Alemán-Mateo Heliodoro, Romero Julián Esparza, Morales Nayeli Macías, Salazar Gabriela, Triana Manuel Hernández, Valencia Mauro E
División de Nutrición, Centro de Investigación en Alimentación y Desarrollo, Carretera a la Victoria Km. 0.6, Apartado Postal 1735, 83000 Hermosillo, México.
Gerontology. 2004 Nov-Dec;50(6):366-72. doi: 10.1159/000080174.
In Mexico, there is scarce information about the body composition in the elderly. Some researchers have measured body fat by anthropometry and bioelectrical impedance. These techniques are practical and can be used in the field; however, proper validation is required. This implies the use of accurate and precise methods. In the elderly, Siri's three-compartment (3C) model has been proposed as feasible alternative to the gold standard four-compartment model.
To evaluate the body composition by the 3C model and the relative validity of densitometry and hydrometry methods to assess the percentage body fat (%BF) in 37 healthy Mexican elderly subjects.
The body density was measured by air displacement plethysmography, total body water was evaluated by means of an isotopic dilution technique, and two different hydration factors were used to determine the fat-free mass. These measurements were used to calculate %BF by the 3C model. Accuracy and precision of the methods were tested by a two-way analysis of variance and regression procedures and bias by Bland and Altman analysis.
In men and women as a whole group, the %BF by the 3C model was 34.4 +/- 8.01. Women had higher values of %BF as compared with men (41.7 +/- 3.7 vs. 29.4 +/- 6.4; p < 0.0001). The regression procedures showed that air displacement plethysmography was accurate and precise only in women and in the whole group. Regression analyses of %BF by total body water (using both hydration factors) and 3C model showed that the intercepts were not different from zero and that the slopes were not different from 1.0 in men and women separately and as group.
In this study, the total-body water method revealed a good relative validity (accuracy, precision, and freedom from bias) as compared with the 3C model in men and women both separately and as a group and may be acceptable for the estimation of %BF in individuals or groups of healthy elderly subjects.
在墨西哥，关于老年人身体成分的信息匮乏。一些研究人员通过人体测量法和生物电阻抗法测量体脂。这些技术很实用，可在现场使用；然而，需要进行适当的验证。这意味着要使用准确且精确的方法。在老年人中，已提出西里的三成分（3C）模型作为金标准四成分模型的可行替代方案。
通过3C模型评估37名健康墨西哥老年受试者的身体成分，以及评估密度测定法和比重测定法评估体脂百分比（%BF）的相对有效性。
通过空气置换体积描记法测量身体密度，采用同位素稀释技术评估总体水含量，并使用两种不同的水合因子来确定去脂体重。这些测量值用于通过3C模型计算%BF。通过双向方差分析和回归程序测试方法的准确性和精密度，并通过布兰德和奥特曼分析测试偏差。
在男性和女性的整个组中，3C模型得出的%BF为34.4±8.01。与男性相比，女性的%BF值更高（41.7±3.7对29.4±6.4；p<0.0001）。回归程序表明，空气置换体积描记法仅在女性和整个组中准确且精确。通过总体水含量（使用两种水合因子）和3C模型对%BF进行的回归分析表明，男性和女性分别以及作为一个组时，截距与零无差异，斜率与1.0无差异。
在本研究中，与3C模型相比，总体水含量法在男性和女性分别以及作为一个组时均显示出良好的相对有效性（准确性、精密度和无偏差），并且对于估计健康老年个体或群体的%BF可能是可接受的。
