The impact of blood pressure and its variability on suicide mortality: a nationwide population-based study

The association between blood pressure (BP) and its variability (BPV) with psychological disorders has been established. We aimed to investigate whether this relationship extends to the risk of suicide in a large, nationally representative cohort. This retrospective cohort study included 1,983,107 participants from the Korean National Health Insurance Service database, collected between 2005 and 2009, with 11.1 years of follow-up. BPV was assessed using at least three health examination datasets and validated variability indices (variability independent of the mean [VIM], average successive variability, and coefficient of variation). The primary endpoint was suicide-related death. Cox proportional hazards models were used to estimate hazard ratios (HRs) for suicide across BPV quartiles. Higher BP and BPV were significantly associated with an increased risk of suicide. Participants in the highest quartile (Q4) of systolic BPV (VIM) had an adjusted HR of 1.13 (95% CI: 1.05-1.22) for suicide. Similarly, those in Q4 of diastolic BPV (VIM) had an HR of 1.16 (95% CI: 1.08-1.24). This association was particularly pronounced in older adults (≥65 years), with an HR of 1.18 (95% CI: 1.03-1.36) for systolic BPV and 1.21 (95% CI: 1.05-1.39) for diastolic BPV in Q4. Consistent findings were observed when using different variability indices. Subgroup analyses according to sex, diabetes, depression, hypertension, and use of antihypertensive medications also supported these findings. These findings suggest that both BP and BPV are novel risk factors for suicide mortality. Considering BP and BPV together may enhance the identification of individuals at higher risk of suicide.