title: Length Normalized Indices for Fat Mass and Fat-Free Mass in Preterm and Term Infants during the First Six Months of Life.
abstract: OBJECTIVE
  Postnatal tissue accretion in preterm infants differs from those in utero, affecting body composition (BC) and lifelong morbidity. Length normalized BC data allows infants with different body lengths to be compared and followed longitudinally. This study aims to analyze BC of preterm and term infants during the first six months of life.
  
  
  METHODS
  The BC data, measured using dual energy X-ray absorptiometry, of 389 preterm and 132 term infants from four longitudinal studies were combined. Fat-mass/length² (FMI) and fat-free mass/length² (FFMI) for postmenstrual age were calculated after reaching full enteral feeding, at term and two further time points up to six months corrected age.
  
  
  RESULTS
  Median FMI (preterm) increased from 0.4 kg/m² at 30 weeks to 2.5, 4.3, and 4.8 kg/m² compared to 1.7, 4.7, and 6 kg/m² in term infants at 40, 52, and 64 weeks, respectively. Median FFMI (preterm) increased from 8.5 kg/m² (30 weeks) to 11.4 kg/m² (45 weeks) and remained constant thereafter, whereas term FFMI remained constant at 11 kg/m² throughout the tested time points.
  
  
  CONCLUSIONS
  The study provides a large dataset of length normalized BC indices. Followed longitudinally, term and preterm infants differ considerably during early infancy in the pattern of change in FMI and FFMI for age.
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Calgary, 780C, Foothills Medical Centre, 1403, 29th Street NW, Calgary, AB T2N 2T9, Canada. ipsita.goswami@ahs.ca.
authors.forename: Ipsita
authors.initials: I
authors.lastname: Goswami
authors.affiliation: Division of Neonatology, Department of Pediatrics, McMaster University, 1280 Main Street West, Room HSC-4F5, Hamilton, ON L8S 4K1, Canada. nielsrochow@gmail.com.
authors.forename: Niels
authors.initials: N
authors.lastname: Rochow
authors.affiliation: Division of Neonatology, Department of Pediatrics, McMaster University, 1280 Main Street West, Room HSC-4F5, Hamilton, ON L8S 4K1, Canada. gefusch@mcmaster.ca.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Fusch
authors.affiliation: Department of Mathematics and Statistics, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada. liuk25@math.mcmaster.ca.
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.affiliation: Division of Neonatology, Department of Pediatrics, McMaster University, 1280 Main Street West, Room HSC-4F5, Hamilton, ON L8S 4K1, Canada. marrin@mcmaster.ca.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Marrin
authors.affiliation: Department of Pediatrics, University of Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald 17475, Germany. matthias.heckmann@uni-greifswald.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Heckmann
authors.affiliation: Department of Pediatrics, Division of Neonatology, Inselspital and University of Berne, Effingerstraße 102, Berne 3010, Switzerland. mathias.nelle@insel.ch.
authors.forename: Mathias
authors.initials: M
authors.lastname: Nelle
authors.affiliation: Division of Neonatology, Department of Pediatrics, McMaster University, 1280 Main Street West, Room HSC-4F5, Hamilton, ON L8S 4K1, Canada. christoph.fusch@klinikum-nuernberg.de.|Department of Pediatrics, Paracelsus Medical University Nuremberg, Nuremberg General Hospital, Prof.-Ernst-Nathan-Str. 1, Nuremberg 90219, Germany. christoph.fusch@klinikum-nuernberg.de.
authors.forename: Christoph
authors.initials: C
authors.lastname: Fusch
mesh_terms: D015502:Absorptiometry, Photon; D050154:Adiposity; D000367:Age Factors; D000886:Anthropometry; D001823:Body Composition; D001827:Body Height; D001835:Body Weight; D002657:Child Development; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D008954:Models, Biological; D009752:Nutritional Status; D047929:Term Birth
keywords: body composition; fat free mass index; fat mass; fat mass index; growth; lean mass; nutrition; postnatal