Association of transitions in frailty with dementia risk: findings from two longitudinal cohort studies.

Introduction: Previous studies have suggested that frailty is an important risk factor for dementia. Frailty is a dynamic condition that may progress or improve. However, the impact of frailty transitions on dementia risk has not been sufficiently examined. Methods: We analyzed data from two prospective cohorts. Frailty status was assessed using the Frailty Index (FI) and categorized into three groups: robust, pre-frail, and frail. Transitions in frailty status were evaluated based on FI at baseline and at a second assessment. The outcome was dementia, which was ascertained by self-reported physician diagnosis. To adjust for potential confounders, a directed acyclic graph was drawn, and Cox proportional hazards models were used to calculate hazard ratio (HR) and 95% confidence interval (95% CI). Results: Based on the inclusion and exclusion criteria, a total of 8,353 participants were included in the analysis of transitions in frailty status. Compared with stable robust participants, robust participants who progressed to pre-frail or frail had an increased risk of dementia (HR = 1.78, 95% CI: 1.18-2.68, Conclusion: Progression in frailty status was associated with an increased risk of dementia compared with stable robust or stable pre-frail status, whereas recovery from pre-frail or frail status was not associated with a significant reduction in dementia risk.