title: Vitamin D levels in prepubertal children in Southern Tasmania: prevalence and determinants.
abstract: OBJECTIVE
  To describe the prevalence and determinants of 25-hydroxy D3(25(OH)D) in children.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Southern Tasmania between June and November 1997.
  
  
  METHODS
  Two hundred and one 8-y old male and female children taking part in a cohort study whose principal endpoints were blood pressure and high-density lipoprotein (HDL) cholesterol.
  
  
  RESULTS
  The mean 25(OH)D level was 79 nmol/l (s.d. 29.5, median 73, range 12-222). Boys had higher levels than girls (82.1 vs 72.8 nmol/l, P=0.02). 25(OH)D was associated with sunlight exposure in winter school holidays (r=0.20, P=0.005) and winter weekends (r=0.16, P=0.02), the month after school holidays (87.5 vs 69.5 nmol, P<0.0001) and body mass index (r=-0.23, P=0.001). Dietary intake of vitamin D was low (mean 40 IU/day, range 5.2-384) and was not associated with 25(OH)D levels (r=0.01, P=0.91). Variation in skin melanin density was weakly associated with 25(OH)D (r=0.09, P=0.19).
  
  
  CONCLUSIONS
  Sunlight is the major determinant of vitamin D stores in our population. Neither variation in skin type within Caucasians nor diet modified this association to any significant extent. Extrapolation of these findings to sunlight bone mass associations in a very similar population suggests that a minimum level of around 50 nmol/l in the population is required for optimal bone development in prepubertal children but this needs to be confirmed with further controlled trials of vitamin D supplementation and bone mass.
  
  
  BACKGROUND
  Arthritis Foundation of Australia, Roche Pharmaceuticals.
authors.affiliation: Menzies Centre for Population Health Research, Hobart. g.jones@utas.edu.au
authors.forename: G
authors.initials: G
authors.lastname: Jones
authors.forename: C
authors.initials: C
authors.lastname: Blizzard
authors.forename: M D
authors.initials: MD
authors.lastname: Riley
authors.forename: V
authors.initials: V
authors.lastname: Parameswaran
authors.forename: T M
authors.initials: TM
authors.lastname: Greenaway
authors.forename: T
authors.initials: T
authors.lastname: Dwyer
mesh_terms: D015992:Body Mass Index; D002112:Calcifediol / Q000097:blood*; D002648:Child; D003430:Cross-Sectional Studies; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D011627:Puberty; D012727:Sex Characteristics; D012879:Skin Physiological Phenomena; D013472:Sunlight; D013648:Tasmania; D014807:Vitamin D / Q000008:administration & dosage
chemical_list: D014807:Vitamin D; D002112:Calcifediol