From the Department of Geography, University of Santiago de Compostela, Santiago de Compostela, Spain.
CIBER of Epidemiology and Public Health (CIBERESP), Spain.
Epidemiology. 2021 Jul 1;32(4):487-498. doi: 10.1097/EDE.0000000000001359.
There is strong evidence concerning the impact of heat stress on mortality, particularly from high temperatures. However, few studies to our knowledge emphasize the importance of hot nights, which may prevent necessary nocturnal rest.
In this study, we use hot-night duration and excess to predict daily cause-specific mortality in summer, using multiple cities across Southern Europe.
We fitted time series regression models to summer cause-specific mortality, including natural, respiratory, and cardiovascular causes, in 11 cities across four countries. We included a distributed lag nonlinear model with lags up to 7 days for hot night duration and excess adjusted by daily mean temperature. We summarized city-specific associations as overall-cumulative exposure-response curves at the country level using meta-analysis.
We found positive but generally nonlinear associations between relative risk (RR) of cause-specific mortality and duration and excess of hot nights. RR of duration associated with nonaccidental mortality in Portugal was 1.29 (95% confidence interval [CI] = 1.07, 1.54); other associations were imprecise, but we also found positive city-specific estimates for Rome and Madrid. Risk of hot-night excess ranged from 1.12 (95% CI = 1.05, 1.20) for France to 1.37 (95% CI = 1.26, 1.48) for Portugal. Risk estimates for excess were consistently higher than for duration.
This study provides new evidence that, over a wider range of locations, hot night indices are strongly associated with cause-specific deaths. Modeling the impact of thermal characteristics during summer nights on mortality could improve decisionmaking for preventive public health strategies.
有大量证据表明热应激对死亡率有影响，尤其是高温。然而，据我们所知，很少有研究强调热夜的重要性，热夜可能会妨碍夜间必要的休息。
在这项研究中，我们使用热夜持续时间和过剩来预测夏季多个人口密集的南欧城市的特定原因的每日死亡率。
我们拟合了时间序列回归模型，以研究夏季特定原因的死亡率，包括自然原因、呼吸原因和心血管原因，涉及四个国家的 11 个城市。我们纳入了一个分布式滞后非线性模型，该模型考虑了经每日平均温度调整后的热夜持续时间和过剩的滞后，滞后时间长达 7 天。我们使用荟萃分析汇总了各国的城市特异性关联，即总体累积暴露-反应曲线。
我们发现特定原因死亡率与热夜持续时间和过剩之间存在正相关关系，但通常是非线性的。与非意外死亡率相关的葡萄牙热夜持续时间的相对风险（RR）为 1.29（95%置信区间[CI] = 1.07，1.54）；其他关联不精确，但我们还发现罗马和马德里的城市特异性估计值呈阳性。热夜过剩的风险范围从法国的 1.12（95% CI = 1.05，1.20）到葡萄牙的 1.37（95% CI = 1.26，1.48）。热夜过剩的风险估计值始终高于持续时间。
这项研究提供了新的证据，表明在更广泛的地点范围内，热夜指数与特定原因的死亡密切相关。对夏季夜间热特性对死亡率的影响进行建模，可以提高预防公共卫生策略的决策水平。
