Neuropathology in a diverse cohort of oldest-old: The LifeAfter90 study

Studies of the oldest-old show great neuropathologic heterogeneity; little is known in diverse populations after age 90.

LifeAfter90 is a lifecourse cohort study of individuals aged ≥ 90 years evaluated every 6 months with optional brain donation; this study presents initial neuropathological findings.

A total of 124 decedents (mean age 96, 49.2% White, 12.1% Black, 16.9% Asian, 18.5% Latino individuals) came to autopsy. At last evaluation, 35% had dementia, 23% cognitive impairment, and 41% normal cognition. 35.5% had intermediate AD, 8.1% had high AD neuropathologic changes, 73% had moderate/severe arteriolosclerosis, 23% one or more microinfarcts, 32% Lewy bodies, 24% TDP-43 deposits, and 4% hippocampal sclerosis. There was a high degree of mixed neuropathology, with 69% having three or more pathologies. Cognitive impairment was most strongly associated with AD pathology.

Multiple pathologies were common, and many individuals maintained normal cognition indicating substantial neuropathologic burden may be present in the absence of overt cognitive impairment, especially in the oldest-old.