The relationship between racial discrimination and white matter among Black older adults

Black older adults experience worse brain and cognitive aging than White older adults, on average. Racially patterned psychosocial stressors may contribute to these disparities. Maintaining white matter health is important for cognitive aging, particularly among Black older adults, and it is uniquely vulnerable to stress. Examining associations between racial discrimination and white matter may elucidate mechanisms of disparities. A sample of Black older adults in the Washington Heights-Inwood Columbia Aging project were included (N = 217). Everyday and major life discrimination were self-reported on well-validated scales. Diffusion tensor imaging quantified white matter fractional anisotropy (FA). Multivariable regressions revealed more major life discrimination was associated with lower FA in the cingulum cingulate gyrus, forceps major, forceps minor, and inferior fronto-occipital fasciculus but greater FA in the superior longitudinal fasciculus temporal projection. Everyday discrimination was not associated with FA. Findings suggest that institutional racism may have a stronger effect on white matter tracts corresponding to cognitive and emotional/affective processing than interpersonal racism. White matter health may be a mechanism through which racially patterned stressors contribute to disparities in brain and cognitive aging.