title: Growth, body composition, and the onset of puberty: longitudinal observations in Afro-Caribbean children.
abstract: BACKGROUND
  Childhood growth and body composition may influence the onset of puberty.
  
  
  OBJECTIVE
  We examined the effects of birth size, growth rates throughout childhood, and body composition on the onset of puberty in Afro-Caribbean children.
  
  
  METHODS
  This was a longitudinal birth cohort study (the Vulnerable Windows Cohort Study) in Jamaica.
  
  
  METHODS
  The anthropometry (weight, height, skinfold measurements, and waist circumference) of 259 children was measured at birth, at 6 wk, every 3 months to 2 yr, and then every 6 months. Tanner staging for puberty and orchidometry were performed every 6 months starting at approximately age 8 yr. Bioelectrical impedance was done at age 11 yr.
  
  
  RESULTS
  In the girls, thelarche, pubarche, and menarche occurred at median ages of 8.8, 9.9, and 12.0 yr, respectively. Pubarche in boys occurred at a median age of 11.3 yr when the median testicular volume was 2.8 ml. Faster weight gain during infancy (age 0-6 months) and childhood, but not birth size, was associated with more advanced puberty (P values <0.05). Fat mass at age 8 yr was associated with more advanced puberty (P values <0.001) in both sexes. At age 11 yr, lean mass, but not fat mass, was associated with more advanced puberty (P values <0.001).
  
  
  CONCLUSIONS
  These data support the hypothesis that faster growth throughout childhood, especially with fat mass accretion, is associated with more advanced puberty apart from menarche. With the onset of puberty, lean mass accretion significantly increases.
authors.affiliation: Tropical Metabolism Research Unit, Tropical Medicine Research Institute, University of the West Indies, Mona, Kingston 7, Jamaica, West Indies. michael.boyne@uwimona.edu.jm
authors.forename: Michael S
authors.initials: MS
authors.lastname: Boyne
authors.forename: Minerva
authors.initials: M
authors.lastname: Thame
authors.forename: Clive
authors.initials: C
authors.lastname: Osmond
authors.forename: Raphael A
authors.initials: RA
authors.lastname: Fraser
authors.forename: Leslie
authors.initials: L
authors.lastname: Gabay
authors.forename: Marvin
authors.initials: M
authors.lastname: Reid
authors.forename: Terrence E
authors.initials: TE
authors.lastname: Forrester
mesh_terms: D000293:Adolescent; D000886:Anthropometry; D001724:Birth Weight / Q000502:physiology; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D002648:Child; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007563:Jamaica; D008137:Longitudinal Studies; D008297:Male; D011627:Puberty / Q000502:physiology*; D012044:Regression Analysis; D012737:Sex Factors; D015430:Weight Gain / Q000502:physiology*