Department of Biostatistics, The University of Texas School of Public Health at San Antonio Regional Campus, San Antonio, TX, USA; Research to Advance Community Health Center, The University of Texas Health Science Center at San Antonio Regional Campus, San Antonio, TX, USA.
Division of Epidemiology and Biostatistics, School of Public Health, The University of Queensland, Brisbane, Australia.
Sci Total Environ. 2016 Aug 15;562:845-851. doi: 10.1016/j.scitotenv.2016.04.042. Epub 2016 Apr 23.
Heat and heat waves have been linked to the increased risk of deaths, hospital admissions, and emergency visits.
This study presents a spatiotemporal analysis of heat and heat wave effects on elderly mortality (≥65years) in Texas.
We compiled a six-year daily weather and mortality counts dataset from 254 counties in Texas during 2006-2011. Heat index (HI), a combination of temperature and relative humidity, was used as the exposure metric in this study. Associations between daily all-cause elderly mortality and daily maximum HI and heat waves (≥2days of county-specific daily maximum HI>95th percentiles) were examined using a quasi-Poisson regression. A Markov random field smoother was included in the model to account for spatial autocorrelations and spatial heterogeneity. The model also controlled for long-term trend and seasonality in mortality, and the effects of day of the week.
On average, the lag effect of heat on elderly mortality risk lasted up to 10days, and the cumulative heat effects started to increase rapidly when daily maximum HI exceeded the 90th percentile in Texas. Elderly living in Northwest Texas and parts of West Texas were at greater risk of elderly mortality attributable to heat waves, and the highest relative risk for elderly mortality occurred in El Paso County (4.70, 95% Confidence Interval=4.33, 5.10).
Our study indicates strong geographical variations of heat wave effects on elderly mortality risk in Texas.
热和热浪与死亡、住院和急诊人数增加有关。
本研究对德克萨斯州热和热浪对老年人死亡率（≥65 岁）的时空影响进行了分析。
我们编制了 2006-2011 年德克萨斯州 254 个县六年的每日天气和死亡率数据。本研究将热指数（HI）作为暴露指标，热指数是温度和相对湿度的组合。使用拟泊松回归法检验了每日全因老年人死亡率与每日最大 HI 和热浪（≥2 天的县特定每日最大 HI>95 百分位数）之间的关系。模型中包括一个马尔可夫随机场平滑器，以解释空间自相关和空间异质性。该模型还控制了死亡率的长期趋势和季节性以及星期几的影响。
平均而言，热对老年人死亡率风险的滞后效应持续长达 10 天，当德克萨斯州的每日最大 HI 超过第 90 百分位时，累积热效应开始迅速增加。居住在德克萨斯州西北部和西部部分地区的老年人因热浪而导致的老年人死亡风险更高，而老年人死亡率的最高相对风险出现在埃尔帕索县（4.70，95%置信区间=4.33，5.10）。
我们的研究表明，德克萨斯州热浪对老年人死亡率风险的影响存在很强的地域差异。
