Race and Apolipoprotein E-e4 Allele Status Differences in the Association Between Loneliness and Cognitive Decline

This study aimed to examine race and apolipoprotein E-e4 allele (APOE-e4) status differences in the longitudinal associations between loneliness and cognitive decline. The study sample is composed of participants ( N = 7696, 64% Black participants and 36% White participants) from the Chicago Health and Aging Project, a population-based cohort study. Mixed-effects regression models were conducted to examine the longitudinal associations between loneliness on global cognitive function and individual tests of cognitive function. Models were also stratified by race and APOE-e4. A greater percentage of Black participants (17%) reported loneliness at baseline visit compared with White participants (12%). Black and White participants who were lonely individuals had a similar rate of decline in global cognitive function at 0.075 (95% confidence interval [CI] = -0.082 to -0.068) standard deviation unit (SDU) per year for Black participants and at 0.075 (95% CI = -0.086 to -0.063) SDU per year for White participants. Lonely participants with APOE-e4 had a higher rate of global cognitive decline at -0.102 (95% CI = -0.115 to -0.088) SDU per year than for lonely participants without APOE-e4 at -0.052 (95% CI = -0.059 to -0.045) SDU per year. The burden of loneliness and its relation to cognitive decline is higher among participants with APOE-e4 compared with those without APOE-e4. Loneliness is associated with cognitive decline in both Black and White participants.