title: The effect of prepubertal calcium carbonate supplementation on the age of peak height velocity in Gambian adolescents.
abstract: BACKGROUND
  Limited evidence suggests that calcium intake before puberty influences adolescent height growth and the timing of puberty. Such an effect might be particularly marked in populations in whom low calcium intake, stunting, and delayed puberty are common.
  
  
  OBJECTIVE
  The objective was to test whether 12 mo of calcium supplementation at age 8-12 y to increase intakes toward international recommendations had long-term effects on adolescent growth and pubertal development in rural Gambian children.
  
  
  METHODS
  This was a longitudinal study of 160 Gambian boys (n = 80) and girls (n = 80) who had participated in a 12-mo, randomized, double-blind, placebo-controlled, calcium carbonate supplementation trial (1000 mg Ca/d, 5 d/wk) at age 8-12 y. Anthropometric measures were made every 1-2 y until age 21-25 y; pubertal status and menarche data were collected. Repeated-measures ANCOVA and Superimposition by Translation and Rotation Method (SITAR) growth models were used to assess the effects of treatment.
  
  
  RESULTS
  In boys, midadolescent height growth was advanced in the calcium group, which resulted in greater stature at a mean age of 15.5 y (mean ± SEM: 2.0 ± 0.8 cm; P = 0.01) and an earlier age of peak height velocity by 7.4 ± 2.9 mo. Subsequently, the calcium group stopped growing earlier (P = 0.02) and was 3.5 ± 1.1 cm shorter (P = 0.002) at a mean age of 23.5 y. Weight and midupper arm circumference paralleled height. No significant effects were observed in girls, but a sex-by-supplement interaction on height growth could not be confirmed.
  
  
  CONCLUSIONS
  Calcium supplementation of boys in late childhood advanced the age of peak height velocity and resulted in shorter adult stature in a population in whom low calcium intakes and delayed puberty are common. This trial was registered at isrctn.org as ISRCTN28836000.
authors.affiliation: Medical Research Council Human Nutrition Research, Cambridge, United Kingdom. ann.prentice@mrc-hnr.cam.ac.uk
authors.forename: Ann
authors.initials: A
authors.lastname: Prentice
authors.forename: Bakary
authors.initials: B
authors.lastname: Dibba
authors.forename: Yankuba
authors.initials: Y
authors.lastname: Sawo
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Cole
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000886:Anthropometry; D001827:Body Height / Q000502:physiology; D002119:Calcium Carbonate / Q000008:administration & dosage*; D002648:Child; D002657:Child Development / Q000187:drug effects* / Q000502:physiology; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005714:Gambia; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008572:Menarche / Q000502:physiology; D015999:Multivariate Analysis; D011627:Puberty / Q000502:physiology; D012044:Regression Analysis; D012737:Sex Factors; D055815:Young Adult
chemical_list: D002119:Calcium Carbonate