Differential associations of socioeconomic status with global brain volumes and white matter lesions in African American and white adults: The HANDLS SCAN study

Objective: The aim of the study was to examine interactive relations of race and socioeconomic status (SES) to magnetic resonance imaging (MRI)-assessed global brain outcomes with previously demonstrated prognostic significance for stroke, dementia, and mortality. Methods: Participants were 147 African Americans (AAs) and whites (ages 33-71 years; 43% AA; 56% female; 26% below poverty) in the Healthy Aging in Neighborhoods of Diversity across the Life Span SCAN substudy. Cranial MRI was conducted using a 3.0 T unit. White matter (WM) lesion volumes and total brain, gray matter, and WM volumes were computed. An SES composite was derived from education and poverty status. Results: Significant interactions of race and SES were observed for WM lesion volume (b = 1.38; η² = 0.036; p = .028), total brain (b = 86.72; η² = 0.042; p < .001), gray matter (b = 40.16; η² = 0.032; p = .003), and WM (b = 46.56; η² = 0.050; p < .001). AA participants with low SES exhibited significantly greater WM lesion volumes than white participants with low SES. White participants with higher SES had greater brain volumes than all other groups (albeit within normal range). Conclusions: Low SES was associated with greater WM pathology-a marker for increased stroke risk-in AAs. Higher SES was associated with greater total brain volume-a putative global indicator of brain health and predictor of mortality-in whites. Findings may reflect environmental and interpersonal stressors encountered by AAs and those of lower SES and could relate to disproportionate rates of stroke, dementia, and mortality.