COMPARISONS BETWEEN DXA AND BIOIMPEDANCE DEVICES FOR APPENDICULAR LEAN MASS AND MUSCLE QUALITY IN HISPANIC ADULTS.

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 yrs.) participated in this study. ALM was measured with single-frequency (SFBIA), multi-frequency (MFBIA), and DXA. ALMTOTAL (left arm + right arm + left leg + right leg) and ALMARMS (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. MQIARMS was defined as the ratio between HGS and ALMARMS. MQITOTAL was established as the ratio between HGS and ALMTOTAL. SFBIA and MFBIA had strong correlations with DXA for all ALM and MQI metrics (CCC values ranged from 0.86 [MQIMFBIA-ARMS] to 0.97 [Arms LMSFBIA]; all p < 0.001). Equivalence testing varied between methods (e.g., SFBIA vs. DXA) when examining the different metrics (i.e., ALMTOTAL, ALMARMS, MQITOTAL, and MQIARMS). MQIARMS 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 ALMTOTAL and ALMARMS in a Hispanic population. However, SFBIA and MFBIA have better agreement with DXA when used to compute MQIARMS than MQITOTAL.