Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Human Movement Science Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Gillsings School of Public Health, Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Human Movement Science Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Clin Nutr ESPEN. 2020 Dec;40:401-405. doi: 10.1016/j.clnesp.2020.09.033. Epub 2020 Oct 13.
BACKGROUND & AIMS: Body composition assessment has large variability. A dual-energy x-ray absorptiometry (DXA) derived four compartment (4C) method has been developed as an accurate and reliable method for assessing body composition in overweight/obese adults. This investigation was aimed at understanding the validity of the DXA-derived 4C equation for use in normal weight individuals, stratified by sex, and with varied levels of lean mass. Values were also compared against DXA alone.
78 men and women (68% female; Mean ± SD; Age: 19.2 ± 1.2 yrs; Ht: 168.8 ± 9.1 cm; Wt: 62.8 ± kg) completed a traditional 4C body composition reference assessment. Body composition was also assessed using a DXA-4C model. Validity was evaluated from total error (TE), constant error, and standard error of the estimate (SEE). Proportional bias was identified with Bland Altman plots.
Although significantly different (p < 0.05) the DXA-4C model produced ideal TE and SEE compared to the 4C criterion for all body composition outcomes of fat mass (TE: 2.1 kg; SEE: 1.9 kg), lean mass (TE: 2.1 kg; SEE: 1.8 kg), and percent body fat (TE: 3.6%; SEE: 3.4%). Validity results did not differ for men vs. women. DXA-4C estimates were slightly better in individuals with higher lean mass. DXA alone resulted in significantly greater error than DXA-4C (p < 0.05).
Body composition assessed from DXA-4C is an accurate approach, particularly in those with high levels of lean mass. This model appears to be more accurate than DXA alone.
人体成分评估存在较大的变异性。双能 X 射线吸收法（DXA）衍生的四分量（4C）方法已被开发为评估超重/肥胖成年人身体成分的准确可靠方法。本研究旨在了解 DXA 衍生的 4C 方程在正常体重个体中的有效性，按性别分层，并具有不同水平的瘦体重。还将这些值与 DXA 单独进行了比较。
78 名男性和女性（68%为女性；平均值±标准差；年龄：19.2±1.2 岁；身高：168.8±9.1 厘米；体重：62.8±kg）完成了传统的 4C 身体成分参考评估。身体成分也使用 DXA-4C 模型进行评估。通过总误差（TE）、恒定误差和估计的标准误差（SEE）评估有效性。比例偏差通过 Bland Altman 图确定。
尽管 DXA-4C 模型产生的结果与 4C 标准相比存在显著差异（p<0.05），但对于所有身体成分结果（脂肪量的 TE：2.1kg；SEE：1.9kg）、瘦体重（TE：2.1kg；SEE：1.8kg）和体脂百分比（TE：3.6%；SEE：3.4%），DXA-4C 模型的 TE 和 SEE 都非常理想。男性与女性的有效性结果没有差异。在瘦体重较高的个体中，DXA-4C 估计值略好。DXA 单独使用的误差明显大于 DXA-4C（p<0.05）。
DXA-4C 评估的身体成分是一种准确的方法，特别是在瘦体重水平较高的个体中。该模型似乎比 DXA 单独使用更准确。
