Associations between social and intellectual activities with cognitive trajectories in Chinese middle-aged and older adults: a nationally representative cohort study

Background: Associations between the frequency of social and intellectual activities and cognitive trajectories are understudied in Chinese middle-aged and older adults. We aimed to examine this association in a nationally representative longitudinal study. Methods: The China Health and Retirement Longitudinal Study (CHARLS) is a nationally representative sample of Chinese middle-aged and older participants. The frequency of social and intellectual activities was measured at baseline. Interview-based cognitive assessments of orientation and attention, episodic memory, and visuospatial skills and the calculation of combined global scores were assessed every 2 year. Cognitive trajectories over the study period were analyzed using group-based trajectory model , and the associations of the trajectory memberships with social and intellectual activities were analyzed using multinomial logistic regression. Odd ratios (OR) and 95% confidence intervals (CI) were reported. Results: Among 8204 participants aged 50-75 years, trajectory analysis identified three longitudinal patterns of cognitive function based on the global cognitive scores: “ persistently low ” (n = 1550, 18.9%); “persistently moderate” (n = 3194, 38.9%); and “persistently high” (n = 3460, 42.2%). After adjustment for sociodemographic variables, lifestyles, geriatric symptoms and health conditions, more frequent intellectual activities (OR: 0.54, 95% CI: 0.38-0.77) and social activities (OR: 0.79, 95% CI: 0.65-0.95) were both associated with a lower likelihood of being in the “persistently low” global cognitive trajectory group. Conclusions: More frequent social and intellectual activities were associated with more favorable cognitive aging trajectories.