METABOLIC ACTIVITY IN LIMB AND TRUNK LEAN AND FAT TISSUE IN HEALTHY OLDER ADULTS

Abstract

1890 The purpose of this study was to investigate the relationship among limb lean tissue (LL), trunk lean tissue (TL), total fat mass (FM), and resting energy expenditure (REE) in healthy older adults. FM, LL, and TL were assessed by dual energy x-ray absorptiometry, and REE was measured after an overnight fast using indirect hood calorimetry in 38 adults (22 F, 16 M; 66.7±.7 yr, 169.0±1.6 cm, 70.8±2.4 kg). Zero-order linear correlations indicated that LL (r=.82, p<.001), TL (r=.87, p<.001), and FM (r=.38, p<.02) were all significantly related to REE. After adjusting for other variables in the model, partial correlations showed that TL (R=.48, p<.003) and FM (R=.63, p<.000) were independently related to REE but LL (R=.15, p<.378) was not independently related to REE. The slope from multiple regression analysis for TL was over 4 times larger (28.2 kcal/kg) than for FM (5.9 kcal/kg) and LL (5.8 kcal/kg). Findings must be interpreted cautiously due to multicollinearity between lean tissue variables. Since a major contributor of TL is metabolically active organ tissue, it is possible the larger slope for TL is due to differences in organ mass. Further studies are needed to address the interrelationship between lean tissue, FM and REE in older adults. Supported by the Ralph L. Smith Foundation.