Researchers at Zhengzhou University report evidence that physical frailty is associated with dementia and that genetic background, brain structure, and immunometabolic function may mediate this link.
Dementia causes loss of cognitive abilities and daily functioning, and reached an estimated 57 million cases worldwide in 2021 with projections indicating a rise to 153 million by 2050. Treatments remain limited in effectiveness, creating a need for early identification of risk factors.
Previous studies have noted associations between frailty and elevated risk of incident dementia. Frailty is characterized by decreased physical function and a reduced ability to overcome stressors. Genetic susceptibility might influence the frailty-dementia relationship, and immunometabolic processes and brain structure are implicated, though mechanisms remain unclear.
In the study, “Association of Frailty With Dementia and the Mediating Role of Brain Structure and Immunometabolic Signatures,” published in Neurology, researchers conducted a prospective cohort investigation to elucidate the link between physical frailty and dementia, assess causality, and explore biologic mechanisms.
UK Biobank contributed data from 489,573 participants without dementia at enrollment between 2006 and 2010, with a median follow-up of 13.58 years during which 8,900 dementia cases were documented. Brain MRI was available for a subset.
Physical frailty was defined by five criteria: weight loss, exhaustion, physical inactivity, slow walking speed, and low grip strength. Components were summed to a 0–5 score and categorized as nonfrail, prefrail, or frail. Biomarker panels included peripheral blood cell counts, biochemical measures, and metabolomic markers with correction for multiple testing.
Risk climbed with frailty status, with prefrailty associated with higher hazard versus nonfrailty (HR 1.50, 95% CI 1.44–1.57) and frailty associated with a larger increase (HR 2.82, 95% CI 2.61–3.04). Joint analyses placed the greatest hazards where frailty met genetic susceptibility, including HR 3.87 (95% CI 3.30–4.55) for high polygenic risk with frailty and HR 8.45 (95% CI 7.51–9.51) for APOE-e4 gene carriers with frailty.
Neuroimaging and biomarker findings linked frailty severity with image-derived brain measures and immunometabolic markers. Mendelian randomization supported a potential causal effect of physical frailty on dementia (OR 1.79, 95% CI 1.03–3.12), with reverse analysis reporting a null association (OR 1.00, 95% CI 0.98–1.01).
Authors conclude that the findings support a causal association between physical frailty and dementia, suggesting frailty may serve as a correlative early marker of vulnerability.
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More information:
Xiangying Suo et al, Association of Frailty With Dementia and the Mediating Role of Brain Structure and Immunometabolic Signatures, Neurology (2025). DOI: 10.1212/wnl.0000000000214199
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