Impact of body-composition methodology on the composition of weight loss and weight gain

• Published in: European journal of clinical nutrition Vol. 67; no. 5; pp. 446 - 454
• Main Authors: Pourhassan, M, Schautz, B, Braun, W, Gluer, C-C, Bosy-Westphal, A, Müller, M J
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.05.2013; Nature Publishing Group
• Subjects: 631/114/2397; 631/1647/245/1628; 692/699/1702/393; 692/700/1421/1770; Absorptiometry, Photon - methods; Adipose Tissue; Adult; Bias; Biological and medical sciences; Body Composition; Body fat; Body Fluid Compartments; Body Mass Index; Body size; Body Water; Body weight; Body weight gain; Body weight loss; Body Weights and Measures - methods; Changes; Clinical Nutrition; Densitometers; Densitometry; Densitometry - methods; Deuterium; Deuterium Oxide; Dilution; Drinking (Physiology); Dual energy X-ray absorptiometry; Electric Impedance; Epidemiology; Error reduction; Fat-free body mass; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Humans; Hydration; Indicator Dilution Techniques; Internal Medicine; Investigative techniques, diagnostic techniques (general aspects); Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Measurement; Medical sciences; Medicine; Medicine & Public Health; Metabolic Diseases; Methods; Middle Aged; Muscle, Skeletal; Muscles; Muscular system; Obesity; Osteoarticular system. Muscles; Public Health; Radiodiagnosis. Nmr imagery. Nmr spectrometry; review; Skeletal muscle; Systematic errors; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Weight; Weight Gain; Weight Loss; Weight reduction; Germany; magnetic resonance imaging (MRI); body composition; air-displacement plethysmography (ADP); four-compartment model (4C model); dual-energy X-ray absorptiometry (DXA); deuterium dilution (D; O; Methodology; Weight loss; Metabolic diseases; Nuclear magnetic resonance imaging; Weight gain; Body composition; Air plethysmography; Dilution; Dual energy absorptiometry; Medical imagery; Models
• ISSN: 0954-3007; 1476-5640; 1476-5640
• DOI: 10.1038/ejcn.2013.35

Background/Objectives: We intended to (i) to compare the composition of weight loss and weight gain using densitometry, deuterium dilution (D 2 O), dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI) and the four-compartment (4C) model and (ii) to compare regional changes in fat mass (FM), fat-free mass (FFM) and skeletal muscle as assessed by DXA and MRI. Subjects/Methods: Eighty-three study participants aged between 21 and 58 years with a body mass index range of 20.2–46.8 kg/m 2 had been assessed at two different occasions with a mean follow-up between 23.5 and 43.5 months. Body-weight changes within < 3% were considered as weight stable, a gain or a loss of >3% of initial weight was considered as a significant weight change. Results: There was a considerable bias between the body-composition data obtained by the individual methods. When compared with the 4C model, mean bias of D 2 O and densitometry was explained by the erroneous assumption of a constant hydration of FFM, thus, changes in FM were underestimated by D 2 O but overestimated by densitometry. Because hydration does not normalize after weight loss, all two-component models have a systematic error in weight-reduced subjects. The bias between 4C model and DXA was mainly explained by FM% at baseline, whereas FFM hydration contributed to additional 5%. As to the regional changes in body composition, DXA data had a considerable bias and, thus, cannot replace MRI. Conclusions: To assess changes in body composition associated with weight changes, only the 4C model and MRI can be used with confidence.