Tao Junwen, Xu Zhiwei, Ho Hung Chak, Zheng Hao, Xing Xiuya, Hu Jihong, Tong Shilu, Kim Ho, Hossain Mohammad Zahid, Su Hong, Huang Cunrui, Cheng Jian
Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China.
Anhui Province Key Laboratory of Major Autoimmune Disease, Hefei, China.
Lancet Reg Health West Pac. 2025 Aug 7;61:101653. doi: 10.1016/j.lanwpc.2025.101653. eCollection 2025 Aug.
Heatwave is a global health threat. However, existing heatwave definitions often rely on fixed temperature thresholds without incorporating region-specific health outcomes or population acclimatization, limiting their applicability across diverse climatic and demographic contexts. We aimed to assess the impact of localized heatwave on mortality based on a proposed framework of health-based heatwave definition.
Based on daily data on death and weather from 25 cities in Australia, China, South Korea, and Thailand, we proposed a health-based excess heat factor (HEHF) to define the localized heatwave. First, a tiered health risk-based (THR) approach was used to fit the heatwave-mortality association to detect the region-specific temperature threshold for heatwave. Then, the HEHF was derived from a three-day-averaged temperature exceeding the region-specific heatwave threshold multiplied by the acclimatization index, reflecting the difference between recent (past three-day) and preceding (past thirty-day) average temperatures. Finally, the mortality burden attributable to heatwaves was estimated to compare the performance of distinct heatwave definitions including the HEHF, percentile-based definition, and country-specific official definition.
A total of 2,255,634 deaths from four countries were analyzed. Heatwave of all definitions was associated with an increased mortality risk in four countries, with a higher risk estimated by HEHF. The HEHF not only detected a health-based, localized, and time-varying temperature threshold for the heatwave but also captured a continuous pattern of mortality risk associated with changes in heatwave intensity. Compared with percentile-based and country-specific official definitions, using the HEHF also yielded a larger proportion of deaths attributable to heatwaves, accounting for 8.68% (95% CI: 7.19%, 10.50%) in China, 4.50% (95% CI: 3.33%, 5.58%) in Thailand, 2.99% (95% CI: 1.54%, 4.33%) in Australia, and 1.98% (95% CI: 1.24%, 2.71%) in South Korea. The subtropical zone exhibited a higher attributable fraction than temperate and tropical zones.
This multi-country study has developed a generalizable and health-based framework for defining the localized heatwave, assisting in assessing and comparing health impact of heatwaves across regions and climates.
National Natural Science Foundation of China.
热浪是一种全球健康威胁。然而，现有的热浪定义通常依赖于固定的温度阈值，未纳入特定区域的健康结果或人群适应性，限制了它们在不同气候和人口背景下的适用性。我们旨在基于一个基于健康的热浪定义框架，评估局部热浪对死亡率的影响。
基于澳大利亚、中国、韩国和泰国25个城市的每日死亡和天气数据，我们提出了一个基于健康的过热因子（HEHF）来定义局部热浪。首先，采用基于分层健康风险（THR）的方法来拟合热浪与死亡率的关联，以检测特定区域的热浪温度阈值。然后，HEHF由超过特定区域热浪阈值的三日平均温度乘以适应指数得出，该指数反映了近期（过去三天）和先前（过去三十天）平均温度之间的差异。最后，估计热浪所致的死亡负担，以比较包括HEHF、基于百分位数的定义和各国官方定义在内的不同热浪定义的表现。
分析了来自四个国家的总共2255634例死亡病例。所有定义的热浪都与四个国家的死亡风险增加相关，HEHF估计的风险更高。HEHF不仅检测到了基于健康的、局部的和随时间变化的热浪温度阈值，还捕捉到了与热浪强度变化相关的连续死亡风险模式。与基于百分位数的定义和各国官方定义相比，使用HEHF还导致归因于热浪的死亡比例更大，在中国占8.68%（95%CI：7.19%，10.50%），在泰国占4.50%（95%CI：3.33%，5.58%），在澳大利亚占2.99%（95%CI：1.54%，4.33%），在韩国占1.98%（95%CI：1.24%，2.71%）。亚热带地区的归因比例高于温带和热带地区。
这项多国研究开发了一个可推广的、基于健康的框架来定义局部热浪，有助于评估和比较不同地区和气候条件下热浪对健康的影响。
中国国家自然科学基金。
