A NEW study, analysing data from 29,849 participants across four large cohort studies in the United States and the United Kingdom, found significant increases in frailty occurring four to nine years before the onset of dementia, suggesting it as a potential marker for identifying dementia risk. Frailty, a measure of biological ageing and overall health, may thus play a critical role in early identification of dementia risk, which could improve the effectiveness of preventative strategies. The data were drawn from diverse cohorts, including the English Longitudinal Study of Ageing, the Health and Retirement Study, the Rush Memory and Aging Project, and the National Alzheimer Coordinating Center, involving individuals aged 60 and older who did not have cognitive impairment at the outset of the study.
To investigate the relationship between frailty and dementia, the study retrospectively calculated frailty index scores for participants and tracked dementia diagnoses over time, with follow-up spanning 257,963 person-years and resulting in 3,154 incident cases of dementia. Bayesian generalised linear mixed regression models were used to assess changes in frailty levels relative to dementia onset. Results indicated a statistically significant increase in frailty in the four to nine years preceding dementia onset, with adjusted hazard ratios (aHRs) for dementia risk linked to frailty ranging from 1.18 (95% CI, 1.13-1.24) to 1.73 (95% CI, 1.57-1.92). Notably, even among individuals whose initial frailty measurements predated this four- to nine-year period of acceleration, frailty remained positively associated with higher dementia risk, with aHRs from 1.18 (95% CI, 1.12-1.23) to 1.43 (95% CI, 1.14-1.80).
These findings underscore the potential of frailty as a clinical marker for dementia risk, which could help in selecting high-risk individuals for preventative interventions and clinical trials. In clinical practice, routine frailty assessments could facilitate early identification of those at higher risk for dementia, potentially enabling more targeted behavioural or pharmacological interventions. Future research should explore specific frailty-reduction strategies and assess their effectiveness in delaying or preventing dementia, ultimately providing a cost-effective and accessible tool for enhancing dementia prevention and population health strategies.
Reference
Ward DD et al. Frailty trajectories preceding dementia in the US and UK. JAMA Neurol. 2024;DOI:10.1001/jamaneurol.2024.3774.
