Association between long-term healthy aging trajectories and all-cause mortality among middle-aged and older adults.

BACKGROUND: Healthy aging is associated with lower mortality and better quality of life. This observational study examines how different healthy aging trajectories relate to all-cause mortality in middle-aged and older adults and seeks to identify subgroups at elevated risk based on individual characteristics. METHODS: We used data from the Korean Longitudinal Study of Aging (KLoSA) collected between 2006 and 2020. The analytic sample comprised 4,168 adults aged 45 years and older. Healthy aging trajectories were derived from 2006 to 2014 using group-based trajectory modeling (GBTM) applied to a composite score (range 0-5) constructed from five binary domains: presence of chronic disease(s), limitations in activities of daily living (ADL), depressive symptoms, cognitive impairment (MMSE-K), and lack of social participation. Four trajectory groups were identified: sustained healthy aging, mild unhealthy aging, moderate unhealthy aging, and severe unhealthy aging. Associations between trajectory group and all-cause mortality during the 2014-2020 follow-up were estimated using Cox proportional hazards models; subgroup analyses were performed by gender and by age group. RESULTS: Compared with the sustained healthy aging group, the moderate unhealthy aging group had higher all-cause mortality (HR = 1.946; 95% CI, 1.282-2.954; p = 0.002), and the severe unhealthy aging group also had higher mortality (HR = 2.222; 95% CI, 1.353-3.648; p = 0.002). Kaplan-Meier curves showed significant differences in survival across trajectory groups (log-rank p < 0.001). In subgroup analyses, females in the moderate (HR = 4.793; 95% CI, 1.833-12.534; p = 0.001) and severe (HR = 7.109; 95% CI, 2.592-19.498; p = 0.001) unhealthy aging groups had markedly higher mortality risk. Participants aged 45-64 years in the mild (HR = 2.493; 95% CI, 1.121-5.547; p = 0.025) and moderate (HR = 2.578; 95% CI, 1.092-6.082; p = 0.031) unhealthy aging groups also showed higher risk. CONCLUSION: Moderate and severe unhealthy aging trajectories were associated with higher all-cause mortality among middle-aged and older adults, particularly among females and adults aged 45-64 years. These findings underscore the need for tailored health management and support policies that account for gender and age differences.