X-Message-Number: 27775
Date: Wed, 29 Mar 2006 18:43:21 -0800 (PST)
From: Doug Skrecky <>
Subject: dementia a side-effect of an extended lifespan?

[Some people reject the concept of life-extension, for fear that this
would result in a prolonged period of dementia. The reality is that
dementia itself is the best single predictor of death. An extended
lifespan is only realistic if dementia is avoided.]

Neurology. 2004 Apr 13;62(7):1156-62.
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. CONCLUSION: In this population, dementia was
the strongest predictor of mortality, with a risk two to three times
those of other life-shortening illnesses.

J Am Geriatr Soc. 2003 Oct;51(10):1365-73.
Predictors of mortality in 2,249 nonagenarians--the Danish 1905-Cohort Survey.
  OBJECTIVES: : To elucidate whether well-known predictions of mortality
are reduced or even reversed, or whether mortality is a stochastic
process in the oldest old. DESIGN: : A multidimensional survey of the
Danish 1905 cohort conducted in 1998 with follow-up of vital status after
15 months. SETTING: : Denmark. PARTICIPANTS: : All Danes born in 1905,
irrespective of physical and mental status were approached. Two thousand
two hundred sixty-two persons of 3,600 participated in this
survey. MEASUREMENTS: : Professional interviewers collected data
concerning sociodemographic factors, smoking, alcohol consumption, body
mass index, physical and cognitive performance, and health during a visit
at the participant's residency. Cox regression models were used to
evaluate predictors of mortality. RESULTS: : Five hundred seventy-nine
(25.7%) of the 2,249 participants eligible for the analysis died during
the 15 months follow-up. Multivariate analyses showed that marital
status, education, smoking, obesity, consumption of alcohol, and number
of self-reported diseases were not associated with mortality. Disability
and cognitive impairment were significant risk factors in men and
women. In addition poor self-rated health was associated with an increase
in mortality in women. CONCLUSION: : In the oldest old, several known
predictors of mortality, such as sociodemographic factors, smoking, and
obesity, have lost their importance, but a high disability level, poor
physical and cognitive performance, and self-rated health (women only),
predict mortality, which shows that mortality in the oldest old is not a
stochastic process.

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