Motoric cognitive risk syndrome and incident dementia in older adults from the Québec NuAge cohort

Background: The co-occurrence of slow walking speed and subjective cognitive complaint (SCC) in non-demented individuals defines motoric cognitive risk syndrome (MCR), which is a pre-dementia stage. There is no information on the association between MCR and incident dementia in Québec's older population.

Objective: The study aims to examine the association of MCR and its individual components (i.e. SCC and slow walking speed) with incident dementia in community-dwelling older adults living in the province of Québec (Canada).

Design: Québec older people population-based observational cohort study with 3 years of follow-up.

Setting: Community dwellings.

Subjects: A subset of participants (n = 1,098) in 'Nutrition as a determinant of successful aging: The Québec longitudinal study' (NuAge).

Methods: At baseline, participants with MCR were identified. Incident dementia was measured at annual follow-up visits using the Modified Mini-Mental State (≤79/100) test and Instrumental Activity Daily Living scale (≤6/8) score values.

Results: The prevalence of MCR was 4.2% at baseline and the overall incidence of dementia was 3.6%. MCR (Hazard Ratio (HR) = 5.18, with 95% confidence interval (CI) = [2.43-11.03] and P ≤ 0.001) and SCC alone (HR = 2.54, with 95% CI = [1.33-4.85] and P = 0.005) were associated with incident dementia, but slow walking speed was not (HR = 0.81, with 95%CI = [0.25-2.63] and P = 0.736).

Conclusions: MCR and SCC are associated with incident dementia in NuAge study participants.