兰州市日均气温与心血管疾病日入院人次的时间序列研究

Relationship between daily mean temperature and number of daily hospitalization of cardiovascular diseases in Lanzhou:a time-series study

目的研究日均气温对心血管疾病日入院人次的影响。方法收集兰州市城区4家综合性医院2004年1月1日至2007年12月31日心血管疾病患者入院资料和该地区同期气象因素及大气污染物（PM10、SO2、NO2）的时间序列资料。选用时间序列分析的广义相加模型，在控制星期几效应及其他混杂因素的基础上，探讨日均气温对兰州市居民心血管疾病日入院人次的影响。结果当兰州市日均气温为10℃时，气温对居民心血管疾病日入院人次的影响最小。日均气温低于10℃时，每降低1℃滞后3d时因心血管疾病而发生入院治疗的超额危险度最大，为2．55％（R尺95％CI：0．9552-0．9938）；日均气温高于10℃时，每升高1℃时当天因心血管疾病而发生入院治疗的超额危险度最大，为1．33％（RR95％CI：1．0070—1．0196）。结论兰州市日均气温低于10℃时，居民心血管疾病日入院人次随着气温的降低而增加；当日均气温高于10℃时，日入院人次随着气温的升高而增加。

Objective To study the effects of daily mean temperature（DMT） on the number of daily hospitalization of cardiovascular diseases. Methods The data of cardiovascular diseases patients hospitalized between January 1, 2004 and December 31, 2007 were collected. The data of meteorological factors and the air pollutants （PM10,SO2 and NO2） were also collected at the same time periods. Time-series analysis and generalized additive models （GAM） were used to explore the relationship between DMT and the number of daily hospitalization of cardiovascular diseases in Lanzhou after controlling the week effect and other confounding factors. Results When the daily mean temperature was about 10℃, it presented the minimal impact on the number of daily hospitalization of cardiovascular diseases; When the temperature was below 10 ℃, the excess risk （ER） of cardiovascular diseases （lag 3） caused by every decrease of 1℃ was the largest （ER=2.55%, 95%CI of RR： 0.955 2-0.993 8）; When the temperature was above 10 ℃, the ER of cardiovascular diseases （lag 0） of every increase of 1 ℃ was the largest （ER =1.33%, 95% CI of RR： 1.007 0-1.019 6）. Conclusion At DMT ≤10 ℃ ,the number of daily hospitalization of cardiovascular diseases in Lanzhou increases with DMT decreases; at DMT〉10℃, the number of daily hospitalization of cardiovascular diseases in Lanzhou increases with DMT increases.