The association of cumulative frailty with subsequent cognitive decline, dementia incidence, and all-cause mortality: a longitudinal cohort study.

BACKGROUND: Frailty is dynamic, but associations of cumulative frailty with later cognition, dementia, and death remain unclear. METHODS: We analysed Waves 4-8 of the Survey of Health, Ageing and Retirement in Europe. Cumulative frailty was the area under the curve of five-component frailty scores across Waves 4-6. Cognitive change (Waves 7-8), incident dementia, and all-cause mortality were examined using adjusted linear mixed-effects and Cox models. RESULTS: Cognitive, dementia, and mortality analyses included 11,846, 12,108, and 22,696 participants, respectively. Per 1-SD higher cumulative frailty, annual declines were faster in immediate memory (β = -0.009 SD/year; 95% CI -0.013 to -0.004), delayed memory (-0.005; -0.009 to -0.001), and global cognition (-0.007; -0.010 to -0.003). Versus robust participants, frail participants had higher risks of dementia (HR 5.307; 95% CI 3.504-8.036) and mortality (HR 2.922; 2.437-3.504); dementia associations persisted in competing-risk analysis. Nonlinear associations were observed for global cognition, dementia, and mortality. CONCLUSION: Greater cumulative frailty was associated with faster cognitive decline and higher dementia and mortality risks, supporting repeated frailty assessment to identify vulnerable older adults.