Evaluation of lean body mass in obese children.
Multiple skinfold anthropometry (MSA) and bioelectrical impedance analysis (BIA) are useful as clinically non-invasive, inexpensive and portable techniques, although it is not clear if they can be used interchangeably in the same patient to routinely assess her/his body composition. In order to compare BIA, MSA and DXA in the estimation of lean body mass (LBM) of a pediatric obese population, 103 obese [body mass index (BMI) > 97th percentile] children (median age: 11 years; range: 5.4-16.7 years) underwent nutritional evaluation. After an overnight fast, the subjects' anthropometric measurements were performed by the same investigator: body weight (BW), height, skinfold thickness (four sites); fat body mass (FBM) using Brook or Durnin equations and dual X-ray absorptiometry (DXA). BIA was performed using a bioelectrical impedance analyzer (Analicor-Eugedia, 50 kHz) and Houtkooper's equation to calculate LBM. Linear regression analysis was performed to evaluate the relationship between the prediction of LBM by MSA, DXA and BIA. The differences between the three techniques were analysed using Student's t-test for paired observations and the Bland and Altmann method. A considerable lack of agreement was observed between DXA- and BIA-LBM (delta = -4.37 kg LBM; delta-2sigma = -11.6 kg LBM; delta+2sigma = +2.8 kg LBM); between DXA- and MSA-LBM (delta = -1.72 kg LBM; delta-2sigma = -8.2 kg LBM; delta+2sigma = +4.8 kg LBM) and between BIA- and MSA-LBM (delta = -2.65 kg LBM; delta-2sigma = -10.5 kg LBM; delta+2sigma = +5.2 kg LBM).


CONCLUSIONS
In obese children, DXA, BIA and MSA should not be used interchangeably in the assessment of LBM because of an unacceptable lack of agreement between them. The discrepancies between methods increase with the degree of obesity.
Campanozzi
Angelo
A
Pediatric Gastroenterology, Hepatology and Nutrition, Hôpital Necker-Enfants Malades, University of Paris 5 Renè Descartes, 149, Rue de Sevres, Paris, France.
Dabbas
Myriam
M
Ruiz
Jean Charles
JC
Ricour
Claude
C
Goulet
Olivier
O
D015502:Absorptiometry, Photon; D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D015596:Nutrition Assessment; D009765:Obesity / Q000175:diagnosis / Q000503:physiopathology*; D011379:Prognosis; D012720:Severity of Illness Index; D012885:Skinfold Thickness