Association between ankle injury and nonspecific low back pain: a retrospective cohort study using the National Health Insurance Database.

This study investigated the association between ankle injury and the subsequent onset of non-specific low back pain (LBP), and identified the potential contributions of age, sex, body mass index (BMI), and physical activity (PA) to LBP development. This retrospective cohort study used data from the Korean National Health Insurance Sharing Service (2002-2021). Kaplan-Meier analyses estimated cumulative incidence and mean survival time to LBP onset. Cox proportional hazards models were employed to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for LBP onset, adjusting for age, sex, BMI, and PA. LBP occurred in 118,086 of 218,683 individuals (54.0%) with ankle injury and 246,425 of 2,582,974 healthy controls (9.54%). After adjusting for covariates, the ankle-injury group was associated with a higher incidence of LBP than the control group (HR=19.021; 95% CI=18.877-19.167). These findings warrant future biomechanical studies to clarify the mechanisms that associate ankle injury with LBP.