Huffman Derek M, Landy Niamh M, Potter Eva, Nagy Tim R, Gower Barbara A
University of Alabama at Birmingham, Department of Nutrition Sciences, Division of Physiology and Metabolism.
Int J Body Compos Res. 2005 Jan 1;3(1):25-30.
The purpose of this study was to assess the agreement of the Lunar DPX-L with the newer Prodigy dual-energy X-ray absorptiometer (DXA) for determining total-body and regional (arms, legs, trunk) bone mineral density (BMD), bone mineral content (BMC), fat mass (FM), lean tissue mass (LTM), total body mass (BM) and percent fat. A total of 106 apparently healthy males (n=34) and females (n=72) between the ages of 8-72 years were scanned consecutively on the DPX-L (software version 1.35) and Prodigy DXA (enCORE v. 3.6 software). Paired t-tests indicated significantly higher measures by Prodigy for BM (percent difference= 1.1%) and total-body BMD (2.2%), BMC (2.9%), FM (3.5%), and percent fat (2.8%; P<0.001), but not LTM (-0.2%). Regional estimates of FM and bone tended to be overestimated by Prodigy relative to DPX-L. The percent difference was most pronounced for FM in the arms (14.2%) and trunk (8.5%), BMD in the legs (4.9%), LTM in arms (5.6%), and BMC in the trunk (5.9%); but all total-body and regional measures were strongly and significantly correlated (P<0.001). The method of Bland and Altman indicated that the Prodigy overestimated DPX-L for BM (r=0.343; P<0.001), and total-body measures of BMD (r=0.460; P<0.001), and BMC (r=0.321; P<0.001) at higher values, as indicated by the significant, positive association between difference (Prodigy-DPX-L) versus mean ((Prodigy+DPX-L)/2). Regionally, Prodigy overestimated DPX-L for BMD in the legs, BMC in the legs and trunk, and FM in the arms at higher values (P<0.001). In contrast, FM in the legs was underestimated by Prodigy relative to DPX-L at higher values (P<0.001), and no regional bias was observed for LTM. In conclusion, we recommend that correction equations be used for comparing BM, total-body BMD and BMC, and regionally for BMD in the legs, BMC in the legs and trunk, and FM in the arms and legs. The use of correction equations for other estimates is not required for making direct comparisons.
本研究的目的是评估Lunar DPX-L与更新的双能X线骨密度仪（DXA）Prodigy在测定全身及局部（手臂、腿部、躯干）骨矿物质密度（BMD）、骨矿物质含量（BMC）、脂肪量（FM）、瘦组织量（LTM）、全身质量（BM）和体脂百分比方面的一致性。对106名年龄在8至72岁之间的明显健康男性（n = 34）和女性（n = 72），先后使用DPX-L（软件版本1.35）和Prodigy DXA（enCORE v. 3.6软件）进行扫描。配对t检验表明，Prodigy测得的BM（百分比差异 = 1.1%）、全身BMD（2.2%）、BMC（2.9%）、FM（3.5%）和体脂百分比（2.8%；P < 0.001）显著更高，但LTM（-0.2%）除外。相对于DPX-L，Prodigy对局部FM和骨的估计往往偏高。手臂（14.2%）和躯干（8.5%）的FM、腿部（4.9%）的BMD、手臂（5.6%）的LTM以及躯干（5.9%）的BMC的百分比差异最为明显；但所有全身和局部测量值均呈强显著相关（P < 0.001）。Bland和Altman方法表明，Prodigy在较高值时高估了DPX-L的BM（r = 0.343；P < 0.001）、全身BMD测量值（r = 0.460；P < 0.001）和BMC测量值（r = 0.321；P < 0.001），差异（Prodigy - DPX-L）与均值（（Prodigy + DPX-L）/2）之间存在显著正相关。在局部，Prodigy在较高值时高估了DPX-L的腿部BMD、腿部和躯干的BMC以及手臂的FM（P < 0.001）。相比之下，Prodigy在较高值时相对于DPX-L低估了腿部的FM（P < 0.001），且未观察到LTM的局部偏差。总之，我们建议使用校正方程来比较BM、全身BMD和BMC，以及局部的腿部BMD、腿部和躯干的BMC以及手臂和腿部的FM。进行直接比较时，其他估计值无需使用校正方程。
