X-Message-Number: 30844
Date: Thu, 3 Jul 2008 19:15:36 -0700 (PDT)
From: 
Subject: body mass index and mortality in an 80-year-old population

[I typed in Table 2 from the following paper. The data suggests a simple
life extension strategy for 80 year olds. For those with a BMI of less than
25, the data suports consuming more calories from a healthy diet, and
increasing weight till it reachs at least BMI 25. An intervention trial
along these lines would seem to be indicated. I note also in passing that a
vitamin D supplement would be a prudent additive even for the control group,
so as to remove the confounding effects of vitamin D on mortality. Also note
that dietary protein is typically below the requirement to block sarcopenia
in older adults.]

BMI                  <18.5  18.5-24.9  >25
Cause of mortality %
Overall              25.0   16.0       7.7
Cardiovascular       11.5    2.8       3.9
Cancer                7.7    4.1       1.9
Pneumonia             3.8    3.2       1.3

______________________________________________________________

J Am Geriatr Soc. 2007 Jun;55(6):913-7.
Association between body mass index and mortality in an 80-year-old
population.
    Takata Y, Ansai T, Soh I, Akifusa S, Sonoki K, Fujisawa K, Awano S,
Kagiyama S, Hamasaki T, Nakamichi I, Yoshida A, Takehara T. Division of
General Internal Medicine, Department of Health Promotion, Kyushu Dental
College, Kitakyushu, Japan.
    OBJECTIVES: To evaluate the association between body mass index (BMI)
and all-cause mortality and cardiovascular disease (CVD) in an 80-year-old
population. DESIGN: Cohort study. SETTING: Community-based. PARTICIPANTS:
Six hundred ninety-seven of 1,282 (54.4%) 80-year-old candidate individuals.
MEASUREMENTS: The dates and causes of all deaths were followed up for 4
years. RESULTS: The relative hazard ratios (HRs) for all-cause mortality
were lower in overweight subjects (BMI > or= 25.0) than in underweight
(BMI<18.5) or normal-weight (BMI 18.5-24.9) subjects. Similarly, the HRs for
mortality due to CVD in overweight subjects were 78% less (HR=0.22, 95%
confidence interval (CI)=0.06-0.77) than those in underweight subjects, and
those in normal weight subjects were 78% less (HR=0.22, 95% CI=0.08-0.60)
than those in underweight subjects. Mortality due to CVD was 4.6 times (HR
4.64, 95% CI=1.68-12.80) as high in underweight subjects as in normal-weight
subjects, and mortality due to cancers was 88% lower (HR=0.12, 95%
CI=0.02-0.78) in the overweight group than in the underweight group. There
were no differences in mortality due to pneumonia. CONCLUSION: Overweight
status was associated with longevity and underweight with short life, due to
lower and higher mortality, respectively, from CVD and cancer.
PMID: 17537093

[Except for those with renal failure, any healthy diet for older adults
would likely have to include an increased protein ration, in order to
reverse aging associated changes in muscle mass.]

Am J Clin Nutr. 2008 Jan;87(1):150-5.
Dietary protein intake is associated with lean mass change in older,
community-dwelling adults: the Health, Aging, and Body Composition (Health
ABC) Study.
    Houston DK, Nicklas BJ, Ding J, Harris TB, Tylavsky FA, Newman AB, Lee
JS, Sahyoun NR, Visser M, Kritchevsky SB; Health ABC Study. Sticht Center on
Aging, Wake Forest University School of Medicine, Winston-Salem, NC
27157-1207, USA.
    BACKGROUND: Dietary surveys suggest that many older, community-dwelling
adults consume insufficient dietary protein, which may contribute to the
age-related loss of lean mass (LM). OBJECTIVE: The objective of the study
was to determine the association between dietary protein and changes in
total LM and nonbone appendicular LM (aLM) in older, community-dwelling men
and women. DESIGN: Dietary protein intake was assessed by using an
interviewer-administered 108-item food-frequency questionnaire in men and
women aged 70-79 y who were participating in the Health, Aging, and Body
Composition study (n=2066). Changes in LM and aLM over 3 y were measured by
using dual-energy X-ray absorptiometry. The association between protein
intake and 3-y changes in LM and aLM was examined by using multiple linear
regression analysis adjusted for potential confounders. RESULTS: After
adjustment for potential confounders, energy-adjusted protein intake was
associated with 3-y changes in LM [beta (SE): 8.76 (3.00), P=0.004] and aLM
[beta (SE): 5.31 (1.64), P=0.001]. Participants in the highest quintile of
protein intake lost approximately 40% less LM and aLM than did those in the
lowest quintile of protein intake (x+/-SE: -0.501+/-0.106 kg compared
with -0.883+/-0.104 kg for LM; -0.400+/-0.058 kg compared
with -0.661+/-0.057 kg for aLM; P for trend<0.01). The associations were
attenuated slightly after adjustment for change in fat mass, but the results
remained significant. CONCLUSION: Dietary protein may be a modifiable risk
factor for sarcopenia in older adults and should be studied further to
determine its effects on preserving LM in this population.
PMID: 18175749

Am J Clin Nutr. 2008 May;87(5):1562S-1566S.
Role of dietary protein in the sarcopenia of aging.
    Paddon-Jones D, Short KR, Campbell WW, Volpi E, Wolfe RR. Department of
Physical Therapy, The University of Texas Medical Branch, Galveston, TX
77555-1144, USA.
    Sarcopenia is a complex, multifactorial process facilitated by a
combination of factors including the adoption of a more sedentary lifestyle
and a less than optimal diet. Increasing evidence points to a blunted
anabolic response after a mixed nutrient meal as a likely explanation for
chronic age-related muscle loss. There is currently insufficient longer-term
research with defined health outcomes to specify an optimal value for
protein ingestion in elderly individuals. However, there is general
agreement that moderately increasing daily protein intake beyond 0.8 g x
kg(-1) x d(-1) may enhance muscle protein anabolism and provide a means of
reducing the progressive loss of muscle mass with age. The beneficial
effects of resistance exercise in aging populations are unequivocal.
However, research has not identified a synergistic effect of protein
supplementation and resistance exercise in aging populations. There is
little evidence that links high protein intakes to increased risk for
impaired kidney function in healthy individuals. However, renal function
decreases with age, and high protein intake is contraindicated in
individuals with renal disease. Assessment of renal function is recommended
for older individuals before they adopt a higher-protein diet.
PMID: 18469288

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