Social Engagement, Depressive Symptoms, and Loneliness, and Longitudinal Cognitive Decline in a Population-Based Cohort of Older Adults.

Objective: The primary objective of this study is to examine the association between social engagement and cognitive decline among participants with and without depressive symptoms and/or loneliness. Methods: Study data is from the Chicago Health and Aging Project (CHAP), a population-based cohort study, located on the south side of Chicago, which consisted of interviews occurring every 3 years from 1993 to 2012. We conducted mixed effects regression analysis to examine the association between social engagement and global cognitive decline in CHAP participants. Models adjusted for and were stratified by depressive symptoms status and loneliness status. Results: The study sample includes 10,572 participants (63% black and 61% female). A total of 2,481 participants experienced more depressive symptoms, and 1,751 participants were lonely. A higher frequency of social engagement was associated with a slower rate of cognitive decline in individuals with and without depressive symptoms and/or loneliness. Participants who were lonely had approximately a 17% (β = 0.009/β = -0.054) slower rate of cognitive decline, and participants who were not lonely had a slower rate of about 12% (β = 0.006/β = -0.051), for a one-unit increase in social engagement. For each unit of increase in social engagement, participants with greater depressive symptomology had a slower rate of cognitive decline of approximately 14% (β = 0.009/β= -0.063), and participants with no to few depressive symptoms had a slower rate of decline of about 12% (β = 0.006/β = -0.049). Discussion: Social engagement slows cognitive decline in individuals with loneliness and/or depression. It is essential to build strategies for adhering to social activities into interventions that seek to minimize risk of cognitive impairment.