title: Prediction equations for fat and fat-free body mass in adolescents, based on body circumferences.
abstract: BACKGROUND
  Fat mass (FM) and fat-free body mass (FFB) are important parameters for assessing nutritional status, since they are associated with higher prevalence of excess body fat and malnutrition worldwide.
  
  
  OBJECTIVE
  To develop prediction equations for fat and fat-free body mass in adolescents using body circumferences.
  
  
  METHODS
  This cross-sectional study included 218 adolescents (10-16 years) with normal weight as defined by body mass index. FM(Pred) and FFB(Pred) were estimated using stepwise multiple linear regression, considering age and body circumferences. Response variables, FM(BIA) and FFB(BIA) were estimated using bioelectric impedance analysis (BIA). The accuracy of the prediction equations was evaluated using the coefficient of determination (R(2)) and Akaike's Information Criterion (AIC).
  
  
  RESULTS
  The best prediction equations for males were FM(Pred) = -7.114 - 0.592(age) - 0.958(wrist)+0.191(hip)+0.295(abdomen); R(2) = 0.552; AIC = 416.04 and FFB(Pred) = - 52.180+1.913(age)+1.954(wrist)+1.635(forearm); R(2) = 0.869; AIC = 578.24. For females, the best equations were FM(Pred) = -17.580 - 0.678(wrist)+0.221(abdomen)+0.241(hip)+0.202(proximal thigh) - 0.228(calf); R(2) = 0.838; AIC = 415.36 and FFB(Pred) = -31.066+0.90(age)+1.090(wrist) - 0.139(abdomen)+0.326(hip)+0.632(calf); R(2) = 0.878; AIC = 512.48.
  
  
  CONCLUSIONS
  The equations developed to estimate fat body mass in females and fat-free body mass in both genders had high adjusted coefficients of determination and are therefore preferable to those derived using BIA.
authors.affiliation: Health Sciences Postgraduate Program, Federal University of Rio Grande do Norte, Health Sciences Center. Av. Gal. Cordeiro de Farias, s/n-Petropólis, Natal, CEP 59010-180, Brazil.
authors.forename: Clélia Oliveira
authors.initials: CO
authors.lastname: Lyra
authors.forename: Severina Carla Vieira Cunha
authors.initials: SC
authors.lastname: Lima
authors.forename: Kenio Costa
authors.initials: KC
authors.lastname: Lima
authors.forename: Ricardo Fernando
authors.initials: RF
authors.lastname: Arrais
authors.forename: Lucia Fátima Campos
authors.initials: LF
authors.lastname: Pedrosa
mesh_terms: D000273:Adipose Tissue / Q000502:physiology*; D050154:Adiposity / Q000502:physiology*; D000293:Adolescent; D000886:Anthropometry; D049628:Body Size / Q000502:physiology*; D001835:Body Weight / Q000502:physiology*; D002648:Child; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D012044:Regression Analysis