Fat-free mass index and fat mass index percentiles in Caucasians aged 18–98 y

• DOI: 10.1038/sj.ijo.0802037
• Publication Date: 2002-07-28T21:36:31Z
• Authors: Y Schutz; UUG Kyle; C Pichard
• Keywords: Adult; Aged, 80 and over; Male; 0301 basic medicine; 2. Zero hunger; Adolescent; Middle Aged; Body Mass Index; 03 medical and health sciences; Cross-Sectional Studies; Adipose Tissue; Reference Values; Body Composition; Electric Impedance; Humans; Regression Analysis; Female; Obesity; Aged

To determine reference values for fat-free mass index (FFMI) and fat mass index (FMI) in a large Caucasian group of apparently healthy subjects, as a function of age and gender and to develop percentile distribution for these two parameters.Cross-sectional study in which bioelectrical impedance analysis (50 kHz) was measured (using tetrapolar electrodes and cross-validated formulae by dual-energy X-ray absorptiometry in order to calculate FFMI (fat-free mass/height squared) and FMI (fat mass/height squared).A total of 5635 apparently healthy adults from a mixed non-randomly selected Caucasian population in Switzerland (2986 men and 2649 women), varying in age from 24 to 98 y.The median FFMI (18-34 y) were 18.9 kg/m(2) in young males and 15.4 kg/m(2) in young females. No difference with age in males and a modest increase in females were observed. The median FMI was 4.0 kg/m(2) in males and 5.5 kg/m(2) in females. From young to elderly age categories, FMI progressively rose by an average of 55% in males and 62% in females, compared to an increase in body mass index (BMI) of 9 and 19% respectively.Reference intervals for FFMI and FMI could be of practical value for the clinical evaluation of a deficit in fat-free mass with or without excess fat mass (sarcopenic obesity) for a given age category, complementing the classical concept of body mass index (BMI) in a more qualitative manner. In contrast to BMI, similar reference ranges seems to be utilizable for FFMI with advancing age, in particular in men.