Observational study links frailty index and neuroimaging markers to dementia risk in UK Biobank cohort

This observational study analyzed 63,509 dementia-free participants from the UK Biobank (mean age 65.0 ± 7.7 years) to develop a cerebral frailty risk score (CFRS) integrating a frailty index (FI) and neuroimaging markers for dementia prediction. The study found that a higher FI was associated with reduced hippocampal volume, decreased cortical thickness, greater white matter hyperintensities burden, and impaired brain diffusion metrics. Furthermore, FI and neuroimaging markers additively increased the risks of incident dementia and mortality, though specific effect sizes and absolute numbers were not reported.

For dementia risk prediction, an extreme gradient boosting model with an accelerated failure time framework, which highlighted FI and key regional neuroimaging features, achieved a nested C-index of 0.825 and an integrated area under the curve (iAUC) of 0.759. The final derived CFRS demonstrated strong performance, with an optimism-corrected C-index of 0.838 and an iAUC of 0.778 for predicting dementia onset.

Safety and tolerability data were not reported. Key limitations include the observational design, which precludes causal inference, and the lack of reported effect sizes, confidence intervals, and follow-up duration for the primary associations. Funding and conflicts of interest were also not reported. The findings suggest a potential utility for a CFRS framework in dementia risk stratification, but its clinical application remains speculative and requires validation in independent cohorts and interventional studies.