Agreement between skinfold-predicted percent fat and percent fat from whole-body bioelectrical impedance analysis in children and youth

Purpose. The purpose of the study was to determine the agreement of percent body fat estimates and obesity classification derived via whole-body bioelectrical impedance analysis (%BF-BIA) with percent body fat estimates and obesity classification from skinfolds (%BF-SF) in children and adolescents. Methods. BIA and SF data were collected on 609 boys and 645 girls aged 7 to 14 years. Results. Although moderate correlations were observed between the measures, Bland-Altman analyses revealed fixed and proportional bias, and 95% limits of agreement covered a range of over 20%BF. Agreement of obesity classification was moderately high in boys (κq=0.77) and girls (κq=0.81), but fewer children were classified as obese via %BF-BIA (14.5%) than via %BF-SF (19.8%). Conclusions. The results indicate that whole-body BIA provides %BF estimates that are systematically different from %BF estimates from skinfolds in children and adolescents.