Regional changes in temperature-related mortality before and during the COVID-19 pandemic: a continental modelling analysis in 805 European regions

• Published in: Environmental research Vol. 278; p. 121697
• Main Authors: Paniello-Castillo, Blanca, Quijal-Zamorano, Marcos, Gallo, Elisa, Basagaña, Xavier, Ballester, Joan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.08.2025
• Subjects: Adaptation; Climate change; Cold; Cold Temperature; COVID-19 - epidemiology; COVID-19 - mortality; COVID-19 pandemic; DLNM; Europe - epidemiology; Heat; Hot Temperature; Humans; Models, Theoretical; Mortality; Pandemics; SARS-CoV-2; Temperature; Time series; Europe; COVID-19 pandemic; Climate change; Temperature; Heat; Cold; Mortality; DLNM; Time series; Adaptation
• ISSN: 0013-9351; 1096-0953; 1096-0953
• DOI: 10.1016/j.envres.2025.121697

The COVID-19 pandemic drastically disrupted usual seasonal mortality patterns, creating challenges in assessing temperature-related mortality. While previous studies explored the effect of temperature on SARS-CoV-2 transmission, few examined its relationship with mortality during the pandemic, often excluding COVID-19 deaths or relying on pre-pandemic models. In this study, we developed an innovative methodological framework that accounts for COVID-19 waves, allowing us to estimate changes in the short-term effects of temperature on mortality and assess the role of adaptation and maladaptation before and after the onset of the pandemic. We analyzed pre- (2015–2019) and pandemic (2020–2023) mortality data from Eurostat, covering 805 contiguous regions across 32 European countries. To adjust for COVID-19 deaths, we selected specific time windows during COVID-19 waves, and increased the degrees of freedom (d.f.) for these windows as necessary until achieving well-behaved residuals. Adjusting for COVID-19 deaths reduced uncertainty in the pandemic association, providing more precise estimates. When adjusting for COVID-19 deaths, we observed a significant reduction in cold and heat-related mortality risks in all sub-regions except in the southern regions for heat, which experienced a significant increase. When assessing the role of adaptation between pre- and pandemic periods, we observed significant changes for heat risks in southern and western regions with higher risks in the pandemic period than in the pre-pandemic one. For cold, all sub-regions except the southern ones had higher risks in the pre-pandemic period. Our work defines a new innovative methodological framework for future epidemiological studies using data from the pandemic period. The proposed methodology demonstrates the importance of using pandemic data and adjusting for COVID-19 deaths to accurately capture current vulnerabilities. The findings highlight different regional adaptation processes and underscore the need for enhanced heat adaptation measures, particularly in vulnerable regions. •Our methodology emphasizes using pandemic data and adjusting for COVID-19 deaths.•Heat-related risks increased in Southern and Western Europe during the pandemic.•Cold-related risks were higher in the pre-pandemic period for northern, eastern and western regions.•Findings reveal regional adaptation differences and stress the need for better heat adaptation.