title: Estimation of total-body skeletal muscle mass in children and adolescents.
abstract: OBJECTIVE
  The estimation of total-body skeletal muscle mass (SMM) has been predicted in healthy adults using anthropometric measurements and urine creatinine excretion. SMM measurement is compulsory to evaluate exercise performance and the influence of physical training on muscle mass. However, there is a lack of information on children and adolescents when quantifying appendicular skeletal muscle mass.
  
  
  METHODS
  Thirty-nine Caucasian children and adolescents (male and female, 7-16 yr old) and 20 adults (men and women, 20-24 yr old) were tested for total-body SMM using dual-energy x-ray absorptiometry measurement (DEXA), anthropometric measurements (ANTHR), and urine creatinine (UCrn) determination. Skinfold thickness and circumference were measured at mid-arm (CAG), mid-thigh (CTG), and mid-calf (CCG) and the skin-corrected circumferences (cm), together with height (Ht; m), age (yr), and sex (0 for female, 1 for male). The UCrn excretion (g.24 h(-1)) was also determined in all subjects. The ANTHR and UCrn measurements were then compared with DEXA as reference value.
  
  
  RESULTS
  The multiple linear regression from anthropometric measurements gave the following equation to evaluate the total-body skeletal muscle mass (SMM) in children and adolescents: SMM (kg) = Ht x [(0.0064 x CAG) + (0.0032 x CTG) + (0.0015 x CCG)(2)] + (2.56 x sex) + (0.136 x age). The prediction of SMM from a 24-h urine collection was obtained with the following equation: SMM (kg) = (10.62 x Crn) + 6.63. The correlation coefficient (r(2)) was 0.966 and 0.710 for the anthropometric and creatinine methods, respectively (P < 0.001).
  
  
  CONCLUSIONS
  Besides DEXA technique, the determination of total-body skeletal muscle mass in children and adolescents can be highly validated with satisfactory confidence by simple anthropometric measurements or 24-h urine creatinine excretion.
authors.affiliation: Physiological Chemistry Department, Higher Institute of Physical Education and Physiotherapy, CP 168, Free University of Brussels, 28 Avenue Paul Héger, B-1000 Brussels, Belgium. jrpoortm@ulb.ac.be
authors.forename: Jacques R
authors.initials: JR
authors.lastname: Poortmans
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boisseau
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Moraine
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Moreno-Reyes
authors.forename: Serge
authors.initials: S
authors.lastname: Goldman
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000886:Anthropometry; D015415:Biomarkers / Q000652:urine; D001823:Body Composition; D002648:Child; D002669:Child Welfare; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000378:metabolism; D011237:Predictive Value of Tests; D011597:Psychomotor Performance / Q000502:physiology
chemical_list: D015415:Biomarkers; D003404:Creatinine