The exceptional heatwaves of 2017 and all-cause mortality: An assessment of nationwide health and economic impacts in China

Heatwaves with unprecedented conditions have devastating health impacts. The summer of 2017 saw unusual heat in China and other regions on earth. Although epidemiologic evidence is clear for elevated mortality risks of heatwaves, the economic impacts due to heatwave-associated mortality remain poorly characterized. Hence, this study systematically assessed the mortality and economic impacts of the 2017 exceptional heatwaves in China. We first used the generalized linear mixed-effect model with Poisson distribution to examine the mortality risks of the 2017 heatwaves in 91 Chinese counties. Further, we calculated the excess deaths attributable to heatwaves in 2852 counties. Finally, we evaluated the city- and province-level death-related economic burden of the 2017 heatwaves based on the value of statistical life (VSL). We found that the 2017 exceptional heatwaves had a statistically significant association (relative risk was 1.23, 95% confidence interval 1.14-1.32) with all-cause mortality across 91 Chinese counties. Nationwide, a total of 16,299 all-cause deaths that occurred in 2017 were attributable to the exceptional heatwaves, resulting in an overall death-related economic loss of 61,304 million RMB as valued by VSL. Given that extraordinary heatwaves are projected to be more frequent under global climate change, our findings could enhance the current understanding of heatwaves' health and economic impacts and add valuable insights in projection studies of estimating the future health burden of heatwaves.