Impaired muscle function, including its decline, is related to greater long‐term late‐life dementia risk in older women

Background Impaired muscle function has been identified as a risk factor for declining cognitive function and cardiovascular health, both of which are risk factors for late‐life dementia (after 80 years of age). We examined whether hand grip strength and timed‐up‐and‐go (TUG) performance, including their change over 5 years, were associated with late‐life dementia events in older women and whether any associations provided independent information to Apolipoprotein E ℇ4 (APOE ℇ4) genotype. Methods Grip strength and TUG were assessed in community‐dwelling older women (mean ± SD; age 75.0 ± 2.6 years) at baseline (n = 1225) and 5 years (n = 1052). Incident 14.5‐year late‐life dementia events (dementia‐related hospitalization/death) were obtained from linked health records. Cardiovascular risk factors (Framingham Risk Score), APOE genotyping, prevalent atherosclerotic vascular disease and cardiovascular‐related medications were evaluated at baseline. These were included in multivariable‐adjusted Cox‐proportional hazards models assessing the relationship between muscle function measures and late‐life‐dementia events. Results Over follow‐up, 207 (16.9%) women had a late‐life dementia event. Compared with women with the highest grip strength (Quartile [Q] 4, 25.8 kg), those with the lowest grip strength (Q1, 16.0 kg) had greater hazard for a late‐life dementia event (HR 2.27 95% CI 1.54–3.35, P