Social network characteristics and cognitive function, decline, and mortality: A joint modeling approach

INTRODUCTION: Maintaining social relationships is challenging in advanced old age due to frequent changes in social networks. Little is known about whether social networks are associated with cognitive function, decline, and mortality in this population, or whether these associations differed by sex/gender. METHODS: Participants aged ≥90 years (n = 677; mean age = 92.9, SD = 2.2) from the multi-ethnic LifeAfter90 Study completed cognitive testing every 6 months (2019–2022). Joint models examined associations of social networks with cognitive decline and mortality, overall, and by sex/gender. RESULTS: Over 1.63 years of follow-up, 163 (24%) participants died. Baseline structural and functional social network characteristics were associated with higher executive function and verbal episodic memory, with consistent findings across sex/gender. Social networks did not predict cognitive decline or mortality. DISCUSSION: Among adults aged 90+, social networks were linked to better cognitive function but not to short-term cognitive decline or mortality.