P0052 PP TOTAL BODY FAT MASS ASSESSMENT IN ADOLESCENTS. AGREEMENT BETWEEN SKINFOLD THICKNESSES AND DUAL X-RAY ABSORPTIOMETRY

Abstract

Introduction: Anthropometric assessment of subcutaneous fat tissue by skinfold thicknesses (ST) is a fast and noninvasive method that has shown good correlation with the amount of body fat (BF) in children and adolescents (1). Several predicted equations have been performed to estimate %BF by ST. The aim of the study is to compare %BF estimated by skinfolds (%BFS) with %BF measured by dual X-ray absorptiometry (DXA) in adolescents. Methods: We have studied 280 adolescents aged 13 to 17 years (113 males and 167 females), that were representative of the city of Zaragoza (Spain). Weight, height, skinfold thicknesses were measured using standardized methodology (2). In all subjects, %BF was assessed by DXA (%BFD) and %BFS were calculated with all different prediction equations frequently used in clinical or epidemiological studies. Agreement between %BFS and %BFD was performed with Bland-Altman analysis method. Results: Correlations between %BFD and %BFS with all equations studied ranged from 0.88–0.93 in males and 0.81–0.88 in females (p<0.0001). Mean %BF differences between DXA and ST ranged from −1.34% to 0.53% (SD: −12.0 to 10.3%) in male adolescents depending on the equation; and from −0.01% to 6.25% (SD: −8.7 to 15.7%) in females. %BFD and %BFS did not show good agreement in Bland-Altman plots because differences between both methods increased and were excessive when the degree of adiposity also increased. Agreement, mean %BF differences and confidential intervals were appropriated only for equations performed by Slaughter et al. (3). Conclusion: In spite of a good correlation between %BFD and %BFS, most of the %BFS prediction equations are not accurate enough for adolescents, particularly in those with more adiposity. Slaughter et al. prediction equations have the best agreement for the assessment of %BF, both in males and in females.