A self-report risk index to predict occurrence of dementia in three independent cohorts of older adults: the ANU-ADRI.
OBJECTIVE
The Australian National University AD Risk Index (ANU-ADRI, http://anuadri.anu.edu.au) is a self-report risk index developed using an evidence-based medicine approach to measure risk of Alzheimer's disease (AD). We aimed to evaluate the extent to which the ANU-ADRI can predict the risk of AD in older adults and to compare the ANU-ADRI to the dementia risk index developed from the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study for middle-aged cohorts.


METHODS
This study included three validation cohorts, i.e., the Rush Memory and Aging Study (MAP) (n = 903, age ≥53 years), the Kungsholmen Project (KP) (n = 905, age ≥75 years), and the Cardiovascular Health Cognition Study (CVHS) (n = 2496, age ≥65 years) that were each followed for dementia. Baseline data were collected on exposure to the 15 risk factors included in the ANU-ADRI of which MAP had 10, KP had 8 and CVHS had 9. Risk scores and C-statistics were computed for individual participants for the ANU-ADRI and the CAIDE index.


RESULTS
For the ANU-ADRI using available data, the MAP study c-statistic was 0·637 (95% CI 0·596-0·678), for the KP study it was 0·740 (0·712-0·768) and for the CVHS it was 0·733 (0·691-0·776) for predicting AD. When a common set of risk and protective factors were used c-statistics were 0.689 (95% CI 0.650-0.727), 0.666 (0.628-0.704) and 0.734 (0.707-0.761) for MAP, KP and CVHS respectively. Results for CAIDE ranged from c-statistics of 0.488 (0.427-0.554) to 0.595 (0.565-0.625).


CONCLUSIONS
A composite risk score derived from the ANU-ADRI weights including 8-10 risk or protective factors is a valid, self-report tool to identify those at risk of AD and dementia. The accuracy can be further improved in studies including more risk factors and younger cohorts with long-term follow-up.
Centre for Research on Ageing, Health and Wellbeing, The Australian National University, Canberra, Australia.
Kaarin J
KJ
Anstey
Centre for Research on Ageing, Health and Wellbeing, The Australian National University, Canberra, Australia.
Nicolas
N
Cherbuin
Centre for Research on Ageing, Health and Wellbeing, The Australian National University, Canberra, Australia.
Pushpani M
PM
Herath
Aging Research Center, Karolinska Institutet-Stockholm University, Stockholm, Sweden.
Chengxuan
C
Qiu
Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
Lewis H
LH
Kuller
Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
Oscar L
OL
Lopez
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois, United States of America.
Robert S
RS
Wilson
Aging Research Center, Karolinska Institutet-Stockholm University, Stockholm, Sweden ; Stockholm Gerontology Research Center, Stockholm, Sweden.
Laura
L
Fratiglioni
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000453:epidemiology; D003704:Dementia / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012306:Risk; D057566:Self Report