Vitamin D Supplementation D_SAF Pilot Study
Condition: Vitamin D Deficiency
MeSH terms: Vitamin D Deficiency
Study type: Interventional

Summary: 
      This study is a randomised control trial (RCT) pilot study to determine the appropriate
      vitamin D dose for the main study. The pilot study includes three matched groups, which will
      form two vitamin D supplementation groups (at 25,000 IU and 50,000 IU every two months), and
      a third placebo supplementation group. The aim was to develop an appropriate supplementation
      regimen that was compatible with recruit training and maintained serum vitamin D (25OHD)
      status above 50 nmol/l during recruit training.
    

Detailed description: 
      Study Overview:

      Aim: The dose-response to vitamin D3 supplementation in Royal Marine recruits undertaking
      military training. Part-A of this research project will provide a pilot study for the main
      study. Volunteer recruits will initially complete a healthy history, smoking habit and
      alcohol consumption questionnaire. Height, body mass (from which BMI will be calculated), and
      calf girth/skinfold will be measured. A 20 ml blood sample will be drawn in two parts: a 15
      ml blood sample (gold top serum vacutainers) for determination of vitamin D status, calcium
      and albumin concentrations, PTH levels, serum collagen type I cross-linked C-telopeptide
      (CTx), carboxy-terminal propeptide of type I collagen (P1NP), ferritin (Fe) and antibody
      responses against S. aureus or other antigens; and a 5 ml blood sample (white top EDTA plasma
      vacutainers) will be drawn for determination of plasma cytokine levels. At one sample point
      only, DNA will be extracted from the cell pellet acquired following centrifuging of the whole
      blood to separate the plasma. This DNA will be analysed for the specific single nucleotide
      polymorphisms (SNPs) that have been shown to be associated with vitamin D metabolism.
      Permission will also be sought to collate the outcome of the week-1 and week-9 Royal Marine
      Fitness Assessment (RMFA). The pilot study recruit cohort will be randomised into one of
      three groups: (i) a vitamin-D3 supplementation providing 25,000 IU administered orally every
      two months (equivalent to ~400 IU.d-1); (ii) a vitamin-D3 supplementation providing 50,000 IU
      administered orally every two months (equivalent to ~800 IU.d-1); and (iii) a placebo
      (administered orally every two months) supplementation control group. The vitamin D and
      placebo supplements will be manufactured by Pharmaterials Ltd., Unit B, 5 Boulton Road,
      Reading, RG2 0NH, UK. Both the active and placebo supplements will be presented as identical
      (size and appearance) tablets, indiscernible from each other for either the volunteer or the
      study team in situ at CTC. All three groups will receive one tablet at each time point.
      Recruits will be randomly assigned to a study group, but the three groups will be matched for
      age, height, body mass and aerobic fitness. Randomisation of supplement/placebo
      administration to study volunteers will be undertaken by Statisticians from the University of
      Surrey. Study team staff will monitor supplement taking and will further confirm supplement
      taking through exit interviews. Further 20 ml blood samples will be drawn every two months
      (i.e. at weeks 8, 16 and 32 of RM training), and the smoking habit and alcohol consumption
      questionnaire will be readministered. The Food Frequency Questionnaire (FFQ)25,26 will be
      administered in week- 6 of training; this will allow the recruits' habitual RM training diet
      to be established following the civilian to military transition. Permission will be sought to
      collate the outcome of the week-1 and week-9 Royal Marine Fitness Assessment (RMFA).
      Permission will also be sought to prospectively collate data from the Defence Medical
      Information Capability Programme (DMICP) system describing the prevalence of injury and
      illness in study volunteers.
    

Intervention name(s): 25,000 IU; 50,000 IU; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): Vitamin-D3 supplementation providing 25,000 IU administered orally every two months (equivalent to ~400 IU/d);; Vitamin-D3 supplementation providing 50,000 IU administered orally every two months (equivalent to ~800 IU/d);; A placebo (administered orally every two months) supplementation control group.
Allocation: Randomized
Intervention model: Factorial Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Prevention