The temporal shift of temperature-related injury incidence risk and its driving factors in China: a nationwide case-crossover study from 2006 to 2021.

Abstract

Although several studies have demonstrated an association between ambient temperature and injury, the temporal trend of temperature-related injury risk remains unknown. This study aimed to examine changes in the effect of temperature on injury incidence and to explore its driving factors. A time-stratified case-crossover study including over 11.5 million injury cases from 243 surveillance hospitals in China was conducted, and the injury incidence risks associated with temperature during the periods 2006-2013 and 2014-2021 were compared using conditional logistic regression model combined with distributed lag nonlinear model (DLNM). The socio-economic driving factors of the temporal change from 2006-2013 to 2014-2021 were further explored based on mixed-effects linear model and random forest algorithm. The study encompassed a total of 11,512,467 injury cases from 2006 to 2021. The temperature-injury incidence relationship was linear, exhibiting a steeper slope between 2006 and 2013 compared to 2014 and 2021. The excess risk (ER) for per 1 °C increase in temperature was 1.08% (95% CI: 1.06%, 1.10%) for 2006-2013, which was significantly higher than the 0.83% (95% CI: 0.82%, 0.84%) for 2014-2021, representing a 23.31% (95% CI: 21.53%, 24.95%) decrease. Among 31 provinces, 74.19% experienced a decline in ER, predominantly in coastal regions. The primary factors influencing this temporal shift in temperature-related injury risk were identified as the child dependency ratio, air conditioners ownership per 100 rural households, and the birth rate. Overall, the risk of temperature-related injuries in China has decreased over the past two decades, with demographic and socioeconomic factors playing pivotal roles in this decline. National Natural Science Foundation of China.