Amanda Jansen van Rensburg
University of Pretoria, South Africa
Title: Agreement of fat-free mass by dual-energy x-ray absorptiometry and calculated from bioelectrical impedance equations in pre-adolescent school children (Pretoria, South Africa).
Biography
Biography: Amanda Jansen van Rensburg
Abstract
absorptiometry (DXA) are accurate, precise and suitable for children. They are however, costly, technically challenging, time-consuming and not always readily available. Bioelectrical impedance analysis (BIA) is a convenient alternative. The Seca medical body composition analyzer (mBCA) 515/514 has not yet been validated for prediction of body composition in children. The objective of the study was to determine the agreement between fat-free mass (FFM), measured by DXA and calculated from multifrequency bioelectrical impedance using published prediction equations, in pre-adolescent children. Data were collected by means of a cross-sectional study on 83 conveniently sampled African children (44 girls, 39 boys; mean (SD) age 8.5 (1.4) years). Standing height was measured with a Seca 274 stadiometer and body weight using the seca mBCA 515/514. Body composition was measured with the mBCA 515/514 and whole-body DXA scans. Differences between measured and calculated FFM were tested for significance by paired sample t-tests. Agreement between FFM from the reference method and the individual equations was explored using the Bland-Altman method and the intra-class correlation coefficients. Statistically significant differences (p<0.05) between calculated and measured FFM were observed in all but three equations. Acceptable limits of agreement were identified in two of these equations. For these equations, the Bland-Altman analysis showed a mean difference close to zero of 0.15 (-2.683; 2.374) and 0.01 (-2.681 ; 2.663). These two equations can be used to calculate FFM in this specific population using impedance values from the Seca mBCA 515/514.