Stressful Life Events and Racial Disparities in Cognition Among Middle-Aged and Older Adults

Article type: Research Article

Authors: Zuelsdorff, Megan^{a; b; *} | Okonkwo, Ozioma C.^{b; c} | Norton, Derek^d | Barnes, Lisa L.^{e; f} | Graham, Karen L.^{e; g} | Clark, Lindsay R.^{b; c} | Wyman, Mary F.^{b; c} | Benton, Susan F.^{b; h} | Gee, Alexanderⁱ | Lambrou, Nickolas^{b; c} | Johnson, Sterling C.^{b; c; j} | Gleason, Carey E.^{b; c}

Affiliations: [a] School of Nursing, University of Wisconsin - Madison, Madison, WI, USA | [b] Wisconsin Alzheimer’s Disease Research Center, Madison, WI, USA | [c] Geriatric Research, Education, and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, WI, USA | [d] Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI, USA | [e] Rush Alzheimer’s Disease Center, Chicago, IL, USA | [f] Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA | [g] Rush University College of Nursing, Chicago IL, USA | [h] Department of Family Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA | [i] Nehemiah Center for Urban Leadership Development, Madison, WI, USA | [j] Wisconsin Alzheimer’s Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA

Correspondence: [*] Correspondence to: Megan Zuelsdorff, PhD, Assistant Professor, School of Nursing, University of Wisconsin – Madison, 701 Highland Avenue, Madison, WI 53705, USA. Tel.: +1 608 262 5951; E-mail: [email protected].

Abstract: Background:It is well-documented that African Americans have elevated risk for cognitive impairment and dementia in late life, but reasons for the racial disparities remain unknown. Stress processes have been linked to premature age-related morbidity, including Alzheimer’s and related dementias (ADRD), and plausibly contribute to social disparities in cognitive aging. Objective:We examined the relationship between stressful life events and cognitive decline among African American and White participants enrolled in the Wisconsin Registry for Alzheimer’s Prevention (WRAP). Methods:Linear mixed models including demographic, literacy, and health-related covariates were used to estimate (1) relationships between a life event index score and decline in cognitive test performance in two domains of executive function (Speed & Flexibility, Working Memory) and one domain of episodic memory (Verbal Learning & Memory) among 1,241 WRAP enrollees, stratified by race, and (2) contributions of stressful life events to racial differences in cognition within the full sample. Results:African Americans (N = 50) reported more stressful life events than Whites (N = 1,191). Higher stress scores associated with poorer Speed & Flexibility performance in both groups, though not with declines across time, and partially explained racial differentials in this domain. Among African Americans only, stressor exposure also associated with age-related decline in Verbal Learning & Memory. Stressor-cognition relationships were independent of literacy and health-related variables. Conclusions:Greater lifetime stress predicted poorer later-life cognition, and, in a small sample of African Americans, faster declines in a key domain of episodic memory. These preliminary findings suggest that future work in large minority aging cohorts should explore stress as an important source of modifiable, socially-rooted risk for impairment and ADRD in African Americans, who are disproportionately exposed to adverse experiences across the life course.

Keywords: African Americans, Alzheimer’s disease, life course, stress

DOI: 10.3233/JAD-190439

Journal: Journal of Alzheimer's Disease, vol. 73, no. 2, pp. 671-682, 2020