The neuropathology of older persons with and without dementia from community versus clinic cohorts.
Level 3 - non-randomized controlled study
Comparative analysis of prospective clinic- and community-based cohorts
PubMed 19749406 · doi:10.3233/JAD-2009-1227
What was done
Investigators compared postmortem neuropathology across autopsied older adults from two community-based cohorts (Rush Religious Orders Study, n=386; Memory and Aging Project, n=195) and one specialty clinic cohort (Rush Alzheimer's Disease Center Clinical Core, n=392; total n=973). Final clinical classifications comprised no cognitive impairment (n=202), mild cognitive impairment (n=150), probable Alzheimer's disease (n=474), possible Alzheimer's disease (n=88), and other dementias (n=59). Neuropathological evaluations assessed Alzheimer's disease pathology severity, cerebral infarcts, and Lewy body disease.
What was found
Community-based participants with clinical Alzheimer's disease had significantly less severe Alzheimer's disease pathology (p<0.001) and significantly more cerebral infarcts (p<0.001) compared with clinic-based participants. Community-based persons with mild cognitive impairment also had more infarcts and mixed pathologies. The clinic-based cohort showed a higher proportion of Lewy bodies and atypical pathologies (p<0.001). Specific numerical values for pathology burdens and proportions were not reported in the abstract.
Why it matters
Neuropathological findings from specialty memory clinics cannot be assumed to represent the broader population, as community-dwelling older adults with cognitive impairment more frequently have vascular infarcts and mixed pathologies rather than pure, severe Alzheimer's pathology.
Limits
The abstract does not provide exact percentages, effect sizes, confidence intervals, or demographic adjustments (e.g., age, sex). Autopsy studies carry inherent selection and survival biases, and all participants were drawn from cohorts managed by a single research center.
Cited by
- supports In the Religious Orders Study, autopsy examinations revealed that several elderly nuns had physical Alzheimer's disease pathology without showing cognitive deficits during life.