👤 Lachlan Cribb

Functional decline may be an early indicator of dementia. This study examined the trajectories of frailty, grip strength, and gait speed over the 11 years prior to dementia, compared to matched individuals without dementia. A total of 1092 dementia cases were matched on age, sex and education to 4368 controls from a cohort of community-dwelling older adults recruited in Australia and the USA, aged 65 years or above at recruitment. Frailty was characterised by a deficit-accumulation index involving 67 items. Hand grip strength and gait speed were measured regularly by physical examination. Linear mixed-effects models estimated the backward trajectories of frailty, grip strength and gait speed before dementia, compared to controls. Secondary analyses were stratified by sex and ApoE ε4 carrier status. Higher frailty burden, with a steeper increase over time, was found in the years before dementia, compared to controls (P-interaction < .001). Hand grip strength and gait speed declined more rapidly in dementia cases than in controls (P-interaction < .001 for both). Differences between cases and controls became consistently significant four to six years prior to dementia (P-contrast < .001). An earlier divergence across all three measures was observed for females, and to a lesser extent in ApoE ε4 non-carriers. Functional decline occurs within the decade before dementia onset, with gait speed being the earliest indicator. These findings support the utility of functional measures as early markers of dementia risk, with potential implications for targeted monitoring and preventative strategies. Show less

Promising evidence indicates that treating hearing loss with hearing aids (HAs) could reduce dementia risk. We extend this evidence by investigating the effect of HAs on plasma biomarkers of Alzheimer's disease and related dementias (ADRD). We emulated two target trials using observational data from Australian participants of the ASPREE study. Eligible participants had self-reported hearing problems, no past HA use, and were dementia-free. HA prescriptions and frequency of HA use were measured by questionnaire. Phosphorylated-tau181 (pTau181), neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), and amyloid-β (Aβ) 42/40 were measured after approximately 6-8 years. We estimated the effect of new HA prescription (first target trial) and the frequency of HA use (second target trial) using targeted maximum likelihood estimation, with multiple imputation for missing data. Across imputed datasets, a median of 2842 eligible individuals were included (mean age 75 years, 48% female), with a median of 735 receiving a new HA prescription. Among survivors, the estimated mean differences comparing HA prescription and no HA prescription were 1.8 pg/mL (95% CI: -0.6, 4.1), 0.1 pg/mL (-7.8, 8.0), -2.2 pg/mL (-14.5, 10.1), and -0.7 (-2.6, 1.2) for the concentrations of pTau181, NfL, GFAP, and (Aβ42 × 1000)/Aβ40, respectively. Mean differences did not differ substantially across levels of potential baseline effect modifiers, including APOE-ε4 genotype and cognition. In community-dwelling older people with hearing loss and no dementia, we found minimal effects of HA prescription and frequency of HA use on plasma ADRD biomarkers after a 7-year follow-up. Show less