Portable A-Mode Ultrasound for Body Composition Assessment in Adolescents

Objectives: Ultrasound (US) imaging is a low-cost, highly feasible alternative method for monitoring the nutritional status of a population; however, only a few studies have tested the body composition agreement between US and reference standard methods, especially in adolescents. The purposes of this study were to assess the agreement of portable US with a reference standard method, dual-energy x-ray absorptiometry (DXA), for body fat percentage (BF%) in adolescents and to verify whether the use of a new mathematical model, based on the anatomic thickness obtained by US, is capable of improving BF% prediction.

Methods: This research was a descriptive study. Measures of total body mass, BF% on DXA, and BF% on US were collected from 105 adolescents.

Results: The participants included 71 male adolescents (median age ± interquartile range, 14.0 ± 2.0 years) and 34 female adolescents (13.0 ± 2.3 years). Ultrasound yielded significantly lower BF% values than DXA for male (mean ± SD, US, 9.6% ± 6.6%; DXA, 20.0% ± 7.2%; R= 0.848; P< .05) and female (US, 22.5% ± 5.7%; DXA, 30.3% ± 4.9%; R = 0.495; P < .05) participants. In addition, Bland-Altman analysis showed low concordance. When a multivariate regression was tested, the results improved for both sexes (US, 20.3% ± 4.6%; R= 0.848; P= .503) and female participants (US, 29.0% ± 5.7%; R = 0.712; P = .993) with a standard estimate of error of 1.57%.

Conclusions: This study has shown that US applied in a specific regression for BF% prediction in adolescents has a strong correlation with DXA as well as concordance with Bland-Altman analysis.