Clinical trial NCT01488227: A Prospective Trial on the Effects of Vitamin D Supplementation in Collegiate Swimmers and Divers
Official title: A Prospective Trial on the Effects of Vitamin D Supplementation on 25(OH)D, Body Composition and Injury in Collegiate Swimmers and Divers
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE3
Conditions: Healthy
Keywords: Vitamin D status in athletes
Vitamin D
25(OH)D
athletes
body composition
inflammatory markers
illness
injury
Lead sponsor: University of Kentucky
Sponsor class: OTHER
First posted: 2011-12-08
Enrollment: 45
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL

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.

Eligibility criteria: 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.

Primary outcomes:
measure: 25(OH)D)
timeFrame: 3 measurement periods over 6 months
Secondary outcomes:
measure: Inflammatory Cytokines
timeFrame: Baseline and Enpoint
measure: Bone Turnover Markers
timeFrame: Baseline, Midpoint, Endpoint
measure: DXA Body Composition
timeFrame: Baseline and Endpoint
measure: Vitamin D Lifestyle Survey
timeFrame: Baseline, Midpoint, Endpoint
measure: injury and illness incidence
timeFrame: 6 months
Other outcomes:
Locations:
city: Lexington
country: United States
facility: University of Kentucky
state: Kentucky
Study officials:
affiliation: University of Kentucky
name: Maja Redzic, B.S.
role: STUDY_DIRECTOR
affiliation: University of Kentucky
name: Regina M Lewis, B.S.
role: STUDY_DIRECTOR
affiliation: University of Kentucky
name: David T Thomas, PhD
role: PRINCIPAL_INVESTIGATOR
References: