Short-term association between hot nights and mortality: a multicountry analysis in 178 locations considering hourly ambient temperature
Author(s)
Francesco Sera
Aurelio Tobı́as
Masahiro Hashizume
Yasushi Honda
Ho Kim
Ana Maria Vicedo-Cabrera
Shilu Tong
Éric Lavigne
Jan Kyselý
Mathilde Pascal
Francesca de’Donato
Susana das Neves Pereira da Silva
Joana Madureira
Veronika Huber
Aleš Urban
Joel Schwartz
Michelle L. Bell
Ben Armstrong
Carmen Íñiguez
Rosana Abrutzky
Micheline de Sousa Zanotti Stagliorio Coêlho
Paulo Hilario Nascimento Saldiva
Patricia Matus Correa
Nicolás Valdés Ortega
Haidong Kan
Samuel Osorio
Antonio Gasparrini
Souzana Achilleos
Hans Orru
Ene Indermitte
Niilo Ryti
Alexandra Schneider
Klea Katsouyanni
Antonis Analitis
Fatemeh Mayvaneh
Alireza Enteyari
Raanan Raz
Paola Michelozzi
Yoonhee Kim
Barrak Alahmad
John Paul Cauchi
Magali Hurtado‐Díaz
Eunice Elizabeth Félix Arellano
Ala Overcenco
Jochem O. Klompmaker
Gabriel Carrasco
Xerxes Seposo
Paul Lester Chua
Iulian‐Horia Holobâcă
Yuming Guo
Jouni J. K. Jaakkola
Noah Scovronick
Fiorella Acquaotta
Whanhee Lee
Bertil Forsberg
Martina S. Ragettli
Shanshan Li
Antonella Zanobetti
Valentina Colistro
Trần Ngọc Đăng
Do Van Dung
Date Issued
22 de agosto de 2025
Type
Article
Volume
203
Start Page
109719
End Page
109719
Abstract
BACKGROUND: The rise in hot nights over recent decades and projections of further increases due to climate change underscores the critical need to understand their impact. This knowledge is essential for shaping public health strategies and guiding adaptation efforts. Despite their significance, research on the implications of hot nights remains limited. OBJECTIVE: This study estimated the association between hot-night excess (the sum of excess heat during the nighttime above a threshold) and duration (the percent of nighttime with a positive excess) based on hourly ambient temperatures and daily mortality in the warm season over multiple locations worldwide. METHODS: We fitted time series regression models to mortality in 178 locations across 44 countries using a distributed lag non-linear model over lags of 0-3 days, controlling for daily maximum temperature and daily mean absolute humidity. Next, we used a multivariate meta-regression model to pool results and estimated attributable burdens. RESULTS: We found a positive, increasing mortality risk with hot-night excess and duration. Assuming 0 as a reference, the pooled relative risks of death associated with extreme excess and duration, defined as the 90th percentile in each index, were both similar at 1.026 (95 % CI, 1.017; 1.036) and 1.026 (95 % CI, 1.013; 1.040). The overall estimated attributable fractions were also observed to be closely similar at 0.60 % (95 % CI, 0.09; 1.10 %) and 0.62 % (95 % CI, 0.00; 1.23 %), respectively. DISCUSSION: This study provides new evidence that hot nights have a specific contribution to heat-related mortality risk. Modeling thermal characteristics' sub-hourly impact on mortality during the night could improve decision-making for long-term adaptions and preventive public health strategies.
Subjects