Decreased muscle mass and increased central adiposity are independently related to mortality in older men.
BACKGROUND
Aging is associated with significant changes in body composition. Body mass index (BMI; in kg/m(2)) 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.


METHODS
The study was a prospective study of 4107 men aged 60-79 y 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.


CONCLUSIONS
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.
Wannamethee
S Goya
SG
Department of Primary Care and Population Sciences, Royal Free and University College Medical School, London, United Kingdom. goya@pcps.ucl.ac.uk
Shaper
A Gerald
AG
Lennon
Lucy
L
Whincup
Peter H
PH
D050153:Abdominal Fat / Q000033:anatomy & histology; D050154:Adiposity; D000328:Adult; D000368:Aged; D001823:Body Composition; D015992:Body Mass Index; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D018482:Muscle, Skeletal / Q000033:anatomy & histology*; D049629:Waist-Hip Ratio