Cerebrovascular Pathology and Cognitive Outcomes in Older Black Decedents.

BACKGROUND

Few neuropathologic studies focus on the associations of cerebrovascular pathologies with cognition in older Black adults.

METHODS

We conducted a nested substudy of participants who were enrolled in 1 of 4 harmonized longitudinal cohort studies-the Minority Aging Research Study, African American Clinical Core, Rush Memory and Aging Project, and Religious Order Study before coming to autopsy. Neuropathologic evaluation included assessment of cerebrovascular and neurodegenerative pathologies. We first documented single and mixed cerebrovascular profiles and neurodegenerative pathologies in 112 Black decedents and examined the pathological burden with cognitive function proximate to death. In secondary analyses, we matched 2:1 the 112 Black decedents to 214 White decedents from the same cohorts using Mahalanobis distance matching and conducted linear regression models to examine racial differences in the burden of each vascular pathology and their associations with cognition.

RESULTS

In older Black decedents, macroscopic infarcts were present in 37%, microinfarcts in 30%, basal ganglia arteriolosclerosis in 20%, cerebral amyloid angiopathy in 32%, and atherosclerosis in 14%. Single cerebrovascular profiles were present in 29% and mixed cerebrovascular profiles in 40%. Microinfarcts (estimate=-0.51, SE=0.23, P=0.03) and arteriolosclerosis in the basal ganglia (estimate =-0.29, SE=0.13, P=0.03) were associated with lower global cognition independent of neurodegenerative pathologies. Further, microinfarcts were associated with lower episodic and semantic memory, and perceptual speed, whereas arteriolosclerosis was associated with only semantic memory. Mixed vascular profiles were also associated with lower episodic memory and perceptual speed. In secondary analyses, the burden of cerebrovascular pathologies and cognitive associations were similar across races.

CONCLUSIONS

Cerebrovascular pathologies are common in older Black decedents, most often as a mixed cerebrovascular pathology profile. Arteriosclerosis and microinfarcts were associated with lower cognition above and beyond the presence of neurodegenerative pathologies. Burden and cognitive associations with cerebrovascular pathologies were similar across races.