Old-age poverty, basic pension policy periods, and late-life suicide in South Korea: a descriptive ecological analysis, 2012–2024

South Korea has exceptionally high old-age poverty and late-life suicide rates. Both declined during a period spanning the 2014 introduction of the Basic Pension and subsequent benefit changes. We described their national trajectories from 2012 to 2024 and compared late-life suicide rates across policy periods without attempting to identify causal reform effects. National cause-of-death data and official registered-resident mid-year population denominators were organised as a balanced ecological panel of 12 sex-by-age groups observed over 13 years (156 group-year observations). Year-level predictors were the national old-age relative poverty rate and indicators for 2015, 2019, and 2021 onward. Analyses included population-weighted national regressions, equal-weighted group fixed-effects models, Poisson interaction models with population offsets, and sensitivity analyses using wild cluster bootstrap inference, alternative clustering, and exclusion of the 2020–2022 pandemic period. Between 2012 and 2024, the population-weighted late-life suicide rate declined by 45.7%, from 69.85 to 37.92 per 100,000, while the old-age poverty rate declined by 9.3% points, from 45.2% to 35.9%. In national annual models, a 1-percentage-point higher poverty rate was associated with 2.85 more suicides per 100,000 (95% CI 2.06 to 3.63). However, poverty was strongly collinear with calendar time, and the association was attenuated to near zero after inclusion of a linear time trend (− 0.13, 95% CI − 1.11 to 0.85). Evidence of differential proportional change across age groups was not robust across multiplicative-scale model specifications. Late-life suicide and old-age poverty declined substantially and concurrently in South Korea between 2012 and 2024. This encouraging population-level pattern warrants further investigation, although strong collinearity with calendar time, overlapping policy periods, and the ecological design precluded attribution of the suicide decline to poverty reduction or specific Basic Pension changes.