Ambient temperature and injury-related emergency department visits in China and its Provinces: a large national case-crossover study.

Background: Temperature-related risks on non-accidental morbidity or mortality have been well documented. However, limited studies have investigated the injury morbidity risk and burden attributed to ambient temperature.

Objective: The current study aimed to assess the injury morbidity risk and burden attributed to ambient temperature in China.

Methods: A time-stratified case-crossover study was conducted in 31 provincial-level administrations across mainland China, and 11.5 million injury-related emergency department visits recorded in National Injury Surveillance System (NISS) during 2006-2021 were included in the study. An injury case refers to a patient who takes the first visit to the outpatient or emergency department in NISS due to an injury. Daily meteorological data were collected from the fifth generation of European ReAnalysis-Land. A two-stage approach, including a conditional logistic regression and a multilevel meta-analysis, was applied to estimate the temperature-injury association, which were then applied to assess the morbidity burden attributable to temperature.

Results: We observed that injury risk increased 1.2% (95%CI: 1.0%-1.4%) for a 1 °C increase in daily mean temperature with higher risk for males, children aged 0-4, and residents in tropical and subtropical zone. We also found that animal injury, violence and attack, and injury in agricultural area were more susceptible to temperature. Compared to the 2020s, we projected 5.7 times increase of injury cases and 10.4 times of attributable fraction due to temperature change driven by global warming in the 2090s under SSP5-8.5 scenario in China. Our findings might be informative for injury prevention in the context of climate change in China.

Conclusion: Our findings identify susceptible populations, regions and mechanism-specific injuries when exposure to ambient temperature, which could be informative for injury prevention in the context of climate change in China. https://doi.org/10.1289/EHP16878.