title: New reference centiles for boys' height, weight and body mass index used voice break as the marker of biological age.
abstract: OBJECTIVE
  We aimed to develop the first references for body height, body weight and body mass index (BMI) for boys based on the individual developmental tempo with respect to their voice break status.
  
  
  METHODS
  We re-analysed data from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS study) on body height, body weight and body mass index based on the voice break, or mutation, in 3956 boys aged 10-17 years. We used the LMS method to construct smoothed references centiles for the studied variables in premutational, mutational and postmutational boys.
  
  
  RESULTS
  Body height, body weight and BMI differed significantly (p < 0.001) between the different stages of voice break. On average, boys were 5.9 cm taller, 5.8 kg heavier and had a 0.7 kg/m² higher BMI with every higher stage of voice break. Currently used growth references for chronological age in comparison with maturity-related references led to an average of 5.4% of boys being falsely classified as overweight.
  
  
  CONCLUSIONS
  These newly developed growth references allowed convenient classifications of underweight and overweight or obese boys with respect to their voice break status. They should be added to currently used references centiles for the body mass index to avoid misclassifying boys' weight.
authors.affiliation: Institute for Biochemistry and Biology, Human Biology, University of Potsdam, Potsdam, Germany. rebekka.mumm@gmail.com.|Biological Anthropology, Faculty of Medicine, University of Freiburg, Freiburg, Germany. rebekka.mumm@gmail.com.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Mumm
authors.affiliation: Aschauhof 3, Altenhof, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Hermanussen
authors.affiliation: Institute for Biochemistry and Biology, Human Biology, University of Potsdam, Potsdam, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Scheffler
mesh_terms: D000293:Adolescent; D041923:Adolescent Development; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D003430:Cross-Sectional Studies; D005858:Germany; D006801:Humans; D008297:Male; D012016:Reference Values; D014831:Voice
keywords: Body mass index; Developmental tempo; Growth reference values; Overweight; Voice break