title: The effect of monthly 50,000 IU or 100,000 IU vitamin D supplements on vitamin D status in premenopausal Middle Eastern women living in Auckland.
abstract: OBJECTIVE
  Middle Eastern female immigrants are at an increased risk of vitamin D deficiency and their response to prescribed vitamin D dosages may not be adequate and affected by other factors. The objectives were to determine vitamin D deficiency and its determinants in Middle Eastern women living in Auckland, New Zealand (Part-I), and to determine serum 25-hydroxyvitamin D (serum-25(OH)D) response to two prescribed vitamin D dosages (Part-II) in this population.
  
  
  METHODS
  Women aged ⩾20 (n=43) participated in a cross-sectional pilot study during winter (Part-I). In Part-II, women aged 20-50 years (n=62) participated in a randomised, double-blind placebo-controlled trial consuming monthly either 50,000, 100,000 IU vitamin D3 or placebo for 6 months (winter to summer).
  
  
  RESULTS
  All women in Part-I and 60% women in Part-II had serum-25(OH)D<50 nmol/l. Serum-25(OH)D was higher in prescribed vitamin D users than nonusers (P=0.001) and in Iranians than Arab women (P=0.001; Part-I). Mean (s.d.) serum-25(OH)D increased in all groups (time effect, P<0.001) and differed between groups (time × dosage interaction, P<0.001; 50,000 IU: from 44.0±16.0 to 70.0±15.0 nmol/l; 100,000 IU: 48.0±11.0 to 82.0±17.0 nmol/l; placebo: 45.0±18.0 to 54.0±18.0 nmol/l). Only 32% and 67% achieved serum-25(OH)D⩾75 nmol/l with 50,000 and 100,000 IU/month, respectively. Predictors of 6-month change in serum-25(OH)D were dose (B-coefficient±s.e.; 14.1±2.4, P<0.001), baseline serum-25(OH)D (-0.6±0.1, P<0.001) and body fat percentage (-0.7±0.3, P=0.01).
  
  
  CONCLUSIONS
  Vitamin D deficiency/insufficiency is highly prevalent in this population. Monthly 100,000 IU vitamin D for 6 months is more effective than 50,000 IU in achieving serum-25(OH)D ⩾75 nmol/l; however, a third of women still did not achieve these levels.
authors.affiliation: Institute of Food, Nutrition and Human Health, Massey University, Auckland, New Zealand.
authors.forename: H
authors.initials: H
authors.lastname: Mazahery
authors.affiliation: Commonwealth Scientific Industrial Research Organisation, Food and Nutrition Flagship, Adelaide, South Australia, Australia.
authors.forename: W
authors.initials: W
authors.lastname: Stonehouse
authors.affiliation: Institute of Food, Nutrition and Human Health, Massey University, Auckland, New Zealand.
authors.forename: P R
authors.initials: PR
authors.lastname: von Hurst
mesh_terms: D000328:Adult; D018912:Arabs; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000627:therapeutic use; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000627:therapeutic use; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006304:Health Status; D006801:Humans; D007492:Iran / Q000208:ethnology; D008875:Middle Aged; D008877:Middle East / Q000208:ethnology; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy* / Q000208:ethnology; D014815:Vitamins / Q000008:administration & dosage* / Q000627:therapeutic use
chemical_list: D050071:Bone Density Conservation Agents; D014815:Vitamins; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D