Temperature variability and mortality in rural and urban areas in Zhejiang province, China: An application of a spatiotemporal index

Kejia Hu; Yuming Guo; Xuchao Yang; Jieming Zhong; Fangrong Fei; Feng Chen; Qi Zhao; Yunquan Zhang; Gongbo Chen; Qian Chen; Tingting Ye; Shanshan Li; Jiaguo Qi

doi:10.1016/j.scitotenv.2018.08.095

Temperature variability and mortality in rural and urban areas in Zhejiang province, China: An application of a spatiotemporal index

Sci Total Environ. 2019 Jan 10:647:1044-1051. doi: 10.1016/j.scitotenv.2018.08.095. Epub 2018 Aug 7.

Authors

Kejia Hu¹, Yuming Guo², Xuchao Yang³, Jieming Zhong⁴, Fangrong Fei⁴, Feng Chen⁵, Qi Zhao², Yunquan Zhang⁶, Gongbo Chen², Qian Chen⁷, Tingting Ye⁷, Shanshan Li², Jiaguo Qi⁸

Affiliations

¹ Institute of Island and Coastal Ecosystems, Ocean College, Zhejiang University, Zhoushan 316021, China; Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne 3004, Australia.
² Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne 3004, Australia.
³ Institute of Island and Coastal Ecosystems, Ocean College, Zhejiang University, Zhoushan 316021, China; Center for Global Change and Earth Observations, Michigan State University, East Lansing 48823, USA. Electronic address: yangxuchao@zju.edu.cn.
⁴ Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China.
⁵ Zhejiang Institute of Meteorological Sciences, Hangzhou 310008, China.
⁶ Department of Epidemiology and Biostatistics, School of Health Sciences, Wuhan University, Wuhan 430071, China.
⁷ Institute of Island and Coastal Ecosystems, Ocean College, Zhejiang University, Zhoushan 316021, China.
⁸ Center for Global Change and Earth Observations, Michigan State University, East Lansing 48823, USA.

PMID: 30180312
DOI: 10.1016/j.scitotenv.2018.08.095

Abstract

Background: Temperature variability (TV) is a potential trigger for death in urban areas, but there is little evidence of this in rural areas. In addition, a typical TV index only considers the temporal variability of temperature and ignores its spatial variability, which should be considered due to the effects of human mobility. Here this study aimed to 1) develop a novel spatiotemporal TV index accounting for human mobility; and 2) based on this index, explore the urban-rural differences in TV-mortality associations in China.

Methods: We collected daily data on fine-gridded hourly temperatures and >2 million deaths that occurred in Zhejiang province, China from 2009 to 2015. A spatiotemporal TV index was developed by calculating the standard deviation of the hourly temperatures from multi-site records over the course of several exposure days. A three-stage analysis was performed to estimate the mortality risks and mortality burdens of TV. Stratified analyses were performed by cause-specific mortality, urban/rural district, age and gender.

Results: Significant associations were found between TV and all types of targeted diseases, age groups, and genders. Percentage increase in mortality associated with a 1 °C increase in TV at 0-7 exposure days were found to be higher for rural dwellers than urban dwellers in the warm season [for all-cause mortality, 2.07% (95% CI: 1.49%, 2.64%) vs. 1.16% (95%CI: 0.70%, 1.62%)]. An estimated all-cause mortality fraction of 5.33% was attributable to TV, with 4.99% in urban areas and 6.02% in rural areas. The elderly (aged 65+ years) and females were more sensitive to TV than young people and males, respectively.

Conclusions: A spatiotemporal TV index was developed, considering both the temporal and spatial variability of temperatures. TV is an independent health risk factor. In China, rural areas generally suffer greater TV-related mortality risks than urban areas in the warm season. Our findings have important implications for developing area-, cause-, and group-specific adaptation strategies and emergency planning to reduce TV-related mortality.

Keywords: China; Hourly; Mortality; Mortality burden; Temperature change; Temperature variability.

MeSH terms

Adolescent
Aged
China / epidemiology
Environmental Exposure / statistics & numerical data*
Female
Humans
Male
Mortality / trends
Risk Factors
Rural Population
Seasons
Temperature
Urban Population