Re: Caloric restriction and longevity?

On Wed, 22 Feb 2006 12:13:53 -0500 (EST), "g" <gillawton@xxxxxxxxxxxxx>
wrote:


"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

Exp Gerontol. 2003 Jan-Feb;38(1-2):35-46.

Calorie restriction in rhesus monkeys.

Mattison JA, Lane MA, Roth GS, Ingram DK.

Intramural Research Program, Gerontology Research Center, National
Institute on Aging, NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.

Calorie restriction (CR) extends lifespan and reduces the incidence and age
of onset of age-related disease in several animal models. To determine if
this nutritional intervention has similar actions in a long-lived primate
species, the National Institute on Aging (NIA) initiated a study in 1987 to
investigate the effects of a 30% CR in male and female rhesus macaques
(Macaca mulatta) of a broad age range. We have observed physiological
effects of CR that parallel rodent studies and may be predictive of an
increased lifespan. Specifically, results from the NIA study have
demonstrated that CR decreases body weight and fat mass, improves
glucoregulatory function, decreases blood pressure and blood lipids, and
decreases body temperature. Juvenile males exhibited delayed skeletal and
sexual maturation. Adult bone mass was not affected by CR in females nor
were several reproductive hormones or menstrual cycling. CR attenuated the
age-associated decline in both dehydroepiandrosterone (DHEA) and melatonin
in males. Although 81% of the monkeys in the study are still alive,
preliminary evidence suggests that CR will have beneficial effects on
morbidity and mortality. We are now preparing a battery of measures to
provide a thorough and relevant analysis of the effectiveness of CR at
delaying the onset of age-related disease and maintaining function later
into life.

.

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, ... effect remains after controlling for baseline health status. ... 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)
  • 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)