Bioelectrical impedance analysis and age-related differences of body composition in the elderly.
OBJECTIVE
Significant changes in body composition that have important health related effects may occur in the elderly. In this study, we evaluated the bioelectrical characteristics in a large group of apparently healthy Caucasian men in the age range 50-80 years, as a function of age and body mass index.


METHODS
We studied 315 men with ages ranging from 50 to 80 years. They were divided into three groups according to body mass index (kg/m(2)): 18.5-24.9 normoweight (NW); 25.0-29.9 overweight (OW); > or =30 obese (OB), and they were classified in nine age subgroups: 50-59 (young-old, YO); 60-69 (old, O); 70-80 (oldest, OS). Fat-free mass, fat mass and body cell mass were investigated using conventional bioelectrical impedance analysis. Body composition was also assessed by bioelectrical impedance vector analysis and the RXc graph method.


RESULTS
Body cell mass decreased significantly with age particularly in subgroups of the OW and OB groups (p<0.05). Mean vector displacement followed a definite pattern, with downward migration of the ellipses in the OW and OB groups, after 70 years of age.


CONCLUSIONS
Ageing was associated with a pattern of vector bioelectrical impedance analysis indicating decreased soft tissue mass (fat-free mass and body cell mass), particularly in OW and OB-OS healthy men. We suggest 70 years of age as a cut-off for significant quantitative and qualitative (tissue electrical properties) body composition modifications. This bioelectrical impedance vector analysis pattern associated with ageing and across the different body mass index categories, may be useful for clinical purposes and can be used in geriatric routine to accurately assess the body composition modifications occurring in the elderly.
Guida
Bruna
B
Department of Neuroscience, Physiology Nutrition Unit, University Federico II, Naples, Italy. bguida@unina.it
Laccetti
Roberta
R
Gerardi
Clara
C
Trio
Rossella
R
Perrino
Nunzia Ruggiero
NR
Strazzullo
Pasquale
P
Siani
Alfonso
A
Farinaro
Eduardo
E
Colantuoni
Antonio
A
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D001823:Body Composition; D015992:Body Mass Index; D017097:Electric Impedance; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000209:etiology / Q000378:metabolism