Date of Award

2016

Degree Type

Thesis

Degree Name

Master of Science in Kinesiology

Department

Kinesiology

First Advisor

Matthew Delmonico

Abstract

Segmental multi-frequency bioelectrical impedance analysis (SMF-BIA) has been shown to be a valid, more portable, and less expensive alternative to dual energy x-ray absorptiometry (DXA) for the measurement of appendicular lean mass (ALM) in several populations. However, few studies have examined the validity of SMF-BIA specifically among populations of older women classified as sarcopenic or dynapenic. The aim of this cross sectional study was to investigate the accuracy of SMF-BIA compared to the gold standard DXA for the measurement of ALM among sarcopenic and/or dynapenic older women. Physical function, ALM, strength, and anthropometric tests were performed to determine the presence of sarcopenia and/or dynapenia in a sample of 25 older (72.3 ± 4.6 years) women using established sarcopenia classification criteria. Estimation of ALM using SMF-BIA and DXA were performed under standardized testing conditions. Both techniques were administered within the same hour with participants adequately hydrated, fasted, following urine elimination, and while wearing hospital scrubs. A Pearson correlation coefficient was used to determine a relationship between the two methods for ALM and agreement between the two techniques was assessed using a Bland-Altman plot method. Statistical significance was set at p < 0.05. A significant and strong correlation was observed between the two techniques with a Pearson’s correlation coefficient of 0.88 (95% CI= 0.75 to 0.95; p < 0.001). The Bland-Altman plot showed a mean difference of 0.5 kg and an indication of overall agreement between techniques. However, SMF-BIA overestimated ALM for one participant (-2.9 kg, 95% CI= -3.76 to -2.03) and underestimated ALM for another participant (1.8 kg, 95% CI= 0.98 to 2.71) compared to DXA. The findings indicate overall agreement between SMF-BIA and DXA for the estimation of ALM among older women with characteristics of sarcopenia, but SMF-BIA may overestimate or underestimate ALM in some individuals. These data suggest that SMF-BIA may be an acceptable alternative to DXA for the assessment of ALM in older women with characteristics of sarcopenia.

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