Mixed pathology is more likely in black than white decedents with Alzheimer dementia

Abstract

Objective: To compare the burden of neuropathology in black and white participants with clinical Alzheimer disease (AD).

Methods: Participants included 122 persons enrolled in the Rush Alzheimer's Disease Clinical Core, a prospective cohort study of AD. Forty-one black decedents were matched two-to-one to 81 white decedents according to age at death, sex, years of education, and cognition proximate to death. We examined common brain pathologies related to dementia (AD, Lewy body, and macroscopic and microinfarct pathology) and arteriolar sclerosis and atherosclerosis. We calculated the frequency of each dementia pathology both alone and in combination (mixed pathologies). Racial differences in the odds of a single pathology vs mixed pathologies, and in the odds of vessel disease and its severity, were examined using logistic regression analyses.

Results: AD pathology was confirmed in >93% of both black and white decedents with AD dementia. However, black decedents were less likely to have Alzheimer pathology as a single dementia pathology than white decedents (19.5% vs 42.0%), and were more likely to have AD mixed with an additional pathology (70.7% vs 50.6%), particularly Alzheimer pathology and Lewy bodies, and Alzheimer pathology, Lewy bodies, and infarcts. Black decedents also had more severe arteriolar sclerosis and atherosclerosis.

Conclusion: Black decedents with AD dementia are more likely to have mixed brain pathologies compared with age-, sex-, education-, and cognition-matched white decedents with AD dementia.

Figure. Racial differences in mixed pathology

Pie chart shows proportions of individual and mixed pathologies in black and white decedents with Alzheimer disease (AD) dementia. INF = infarcts; LB = Lewy bodies.