Volume 90, Issue 5, November (2003), pp. 987-992 © The Author 2003
doi:10.1079/BJN2003983

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Evaluation of two foot-to-foot bioelectrical impedance analysers to assess body composition in overweight and obese adolescents

Stefano Lazzer¹, Yves Boirie¹, Martine Meyer², Michel Vermorel^3
1Protein–Energy Metabolism Research Unit, INRA, University of Auvergne, CRNH, 63001 , Clermont-Ferrand, France
²Hôtel-Dieu Paediatric Hospital, 63001 Clermont-Ferrand, France
³Energy and Lipid Metabolism Research Unit, INRA, Theix, 63122 St Genès Champanelle, France

 (Received 10 February 2003–Revised 25 June 2003–Accepted 23 July 2003)

The objective of the present study was to determine the accuracy of two foot-to-foot (FF) bioelectrical impedance analysers (BIA) to assess body composition in overweight and obese adolescents, compared with dual-energy X-ray absorptiometry (DXA) and hand-to-foot (HF) BIA. Body composition was assessed in fifty-three overweight or obese adolescents (BMI 27·9 (sd 4·1) kg/m²; aged 13–16 years) by DXA (Hologic QDR-4500; Hologic Inc., Bedford, MA, USA) and BIA (HF (BIA 101, RJL System, Detroit, IL, USA) and FF (Body Fat Monitor Scale BF-625, Tanita Corporation of America Inc., Arlington Heights, IL, USA; Téfal Bodymaster Vision, Téfal, Rumilly, France)). Bland–Altman tests showed that, compared with DXA, FF-Tanita and FF-Téfal underestimated (P<0·05) fat mass (FM) less than HF-BIA (−1·7 (sd 3·1), −0·7 (sd 5·8) and −2·3 (sd 2·2) kg respectively, P<0·001). However, the limits of agreement between DXA and FF-Tanita or FF-Téfal were much greater than those obtained with HF-BIA (−7·7 and +4·3, −12·0 and +10·6 v. −2·1 and +6·7 kg respectively). The differences between FM assessed using the FF-Tanita or the FF-Téfal analyser and DXA increased with the waist:hip ratio, and were higher in boys than in girls. The major limiting factor of FF-BIA was the inter-individual variability in FM estimates. In conclusion, FF-BIA and DXA are not interchangeable methods. FF-BIA could be acceptable to assess body composition in large groups of overweight or obese adolescents, but cannot be recommended for body composition assessment in obese subjects because of the large errors in individual estimates.

Keywords:
Obesity, Body composition, Foot-to-foot bioelectrical impedance analysis, Dual-energy X-ray absorptiometry

Abbreviations:
BIA, bioelectrical impedance analyser, BW, body weight, DXA, dual-energy X-ray absorptiometry, FF, foot-to-foot, FM, fat mass, FFM, fat-free mass, HF, hand-to-foot