title: Calibration of bioelectrical impedance analysis for body composition assessment in Ethiopian infants using air-displacement plethysmography.
abstract: OBJECTIVE
  Assessment of infant body composition (BC) is crucial to understand the consequences of suboptimal nutritional status and postnatal growth, and the effects of public health interventions. Bioelectrical impedance analysis (BIA) is a feasible, relatively inexpensive and noninvasive method for assessing BC. However, very little research has been conducted in low- and middle-income populations, where efforts to prevent or treat malnutrition in early life are a public health priority. We aimed to develop equations for predicting fat-free mass (FFM) and fat mass (FM) based on BIA in 0- to 6-month-old Ethiopian infants.
  
  
  METHODS
  The study comprised a total of 186 BC assessments performed in 101 healthy infants, delivered at Jimma University Specialized Hospital. Infant air-displacement plethysmography (IADP) was the criterion method, whereas weight, length, sex, age and an impedance index (L(2)/Z50) were predictors. Prediction equations were developed using stepwise multiple linear regression and the accuracy was evaluated with a 10-fold cross-validation approach.
  
  
  RESULTS
  A linear regression model based on body weight, age and sex predicted FFM, estimated by IADP, with an adjusted R(2) and root mean square error (RMSE) of 0.94 and 200 g, respectively. Adding impedance index to the model resulted in a significantly improved model fit (R(2)=0.95; RMSE=181 g). For infants below 3 months of age, inclusion of impedance index did not contribute to an improved model fit for predicting FFM compared with a model already comprising weight, sex and age.
  
  
  CONCLUSIONS
  The derived equations predicted FFM with acceptable accuracy and may be used in future field surveys, epidemiological studies and clinical trials conducted in similar sub-Saharan African population groups aged 0-6 months.
authors.affiliation: Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.|Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: R
authors.initials: R
authors.lastname: Wibæk
authors.affiliation: Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Kæstel
authors.affiliation: Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.|Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: S R
authors.initials: SR
authors.lastname: Skov
authors.affiliation: Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: D L
authors.initials: DL
authors.lastname: Christensen
authors.affiliation: Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.|Department of Paediatrics and Child Health, College of Public Health and Medical Sciences, Jimma University, Jimma, Ethiopia.
authors.forename: T
authors.initials: T
authors.lastname: Girma
authors.affiliation: Childhood Nutrition Research Centre, UCL Institute of Child Health, London, UK.
authors.forename: J C K
authors.initials: JC
authors.lastname: Wells
authors.affiliation: Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Friis
authors.affiliation: Clinical Epidemiology, Steno Diabetes Center, Gentofte, Denmark.
authors.forename: G S
authors.initials: GS
authors.lastname: Andersen
mesh_terms: D000273:Adipose Tissue; D000367:Age Factors; D000886:Anthropometry / Q000379:methods*; D001823:Body Composition / Q000502:physiology*; D001825:Body Fluid Compartments; D001835:Body Weight; D002138:Calibration; D017097:Electric Impedance; D005002:Ethiopia; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D055641:Mathematical Concepts; D008954:Models, Biological; D009752:Nutritional Status; D010991:Plethysmography / Q000379:methods; D012737:Sex Factors
references.citation: Rev Endocr Metab Disord. 2012 Jun;13(2):93-101
references.pmid: 22418619
references.citation: Eur J Pediatr. 2007 Mar;166(3):215-22
references.pmid: 17047996
references.citation: Diabetes Obes Metab. 2007 Jul;9(4):521-39
references.pmid: 17587395
references.citation: Am J Clin Nutr. 2007 Jan;85(1):90-5
references.pmid: 17209182
references.citation: Am J Clin Nutr. 1989 Sep;50(3):435-43
references.pmid: 2773822
references.citation: Pediatr Res. 2003 Mar;53(3):486-92
references.pmid: 12595599
references.citation: Br J Nutr. 2009 Dec;102(12 ):1776-82
references.pmid: 19682404
references.citation: Acta Paediatr. 2010 Apr;99(4):563-8
references.pmid: 20064135
references.citation: Obesity (Silver Spring). 2010 Jun;18(6):1252-9
references.pmid: 19875994
references.citation: Lancet. 2013 Aug 3;382(9890):427-51
references.pmid: 23746772
references.citation: Am J Clin Nutr. 1989 Nov;50(5):1104-15
references.pmid: 2816795
references.citation: Physiol Meas. 2000 May;21(2):251-62
references.pmid: 10847192
references.citation: Stat Methods Med Res. 1999 Jun;8(2):135-60
references.pmid: 10501650
references.citation: Am J Clin Nutr. 1999 Nov;70(5):847-53
references.pmid: 10539745
references.citation: Br J Nutr. 2012 May;107(10):1545-52
references.pmid: 21917194
references.citation: Am J Clin Nutr. 2013 Oct;98(4):885-94
references.pmid: 23985805
references.citation: Acta Diabetol. 2003 Oct;40 Suppl 1:S246-9
references.pmid: 14618484
references.citation: Eur J Clin Nutr. 2013 Jan;67 Suppl 1:S34-9
references.pmid: 22252106
references.citation: Eur J Clin Nutr. 2013 Jan;67 Suppl 1:S79-85
references.pmid: 23299875
references.citation: Acta Diabetol. 2003 Oct;40 Suppl 1:S212-5
references.pmid: 14618476
references.citation: Pediatr Res. 2011 Nov;70(5):501-6
references.pmid: 21772228
references.citation: Am J Clin Nutr. 1999 May;69(5):904-12
references.pmid: 10232629
references.citation: World Health Organ Tech Rep Ser. 1995;854:1-452
references.pmid: 8594834
references.citation: PLoS One. 2013 Oct 18;8(10):e76426
references.pmid: 24204625
references.citation: Nutr Rev. 2012 Jan;70(1):3-21
references.pmid: 22221213
references.citation: Am J Clin Nutr. 1982 May;35(5 Suppl):1169-75
references.pmid: 7081099
references.citation: Am J Clin Nutr. 1996 Sep;64(3 Suppl):436S-448S
references.pmid: 8780360
references.citation: Am J Hum Biol. 2012 May-Jun;24(3):261-76
references.pmid: 22383142
references.citation: Am J Clin Nutr. 2004 Apr;79(4):653-60
references.pmid: 15051611
references.citation: Annu Rev Nutr. 2002;22:1-17
references.pmid: 12055335
references.citation: Obesity (Silver Spring). 2011 Sep;19(9):1813-7
references.pmid: 21681223
references.citation: Am J Clin Nutr. 2003 Feb;77(2):331-40
references.pmid: 12540391
references.citation: Nutr J. 2008 Sep 09;7:26
references.pmid: 18778488
references.citation: Sci Rep. 2014 Jan 27;4:3889
references.pmid: 24463487
references.citation: Am J Clin Nutr. 1992 Nov;56(5):835-9
references.pmid: 1415001
references.citation: Arch Dis Child. 2006 Jul;91(7):612-7
references.pmid: 16790722
references.citation: Nutrition. 2005 May;21(5):567-73
references.pmid: 15850962
references.citation: Arch Dis Child. 2008 Feb;93(2):168-72
references.pmid: 17804592