A Prospective Trial on the Effects of Vitamin D Supplementation in Collegiate Swimmers and Divers

Study Overview
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Brief Summary
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Objective 1: Determine if Vitamin D supplementation can improve body composition, reduce injuries and illnesses, and improve performance in collegiate swimmers and divers. Objective 2: Examine how baseline Vitamin D levels predict outcome variables over the course of the intervention period.

Detailed Description
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The investigators plan to recruit from approximately 45 male and female University of Kentucky Swimmers and Divers, at least 18 years of age in August 2011. Approximately equal numbers of men and women will be recruited. The entire athletic team(s) will be recruited. With a conservative dropout rate of 30%, the investigators final sample size should be approximately 22 participants (per group).Following baseline measures, participants will be randomized to one of two groups (Vitamin D 4000 IU or Placebo control) and monitored over the course of their athletic season. Measurements will be repeated at Midpoint (3 months) and Endpoint (6 months). Participants will have no recent history of Vitamin D supplementation beyond what is normally found in a multivitamin (400 IUs). Following the informed consent process a medical history and Vitamin D questionnaire (screenings), and urine pregnancy test (for female athletes) will be administered prior to more invasive baseline testing procedures (blood draw and DXA). A blood draw will then be conducted at baseline, midpoint and endpoint. Collected blood for the purposes of this study will assess Vitamin D status (25(OH)D), parathyroid hormone, ionized calcium, bone turnover markers, and inflammatory cytokines. A Vitamin D lifestyle questionnaire will be administered at all 3 time points and incidence of illness and injury will be documented over 6 months following randomization. DXA measures will only occur at Baseline and Endpoint.

Official Title
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A Prospective Trial on the Effects of Vitamin D Supplementation on 25(OH)D, Body Composition and Injury in Collegiate Swimmers and Divers

Conditions
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Healthy

Intervention / Treatment
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* Dietary Supplement: Vitamin D
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: University of Kentucky Swimmers and Divers, at least 18 years old. No recent history of Vitamin D supplementation beyond 400IU Exclusion Criteria: hormone replacement therapy, high dose Vitamin D supplementation, history of renal disease or kidney stones, organ transplantation, sarcoidosis, parathyroid disease, history of high blood calcium levels.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Vitamin D<br>Vitamin D | Dietary Supplement: Vitamin D<br>* 4000 IU of Vitamin D daily for 6 months<br>* Other names: Vitamin D by Nature Made by Pharmavite LLC;|
| Placebo Comparator: Oil pill<br>Contains vegetable and soybean oil supplied by Nature Made by Pharmavite LLC located in Northridge, CA and is United States Pharmacopeia (USP) certified. | Dietary Supplement: Placebo<br>* Acts as a control for the Vitamin D intervention<br>* Other names: Placebo by Nature Made by Pharmavite LLC;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 25(OH)D) | Baseline, Midpoint, and Endpoint measures include a blood draw for 25(OH)D status. | 3 measurement periods over 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inflammatory Cytokines | Baselineand Endpoint measures include a blood draw inflammatory cytokines (TNF alpha, IL1-B, IL6) | Baseline and Enpoint | 
| Bone Turnover Markers | Baseline, Midpoint, and Endpoint measures include a blood draw for bone turnover markers (BSAP, NTx). | Baseline, Midpoint, Endpoint | 
| DXA Body Composition | Baseline and Endpoint measures include Body Composition measures (DXA) for fat, muscle and bone composition | Baseline and Endpoint | 
| Vitamin D Lifestyle Survey | Baseline, Midpoint, and Endpoint measures include a behavioral survey for estimating 25(OH)D status (solar exposure, food and other supplemental intake) | Baseline, Midpoint, Endpoint | 
| injury and illness incidence | We will track injury and illness type and incidence over the course of the 6 month intervention | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vitamin D status in athletes, Vitamin D, 25(OH)D, athletes, body composition, inflammatory markers, illness, injury