The mechanism-specific injury mortality burden associated with heatwave in China in a warming world

Numerous studies have investigated the impact of heatwaves on non-accidental mortality, yet the association and burden of heatwaves on mechanism-specific injury mortality remain underexplored. This study collected 257,267 injury-related fatalities and corresponding daily maximum temperatures (DMT) across seven Chinese provinces from 2013 to 2023. A heatwave was characterized by two or more successive days where the DMT surpassed its 92.5th percentile. Employing a case-crossover design, the study revealed a 12 % increase in injury mortality [95 % confidence interval (CI): 10 %, 14 %] during heatwave days compared to non-heatwave days, with a notably higher risk for drowning (ER = 22 %, 95 % CI: 16 %, 30 %). From 2013 to 2023, heatwaves were responsible for 1.64 % (95 % CI: 1.37 %, 1.90 %) of total injury-related fatalities. Additionally, future mortality burdens from 2030 to 2099 were projected, revealing that under the SSP5-8.5 scenario, the attributable fractions (AFs) of injury mortality due to heatwaves is expected to escalate from 2.66 % in the 2030s (95 % CI: 2.02 %, 3.44 %) to 7.72 % (95 % CI: 5.87 %, 9.97 %) in the 2090s, particularly in southwest China. Regarding specific mechanisms of injury, AFs for drowning is projected to rise significantly from 4.60 % (95 % CI: 3.36 %, 5.87 %) in the 2030s to 13.35 % (95 % CI: 9.75 %, 17.02 %) by the 2090s under the SSP5-8.5 scenario. This investigation underscores that heatwaves pose a significant risk for injury-related mortality, offering valuable insights for the development of adaptation strategies to effectively address climate change.