X-Message-Number: 2803
Date: 05 Jun 94 06:21:36 EDT
From: "Steven B. Harris" <>
Subject: CRYONICS.SCI.Dr Minski's Request

Re mssg. 2793 and Dr. Minski's request:

   The best current article on increases in average life 
expectancy to be statistically expected from eliminating various
major identifiable organ system failures, is this following one
(see internal references as well).  The statistics used assume
only that we remove from consideration various major categories
of things doctors put down on death certificates.  After doing
this there remain still (to be sure) groups of people 
who are said to have "died of" various "causes," such as hip 
fracture, bronchitis, urinary tract infection, falls, 
complications of dementia, chronic medical conditions, etc. 
These people die actually of aging, which is to say that they die
primarily because of underlying aging-process-caused loss of 
physiologic reserve in all key organ systems.  A large number, in 
fact, die for no particular reason that anyone can identify with 
certainty, but the doctor is not allowed to put this on the death 
certificate, so the worst problem they had at the time of death
is put down.  

    The effect of eliminating all of the various major
"clear single organ system failure" deaths, is finally be left
with a residue of deaths which reflect the life expectancy of 
those people who have managed to age into a condition of 
relative "frailty," where all organ systems are working without much 
reserve, but no one organ system is clearly the main problem.  
Death in this state becomes increasingly a result of "chaotic" 
perturbations, and the information on the death certificate 
regarding which particular chaotic excursion has pushed the house
of cards over, becomes less and less valuable in a standard
"causal" sense.  

   The trick is to use the death certificate information to
estimate at what point (in the absence of any treatment for aging) 
in the human life span the chaos point comes-- the point at
which if one thing doesn't get you, because of frailty and loss
of reserve everywhere, something else which looks superficially 
entirely different soon will.  This is what Olshansky et. al have 
done, although they may not think of it exactly like that.  

Olshansky SJ ; Carnes BA ; Cassel C 

In search of Methuselah: estimating the upper limits to human

Abstract: Estimates of the upper limits to human longevity have
important policy implications that directly affect forecasts of
life expectancy, active life expectancy, population aging, and
social and medical programs tied to the size and health status of
the elderly population. In the past, investigators have based
speculations about the upper limits of human longevity on
observations of past trends in mortality. Here the estimate of
the upper bound is based on hypothesized reductions in current
mortality rates necessary to achieve a life expectancy at birth
from 80 to 120 years and an expectation of life at age 50 from 30
to 70 years. With the use of conditional probabilities of death
from complete life tables for the United States, reductions in
mortality required to achieve extreme longevity (that is, 80 to 
120 years) were compared with those resulting from hypothetical 
cures for all cardiovascular diseases, ischemic heart disease, 
diabetes, and cancer. Results indicate that in order for life 
expectancy at birth to increase from present levels to what has 
been referred to as the average biological limit to life (age 
85), mortality rates from all causes of death would need to 
decline at all ages by 55%, and at ages 50 and over by 60%. Given
that hypothetical cures for major degenerative diseases would 
reduce overall mortality by 75%, it seems highly unlikely that 
life expectancy at birth will exceed the age of 85. 
Science 1990 Nov 2;250(4981):634-40 
                                    Steven Harris, M.D.
                                    FAX 310 206-5178  (UCLA)
                                    Office 310 825-1927          

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