title: Skeletal muscle mass reference curves for children and adolescents.
abstract: BACKGROUND
  Skeletal muscle is key to motor development and represents a major metabolic end organ that aids glycaemic regulation.
  
  
  OBJECTIVE
  To create gender-specific reference curves for fat-free mass (FFM) and appendicular (limb) skeletal muscle mass (SMMa) in children and adolescents. To examine the muscle-to-fat ratio in relation to body mass index (BMI) for age and gender.
  
  
  METHODS
  Body composition was measured by segmental bioelectrical impedance (BIA, Tanita BC418) in 1985 Caucasian children aged 5-18.8 years. Skeletal muscle mass data from the four limbs were used to derive smoothed centile curves and the muscle-to-fat ratio.
  
  
  RESULTS
  The centile curves illustrate the developmental patterns of %FFM and SMMa. While the %FFM curves differ markedly between boys and girls, the SMMa (kg), %SMMa and %SMMa/FFM show some similarities in shape and variance, together with some gender-specific characteristics. Existing BMI curves do not reveal these gender differences. Muscle-to-fat ratio showed a very wide range with means differing between boys and girls and across fifths of BMI z-score.
  
  
  CONCLUSIONS
  BIA assessment of %FFM and SMMa represents a significant advance in nutritional assessment since these body composition components are associated with metabolic health. Muscle-to-fat ratio has the potential to provide a better index of future metabolic health.
authors.affiliation: School of Human Sciences, London Metropolitan University, London, UK.
authors.forename: H D
authors.initials: HD
authors.lastname: McCarthy
authors.forename: D
authors.initials: D
authors.lastname: Samani-Radia
authors.forename: S A
authors.initials: SA
authors.lastname: Jebb
authors.forename: A M
authors.initials: AM
authors.lastname: Prentice
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000378:metabolism*; D000293:Adolescent; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D017097:Electric Impedance; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000378:metabolism*; D009752:Nutritional Status; D012016:Reference Values; D006113:United Kingdom
chemical_list: D005947:Glucose
keywords: Bioelectrical impedance; centiles; fat-free mass; skeletal muscle mass