摘要目的 探讨北京市气温热浪(热浪)对当地居民每日心脑血管疾病死亡人数的影响.方法 运用病例交叉设计方法,分析北京市1999年1月1日至2000年6月30日期间热浪对居民每日心脑血管疾病死亡人数的影响,同时研究其对每日急性心肌梗死(AMI)死亡人数的影响.选择死亡发生前第7天作为自身对照,分别计算不同长度的危险期OR值,以最高OR值及其对应的危险期来反映热浪过程对居民心脑血管疾病死亡人数影响的大小、滞后天数及持续时间.结果 研究期间共发生5次热浪.第1次持续9 d,最高气温为38.8℃,平均湿度为46.7%,居民每日心血管疾病死亡、脑血管疾病死亡和AMI死亡的OR值分别为1.384(95%CI:1.128～1,697)、1.776(95%CI:1.456～2.167)和1.276(95%CI:0.905～1.799);第2次热浪持续3 d,最高气温为36.8℃,平均湿度为61.0%,3种死因每日死亡的OR值分别为1.385(95%CI:0.678～2.826)、1.300(95%CI:0.726～2.329)和2.000(95%CI:0.684～5.851);第3次热浪持续7 d,最高气温为41.5℃,平均湿度为58.5%,3种死因每日死亡的OR值分别为2.613(95%CI:2.116～3.228)、2.317(95%CI:1.875～2.863)和3.088(95%CI:2.098～4.546);第4次持续3 d,最高气温为39.6℃,平均湿度为31.9%,3种死因每日死亡的OR值分别为1.333(95%CI:0.724～2.457)、2.429(95%CI:1.007～5.856)和3.333(95%CI:0.917～12.112);第5次热浪持续4d,最高气温为37.4℃,平均湿度为42.0%,3种死因每日死亡OR值分别为2.333(95%CI:1.187～4.588)、1.727(95%CI:0.822～3.630)和1.800(95%CI:0.603～5.371).结论 (1)热浪对居民心脑血管疾病死亡有影响,且存在滞后效应,滞后期为2～4d,其中AMI死亡的滞后期较短,为0～2d;(2)热浪开始当天日最高气温较前一天升温的幅度越大,对居民心脑血管疾病死亡人数影响的滞后期越短,死亡风险越大,对脑血管疾病死亡影响更大;(3)热浪期间日最高气温的波动可以增加居民心脑血管疾病死亡的风险.

abstractsObjective To explore the impct of heat wave on the daily deaths caused by cardiovascular disease and cerebrovascular diseases in Beijing.Methods A case-crossover design was used to study the impact of 5 heat waves on the daily number of deaths from cardiovascular diseases and cerebrovascular disease,from Jan.1,1999 to Jun.30,2000.We also investigated the relationship between the heat wave and acute myocardial infarction deaths.The 7th day before death was chose as the indicator of self-control.The OR value of different lengths of risk period was calculated.The highest OR value and its corresponding risk period was used to reflect the impact of heat wave on daily number of cardiovascular and cerebrovascular disease deaths,lag days and their durations.Results There were five heat waves during the study period.The first heat wave lasted for 9 days,with the maximum temperature as 38.8 ℃ and average humidity as 46.7%.The Off value for the cardiovascular disease death,cerebrovascular disease death and acute myocardial infarction death were 1.384(95%CI:1.128-1.697),1.776(95%CI:1.456-2.167)and 1.276(95%CI:0.905-1.799)respectively.The second heat wave lasted 3 days,with the maximum temperature of 36.8 ℃ and average humidity of 61.0%.The OR value for the three causes of death were 1.385(95%CI:0.678-2.826),1.300(95% CI:0.726-2.329)and 2.000(95% CI:0.684-5.851)respectively.The third heat wave continued for 7 days,with the maximum temperature of 41.5 ℃,and average humidity of 58.5%.The OR value for the daily death counts caused by cardiovascular disease,cerebrovascular diseases and acute myocardial infarction were 2.613(95%CI:2.116-3.228),2.317(95%CI:1.875-2.863)and 3.088(95%CI:2.098-4.546)respectively.The fourth wave lasted for 3 days,with the maximum temperature as 39.6 ℃ and average humidity as 31.9%.The OR value for the deaths caused by cardiovascular disease,cerebrovascular diseases and acute myocardial infarction were 1.333(95%CI:0.724-2.457),2.429(95%CI:1.007-5.856)and 3.333(95%67:0.917-12.112)respectively.The fifth heat wave lasted for 4 days.The maximum temperature was 37.4 ℃,and the average humidity was 42.0% during the period.The OR value for daily death counts caused by cardiovascular disease,cerebrovascular disease and acute myocardial infarction were 2.333(95%CI:1.187-4.588),1.727(95%CI:0.822-3.630)and 1.800(95%CI:0.603-5.371)respectively.Conclusions(1)There were significant increases for daily death counts of both cardiovascular and cerebrovascular disease in Beijing during the heat wave and there appeared hysteresis effect as well.The lag phase of cardiovascular disease and cerebrovascular disease death was generally 2-4 days and acute myocardial infarction death usually was 0-2 days.(2)The rising of maximum temperature was greater at the beginning day of heat wave than the previous day,but the lag time was shorter,and the risk of death was greater,especially for the risk of deaths from cerebrovascular disease.(3)Fluctuations of daily maximum air temperature during the heat wave could increase the risk of death from cardiovascular disease.