Exploring the Influence of Loneliness on Cognitive Decline: Differential Effects in Black and White Older Adults.

Objectives: Loneliness is prevalent among older adults, who may experience age-related or pathological cognitive changes. However, there's a limited understanding of how loneliness affects cognitive decline and if the relationship differs by race. This study investigates the impact of loneliness on cognitive decline among Black and White older adults.

Methods: 3,082 participants with 20,882 follow-ups over 10 years were included from the RUSH RADC cohorts. Participants were categorized as having high or low loneliness based on a median split of de Jong-Gierveld Loneliness Scale scores. Participants were divided into four groups based on race (White vs Black) and loneliness status (High vs Low): 1) White-High (n = 1030), 2) White-Low (n = 913), 3) Black-High (n = 493), 4) Black-Low (n = 646). Linear mixed-effects models were employed to examine group differences in cognitive change over time (global cognition, episodic memory, semantic memory, perceptual speed, visuospatial ability, and working memory).

Results: White adults with high loneliness exhibited increased rates of cognitive decline across all domains (p < .01) compared to Black adults with high or low. Compared to White adults with low loneliness, White adults with high loneliness exhibited increased decline in all domains except perceptual speed and visuospatial ability (p < .001). Black adults with high loneliness exhibited increased decline compared to Black adults with low loneliness in all domains (p < .01).

Discussion: Loneliness is significantly associated with cognitive decline. Results of this study suggest that the loneliness-cognition relationship is stronger in White adults compared to Black older adults.