Cerebral amyloid angiopathy and cognitive function: the HAAS autopsy study.

OBJECTIVE: To investigate the relationship between cerebral amyloid angiopathy (CAA), dementia, and cognitive function in an autopsy sample of 211 Japanese-American men from the population-based Honolulu-Asia Aging Study.

METHODS: Starting in 1991, participants were assessed with the Cognitive Abilities Screening Instrument (CASI) and diagnosed with dementia (including subtype) based on published criteria. At autopsy, neuropathologists blinded to clinical data examined brains for neurofibrillary tangles (NFT), neuritic plaques (NP), and a number of vascular pathologies, including CAA. CAA was detected by immunostaining for betaA4 amyloid in parenchymal vessels in the neocortex and semiquantitatively rated. Linear regression models were used to examine the association of CASI score, dementia subtype, and CAA controlling for age at death, time between CASI administration and death, education, NP and NFT counts, infarcts, hemorrhage, and APOE genotype.

RESULTS: A total of 44.1% of subjects had CAA in at least one neocortical area. The presence of CAA was associated with higher mean NFT and NP counts and having at least one APOE-epsilon4 allele. The interaction between CAA and AD on the adjusted mean CASI score was significant; compared with nondemented men without CAA, the CASI score was 16.6% lower in men with AD and no CAA and 45.9% lower in men with AD plus CAA.

CONCLUSIONS: CAA may contribute to the clinical presentation of dementia by interacting with other neuronal pathologies, leading to more severe cognitive impairment in men with both CAA and AD compared with men with only AD or CAA.