应用生物电阻抗分析法检测营养不良病人的人体组成

目的 :应用生物电阻抗分析法 ,检测营养不良病人人体组成的改变。　方法 :中等程度以上营养不良住院病人 6 8例 ,其中男 4 0例 ,女 2 8例 ,年龄为 5 3± 16 (37～ 6 8)岁作为研究对象。 78名健康志愿者 (男 4 4 ,女 34)为对照者 ,年龄为 5 2± 11(38～ 6 2 )岁。人体组成测定应用HYDRAECF/ICF 4 2 0 0多频率生物电阻抗分析仪。　结果 :营养不良病人实际平均体重是理想体重的 6 8.8% ,其体质指数、肱三头肌皮皱厚度、臂肌围、白蛋白、转铁蛋白、前白蛋白及淋巴细胞总数均明显低于正常值 ,属中、重度营养不良范围。营养不良病人的体脂、瘦组织群、体细胞群及细胞内液含量均明显低于健康志愿者 (P <0 .0 5 )。细胞外液含量比例高于健康志愿者 (5 8.5 %vs 4 8.5 % ) (P <0 .0 5 )。　结论 :营养不良时人体体脂、瘦组织群和体细胞群存在不同程度的消耗 ,机体细胞内液丢失 ,而细胞外液增加。     

Body composition in underweight elderly subjects: reliability of bioelectrical impedance analysis

BACKGROUND AND AIMS: In underweight elderly subjects it is important to estimate body composition and particularly fat-free mass (FFM). Bioelectrical impedance analysis (BIA) is a non-invasive method in determining FFM, but its usefulness in these frail subjects should be verified. The aim of this study is to verify in underweight elderly people the reliability of previously published BIA formulas in detecting FFM. METHODS: Fifty-seven hospitalized elderly subjects (27 males and 30 females) with body mass index <20 kg/m(2) were selected. In all subjects, FFM was detected by dual energy X-ray absorptiometry. Moreover, BIA measurements were performed at standard frequency (50 kHz and 800 microA) and FFM was derived using the main previous published BIA equations. Results: In men, Kyle and Rising equations gave acceptable estimates of FFM with a mean error, respectively, of 1+/-1.9 and 1.4+/-1.7 kg. Also RJL formula could be used after adjusting for a correction factor. In women, no equation seemed sufficiently reliable to estimate FFM. CONCLUSIONS: BIA method seems useful to evaluate body composition in underweight elderly men but it seems to have intrinsic limits in women. Nevertheless, the variability in behavior of the different equations suggests to be careful in adopting BIA equations.