Quantification of whole-body and segmental skeletal muscle mass using phase-sensitive 8-electrode medical bioelectrical impedance devices.
Bioelectrical impedance analysis (BIA) provides noninvasive measures of skeletal muscle mass (SMM) and visceral adipose tissue (VAT). This study (i) analyzes the impact of conventional wrist-ankle vs segmental technology and standing vs supine position on BIA equations and (ii) compares BIA validation against magnetic resonance imaging (MRI) and dual X-ray absorptiometry (DXA).



One hundred and thirty-six healthy Caucasian adults (70 men, 66 women; age 40±12 years) were measured by a phase-sensitive multifrequency BIA (seca medical body composition analyzers 515 and 525). Multiple stepwise regression analysis was used to generate prediction equations. Accuracy was tested vs MRI or DXA in an independent multiethnic population.



Variance explained by segmental BIA equations ranged between 97% for total SMMMRI, 91-94% for limb SMMMRIand 80-81% for VAT with no differences between supine and standing position. When compared with segmental measurements using conventional wrist-ankle technology. the relationship between measured and predicted SMM was slightly deteriorated (r=0.98 vs r=0.99, P<0.05). Although BIA results correctly identified ethnic differences in muscularity and visceral adiposity, the comparison of bias revealed some ethnical effects on the accuracy of BIA equations. The differences between LSTDXAand SMMMRIat the arms and legs were sizeable and increased with increasing body mass index.



A high accuracy of phase-sensitive BIA was observed with no difference in goodness of fit between different positions but an improved prediction with segmental compared with conventional wrist-ankle measurement. A correction factor for certain ethnicities may be required. When compared with DXA MRI-based BIA equations are more accurate for predicting muscle mass.
Institut für Ernährungsmedizin, Universität Hohenheim, Stuttgart, Germany.|Institut für Humanernährung und Lebensmittelkunde, Christian-Albrechts-University Kiel, Kiel, Germany.
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A
Bosy-Westphal
Seca Gmbh &Co. KG., Hamburg, Germany.
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0000-0002-3753-8889
B
Jensen
Institut für Humanernährung und Lebensmittelkunde, Christian-Albrechts-University Kiel, Kiel, Germany.
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Braun
Institut für Humanernährung und Lebensmittelkunde, Christian-Albrechts-University Kiel, Kiel, Germany.
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Pourhassan
Body Composition Unit, New York Obesity Nutrition Research Center, St Luke's-Roosevelt Hospital, New York, NY, USA.
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D
Gallagher
Institut für Humanernährung und Lebensmittelkunde, Christian-Albrechts-University Kiel, Kiel, Germany.
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MJ
Müller
D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D000368:Aged; D001823:Body Composition; D017097:Electric Impedance; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D055815:Young Adult