Temperature-mortality association during and before the COVID-19 pandemic in Italy: A nationwide time-stratified case-crossover study

Wenhua Yu; Rongbin Xu; Tingting Ye; Chunlei Han; Zhuying Chen; Jiangning Song; Shanshan Li; Yuming Guo

doi:10.1016/j.uclim.2021.100948

Temperature-mortality association during and before the COVID-19 pandemic in Italy: A nationwide time-stratified case-crossover study

Urban Clim. 2021 Sep:39:100948. doi: 10.1016/j.uclim.2021.100948. Epub 2021 Aug 6.

Authors

Wenhua Yu¹, Rongbin Xu¹, Tingting Ye¹, Chunlei Han², Zhuying Chen³, Jiangning Song⁴, Shanshan Li¹, Yuming Guo¹

Affiliations

¹ Climate, Air Quality Research Unit, School of Public Health and Preventive Medicine, Monash University, Level 2, 553 St Kilda Road, Melbourne, VIC 3004, Australia.
² School of Public Health and Management, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, PR China.
³ Department of Biomedical Engineering, The University of Melbourne, 203 Bouverie Street, Melbourne, VIC 3053, Australia.
⁴ Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC 3800, Australia.

Abstract

Objectives: To identify the associations of temperature with non-COVID-19 mortality and all-cause mortality in the pandemic 2020 in comparison with the non-COVID-19 period in Italy.

Methods: The data on 3,189,790 all-cause deaths (including 3,134,137 non-COVID-19 deaths) and meteorological conditions in 107 Italian provinces between February 1st and November 30th in each year of 2015-2020 were collected. We employed a time-stratified case-crossover study design combined with the distributed lag non-linear model to investigate the relationships of temperature with all-cause and non-COVID-19 mortality in the pandemic and non-pandemic periods.

Results: Cold temperature exposure contributed higher risks for both all-cause and non-COVID-19 mortality in the pandemic period in 2020 than in 2015-2019. However, no different change was found for the impacts of heat. The relative risk (RR) of non-COVID-19 deaths and all-cause mortality at extremely cold (2 °C) in comparison with the estimated minimum mortality temperature (19 °C) in 2020 were 1.63 (95% CI: 1.55-1.72) and 1.45 (95%CI: 1.31-1.61) respectively, which were higher than all-cause mortality risk in 2015-2019 with RR of 1.19 (95%CI: 1.17-1.21).

Conclusion: Cold exposure indicated stronger impacts than high temperatures on all-cause and non-COVID-19 mortality in the pandemic year 2020 compared to its counterpart period in 2015-2019 in Italy.

Keywords: All-cause mortality; Italy; Non-COVID-19 mortality; Pandemic; Temperature.