Abstract
The purpose of this study was to compare single- and multi-frequency bioimpedance (BIA) devices against dual-energy X-ray absorptiometry (DXA) for appendicular lean mass (ALM) and muscle quality index (MQI) metrics in Hispanic adults. One hundred thirty-one Hispanic adults (18-55 years) participated in this study. ALM was measured with single-frequency bioimpedance analysis (SFBIA), multi-frequency bioimpedance analysis (MFBIA) and DXA. ALM(TOTAL) (left arm + right arm + left leg + right leg) and ALM(ARMS) (left arm + right arm) were computed for all three devices. Handgrip strength (HGS) was measured using a dynamometer. The average HGS was used for all MQI models (highest left hand + highest right hand)/2. MQI(ARMS) was defined as the ratio between HGS and ALM(ARMS). MQI(TOTAL) was established as the ratio between HGS and ALM(TOTAL). SFBIA and MFBIA had strong correlations with DXA for all ALM and MQI metrics (Lin's concordance correlation coefficient values ranged from 0·86 (MQI(MFBIA-ARMS)) to 0·97 (Arms LM(SFBIA)); all P < 0·001). Equivalence testing varied between methods (e.g. SFBIA v. DXA) when examining the different metrics (i.e. ALM(TOTAL), ALM(ARMS), MQI(TOTAL) and MQI(ARMS)). MQI(ARMS) was the only metric that did not differ from the line of identity and had no proportional bias when comparing all the devices against each other. The current study findings demonstrate good overall agreement between SFBIA, MFBIA and DXA for ALM(TOTAL) and ALM(ARMS) in a Hispanic population. However, SFBIA and MFBIA have better agreement with DXA when used to compute MQI(ARMS) than MQI(TOTAL).