Espinosa-Cuevas Maria de los Angeles, Rivas-Rodríguez Lucía, González-Medina Enna Cristal, Atilano-Carsi Ximena, Miranda-Alatriste Paola, Correa-Rotter Ricardo
Departamento de Nefrologia y Metabolismo Mineral, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, México.
Rev Invest Clin. 2007 Jan-Feb;59(1):15-24.
To construct bivariate tolerance ellipses from impedance values normalized for height, which can be used in Mexican population for the assessment of body composition and compare them with others made in different populations.
Body composition was assessed by bioelectrical impedance analysis (BIA) in 439 subjects (204 men and 235 women), 18 to 82 years old, with a BMI between 18-31, using an impedanciometer Quadscan 4000. Resistance, reactance and phase angle were used to calculate bioelectrical impedance vectors and construct bivariate tolerance ellipses.
Mean age in men was 47.1 +/- 16 years and 42.4 +/- 13 for women, mean weight (73.4 + 9 vs. 60.1 + 8 kg) and height (1.68 vs. 1.55 m) were significant greater in men than in women (p < 0.002). Women in comparison with men, had greater values of impedance (622.96 +/- 66.16 S2 vs. 523.59 +/- 56.56 D) and resistance (618.96 +/- 66.10 Q 61.97 vs. 521.73 +/- 61.97 2), as well as of resistance and reactance standardized by height (398.24 +/-46.30 S2/m vs. 308.66 +/- 38.44) (44.32 +/- 7.14 i/m vs. 39.75 +/-6.29) respectively, with a significant difference in all of them (p < 0.0001). Similarly, the reactance was greater in females, nevertheless this difference did not reach statistical significance (68.96 +/- 11.17 vs. 67.18 +/- 10.3; p = 0.0861). The phase angle was greater in men than in women, with a statistically significant difference (7.330 +/- 0.88 vs. 6.360 +/- 0.97; p < 0.0001). Bivariate tolerance ellipses (50%, 75% and 95%) derived from Mexican subjects showed a significant upward deviation (p < 0.05) from previously published references from Mexican American and Italian populations. New ellipses of tolerance were therefore constructed for the Mexican population.
Bioimpedance vectors in Mexican subjects are significantly different from the existing ones, supporting the need of population specific bivariate tolerance ellipses for the evaluation of body composition.
根据身高标准化的阻抗值构建双变量耐受椭圆，用于墨西哥人群的身体成分评估，并与不同人群的相关椭圆进行比较。
采用Quadscan 4000阻抗仪，通过生物电阻抗分析（BIA）对439名年龄在18至82岁、BMI在18 - 31之间的受试者（204名男性和235名女性）进行身体成分评估。利用电阻、电抗和相位角计算生物电阻抗向量并构建双变量耐受椭圆。
男性的平均年龄为47.1±16岁，女性为42.4±13岁，男性的平均体重（73.4 + 9 vs. 60.1 + 8 kg）和身高（1.68 vs. 1.55 m）显著高于女性（p < 0.002）。与男性相比，女性的阻抗值（622.96±66.16 S2 vs. 523.59±56.56 D）、电阻值（618.96±66.10 Q 61.97 vs. 521.73±61.97 2）以及身高标准化后的电阻和电抗值（398.24±46.30 S2/m vs. 308.66±38.44）（44.32±7.14 i/m vs. 39.75±6.29）均更高，且差异均具有统计学意义（p < 0.0001）。同样，女性的电抗值更高，但差异未达到统计学意义（68.96±11.17 vs. 67.18±10.3；p = 0.0861）。男性的相位角大于女性，差异具有统计学意义（7.330±0.88 vs. 6.360±0.97；p < 0.0001）。来自墨西哥受试者的双变量耐受椭圆（50%、75%和95%）与先前发表的墨西哥裔美国人和意大利人群的参考椭圆相比存在显著向上偏差（p < 0.05）。因此，为墨西哥人群构建了新的耐受椭圆。
墨西哥受试者的生物阻抗向量与现有的显著不同，这支持了需要针对特定人群的双变量耐受椭圆来评估身体成分。
