[Study on the association between heatwaves and fall-related mortality risk in seven provinces of China]

Objective: To evaluate the association between heatwaves and fall-related mortality. Methods: A total of 61 421 fall-related mortality from 2013 to 2022 in 7 provinces of China were included in a time-stratified case-crossover design, with daily meteorological data derived from the fifth generation European Reanalysis dataset produced by the European Centre for Medium-Range Weather Forecasts. Conditional logistic regression chimeric distributed lag nonlinear model was used to analyze the association between heatwaves and fall-related mortality and stratified analysis was conducted according to gender and age. Results: Heatwaves were associated with an increased risk of fall-related morality. The risk of fall-related mortality during heatwaves was higher than during non-heatwave periods (OR=1.11, 95%CI: 1.05-1.18). The attributable fraction of fall-related motality due to heatwaves was 10.25% (95%CI: 4.49%-15.36%). For each 1 ℃ increase above the heatwave threshold, the risk of fall-related mortality increased by 34% (OR=1.34, 95%CI: 1.02-1.76). The effect of heatwave duration on fall-related mortality was not statistically significant. Stratified analyses indicated that women experienced a higher risk of fall-related mortality during heatwaves (OR=1.13, 95%CI: 1.04-1.22) compared to man (OR=1.10, 95%CI: 1.04-1.17). Conclusions: Heatwave increases the risk of fall-related mortality, and the intensity of heatwaves modify this risk. Women are vulnerable populations.