Impact of apparent temperature on specific cardiovascular disease admissions: a time-series study and association modification in Xiangyang, China

The effects of temperature variations on different types of cardiovascular disease (CVD) and the moderating roles of sociodemographic factors such as age, gender, and residential area remain poorly understood. Using a retrospective time-series design, this study analyzed hospital admission records from 2018 to 2022, including 70,108 CVD patients in Xiangyang city, China. Distributed lag non-linear models (DLNM) were applied to examine the association of apparent temperature (AT) with hospital admissions for specific CVD types. Gender, age, and residential location were considered as potential moderators, with adjustments for confounders like air pollution and seasonal variations. Temperature extremes significantly influence CVD admissions. Hot effect were associated with a 16.80% increase in ischemic heart disease (IHD) admissions, while other CVD types showed minimal change. Cold effect had more pronounced and sustained effects, with a 15.52% increase in overall CVD admissions and significant rises in hypertensive diseases (27.16%), pulmonary heart disease (177.45%), and IHD (16.77%). Gender, age, and rural residence significantly modified the temperature-CVD relationship, with women, the elderly, and rural residents at heightened risk during extreme temperatures. This study demonstrates a significant association between temperature extremes and CVD admissions, with high temperatures notably increasing the risk of IHD, particularly among women. Cold temperatures exert a more prolonged effect, leading to higher rates of IHD, hypertensive diseases, and pulmonary heart disease. Vulnerable groups, including the elderly, women, and rural residents, are most affected. These findings underscore the necessity for targeted public health strategies to mitigate the health impacts of extreme temperatures on these at-risk populations.