Background: Climate Change has drawn widespread attention across the globe, and rapid urbanization in China has made urban areas the hub of major health risks arising from extreme temperatures. This research was designed to investigate the temperature-mortality (TM) relationship in 38 of the largest cities in China at the city, regional, and national scales and presented a discussion of the nonlinear relationship between temperature and group-specific mortality. Method: A distributed lag nonlinear model was built based on daily mortality data, air pollution, and meteorological variables in each chosen city from 2010 to 2013. Then, a meta-analysis was applied to obtain a TM association nationwide and compare how the TM association differed among the varying climatic regions, economic dev...[ Read more ]

Background: Climate Change has drawn widespread attention across the globe, and rapid urbanization in China has made urban areas the hub of major health risks arising from extreme temperatures. This research was designed to investigate the temperature-mortality (TM) relationship in 38 of the largest cities in China at the city, regional, and national scales and presented a discussion of the nonlinear relationship between temperature and group-specific mortality. Method: A distributed lag nonlinear model was built based on daily mortality data, air pollution, and meteorological variables in each chosen city from 2010 to 2013. Then, a meta-analysis was applied to obtain a TM association nationwide and compare how the TM association differed among the varying climatic regions, economic development areas, and subgroups at various levels. Results: At the city level, even though TM relationships varied in different cities, certain acclimatization tendencies were observed. At the regional level, the largest cold effect was found in the middle and south subtropical zones (relative risk, RR, 1.82; 95% confidence interval, CI, 1.43-2.31) and the highest heat RR value highlighted the north subtropics (RR, 1.75; 95% CI, 1.20-2.55). Regions with local annual mean temperatures between 16 and 20°C had the highest mortality risk at extreme temperatures. Moreover, lower socioeconomic conditions showed a significant association with a higher risk of mortality at extreme temperatures, with a cold effect of RR at 1.84 (95% CI, 1.51-2.24) and a heat effect at 1.33 (95% CI, 1.09-1.62). At the national level, the extremely low temperature had a greater effect on mortality, with RR at 1.44 (95% CI, 1.30-1.53), and an increase of RR at 1.83% (95% CI, 1.78-1.87%) for a 1°C temperature reduction below the minimum-mortality temperature. Women and the elderly were more sensitive to extreme temperatures, with deaths from the cardiorespiratory disease are more likely to be affected by climate extremes. Conclusions: The risk of extreme temperatures on public health should be emphasized in China, especially cold effects in southern low-GDP cities. More adaptive guidance for vulnerable subgroups and regional-specific protective plans should be supported to ensure equitable health outcomes and to decrease the overall impacts of climate change on public health.