Background: The associations of physical activity with Alzheimer's disease (AD) pathologies remain controversial.
Objective: To quantitatively assess the association between the frequency of physical activity with cerebrospinal fluid (CSF) biomarkers in AD and further explore the mechanism by which AD pathologies regulate the correlation between physical activity and cognition.
Methods: A total of 918 participants without dementia from Chinese Alzheimer's Biomarker and Lifestyle (CABLE) were examined in this population-based cross-sectional study. Multiple linear models were used to evaluate the associations of physical activity with CSF biomarkers and cognition. Moreover, mediation analyses were conducted to investigate the potential relationships between physical activity, AD pathologies, and cognitive function.
Results: Regular physical activity was positively associated with CSF Aβ42 (p < 0.001) and Aβ42/40 (p < 0.001), while it was negatively associated with p-tau/Aβ42 (p < 0.001) and t-tau/Aβ42 (p < 0.001). Of all participants, regular physical activity was associated with increased cognitive function (p < 0.001). The interaction effect indicated that age moderated the association between physical activity frequency and CSF Aβ42 (p = 0.014) and p-tau/Aβ42 (p = 0.041). The impact of physical activity on cognition was mediated in part by amyloid pathologies, accounting for 4.87% to 21.56% of the total effect (p < 0.05).
Conclusion: This study showed the beneficial impact of physical activity on AD pathologies and cognition in participants without dementia.
Keywords: Alzheimer’s disease; biomarkers; cerebrospinal fluid; cognition; physical activity.