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

• Published in: European journal of clinical nutrition Vol. 69; no. 3; pp. 367 - 372
• Main Authors: Mazahery, H, Stonehouse, W, von Hurst, P R
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2015; Nature Publishing Group
• Subjects: 25-Hydroxyvitamin D; 692/699/1702/295; 692/700/478/174; 692/700/565/2072; Adult; Arabs; Body fat; Bone Density Conservation Agents - administration & dosage; Bone Density Conservation Agents - therapeutic use; Calciferol; Cholecalciferol - administration & dosage; Cholecalciferol - therapeutic use; Clinical Nutrition; Dietary Supplements; Dosage; Double-Blind Method; Drug dosages; Epidemiology; Ethnicity; Female; Females; Health risk assessment; Health Status; Humans; Immigrants; Internal Medicine; Iran - ethnology; Medicine; Medicine & Public Health; Metabolic Diseases; Middle Aged; Middle East - ethnology; New Zealand - epidemiology; Noncitizens; original-article; Prevalence; Prevention; Public Health; Summer; Surveys; Vitamin D; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin D deficiency; Vitamin D Deficiency - blood; Vitamin D Deficiency - drug therapy; Vitamin D Deficiency - ethnology; Vitamin D3; Vitamin deficiency; Vitamins - administration & dosage; Vitamins - therapeutic use; Winter; Young women; New Zealand; Auckland New Zealand
• ISSN: 0954-3007; 1476-5640
• DOI: 10.1038/ejcn.2014.264

Background/Objectives: 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. Participants/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 D 3 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; P art-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.