X-Message-Number: 1443
From:  (David Lubkin)
Date: Fri, 11 Dec 92 11:29:59 EST
Subject: Longevity in humans and fruit flies

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Check out the 16 Oct 92 and 15 Nov 91 issues of Science.  There are research 
papers and an article accompanying them reporting new studies of longevity.

The rule of thumb that's bandied around (the Gompertz law) is that 
mortality rates increase exponentially with age.  It seems to be true for
most of adulthood, but none of the studies until now looked at the very
old, e.g., humans over 85.  Now they're starting to, and finding that the
curve doesn't fit.  Death rates level off or even drop (for fruit flies,
the death rate drops way down after a certain age).

Excerpt:  "The simplest version of the biological theories, popularized by
gerontologist James Fries, is the notion that the body naturally wears out
at 85 or so, like an old car whose major systems are all failing at once.
But that explanation doesn't fit the fruit fly data, nor Vaupel's human
data.  Vaupel proposes instead that death rates are not driven by an 
absolute limit to lifespan, but rather that they reflect a collection of
causes of death, to which some individuals are more susceptible than others.
Like fruit flies, he says, 'people are different from each other in terms of
their vulnerability to mortality.'"

The overview article and fruit fly studies are in the 16 Oct 92 issue; a
Scandinavian census analysis is in the 15 Nov 91 issue.

-- David Lubkin.

=========================  =========================
The state is the great fictitious entity by which everyone seeks to live 
at the expense of everyone else.  -- Frederic Bastiat
========================================================================

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