History of suicidality and mortality risk: A nationwide cohort study

Suicidality is associated with suicide-related and other mortality. However, long-term studies examining this relationship in the general population remain limited. This study evaluated the relationship between history of suicidality and suicide, external, and intrinsic mortality in the Korean adult population.

This cohort study linked Korea National Health and Nutrition Examination Survey (KNHANES, 2007-2018) data with national cause-of-death records (2007-2022). We analyzed 62,631 adults (≥19 years) followed for a mean of 9.5 years (597,807.5 person-years). Exposure was suicidality (history of suicidality including, suicide ideation, plans, or attempts). Outcomes were suicide, external causes, and intrinsic mortality, analyzed using Kaplan-Meier curves and multivariable Cox regression.

Of 62,631 participants, 6733 (10.8 %) reported suicidality. Suicidality was linked to increased risks of suicide mortality (HR, 2.8; 95 % CI, 2.0-4.1), external causes mortality (HR, 1.8; 95 % CI, 1.3-2.6), and intrinsic mortality (HR, 1.3; 95 % CI, 1.2-1.4) during the follow-up period. Suicidal plans or attempts showed stronger risks for suicide (HR, 4.3; 95 % CI, 2.1-8.6) and external causes mortality (HR, 3.0; 95 % CI, 1.4-6.1) than ideation alone. Post-2013, with the revised question "seriously considered suicide, " the suicide mortality risk ratio rose from 2.1 (95 % CI, 1.3-3.2) to 4.6 (95 % CI, 1.7-12.0), indicating improved predictive validity.

Suicidality is associated with increased risks of suicide, external causes, and intrinsic mortality. Individuals positively responding to suicide questions in national surveys face elevated suicide mortality risk, necessitating national policy support for appropriate prevention interventions.