Four-compartment model and validation of deuterium dilution technique to estimate fat-free mass in Mexican youth

• Published in: Nutrition (Burbank, Los Angeles County, Calif.) Vol. 25; no. 2; pp. 194 - 199
• Main Authors: Ramírez, Erik, Ph.D, Valencia, Mauro E., Ph.D, Moya-Camarena, Silvia Y., Ph.D, Alemán-Mateo, Heliodoro, Ph.D, Méndez, Rosa O., M.Sc
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-02-2009; [New York]: Elsevier Science Inc; Elsevier; Elsevier Limited
• Subjects: Accuracy; Adolescent; adolescent nutrition; Adolescents; Age; Agreements; Bias; Biological and medical sciences; Body composition; Body Composition - physiology; Body fat; Body mass index; Body Water - metabolism; Body Water - physiology; Body Weight - physiology; bone density; Bone Density - physiology; Child; child nutrition; Children; Children & youth; Confidence intervals; Cross-Sectional Studies; Deuterium; Deuterium Oxide; deuterium oxide dilution technique; Dilution; Disease control; Estimates; estimation; fat free mass; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Gastroenterology and Hepatology; Gender; Humans; Hydration; Hydration constants; Indicator Dilution Techniques - standards; Isotopes; Laboratories; Male; Mathematics; Mexicans; Mexico; model validation; Muscle, Skeletal - metabolism; Nutrition research; Obesity - diagnosis; Obesity - epidemiology; Reproducibility of Results; Sensitivity and Specificity; Sex Factors; Studies; Vertebrates: anatomy and physiology, studies on body, several organs or systems; youth; Mexico; Deuterium; Hydration constants; Children; Adolescents; Body composition; Human; Validation; Hydration; Vertebrata; Dilution; Mammalia; Adolescent; Lean body mass; Models; Technique; Child
• ISSN: 0899-9007; 1873-1244
• DOI: 10.1016/j.nut.2008.08.007

Abstract Objective To validate the measurement of fat-free mass (FFM) with the deuterium oxide (D2 O) dilution technique (2C) against the four-compartment (4C) model in Mexican children. Methods This was designed as a cross-sectional, non-probabilistic study. Sixty subjects (30 male and 30 female) 6–14 y of age were recruited and completed the study during 5 mo. Total body water was measured using the D2 O dilution technique and FFM was calculated using Fomon's (6–10 y) and Lohman's (11–14 y) hydration constants. Body composition using the 4C model was calculated with Lohman's equation. Results Group mean accuracy showed no differences in FFM determined by D2 O dilution and the 4C model (1.24 kg, P > 0.4), by gender (2.1 kg, P > 0.2), or by method-by-gender interaction ( P > 0.7). FFMs were 26.9 and 25.7 kg by the 4C and 2C models, respectively. The test for coincidence of slopes and intercepts between the 2C and 4C models and the line of identity were not different ( P > 0.05). Precision by R2 explained 98% of the variance (standard error of the estimate 1.2 kg). Bias for the difference in FFM was not significant (−1.27, 95% confidence interval −1.5 to −0.9) and no association between the mean of the differences and the magnitude of the measurements was found ( P > 0.05). Mean bias was −1.27 kg for FFM ( P > 0.05), and limits of agreement were −3.1 to 0.8 kg. Conclusion The D2 O dilution technique used with these hydration constants was accurate, precise, and free of bias in Mexican children and adolescents compared with the 4C model.