Zhang Jin-Liang, Liu Ling, Chai Fa-He
State Key Laboratory of Environmental Criteria and Risk Assessment and Environmental Standards Institute, Chinese Research Academy of Environmental Sciences (CRAES), Beijing 100012, China.
Zhonghua Liu Xing Bing Xue Za Zhi. 2012 Jul;33(7):710-6.
To explore the effects of heat wave on daily deaths caused by acute myocardial infarction (AMI) in Beijing.
A case-crossover design was used to study the impact of 5 heat waves on the daily number of AMI deaths from Jan. 1, 1999 to Jun. 30, 2000. The effect of heat wave on death in different gender or age groups was also compared. The 7th day before and after death occurred was chosen as its own bi-directional self-control. The OR value and its corresponding risk period was used to reflect the impact of heat wave on daily number of AMI deaths, lag days and duration.
There were five heat waves during the study period. The first heat wave sustained 9 days and the maximum temperature was 38.8°C with average humidity as 46.7%. The OR value for the AMI death was 1.437 (95%CI: 1.066 - 1.937). The second heat wave lasted 3 days, with the maximum temperature of 36.8°C and average humidity of 61.0%. The OR value for the AMI death was 1.846 (95%CI: 0.671 - 5.076). The third heat wave continued 7 days, with the maximum temperature of 41.5°C with average humidity of 58.5%. The OR value for the daily death counts caused by AMI was 2.427 (95%CI: 1.825 - 3.229). The fourth lasted for 3 days, with the maximum temperature of 39.6°C and average humidity as 31.9%. The OR value for the AMI deaths was 2.857 (95%CI: 1.088 - 7.506). The fifth heat wave lasted for 4 days, with the maximum temperature as 37.4°C, and average humidity as 42.0% during this period. The OR value for daily death counts caused by AMI was 1.500 (95%CI: 0.632 - 3.560). The OR value of the first heat wave for daily death counts of men and women caused by AMI were 1.153 (95%CI: 0.756 - 1.758) and 1.818 (95%CI: 1.185 - 2.790) respectively. The OR value for daily death counts of under 65 age was 1.200 (95%CI: 0.669 - 2.153), with the OR value for the older than 64 age group was 1.534 (95%CI: 1.083 - 2.173). The OR value for daily death counts of older than 64 age women was 1.818 (95%CI: 1.109 - 2.981). The OR values of the third heat wave for daily death counts of men and women caused by AMI were 2.392 (95%CI: 1.649 - 3.470) and 2.514 (95%CI: 1.613 - 3.919) respectively. The OR value for daily death counts of under 65 age group was 2.000 (95%CI: 1.149-3.482) and the OR value for the older than 64 age group was 2.623 (95%CI: 1.880 - 3.660). The OR value for daily death counts of older than 64 age group women was 2.800 (95%CI: 1.676 - 4.678).
(1) Significant increase for daily death counts of AMI in Beijing was noticed during the heat wave and usually causing hysteretic effect. The lag phase was 0 - 2 days in general. (2) The increase of maximum temperature was greater at the beginning day when the heat wave occurred in the previous day, with shorter lag time and greater risk of AMI death. (3) The risk of AMI death in women was greater than in men during the heat wave period. (4) The risk of AMI death among those older than 64 age group was greater than the under 65 year olds. (5) The impact of heat wave to the elderly female was greater.
探讨热浪对北京急性心肌梗死（AMI）所致每日死亡的影响。
采用病例交叉设计，研究1999年1月1日至2000年6月30日期间5次热浪对AMI每日死亡数的影响。还比较了热浪对不同性别或年龄组死亡的影响。将死亡发生前后第7天作为自身双向自我对照。采用OR值及其相应的危险期来反映热浪对AMI每日死亡数、滞后天数和持续时间的影响。
研究期间出现了5次热浪。第一次热浪持续9天，最高温度为38.8℃，平均湿度为46.7%。AMI死亡的OR值为1.437（95%CI：1.066 - 1.937）。第二次热浪持续3天，最高温度为36.8℃，平均湿度为61.0%。AMI死亡的OR值为1.846（95%CI：0.671 - 5.076）。第三次热浪持续7天，最高温度为41.5℃，平均湿度为58.5%。AMI所致每日死亡数的OR值为2.427（95%CI：1.825 - 3.229）。第四次持续3天，最高温度为39.6℃，平均湿度为31.9%。AMI死亡的OR值为2.857（95%CI：1.088 - 7.506）。第五次热浪持续4天，最高温度为37.4℃，此期间平均湿度为42.0%。AMI所致每日死亡数的OR值为1.500（95%CI：0.632 - 3.560）。第一次热浪对男性和女性AMI所致每日死亡数的OR值分别为1.153（95%CI：0.756 - 1.758）和1.818（95%CI：1.185 - 2.790）。65岁以下年龄组每日死亡数的OR值为1.200（95%CI：0.669 - 2.153），64岁以上年龄组的OR值为1.534（95%CI：1.083 - 2.173）。64岁以上年龄组女性每日死亡数的OR值为1.818（95%CI：1.109 - 2.981）。第三次热浪对男性和女性AMI所致每日死亡数的OR值分别为2.392（95%CI：）1.649 - 3.470）和2.514（95%CI：1.613 - 3.919）。65岁以下年龄组每日死亡数的OR值为2.000（95%CI：1.149 - 3.482），64岁以上年龄组的OR值为2.623（95%CI：1.880 - 3.660）。64岁以上年龄组女性每日死亡数的OR值为2.800（95%CI：1.676 - 4.678）。
（1）热浪期间北京AMI每日死亡数显著增加，且通常产生滞后效应。滞后阶段一般为0 - 2天。（2）热浪前一天发生时，首日最高温度升高幅度更大，滞后时间更短，AMI死亡风险更高。（3）热浪期间女性AMI死亡风险高于男性。（4）64岁以上年龄组AMI死亡风险高于65岁以下人群。（5）热浪对老年女性的影响更大。
