[Estimating and projecting the acute effect of cold spells on excess mortality under climate change in Guangzhou]

Objective: To estimate future excess mortality attributable to cold spells in Guangzhou, China. Methods: We collected the mortality data and metrological data from 2009-2013 of Guangzhou to calculated the association between cold spell days and non-accidental mortality with GLM model. Then we projected future daily average temperatures (2020-2039 (2020s) , 2050-2069 (2050s) , 2080-2099 (2080s) ) with 5 GCMs models and 2 RCPs (RCP4.5 and RCP8.5) to identify cold spell days. The baseline period was the 1980s (1980-1999). Finally, calculated the yearly cold spells related excess death of 1980s, 2020s, 2050s, and 2080s with average daily death count of non-cold spell days, exposure-response relationship, and yearly number of cold spell days. Results: The average of daily non-accidental mortality in Guangzhou from 2009 to 2013 was 96, and the average of daily average was 22.0 ℃. Cold spell days were associated with 3.3% (95%CI: 0.4%-6.2%) increase in non-accidental mortality. In 1980s, yearly cold spells related deaths were 34 (95%CI: 4-64). In 2020s, the number will increase by 0-10; in 2050s, the number will increase by 1-9; and in 2080s, will increase by 1-9 under the RCP4.5 scenario. In 2020s, the number will increase by 0-9; in 2050s, the number will increase by 1-6; and in 2080s, will increase by 0-11 under the RCP8.5 scenario. Conclusion: The cold spells related non-accidental deaths in Guangzhou will increase in future under climate change.