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Background We have undertaken a large unselected,
community-based neuropathology study
in an elderly
(70–103 years) UK population in relation to prospectively
evaluated dementia status. The study tests the assumption
that dementing disorders as defined by current diagnostic
protocols underlie this syndrome in the community at large.
Methods Respondents in the Medical Research Council
Cognitive Function and Ageing Study were approached for
consent to examine the brain at necropsy. Dementia status
was assigned by use of the automated geriatric examination
pathological features were standardised by use of the
protocol of the Consortium to Establish a Registry of
Alzheimer’s Disease, which assesses the severity and
distribution of Alzheimer-type pathology, vascular lesions,
and other potential causes of dementia. A statistical model
of dementia risk related predominantly to Alzheimer-type and
vascular pathology was developed by multivariate logistic
Findings We report on the first 209 individuals who have
come to necropsy. The median age at death was 85 years
for men, and 86 years for women. Cerebrovascular (78%)
(70%) pathology were common.
Dementia was present in 100 (48%), of whom 64% had
features indicating probable or definite Alzheimer’s disease.
However, 33% of the 109 non-demented people had
equivalent densities of neocortical neuritic plaques. Some
degree of neocortical neurofibrillary pathology was found in
61% of demented and 34% of non-demented individuals.
Vascular lesions were equally common in both groups,
although the proportion with multiple vascular pathology was
higher in the demented group (46% vs 33%).
Interpretation Alzheimer-type and vascular pathology were
the major pathological correlates of cognitive decline in this
elderly sample, as expected, but most patients had mixed
disease. There were no clear thresholds of