心脑血管疾病死亡风险的相关性,并进一步采用双变量响应面模型和分层法对大气氧化性污染物与气温对居民心脑血管疾病死亡风险的交互作用进行定性与定量分析。[结果]研究期间广州市大气臭氧(O_(3))、空气氧化性指标(O_(x))和二氧化氮(NO_(2))每日平均浓度分别为60.3、50.9和32.5μg·m^(−3),每日平均气温为22.3℃,冠心病和脑卒中每日平均死亡人数分别为20人和15人。O_(3)、O_(x)和NO_(2)浓度每升高10μg·m^(−3),O_(3)、O_(x)和NO_(2)对冠心病和脑卒中死亡风险在累积滞后2~5 d时达到最大:居民冠心病死亡超额风险(ER)最大值分别为1.26%(95%CI:0.79%~1.74%)、1.61%(95%CI:0.99%~2.23%)和1.33%(95%CI:0.59%~2.07%),脑卒中死亡ER最大值分别为1.56%(95%CI:1.04%~2.09%)、2.30%(95%CI:1.60%~3.01%)和2.93%(95%CI:2.07%~3.79%)。气温与冠心病和脑卒中死亡风险的暴露-反应关系呈反“J”型分布,最适气温分别为25.7℃和27.3℃。交互作用分析结果显示,高温与高浓度O_(3)和O_(x)对冠心病死亡风险存在协同放大作用,交互作用相对超额危险度分别为0.103(95%CI:0.028~0.178)和0.079(95%CI:0.004~0.154),未发现低温与大气氧化性污染物对心脑血管疾病死亡风险存在交互作用。[结论]大气氧化性污染物暴露可引起居民心脑血管疾病死亡风险升高,且高温与其存在协同作用。

[Background]The increasing threats of air pollution and extreme weather have been widely recognized in recent years in China,but their individual and joint effects on cardiocerebrovascular mortality are unclear.[Objective]This study aims to investigate the individual effects of and potential interactions between oxidant pollutants and ambient temperature on cardio-cerebrovascular mortality risks.[Methods]We collected daily data on death counts of cardio-cerebrovascular diseases,concentrations of ambient air pollutants,and meteorological parameters in Guangzhou,China between 1 January 2006 and 31 December 2016.A generalized additive model with a Poisson distribution was conducted to assess the associations of oxidant pollutants and ambient temperature with cardio-cerebrovascular mortality risks.Bivariate response surface models and stratified analyses were further adopted to qualitatively and quantitatively examine the potential interactions between oxidant pollutants and ambient temperature on cardio-cerebrovascular mortality risks.[Results]During the study period,the daily averages were 60.3μg·m^(−3) for ozone(O_(3)),50.9μg·m^(−3) for combined atmospheric oxidant capacity(O_(x)),32.5μg·m^(−3) for nitrogen dioxide(NO_(2)),and 22.3℃for ambient temperature.The average daily death counts of coronary and stroke diseases were 20 and 15,respectively.Per 10μg·m^(−3) increment in O_(3),O_(x),and NO_(2) were associated with increased coronary mortality risks(excess risk,ER)of 1.26%(95%CI:0.79%-1.74%),1.61%(95%CI:0.99%-2.23%),and 1.33%(95%CI:0.59%-2.07%),and with increased stroke mortality risks of 1.56%(95%CI:1.04%-2.09%),2.30%(95%CI:1.60%-3.01%),and 2.93%(95%CI:2.07%-3.79%)over cumulative lags of 2-5 days,respectively.The exposure-response relationships between ambient temperature and coronary and stroke mortality risks exhibited an inverse"J"shape,with the minimum mortality at temperatures of 25.7℃for coronary disease and 27.3℃for stroke.Our results further showed potentially synergic effects of higher temperatures and higher levels of O_(3) and O_(x) exposures on coronary mortality risks,and the relative ER due to interactions was 0.103(95%CI:0.028-0.178)for O_(3) and 0.079(95%CI:0.004-0.154)for O_(x).We didn't find evidence of an interaction between oxidant pollutants and low temperature.[Conclusion]Short-term exposures to oxidant pollutants are associated with increased cardio-cerebrovascular mortality risks,and the interactive effects of high temperature and oxidant pollutants are synergistic in relation to cardio-cerebrovascular mortality risks.