Abstract des Autors

Background: Physical and cognitive activities are associated with decreased risk of mild cognitive impairment and dementia. However, the longitudinal associations between physical and cognitive activities with trajectories of Alzheimer’s disease (AD) neuroimaging biomarkers among older adults free of dementia remain unclear. Method: We conducted a longitudinal study derived from the population-based Mayo Clinic Study of Aging, including individuals aged ≥ 50 years who were free of dementia. Participants had information on physical and cognitive activity engagement in midlife (ages 30-45 for participants aged 50-69; ages 50-65 for participants aged ≥ 70) and late-life (12 months prior to baseline assessment), and AD biomarker assessments. We calculated linear mixed-effect models to examine the association between baseline physical and cognitive activity composite scores for mid- and late-life, and trajectories for individual yearly change in amyloid deposition (measured by PiB-PET), tau burden (measured by Tau-PET), regional glucose hypometabolism (measured by FDG-PET), cortical thickness (measured by MRI), and white matter hyper intensities (WMH, measured by FLAIR-MRI). The models were adjusted for age, sex, and APOE ɛ4 carrier status. Result: The sample included 2755 persons (52% males; 2462 cognitively unimpaired, 293 with MCI). The mean [SD] age was 72.7 [9.8] years; 774 participants were APOE ɛ4 carriers. Although, overall, participants showed an increase in amyloid deposition, tau burden, WMH, and a decrease in glucose metabolism and cortical thickness over time, those with higher late-life physical activity experienced less pronounced increase in Tau-PET SUVR over time [estimate for late-life physical activity with time interaction: -0.002; 95% CI -0.004, -0.000; p = 0.034]. In addition, participants with higher cognitive activities in midlife [est. for midlife cognitive activity with time interaction: 0.001; 95% CI 0.000, 0.003; p = 0.026] and late-life [est. for late-life cognitive activity with time interaction 0.002; 95% CI 0.001, 0.003; p = 0.005] had less pronounced decrease in FDG-PET SUVR over time. There were no further significant interactions. Conclusion: Preliminary findings suggest significant associations between 1) late-life physical activity and less tauopathy, and 2) cognitive activities in mid- and late-life with less synaptic dysfunction over time. Further research is needed to validate study findings.