Effects of fat mass and body fat distribution on resting metabolic rate in the elderly

• Published in: Metabolism, clinical and experimental clinical and experimental, 2001-08, Vol.50 (8), p.972-975
• Main Authors: L[uuml ]hrmann, Petra M., Herbert, Birgit M., Neuh[auml ]user-Berthold, Monika
• Format: Article
• Language: English
• Subjects: Adipose Tissue; Aged; Aged, 80 and over; Basal Metabolism; Biological and medical sciences; Body Composition; Development. Metamorphosis. Moult. Ageing; Female; Fundamental and applied biological sciences. Psychology; Humans; Intermediate and energetic metabolism; Male; Metabolisms and neurohumoral controls; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0026-0495; 1532-8600
• DOI: 10.1053/meta.2001.24871

The aim of the present study was to investigate the relationship between resting metabolic rate (RMR) and fat-free mass, fat mass, and body fat distribution in 164 women (age 60 to 85 years; body mass index [BMI], 18.5 to 35.6 kg/m2) and 98 men (age 60 to 85 years; BMI, 18.3 to 36.5 kg/m2). After an overnight fast, RMR was assessed by indirect calorimetry and body composition by bioelectrical impedance analysis. Waist-to-hip ratio (WHR) was used to determine fat distribution. Results from linear regression analysis showed that most of the variance in RMR could be attributed to fat-free mass in women (R2 = 0.54) and men (R2 = 0.44), respectively. Fat mass explained an additional 3% and 2% of the variability in RMR in women and men, respectively. In stepwise multiple regression analysis, considering body composition and fat distribution, only fat-free mass and WHR were significant predictors of RMR in both sexes. In addition to fat-free mass, in women 6% and in men 8% of the variability in RMR was attributable to WHR. Grouping subjects according to their WHR, RMR, and RMR adjusted for fat-free mass and fat mass showed a significant increase with increasing WHR in both sexes. Results indicate that RMR not only depends on fat-free mass but also is influenced by fat mass, especially by fat distribution. These findings support our hypothesis of an elevated RMR with increasing abdominal body fat as a direct consequence of its greater metabolic activity.