Re: Body composition analysis? (Was: Death rates in people with BMIs over 30?)

[Guest guest]

This is an odd study. For a start it could easily be skewed by

inadequate consideration of individuals in the low BMI group (BMI

18.5). The high mortality in this group is likely to be confounded by

those with existing disease, overt or covert. Low BMI in the fit

elderly - long-term runners for example - does not imply increased

mortality.

In my view, 102 cms waist circumference (40 inches) cutoff for males

as a threshold for risk is too high. I know this is an US NIH

standard, but other opinions suggest the cutoff should be as low as

94 cms men, and 80 cms women. (Outliers include Asians (lower) and

perhaps Pacific Islanders (higher). The International Diabetes

Federation uses these lower standards.

Get your tape measures men and women of Supertraining. At 102 cms

waist I would definitely be " fat " ! (I have 10 cms to go.)

Ultimately, in health terms, what matters is the constellation of

metabolic abnormalities. For 'metabolic syndrome' to be diagnosed you

generally need three of the following:

-- Central obesity (however defined)

-- Low HDL cholesterol (under 40 mg/dl; 1.04 mmol/L for men - 50 and

1.29 women)

-- High triglycerides (>150 mg/dl; 1.7 mmol/L)

-- High blood glucose (>110 mg/dl; 6.1 mmol/L). (IDF says 100 and 5.6)

-- Hypertension, high blood pressure (>135-140 and >85-90 sys. and

dias.)

Interestingly, metabolic syndrome is also diagnosed in people

with 'normal' BMI. In one study, the risk rose significantly from BMI

18.5 upward. eg:

" Compared with men with BMI 18.5-20.9 kg/m(2), the odds for the

metabolic syndrome were 4.13 (95% CI 1.57-10.87) for men with BMI 21-

22.9 kg/m(2), 5.35 (2.41-11.86) for men with BMI 23-24.9 kg/m(2), and

9.08 (4.23-19.52) for men with BMI 25-26.9 kg/m . . . "

Diabetes Care. 2004 Sep;27(9):2222-8. Metabolic syndrome in normal

weight Americans: new definition of the metabolically obese, normal-

weight individual.

St-Onge MP, Janssen I, Heymsfield SB.

Carrying excess fat is risky, no matter where it is.

Gympie, Australia

>

> After reading this information that you posted I have the

following question:

>

> What tests were done to determine body fat vs. lean muscle mass?

>

> If I take any two people and measure their arms and waists I can

say that

> the person with the bigger arm and smaller waist has more muscle

mass than the

> person with larger waist and thin arms but really both could just

have a lot

> of fat on their arms - point being that size of a body part does

not = muscle

> mass; larger arms doesn't mean more muscle mass and smaller waist

doesn't

> mean more muscle mass

>

> Any thoughts on this please?

>

> Edwin Freeman, Jr.

> San Francisco, USA

> ==========================

>

> In a message dated 12/28/2008 1:26:49 A.M. Pacific Standard Time,

> discusdoc@... writes:

>

> ran across this paper on the topic:

>

> Decreased Muscle Mass and Increased Central Adiposity are

Independently

> Related to Mortality in Older Men

>

> S Goya Wannamethee, A Gerald Shaper, Lucy Lennon, and H

Whincup

>

> ABSTRACT

>

> Background: Aging is associated with significant changes in body

> composition. Body mass index (BMI; in kg/m2) is not an accurate

indicator of overweight

> and obesity in the elderly.

>

> Objective: We examined the relation between other anthropometric

indexes of

> body composition (both muscle mass and body fat) and all-cause

mortality in

> men aged 60†" 79 y. Design: The study was a prospective study of

4107 men aged 60

> †" 79y with no diagnosis of heart failure and who were followed

for a

> mean period of 6 y, during which time there were 713 deaths.

Results:

> Underweight men (BMI 18.5) had exceptionally high mortality

rates. After the

> exclusion of these men, increased adiposity

>

> [bMI, waist circumference (WC), and waist-to-hip ratio] showed

little

> relation with mortality after adjustment for lifestyle

characteristics. Muscle mass

> [indicated by midarm muscle circumference

> (MAMC)] was significantly and inversely associated with mortality.

After

> adjustment for MAMC, obesity markers, particularly high WC ( 102

cm) and

> waist-to-hip ratio (top quartile), were associated with increased

mortality. A

> composite measure of MAMC and WC most effectively predicted

mortality. Men with

> low WC ( 102 cm) and above-median muscle mass showed the lowest

mortality

> risk. Men with WC 102 cm and above-median muscle mass showed

significantly

> increased mortality [age-adjusted relative risk: 1.36;95%CI: 1.07,

1.74),

> and this increased to 1.55 (95% CI: 1.01, 2.39) in those with WC

102 and low

> MAMC. Conclusion:

>

> The findings suggest that the combined use of both WC and MAMC

provides

> simple measures of body composition to assess mortality risk in

older men. Am J

> Clin Nutr 2007;86:1339†" 46.

>

> ==========================

>