Neighborhood Bonding and Bridging Social Capital, Social Activity Participation, and Short-term Cognitive Variability in Later Life.

Objectives: Investigating social determinants of health and related outcomes may help identify effective and sustainable intervention targets. This study examined whether contextual-level social capital (bonding and bridging capital) and individual-level social participation were associated with short-term cognitive variability, an early indicator of normal and pathological cognitive aging.

Methods: The sample consisted of urban community-dwelling older adults (N = 304, mean age = 77.5, range = 70-91) from the Einstein Aging Study. Bonding and bridging social capital measures were derived at the zip code tabulation area (ZCTA)-level and linked with participants' addresses. Formal and informal social activity participation was assessed using self-reported questionnaires. Cognitive performance was assessed using three smartphone-administered cognitive tasks that measured processing speed (Symbol match) and associative working memory performance (Color-shape binding, Color-dot) 6 times a day for 14 days. Heterogeneous variance multilevel models using log-linear prediction of residual variance were used to simultaneously assess mean and variability of cognitive performance.

Results: Both social capital measures were significantly associated with reduced cognitive variability across the three tests, with stronger effects of bridging (6.3∼8.8% reduction in residual variance) than bonding social capital (3.3∼5.4% reduction). Social participation was independently associated with reduced cognitive variability (3.0∼8.6% reduction). Effects of social capital and social participation on mean levels of cognition mostly failed to reach statistical significance.

Discussion: Both structural and individual-level social integration played a crucial role in short-term cognitive variability beyond mean-level performance. Multi-level interventions aimed at strengthening social ties and engagement might mitigate cognitive instability and future cognitive impairment.