Re: Caloric restriction and longevity?


"James Michael Howard" <jmhoward@xxxxxxxxxxxxxxxx> wrote in message
news:dtb2oa$176q$1@xxxxxxxxxxxxxxxxxxxxxx
On Sun, 19 Feb 2006 00:49:12 -0500 (EST), dkomo <dkomo871@xxxxxxxxxxx>

(Mega excisive snippage)

From the Department of Demography, University of California, Berkeley, CA
(D.A.G.); and Office of Population Research, Princeton University,
Princeton, NJ (N.G.).

PURPOSE: Studies based on Western populations showed a negative
relationship between dehydroepiandrosterone sulfate (DHEAS) level and
mortality, but no study examined this relationship in a non-Western
country. We use data from a large, nationally representative sample (n =
963) of older Taiwanese to investigate whether serum DHEAS, predicts
subsequent mortality during a 3-year period (2000 to 2003) and whether an
effect remains after controlling for baseline health status. METHODS:
Baseline data collection included an individual interview, physical
examination, and blood sample. A logit model is used to test the
relationship between DHEAS level and risk for mortality, controlling for
age, sex, and smoking status. RESULTS: Results show a marginally
significant inverse relationship between DHEAS level and 3-year mortality
risk. Participants with low DHEAS levels (<54.5 mug/dL) have 64% greater
odds of dying than those with higher DHEAS levels (p < 0.06). After
adjusting for various indicators of health status in 2000, the odds ratio
(OR) for low DHEAS level remains substantial (OR = 1.41), but not
statistically significant. CONCLUSIONS: Although the analysis is limited
by
the short follow-up and small number of deaths, results are consistent
with
the notion that DHEAS level has a sizeable effect on mortality.

A correlation does not a cause and effect determination make.

What might we expect if we were to draw blood samples from 10,000
individuals at random and wait three years; then,

Discard all samples from those who had not died within those three years;
then,

Discard all samples of those who had died from externally imposed trauma
(accidents, murder, etc.); then,

Discard all samples of those who had died as a direct or indirect result of
an invasive pathogenic etiology (such as influenza, AIDS); then,

Discard all samples of those who had died from any life-style related
disorder (for example, narcotic overdose, smoking-related lung cancer,
alcohol abuse-related cirrhosis; smoking-related cardio vascular morbidity;
then,

Any other cause unrelated to DHEA; then, if any remained at all,

We MIGHT have a sufficiently controlled sample to work with... maybe.

And then, if a substantial number of the remainder had lower DHEA levels, we
would have a correlation that might be significant... maybe.

But we would NOT have established a cause and effect relationship -- but a
correlation, only.

It would take an enormous amount of work, in an enormous number of studies,
of an enormous number of people, with an enormous number of controls... to
arrive at much of significance.

Look how much has gone into studies of triglyceride levels and
cardio-vascular studies. And in some ways the jury is still out.

g


.

Relevant Pages

  • Re: Caloric restriction and longevity?
    ... mortality, but no study examined this relationship in a non-Western ... of older Taiwanese to investigate whether serum DHEAS, ... examination, and blood sample. ... Discard all samples from those who had not died within those three years; ...
    (sci.bio.evolution)
  • DHEA and mortality
    ... Dehydroepiandrosterone Sulfate (DHEAS) and Risk for Mortality Among Older ... significant inverse relationship between DHEAS level and 3-year mortality ...
    (sci.med.diseases.cancer)
  • DHEA and mortality
    ... Dehydroepiandrosterone Sulfate (DHEAS) and Risk for Mortality Among Older ... significant inverse relationship between DHEAS level and 3-year mortality ...
    (sci.med.pathology)
  • DHEA and mortality
    ... Dehydroepiandrosterone Sulfate (DHEAS) and Risk for Mortality Among Older ... significant inverse relationship between DHEAS level and 3-year mortality ...
    (sci.anthropology)
  • DHEA and mortality
    ... Dehydroepiandrosterone Sulfate (DHEAS) and Risk for Mortality Among Older ... significant inverse relationship between DHEAS level and 3-year mortality ...
    (sci.med)