Brain volume and survival from age 78 to 85: the contribution of Alzheimer-type magnetic resonance imaging findings.
OBJECTIVE
To test the prediction of survival using magnetic resonance imaging (MRI)-derived global and regional brain volumes in subjects aged 78 to 79 without dementia.


METHODS
Observational follow-up study.


METHODS
University teaching hospital.


METHODS
Participants born in 1921, recruited in 1997/98 to a longitudinal study, who underwent brain MRI in 1999/2000.


METHODS
Vital status on May 12, 2006, global and regional brain volumes.


RESULTS
Thirty-seven of 98 (34.9%) participants died during follow-up. After adjustment for cognitive ability at time of MRI examination, childhood intelligence, sex, hypertension, smoking history, obesity, hyperlipidemia, and age at MRI, proportion of intracranial volume occupied by the brain (brain fraction) predicted death before age 85 (P=.04). Participants with brain fraction less than 0.726 had more than twice the relative risk (2.8, 95% confidence interval=1.1-7.3) of death than participants with brain fraction greater 0.726. Lower survival was significantly associated with lower gray matter volumes in bilateral parietal and left frontoparietal areas and with lower white matter volumes in left parietal and right posterior temporal regions. Cox regression analysis showed that parietal white matter volume (P=.003), a subsequent diagnosis of dementia (P<.001), and sex (P=.004) were independent predictors of survival.


CONCLUSIONS
In participants aged 78 to 79, a lower global brain fraction predicted survival to approximately age 85. Smaller regional volumetric brain reductions, seen in Alzheimer's disease (AD), also predicted survival independent of dementia. The presence of prodromal AD probably explain the main findings.
Staff
Roger T
RT
Department of Nuclear Medicine, Aberdeen Royal Infirmary, Aberdeen, United Kingdom.
Murray
Alison D
AD
Ahearn
Trevor
T
Salarirad
Sima
S
Mowat
Donald
D
Starr
John M
JM
Deary
Ian J
IJ
Lemmon
Helen
H
Whalley
Lawrence J
LJ
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D000544:Alzheimer Disease / Q000401:mortality / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D016009:Chi-Square Distribution; D016000:Cluster Analysis; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D015577:Geriatric Assessment / Q000379:methods; D006801:Humans; D008017:Life Expectancy; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009929:Organ Size; D011237:Predictive Value of Tests; D011379:Prognosis; D018570:Risk Assessment / Q000379:methods; D012606:Scotland / Q000453:epidemiology; D016019:Survival Analysis; D015996:Survival Rate