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Development of bioelectrical impedance-derived indices of fat and fat-free mass for assessment of nutritional status in childhood

A Corrigendum to this article was published on 07 May 2008



(1) To develop a method of manipulating bioelectrical impedance (BIA) that gives indices of lean and fat adjusted for body size, using a large normative cohort of children. (2) To assess the discriminant validity of the method in a group of children likely to have abnormal body composition.


Two prospective cohort studies.


Normative data: Avon Longitudinal Study of Parents and Children (ALSPAC), population based cohort; proof of concept study: tertiary feeding clinic and special needs schools.


Normative data: 7576 children measured aged between 7.25 and 8.25 (mean 7.5) (s.d.=0.2) years; proof of concept study: 29 children with either major neurodisability or receiving artificial feeding, or both, mean age 7.6 (s.d.=2) years.


Leg-to-leg (ZT) and arm-to-leg (ZB) BIA, weight and height. Total body water (TBW) was estimated from the resistance index (RI=height2/Z), and fat-free mass was linearly related to TBW. Fat mass was obtained by subtracting fat-free mass from total weight. Fat-free mass was log-transformed and the reciprocal transform was taken for fat mass to satisfy parametric model assumptions. Lean and fat mass were then adjusted for height and age using multiple linear regression models. The resulting standardized residuals gave the lean index and fat index, respectively.


In the normative cohort, the lean index was higher and fat index lower in boys. The lean index rose steeply to the middle of the normal range of body mass index (BMI) and then slowly for higher BMI values, whereas the fat index rose linearly through and above the normal range. In the proof of concept study, the children as a group had low lean indices (mean (s.d.) −1.5 (1.7)) with average fat indices (+0.21 (2.0)) despite relatively low BMI standard deviation scores (−0.60 (2.3)), but for any given BMI, individual children had extremely wide ranges of fat indices. The lean index proved more stable and repeatable than BMI.


This clinical method of handling BIA reveals important variations in nutritional status that would not be detected using anthropometry alone. BIA used in this way would allow more accurate assessment of energy sufficiency in children with neurodisability and may provide a more valid identification of children at risk of underweight or obesity in field and clinical settings.

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  • Azcue MP, Zello GA, Levy LD, Pencharz PB (1996). Energy expenditure and body composition in children with spastic quadriplegic cerebral palsy. J Pediatr 129, 870–876.

    Article  CAS  Google Scholar 

  • Bland J, Altman D (1995). Comparing methods of measurement: why plotting difference against standard method is misleading. Lancet 346, 1085–1087.

    Article  CAS  Google Scholar 

  • Chad KE, McKay HA, Zello GA, Bailey DA, Faulkner RA, Snyder RE (2000). Body composition in nutritionally adequate ambulatory and non-ambulatory children with cerebral palsy and a healthy reference group. Dev Med Child Neurol 42, 334–339.

    Article  CAS  Google Scholar 

  • Davies PS, Preece MA, Hicks CJ, Halliday D (1988). The prediction of total body water using bioelectrical impedance in children and adolescents. Ann Hum Biol 15, 237–240.

    Article  CAS  Google Scholar 

  • Deurenberg P, Smit HE, Kusters CS (1989). Is the bioelectrical impedance method suitable for epidemiological field studies? Eur J Clin Nutr 43, 647–654.

    CAS  PubMed  Google Scholar 

  • Fomon S, Haschke F, Ziegler E, Nelson S (1982). Body composition of refercne children from birth to age 10 years. Am J Clin Nutr 35, 1169–1175.

    Article  CAS  Google Scholar 

  • Foster KR, Lukaski HC (1996). Whole-body impedance – what does it measure? Am J Clin Nutr 64, 388S–396S.

    Article  CAS  Google Scholar 

  • Freeman JV, Cole TJ, Chinn S, Jones PRM, White EM, Preece MA (1995). Cross sectional stature and weight reference curves for the UK, 1990. Arch Dis Child 73, 17–24.

    Article  CAS  Google Scholar 

  • Fung EB, Samson-Fang L, Stallings VA, Conaway M, Liptak G, Henderson RC et al. (2002). Feeding dysfunction is associated with poor growth and health status in children with cerebral palsy. J Am Diet Assoc 102, 361–373.

    Article  Google Scholar 

  • Golding J, Pembrey M, Jones R, ALSPAC study team (2001). The Avon Longitudinal Study of Parents and Children. I. Study methodology. Paediatr Perinat Epidemiol 15, 74–87.

    Article  CAS  Google Scholar 

  • Goran MI, Shewchuk R, Gower BA, Nagy TR, Carpenter WH, Johnson RK (1998). Longitudinal changes in fatness in white children: no effect of childhood energy expenditure. Am J Clin Nutr 67, 309–316.

    Article  CAS  Google Scholar 

  • Houtkooper LB, Lohman TG, Going SB, Howell WH (1996). Why bioelectrical impedance analysis should be used for estimating adiposity. Am J Clin Nutr 64, 436S–448S.

    Article  CAS  Google Scholar 

  • Jebb SA, Cole TJ, Doman D, Murgatroyd PR, Prentice AM (2000). Evaluation of the novel Tanita body-fat analyser to measure body composition by comparison with a four-compartment model. Br J Nutr 83, 115–122.

    Article  CAS  Google Scholar 

  • Kushner RF, Schoeller DA, Fjeld CR, Danford L (1992). Is the impedance index (ht2/R) significant in predicting total body water? Am J Clin Nutr 56, 835–839.

    Article  CAS  Google Scholar 

  • Liu LF, Roberts R, Moyer-Mileur L, Samson-Fang L (2005). Determination of body composition in children with cerebral palsy: bioelectrical impedance analysis and anthropometry vs dual-energy x-ray absorptiometry. J Am Diet Assoc 105, 794–797.

    Article  Google Scholar 

  • Lohman TG (1989). Assessment of body composition in children. Paediatr Exerc Sci 1, 21.

    Article  Google Scholar 

  • Maynard LM, Wisemandle W, Roche AF, Chumlea WC, Guo SS, Siervogel RM (2001). Childhood body composition in relation to body mass index. Pediatrics 107, 344–350.

    Article  CAS  Google Scholar 

  • Parker L, Reilly JJ, Slater C, Wells JC, Pitsiladis Y (2003). Validity of six field and laboratory methods for measurement of body composition in boys. Obes Res 11, 852–858.

    Article  Google Scholar 

  • Reilly J, Wilson J, McColl J, Carmichael M, Durnin J (1996). Ability of biolectric impedance to predict fat-free mass in prepubertal children. Pediatr Res 39, 176–179.

    Article  CAS  Google Scholar 

  • Rennie KL, Livingstone MB, Wells JC, McGloin A, Coward WA, Prentice AM et al. (2005). Association of physical activity with body-composition indexes in children aged 6–8 y at varied risk of obesity. Am J Clin Nutr 82, 13–20.

    Article  CAS  Google Scholar 

  • Schaefer F, Georgi M, Zieger A, Scharer K (1994). Usefulness of bioelectic impedance and skinfold measurements in predicting fat-free mass derived from total body potassium in children. Pediatric Research 35, 617–624.

    Article  CAS  Google Scholar 

  • Smye S, Sutcliffe J, Pitt E (1993). A comparison of four commercial systems used to measure whole-body electrical impedance. Physiol Meas 14, 473–478.

    Article  CAS  Google Scholar 

  • Stallings VA, Cronk CE, Zemel BS, Charney EB (1995). Body composition in children with spastic quadriplegic cerebral palsy. J Pediatr 126, 833–839.

    Article  CAS  Google Scholar 

  • Sullivan PB, Alder N, Bachlet AM, Grant H, Juszczak E, Henry J et al. (2006). Gastrostomy feeding in cerebral palsy: too much of a good thing? Dev Med Child Neurol 48, 877–882.

    Article  Google Scholar 

  • Wells JC, Cole TJ (2002). Adjustment of fat-free mass and fat mass for height in children aged 8 y. Int J Obes Relat Metab Disord 26, 947–952.

    Article  CAS  Google Scholar 

  • Wells JC, Fuller NJ, Dewit O, Fewtrell MS, Elia M, Cole TJ (1999). Four-component model of body composition in children: density and hydration of fat-free mass and comparison with simpler models. Am J Clin Nutr 69, 904–912.

    Article  CAS  Google Scholar 

  • Wells JC (2003). Body composition in childhood: effects of normal growth and disease. Proc Nutr Soc 62, 521–528.

    Article  CAS  Google Scholar 

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The authors are grateful to all the mothers who took part in the ALSPAC study and to the midwives for their cooperation and help in recruitment and to Pauline Emmett and Imogen Rogers for recognizing the value of including BIA in the assessment protocol. The whole ALSPAC study team comprises interviewers, computer technicians, laboratory technicians, clerical workers, research scientists, volunteers and managers who continue to make the study possible. The authors are also grateful to the special schools for their support of the proof of concept study and to Sarah Rosser who collected the repeatability data. This analysis was supported by funding from British Heart Foundation. The main ALSPAC study was funded by the Wellcome Trust, the Medical Research Council, the University of Bristol, the Department of Health, the Department of the Environment and various other funders. British Heart Foundation, The Wellcome Trust, the Medical Research Council, the University of Bristol, the Department of Health, the Department of the Environment, and other funders.

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Correspondence to C M Wright.

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Guarantor: CM Wright.

Appendix 1

Appendix 1

Table A1

Table a1 Parameter estimates used to estimate TBW, fat-free mass, and the lean and fat index

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Wright, C., Sherriff, A., Ward, S. et al. Development of bioelectrical impedance-derived indices of fat and fat-free mass for assessment of nutritional status in childhood. Eur J Clin Nutr 62, 210–217 (2008).

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