To analyze the association between frailty burden, frailty change, and incident stroke across diverse aging cohorts, while exploring the role of depressive symptoms.
Approach:
Cohorts: Data from five population-based aging cohorts were harmonized: HRS, CHARLS, SHARE, ELSA, and MHAS.
Measurement: Frailty was assessed using a 24-item deficit-accumulation frailty index (FI).
Statistical Analysis: Cohort-specific Cox proportional hazards models estimated associations between baseline FI and incident stroke.
Exploratory Analyses: Secondary analyses evaluated nonlinearity, FI change, depressive symptoms as a pathway marker, and two-wave cross-lagged associations.
Key Findings:
Each 0.1-unit increase in FI was associated with higher stroke risk in HRS, CHARLS, SHARE, and MHAS, but not in ELSA.
Substantial heterogeneity was observed across cohorts.
Fine-Gray sensitivity analyses supported positive frailty-stroke associations across all cohorts.
Nonlinear associations for baseline FI and FI change were suggested by restricted cubic spline analyses.
Depressive symptoms accounted for part of the frailty-stroke associations, with variations by cohort.
Interpretation:
Higher frailty burden was associated with incident stroke in most cohorts, indicating the need for cohort-specific interpretations.
Limitations:
The study was observational and not preregistered, making secondary analyses exploratory.
Cohort-specific estimates may limit generalizability.
Conclusion:
The findings support the need for repeated frailty assessments and integrated mood evaluations in older adults.
