Segmental fat-free mass and lean soft mass: a comparative study with dual X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA) and anthropometry and development of anthropometric prediction models.

backgroundAlthough dual X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), and anthropometry (ANT) are commonly used to evaluate body composition, evidence on their agreement at the segmental level remains limited. This study aimed to compare intra-subject differences in DXA, BIA, and ANT for estimating segmental weight (SW), fat-free mass (FFM), and lean soft mass (LSM) and to examines sex-related influences, and to develop anthropometric prediction equations using DXA as the reference.

methodsA cross-sectional study was conducted on 258 young adults (157 males, 101 females). Participants were assessed using DXA, BIA, and ANT. SW, FFM, and LSM were estimated in kilograms and percentages for the upper limbs, trunk, and lower limbs using DXA and BIA. FFM was also estimated using anthropometry (ANT).

resultsSignificant intra-subject differences were observed between methods across most body segments (

conclusionsDXA, BIA, and ANT showed significant differences in estimating SW, FFM, and LSM, highlighting their lack of interchangeability. Sex was a significant factor, indicating its importance in body composition estimation. The new anthropometric equations showed good comparability with DXA, although their predictive performance was slightly lower in the upper limbs of females for FFM and LSM.