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Seasonality of mortality under a changing climate: a time-series analysis of mortality in Japan between 1972 and 2015.

Authors :
Madaniyazi L
Chung Y
Kim Y
Tobias A
Ng CFS
Seposo X
Guo Y
Honda Y
Gasparrini A
Armstrong B
Hashizume M
Source :
Environmental health and preventive medicine [Environ Health Prev Med] 2021 Jul 03; Vol. 26 (1), pp. 69. Date of Electronic Publication: 2021 Jul 03.
Publication Year :
2021

Abstract

Background: Ambient temperature may contribute to seasonality of mortality; in particular, a warming climate is likely to influence the seasonality of mortality. However, few studies have investigated seasonality of mortality under a warming climate.<br />Methods: Daily mean temperature, daily counts for all-cause, circulatory, and respiratory mortality, and annual data on prefecture-specific characteristics were collected for 47 prefectures in Japan between 1972 and 2015. A quasi-Poisson regression model was used to assess the seasonal variation of mortality with a focus on its amplitude, which was quantified as the ratio of mortality estimates between the peak and trough days (peak-to-trough ratio (PTR)). We quantified the contribution of temperature to seasonality by comparing PTR before and after temperature adjustment. Associations between annual mean temperature and annual estimates of the temperature-unadjusted PTR were examined using multilevel multivariate meta-regression models controlling for prefecture-specific characteristics.<br />Results: The temperature-unadjusted PTRs for all-cause, circulatory, and respiratory mortality were 1.28 (95% confidence interval (CI): 1.27-1.30), 1.53 (95% CI: 1.50-1.55), and 1.46 (95% CI: 1.44-1.48), respectively; adjusting for temperature reduced these PTRs to 1.08 (95% CI: 1.08-1.10), 1.10 (95% CI: 1.08-1.11), and 1.35 (95% CI: 1.32-1.39), respectively. During the period of rising temperature (1.3 °C on average), decreases in the temperature-unadjusted PTRs were observed for all mortality causes except circulatory mortality. For each 1 °C increase in annual mean temperature, the temperature-unadjusted PTR for all-cause, circulatory, and respiratory mortality decreased by 0.98% (95% CI: 0.54-1.42), 1.39% (95% CI: 0.82-1.97), and 0.13% (95% CI: - 1.24 to 1.48), respectively.<br />Conclusion: Seasonality of mortality is driven partly by temperature, and its amplitude may be decreasing under a warming climate.

Details

Language :
English
ISSN :
1347-4715
Volume :
26
Issue :
1
Database :
MEDLINE
Journal :
Environmental health and preventive medicine
Publication Type :
Academic Journal
Accession number :
34217207
Full Text :
https://doi.org/10.1186/s12199-021-00992-8