Physical exercise for prevention of dementia study: a 48-month randomized controlled trial

Abstract

Background Although multimodal exercise interventions are recognized for their potential to attenuate age-related cognitive decline, the current literature lacks longitudinal depth. Specifically, robust randomized evidence addressing the long-term efficacy of structured training protocols remains limited. This single-blind RCT involved 882 community-dwelling older adults categorized as healthy, having subjective memory complaints (SMCs), or having mild cognitive impairment (MCI). Methods Participants were randomized to an experimental group (EG), performing 48 months of supervised moderate-to-high-intensity multimodal training (aerobic, resistance, and stretching), or to a control group (CG), maintaining usual habits. The primary outcome was the 48-month change in Mini-Mental State Examination (MMSE) scores. Secondary outcomes were scores on eight neuropsychological tests assessed at 12, 24, 36, and 48 months. A linear mixed-effects model analysis with repeated measures (LMM) was used to evaluate significant differences between the CG and EG. Results In the final analysis of 674 participants, healthy participants (between-group effect: p = 0.008; η2 p = 0.007; time*group interaction: p < 0.001; η2 p = 0.025) in the EG showed significantly higher MMSE scores than those in the CG. SMC participants in the EG also showed higher MMSE scores than those in the CG (between-group effect: p = 0.052; η2 p = 0.004; time*group interaction: p < 0.001; η2p = 0.031), although the between-group difference only approached statistical significance. Similarly, healthy and SMC participants in the EG demonstrated significantly better performance in the secondary outcomes of memory, attention, and reasoning than those in the CG. The sample size of the MCI group was insufficient to allow for conclusive statistical analyses. Conclusion A 48-month multicomponent exercise program significantly improved cognitive performance in healthy and SMC older adults. Structured physical activity may effectively slow cognitive decline. Clinical Trial Registration https://clinicaltrials.gov/study/NCT02236416. Identifier number: NCT02236416.