Healthy
Conditions
Keywords
Vitamin D status in athletes, Vitamin D, 25(OH)D, athletes, body composition, inflammatory markers, illness, injury
Brief summary
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
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.
Interventions
DIETARY_SUPPLEMENTVitamin D
4000 IU of Vitamin D daily for 6 months
DIETARY_SUPPLEMENTPlacebo
Acts as a control for the Vitamin D intervention
Sponsors
University of Kentucky
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 25(OH)D) | 3 measurement periods over 6 months | Baseline, Midpoint, and Endpoint measures include a blood draw for 25(OH)D status. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Inflammatory Cytokines | Baseline and Enpoint | Baselineand Endpoint measures include a blood draw inflammatory cytokines (TNF alpha, IL1-B, IL6) |
| Bone Turnover Markers | Baseline, Midpoint, Endpoint | Baseline, Midpoint, and Endpoint measures include a blood draw for bone turnover markers (BSAP, NTx). |
| DXA Body Composition | Baseline and Endpoint | Baseline and Endpoint measures include Body Composition measures (DXA) for fat, muscle and bone composition |
| Vitamin D Lifestyle Survey | Baseline, Midpoint, Endpoint | Baseline, Midpoint, and Endpoint measures include a behavioral survey for estimating 25(OH)D status (solar exposure, food and other supplemental intake) |
| injury and illness incidence | 6 months | We will track injury and illness type and incidence over the course of the 6 month intervention |
Countries
United States
Outcome results
None listed