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Mixed brain pathologies more common among blacks with Alzheimer's disease

Results from a prospective cohort study show black individuals with Alzheimer’s disease were more likely to have mixed brain pathologies than white individuals with Alzheimer’s disease.

“Knowledge about the neuropathologic basis of [Alzheimer’s disease] dementia has been based almost exclusively on autopsy studies of white persons. There is a dearth of neuropathologic information available in older black persons with [Alzheimer’s disease] dementia despite the fact that they may have a higher prevalence and incidence of [Alzheimer’s disease] dementia than white persons, as well as a disproportionate burden of vascular disease,” study researcher Lisa L. Barnes, PhD, of Rush Alzheimer’s Disease Center at Rush University in Chicago, and colleagues wrote.

To compare neuropathology between black and white individuals with Alzheimer’s disease, researchers matched 41 black individuals with 81 white individuals from the Rush Alzheimer’s disease Clinical Core according to age at death, sex, years of education and cognition at time of death. Brain pathologies related to dementia, Alzheimer’s disease, Lewy body dementia, macroscopic and microinfarct pathology, and arteriolar sclerosis and atherosclerosis were assessed.

More than 93% of black and white study participants with Alzheimer’s disease dementia exhibited Alzheimer’s disease pathology.

Black participants were less likely to have Alzheimer pathology as a single dementia pathology than white participants (19.5% vs. 42%).

Black individuals were also more likely to have Alzheimer’s disease mixed with an additional pathology (70.7% vs. 50.6%), particularly Alzheimer pathology and Lewy bodies, and Alzheimer pathology, Lewy bodies and infarcts.

Severe arteriolar sclerosis and atherosclerosis were more common among black participants.

“[Alzheimer’s disease] pathology was confirmed in the majority of both races; however, mixed pathologies were far more common in black decedents. However, contrary to our hypothesis that black decedents would have more mixed pathology consisting of [Alzheimer’s disease] pathology and infarcts, we found that black decedents with [Alzheimer’s disease] dementia were more likely to have [Alzheimer’s disease] mixed with Lewy body pathology and [Alzheimer’s disease] mixed with Lewy bodies and infarcts compared with white decedents with dementia,” Barnes and colleagues concluded. – by Amanda Oldt

Disclosure: Barnes reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.