A Single Wintertime Dose of Vitamin D3 to Prevent Winter Decline in Vitamin D Status in Healthy Adults
Condition: Vitamin D Deficiency
MeSH terms: Vitamin D Deficiency
Study type: Interventional
Phase: Phase 4

Summary: 
      The purpose of this study is to determine if a single dose of vitamin D administered orally
      in the fall will provide adequate vitamin D in healthy individuals for the duration of the
      winter, during which vitamin D levels are known to decrease. The investigators are also
      interested in finding out if this level of vitamin D will provide adequate levels for the
      remainder of the year. While the benefits of once-yearly vitamin D administration are clear
      for patients with osteoporosis, osteomalacia, rickets, and other conditions associated with
      vitamin D deficiency and high bone turn-over, studies have not been performed in which high
      doses of vitamin D were used to prevent the seasonal decline of vitamin D concentrations in
      healthy individuals. These findings could provide evidence to support vitamin D
      administration to healthy individuals in the wintertime to improve health outcomes, and
      provide the basis for additional studies in both healthy and sick populations.
    

Detailed description: 
      Vitamin D, synthesized from 7-dehydrocholesterol during ultraviolet- B exposure, aids in the
      absorption of calcium from the G.I. tract. Indirectly, by maintaining optimal calcium
      homeostasis, adequate vitamin D concentrations are essential in skeletal health (by
      preventing rickets and osteomalacia), cardiovascular health (by lowering the risk for
      hypertension), and ultimately decreasing mortality. Due to decreased direct sunlight
      exposures in the winter (characterized by limited outdoor activity, increased clothing
      coverage, and angle of the sun), vitamin D concentrations are shown to decline in individuals
      over the winter. Once-yearly administration of a bolus of vitamin D offers a means of
      preventing the seasonal decline in vitamin D status and preventing vitamin D deficiency. If
      proven successful, a once-yearly dose of vitamin D would provide improved compliance relative
      to daily or monthly dosing and provide an inexpensive and easy way to ensure optimal
      concentrations of vitamin D year-round.

      This pilot study plans to investigate if once a year dosing with vitamin D during the winter
      months in self-identified healthy adults will be effective in maintaining optimal vitamin D
      status for the entire year. In brief, this study will be a randomized, double blind,
      placebo-controlled study to evaluate the efficacy of 250,000 IU of vitamin D3 compared to
      placebo given once in 30 healthy individuals (15 subjects per arm) in November. The serum
      25(OH)D (the best measurable level of vitamin D status) will be measured after both 3-4
      months and 1 year to determine the efficacy of the dose relative to the 15 healthy controls.
      The intent of this clinical investigation is not to evaluate the dietary supplement's ability
      to diagnose, cure, mitigate or prevent disease. This study is to evaluate blood
      concentrations of this regimen of vitamin D.

      Ultimately, this study hopes to determine if a single dose of vitamin D administered orally
      in the fall will provide adequate vitamin D in healthy young individuals for the 3 months
      during winter, during which vitamin D levels are known to decrease, and over the entire year.
      These findings could provide evidence to support vitamin D administration to healthy
      individuals in wintertime to improve health outcomes, and provide the basis for additional
      studies in both healthy and sick populations.

      Secondary outcomes of this study will evaluate other hypothesized effects of vitamin D on
      biomarkers affecting health status and immunity, including markers of inflammation and
      markers of iron status.
    

Intervention name(s): 250,000 IU cholecalciferol as single, oral dose; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): 250,000 IU cholecalciferol (vitamin D3) provided as a single oral dose.
Other intervention name(s): vitamin D3
Intervention MeSH terms: Vitamin D; Cholecalciferol
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Healthy, by self report