The growing body of scientific literature underscores the intricate relationship between meteorological conditions and human health, particularly in the context of extreme temperatures. However, conventional temperature-centric approaches often fall short in capturing the complexity of thermal stress experienced by individuals. Temperature alone, as a metric, fails to encompass the entirety of the thermal stress individuals face, necessitating a more nuanced understanding. In response to this limitation, climatologists have devised thermal indices—composite measures meticulously crafted to reflect the intricate interplay of meteorological factors influencing human perception of temperature. Recognizing the inadequacy of simplistic temperature-focused methodologies, our study aims to address the multifaceted nature of thermal stress. In this study, we explored the association between thermal indices and hospital admissions for circulatory and respiratory diseases in Brazil. We used an extensive dataset spanning 11 years (2008–2018) from the Brazilian Ministry of Health, encompassing a total of 23,791,093 hospitalizations for circulatory and respiratory diseases. We considered four distinct thermal indices—Discomfort Index (DI), Net Effective Temperature (NET), Humidex (H), and Heat Index (HI). We used an extension of the two-stage design with a case time series to assess this relationship. In the first stage, we applied a distributed lag non-linear modeling framework to create a cross-basis function. We next applied quasi-Poisson regression models adjusted by time-varying confounders. In the second stage, we applied -analysis with random effects to estimate the national relative risk (RR). Our findings suggest robust variations among the thermal indices under examination. These variations underscore the intricate nature of associations between temperature and health, with each index capturing distinct aspects of thermal conditions. Our results indicate that extreme thermal conditions, both at the low and high ends, are associated with increased risks of hospital admissions. The diverse impact observed among different indices emphasizes the complex interplay between various meteorological factors and their specific physiological consequences. This underscores the necessity for a comprehensive comprehension of temperature metrics to guide precise public health interventions, recognizing the multifaceted nature of temperature-health relationships.

中文翻译：

---

巴西的热应激和心肺疾病住院率


越来越多的科学文献强调了气象条件与人类健康之间的复杂关系，特别是在极端温度的情况下。然而，传统的以温度为中心的方法往往无法捕捉个体所经历的热应激的复杂性。单独的温度作为一个指标并不能涵盖个人所面临的全部热应力，因此需要更细致的了解。为了应对这一限制，气候学家设计了热指数——精心设计的综合指标，以反映影响人类温度感知的气象因素之间错综复杂的相互作用。认识到简单化的以温度为中心的方法的不足，我们的研究旨在解决热应力的多方面性质。在这项研究中，我们探讨了巴西热指数与循环系统和呼吸系统疾病住院率之间的关联。我们使用了巴西卫生部 11 年（2008 年至 2018 年）的广泛数据集，包含总共 23,791,093 例因循环系统和呼吸系统疾病住院的患者。我们考虑了四种不同的热指数——不适指数 (DI)、净有效温度 (NET)、湿度指数 (H) 和热指数 (HI)。我们使用两阶段设计的扩展和案例时间序列来评估这种关系。在第一阶段，我们应用分布式滞后非线性建模框架来创建跨基函数。接下来，我们应用了由时变混杂因素调整的准泊松回归模型。在第二阶段，我们应用随机效应分析来估计国家相对风险（RR）。我们的研究结果表明所检查的热指数之间存在巨大差异。 这些变化强调了温度与健康之间关联的复杂性，每个指数都捕捉了热条件的不同方面。我们的结果表明，极端的高温条件，无论是低端还是高端，都与住院风险增加有关。不同指数之间观察到的不同影响强调了各种气象因素及其特定生理后果之间复杂的相互作用。这强调了全面理解温度指标的必要性，以指导精确的公共卫生干预措施，认识到温度与健康关系的多方面性质。