Effect of compound exposure to snowstorm and cold spell on acute myocardial infarction mortality

Cold weather events such as cold spell and snowstorm could trigger heart attacks, but the effect of compound exposure to cold weather events remains unknown. This study aimed to estimate and compare the effect of independent and compound exposure to common cold weather events (cold spell and snowstorm) on acute myocardial infarction (AMI) mortality. Daily data on AMI deaths (74,279) and weather conditions were collected in a subtropical-temperate climate transit region of China from 2016 to 2020. We conducted a space-time-stratified case-crossover analysis to fit the association of AMI mortality with cold spell and snowstorm. We observed an increased AMI death risk associated with independent and compound exposure to cold spell or snowstorm. Furthermore, the association of compound exposure to cold spell and snowstorm was greater than the independent exposure but varied by the compound types. A greater risk was observed if the snowstorm and cold spell occurred on the same day [odds ratio (OR): 1.197 (95% confidence interval (CI): 1.153-1.243)] than the scenario that the snowstorm was followed by cold spell [OR: 1.100 (95%CI: 1.079-1.121)] or the cold spell was followed by snowstorm [OR: 1.115 (95%CI: 1.075-1.157)]. This study suggests that compound exposure to cold spell and snowstorm not only has a greater effect on AMI death risk than independent exposure but also differs by the compound types.