Pre-Dementia Stages and Incident Dementia in the NuAge Study

Background: Motoric cognitive risk syndrome (MCR) and mild cognitive impairment (MCI) are two pre-dementia stages with an overlap, which may influence the risk for dementia.

Objective: The study aims to examine the association of MCR, MCI, and their combination with incident dementia in Quebec community-dwelling older adults.

Methods: 1,063 older adults (i.e., ≥65) were selected from a population-based observational cohort study known as the "Nutrition as a determinant of successful aging: The Quebec longitudinal study" (NuAge). Participants were separated into four groups at the baseline assessment: those without MCR and MCI (i.e., cognitively healthy individual; CHI), those with MCR alone, those with MCI alone, and those with MCR plus MCI. Incident dementia was recorded at each annual visit during a 3-year follow-up.

Results: The prevalence of CHI was 87.2%, MCR 3.0%, MCI 8.8%, and MCR plus MCI 0.9%. The overall incidence of dementia was 2.4% and was significantly associated with MCR alone (Odd Ratio (OR) = 5.00 with 95% Confidence interval (CI) = [1.01;24.59] and p = 0.049), MCI alone (OR = 6.04 with 95% CI = [2.36;15.47] and p≤0.001), and the combination of MCR and MCI (OR = 25.75 with 95% CI = [5.32;124.66] and p≤0.001).

Conclusion: Combining MCR and MCI increased the risk for incident dementia. These results also demonstrated that this combination is a better predictor of dementia than MCI or MCR alone.