Negative and Positive Psychosocial Factors in Relation to Cognitive Health in Older African Americans

Abstract

Background and objectives: Identifying potential intervention strategies to reduce cognitive decline, particularly among older African Americans at high risk for Alzheimer's dementia, is critical. This study aimed to investigate whether depressive symptoms, purpose in life, and their interrelations are associated with cognitive decline in older African Americans.

Research design and methods: We included older African Americans from the Minority Aging Research Study (n = 748) and Rush Memory and Aging Project (n = 109), without dementia at baseline. We assessed associations of depressive symptoms, purpose in life, and their interrelations, with baseline levels and change in global cognition using linear mixed-effects models.

Results: At baseline, each unit increment in depressive symptoms was related to worse initial global cognition (mean difference = -0.03 standard unit; p = .003), while higher purpose in life was related to better cognition (mean difference = 0.12; p = .002). Further, participants with ≥1 depressive symptom who had a purpose in life score above the median appeared to have better global cognition (mean difference = 0.10; p = .01), compared to those with depressive symptoms but lower levels of purpose in life. However, we did not find relations of depressive symptoms or purpose in life with rates of cognitive decline over time, likely due to the modest follow-up.

Discussion and implications: In older African Americans, we found that lower depressive symptoms and greater purpose in life were independently related to higher initial levels of global cognition, but not cognitive decline. Preliminary findings of higher global cognition in individuals with depressive symptoms but greater purpose in life merit further investigation if purpose may eventually be considered as an intervention.

Keywords: African Americans; Cognitive function; Depressive symptoms; Linear mixed-effects models; Purpose in life.

Figure 1.

Depressive symptoms at baseline and global cognitive function over time. Notes: For no depressive symptoms and three or more symptoms, trajectories of global cognitive function were plotted for the most common profile of covariates in the study sample (i.e., female in Minority Aging Research Study, 73 years of age, 15 years of education, two medical comorbidities, purpose in life score of 4). Shading represents the 95% pointwise confidence intervals.

Figure 2.

Purpose in life at baseline and global cognitive function over time. Notes: For the highest and lowest quartiles of purpose in life, trajectories of global cognitive function were plotted for the most common profile of covariates in the study sample (i.e., female in Minority Aging Research Study, 73 years of age, 15 years of education, two medical comorbidities, one depressive symptom reported on the Center for Epidemiological Studies—Depression scale). Shading represents the 95% pointwise confidence intervals.