Absolute Humidity, Temperature, and Influenza Mortality: 30 Years of County-Level Evidence from the United States
Absolute Humidity, Temperature, and Influenza Mortality: 30 Years of County-Level Evidence from the United States
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DOI：
10.1093/aje/kws259
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发表时间：
2012-10-01
影响因子：
5
通讯作者：
Shimshack, Jay P.
中科院分区：
文献类型：
--
作者：
Barreca, Alan I.;Shimshack, Jay P.
最近探索环境因素与流感结果之间关系的研究重点关注绝对湿度的作用。然而，现有文献很少提供关于绝对湿度和其他天气变量与人群流感结果之间关系的定量流行病学证据。在本研究中，作者通过分析 1973 年 1 月至 2002 年 12 月期间每月观察到的美国 359 个城市县的纵向天气和流感死亡率数据，帮助填补了这一空白。使用灵活的回归模型同时探索绝对湿度和流感结果以及温度和流感结果之间的完全非线性关系。结果表明，即使在控制温度后，绝对湿度也是观察到的人类流感死亡率的一个特别关键的决定因素。存在重要的非线性关系；湿度水平低于每公斤空气约 6 克水蒸气与流感死亡率增加有关。模型预测表明，美国流感死亡率平均季节性差异的大约一半可以仅用绝对湿度的季节性差异来解释。温度也对流感死亡率产生了一定程度的影响，尽管结果不太稳健。
Recent research exploring associations between environmental factors and influenza outcomes has devoted substantial attention to the role of absolute humidity. However, the existing literature provides very little quantitative epidemiologic evidence on the relations between absolute humidity and other weather variables and influenza outcomes in human populations. In the present study, the authors helped fill this gap by analyzing longitudinal weather and influenza mortality data, observed every month between January 1973 and December 2002, for each of 359 urban US counties. A flexible regression model was used to simultaneously explore fully nonlinear relations between absolute humidity and influenza outcomes and temperature and influenza outcomes. Results indicated that absolute humidity was an especially critical determinant of observed human influenza mortality, even after controlling for temperature. There were important nonlinear relations; humidity levels below approximately 6 g of water vapor per kilogram of air were associated with increases in influenza mortality. Model predictions suggested that approximately half of the average seasonal differences in US influenza mortality can be explained by seasonal differences in absolute humidity alone. Temperature modestly influenced influenza mortality as well, although results were less robust.