Intervention and Prevention
Obesity (2008) 16 5, 1039–1044. doi:10.1038/oby.2007.84
Relative Contributions of Adiposity and Muscularity to Physical Function in Community-dwelling Older Adults
Catherine M. Jankowski1, Wendolyn S. Gozansky1, Rachael E. Van Pelt1, Margaret L. Schenkman2, Pamela Wolfe3, Robert S. Schwartz1 and Wendy M. Kohrt1
- 1Department of Medicine, Division of Geriatric Medicine, University of Colorado Denver, Aurora, Colorado, USA
- 2School of Medicine, Physical Therapy Program, University of Colorado Denver, Aurora, Colorado, USA
- 3Department of Preventive Medicine and Biometrics, University of Colorado Denver, Aurora, Colorado, USA
Correspondence: Catherine M. Jankowski (catherine.jankowski@uchsc.edu)
Received 13 March 2007; Accepted 12 July 2007; Published online 21 February 2008.
Abstract
Objective:
To determine the relative contributions of adiposity and muscularity to multi-dimensional performance-based and perceived physical function in older adults living independently.
Methods and Procedures:
Data from 109 women and men, aged 60 or older, with low serum dehydroepiandrosterone (DHEA) sulfate levels were included in this cross-sectional analysis of baseline measures from a single-site, randomized, controlled trial of DHEA replacement therapy. Physical function was determined by means of performance on the 100-point Continuous Scale-Physical Functional Performance (CS-PFP) test and by self-reporting using the physical function subscale of the Medical Outcomes Short Form-36 (SF36PF). Body composition was measured by dual-energy X-ray absorptiometry (DXA). Linear regression analyses were used to determine the contributions of body mass index (BMI; kg body mass/m2), fat index (FI; kg fat/m2), and appendicular skeletal muscle index (ASMI; kg muscle/m2) to the CS-PFP and SF36PF scores, adjusted for age and sex.
Results:
Age-adjusted regression analyses indicated that FI, but not ASMI, was a significant (P < 0.001) determinant of CS-PFP (R 2 = 0.54) and SF36PF (R 2 = 0.37). When adjusted for age and sex, BMI was nearly as good a predictor of CS-PFP (R 2 = 0.50) and SF36PF (R 2 = 0.34) as FI.
Discussion:
Adiposity was a stronger predictor of measured and self-reported physical function than was muscularity in older adults living independently. BMI, adjusted for sex, is a reasonable substitute for adiposity in the prediction of physical function.
