The Parts Are Greater Than the Whole: Cross-sectional Associations between Depressive Symptoms & Cognitive Function in a Community-based, Urban Sample of African American & White Adults

Abstract

The global burden of dementia has accelerated over the past few decades, resulting in significant increases in prevalence, incidence, worse quality-of-life (QOL) outcomes, disability-adjusted life years (DALYs), mortality rates, and healthcare related costs. In the United States, African American adults are at greater risk of developing dementia than their White counterparts and less likely to receive a timely diagnosis. To reduce this disparity, it is crucial to identify modifiable risk factors not only for dementia, but also for cognitive impairment earlier in the disease progression and across the lifespan. One such risk factor is depression: depression diagnosis and the severity of depressive symptoms are both associated with risk for dementia, global cognitive impairment, and impairment across individual cognitive domains. The literature has largely operationalized depression by diagnosis or symptom count, obscuring the heterogeneity of specific symptoms (i.e., somatic complaints, cognitive and behavioral symptoms, interpersonal problems) present across individuals. Few studies have examined whether a) specific types of depressive symptoms differentially impact individual domains of cognition, and b) whether and how these associations differ between African Americans and Whites. Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) is a 20+ year, community-based, epidemiological study that investigates the influences of sociodemographic variables on health-related outcomes in urban, middle-aged adults. The present study uses HANDLS Wave 1 data to examine how a) overall depressive symptom severity and b) depressive symptom specificity cross-sectionally relate with cognitive function. It assesses whether these associations vary across African American and White participants—adjusting for age, sex, poverty status, and literacy level.