Comparison of imaging biomarkers in the Alzheimer Disease Neuroimaging Initiative and the Mayo Clinic Study of Aging.
OBJECTIVE
To determine whether magnetic resonance imaging measurements observed in the Alzheimer Disease Neuroimaging Initiative (ADNI) convenience sample differ from those observed in the Mayo Clinic Study of Aging (MCSA) population-based sample.


METHODS
Comparison of 2 samples.


METHODS
Fifty-nine recruiting sites for the ADNI in the United States and Canada and the MCSA, a population-based cohort in Olmsted County, Minnesota.


METHODS
Cognitively normal subjects and amnestic subjects with mild cognitive impairment were selected from the ADNI convenience cohort and MCSA population-based cohort. A simple random sample of subjects from both cohorts in the same age range was selected, and a second sample applied matching for age, sex, educational level, apolipoprotein E genotype, and Mini-Mental State Examination score.


METHODS
Baseline hippocampal volumes and annual percentage of decline in hippocampal volume.


RESULTS
In the population-based sample, MCSA subjects were older, had less education, performed worse on the Mini-Mental State Examination, and had a family history of Alzheimer disease less often than did ADNI subjects. Baseline hippocampal volumes were larger in ADNI compared with MCSA cognitively normal subjects in the random sample, although no differences were observed after matching. Rates of decline in hippocampal volume were greater in the ADNI compared with the MCSA for cognitively normal subjects and those with amnestic mild cognitive impairment, even after matching.


CONCLUSIONS
Rates of decline in hippocampal volume suggest that ADNI subjects have a more aggressive brain pathologic process than MCSA subjects and hence may not be representative of the general population. These findings have implications for treatment trials that use ADNI-like recruitment mechanisms and for studies validating new diagnostic criteria for Alzheimer disease in its various stages.
Department of Radiology, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA. whitwell.jennifer@mayo.edu
Jennifer L
JL
Whitwell
Heather J
HJ
Wiste
Stephen D
SD
Weigand
Walter A
WA
Rocca
David S
DS
Knopman
Rosebud O
RO
Roberts
Bradley F
BF
Boeve
Ronald C
RC
Petersen
Clifford R
CR
Jack
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000544:Alzheimer Disease / Q000150:complications / Q000453:epidemiology / Q000473:pathology*; D015415:Biomarkers; D002170:Canada; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology; D015331:Cohort Studies; D018672:Community Health Planning; D003430:Cross-Sectional Studies; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008609:Mental Status Schedule; D011795:Surveys and Questionnaires; D014481:United States
D015415:Biomarkers