Association between ambient temperature and the risk of hospital admission for injury in South Korea.

Background: Extreme temperatures affect health, but nationwide evidence on injury-related hospitalization and economic burden in East Asia is scarce. We aimed to quantify the nonlinear and lagged associations between ambient temperature and injury-related hospitalization and the attributable economic burden. Methods: This nationwide time-stratified case-crossover study used the National Health Insurance Service-National Sample Cohort (2010-2019) of adults (≥20 years). The exposure was the district-specific percentile of daily mean temperature, and the outcome was inpatient hospital admission for injury. Conditional logistic regression with distributed lag nonlinear models (7-day lag, 3 degrees of freedom) was used to estimate relative risks (RRs) and 95% confidence intervals (CIs) at the 1st and 99th percentiles, each relative to the minimum injury temperature, adjusting for holidays, particulate matter concentrations (lag 0-1), and humidity. Analyses were stratified by age, sex, economic activity, residential area, and injury type. Societal economic burden was estimated using a human capital-based cost-of-illness approach. Results: On analyzing 198,937 hospitalizations, a distinct Conclusions: Nonoptimal temperatures increase injury risk and economic burdens while exacerbating inequalities. Integrating economic evaluations and targeted interventions into climate adaptation strategies is thus essential.