Skinniness and Mortality

[Guest guest]

Hi folks:

I am becoming increasingly intrigued by possible links between

skinniness and mortality.

The Shanghai paper, PMID: 9839739, indicated that, no surprise to us,

those with higher BMIs tended to die more from cardio-vascular

diseases. But in their study the higher apparent mortality among

those with especially low BMIs (<18.5) was accounted for by an

increase in fatal infections.

I find this interesting for a number of reasons. First, because of a

previous discussion here (perhaps a year ago?) about data which

suggested slim people are more susceptible to infection. Second,

because of a piece in Dr. Mirkin's newsletter that claimed

considerable muscle mass was essential for good immune function (but

I never saw a reply to my email asking for his sources for this

claim). And now there is this evidence of a more concrete type from

the Shanghai study.

Of course it is possible that what applies to chinese people may not

apply to us. There are a lot of things that are different about

people in China.

But why is it that low BMI apparently results in lowered resistance

to, or ability to fight, infections? Is it lack of sufficient

reserve of lean body mass? Or lack of body fat? Or deficiencies of

nutrients that are vital for good immune function? The last of these

three should not apply to us. But the first two probably do apply to

most of us.

It is interesting that cancer, which one would have thought would

also be elevated where immune function was depressed, does not seem

to be higher. Either in the Shanghai study, or in restricted mice.

Indeed, quite the opposite in the latter case.

In the Shanghai study the fatal infectious diseases encountered most

in slim people were bronchitis, pneumonia, tuberculosis and viral

hepatitis including associated cirrhosis. So what is the connection

between slimness and these diseases?

And is lifting weights a solution? That depends, of course, on what

the connection is.

Thoughts?

Rodney.

--- In , " Rodney " <perspect1111@...>

wrote:

>

> Hi folks:

>

> Here is another paper on this topic which comes to the usual

> conclusions (round up usual suspects?). But it is interesting

because

> it indicates more about the causes of death, especially the causes

in

> those with BMI<18.5:

>

> " CONCLUSION: Underweight and overweight both are associated with an

> increased risk of death in middle-aged Chinese men who never smoked

> cigarettes. The increased total mortality in overweight men is

largely

> due to cardio- and cerebro-vascular diseases while the elevated

risk

> of death in underweight men is attributed primarily to causes of an

> infectious nature. "

>

> PMID: 9839739

>

> The full text is available free but I haven't yet read it.

>

> Rodney.

>