Dementia: the leading predictor of death in a defined elderly population: the Cache County Study.
OBJECTIVE
To examine the relative risk and population attributable risk (PAR) of death with dementia of varying type and severity and other risk factors in a population of exceptional longevity.


METHODS
Deaths were monitored over 5 years using vital statistics records and newspaper obituaries in 355 individuals with prevalent dementia and 4,328 without in Cache County, UT. Mean age was 83.3 (SD 7.0) years with dementia and 73.7 (SD 6.8) years without. History of coronary artery disease, hypertension, diabetes, and other life-shortening illness was ascertained from interviews.


RESULTS
Death certificates implicated dementia as an important cause of death, but other data suggested a stronger association. Adjusted Cox relative hazard and PAR of death were higher with dementia than with any other illness studied. Relative hazard of death with dementia was highest at ages 65 to 74, but the high prevalence of dementia after age 85 resulted in 27% PAR among the oldest old. Mortality increased substantially with severity of dementia. Alzheimer disease shortened survival time most dramatically in younger participants, but vascular dementia posed a greater mortality risk among the oldest old.


CONCLUSIONS
In this population, dementia was the strongest predictor of mortality, with a risk two to three times those of other life-shortening illnesses.
Tschanz
J T
JT
Center for Epidemiologic Studies, Department of Psychology, Utah State University, Logan 84322-4440, USA. joannt@cc.usu.edu
Corcoran
C
C
Skoog
I
I
Khachaturian
A S
AS
Herrick
J
J
Hayden
K M
KM
Welsh-Bohmer
K A
KA
Calvert
T
T
Norton
M C
MC
Zandi
P
P
Breitner
J C S
JC
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000401:mortality; D002423:Cause of Death; D015897:Comorbidity; D003704:Dementia / Q000401:mortality*; D015140:Dementia, Vascular / Q000401:mortality; D005260:Female; D006801:Humans; D008136:Longevity; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D015995:Prevalence; D016016:Proportional Hazards Models; D012306:Risk; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D014589:Utah / Q000453:epidemiology