Reproducibility of dual-energy X-ray absorptiometry measurements in prepubertal girls

Objective: Regulation of growth and development, clinical assessment, and obesity are among the areas of nutrition-related research, wherein accurate assessment of body composition is important. We want to test the hypothesis that dual-energy X-ray absorptiometry (DXA) measurements are reproducible in healthy girls. Research Methods and Procedure,, We determined total body composition measurements in healthy prepubertal girls using DXA twice, 6 weeks apart. Results: We studied 61 healthy, normal-weight, prepubertal girls, aged 4.8 years to 10.3 years. The girls' DXA-derived mean weight between visits 1 and 2 significantly increased (27.14 kg vs. 27.80 kg, p<0.0001), The increased weight was due to significant increases in total body fat-free mass (FFM) (19.53 kg vs. 19.89 kg, p<0.001): total body bone mass (1.05 kg vs. 1.07 kg, p<0.0001), and total body fat mass (7.61 kg vs. 7.91 kg, p<0.03), The girls' DXA-derived mean total hunk mass between visits 1 and 2 significantly increased (11.23 kg vs. 11.63 kg, p<0.0001), as did total leg mass (9.33 kg vs. 9.53 kg, p<0.001), although no significant differences were observed in total arm mass (2.52 kg vs. 2.54 kg, p = 0.37). The Pearson coefficient of correlation (r) and total coefficient of variation (CV) for intraindividual measurements by DXA were: weight-r = 0.99, CV = 1.97%; total body FFM-r = 0.96, CV = 2.30%; total body bone mass-r = 0.99, CV = 2.08%; total body fat mass-r = 0.96, CV = 6.55%; percentage total body fat-0.91, CV = 5.69%; total hunk mass-r = 0.96, CV = 3.59%; total arm mass-r = 0.95, CV = 4.09%; and total leg mass-r = 0.99, CV = 2.75%. Discussion: Total body FFM; total body bone mass, total body fat mass, percentage of total body fat mass, as well as regional mass determinations by DXA, were highly reproducible in healthy normal-weight, prepubertal girls. We highly recommend the use of DXA for total body composition studies in girls aged 5 years to 10 years.