Effects of Vitamin D Supplementation on Strength, Bone Density, and Injury Risk in Collegiate Athletes

Study Overview
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Brief Summary
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The goal of this study is to determine whether Vitamin D supplementation improves strength and bone density, and reduces the risk of injury in collegiate athletes.

Detailed Description
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Vitamin D is a hormone that is important for bone and muscle health. As such, not having enough vitamin D in your body is associated with increased risk of injury and reduced health and athletic performance. It is often recommended that individuals who have low levels of vitamin D take vitamin D supplements. However, the effects of vitamin D supplementation on health and strength gains in collegiate athletes are not known. The goal of this study is to determine whether vitamin D supplementation increases strength and bone density, while reducing the risk of injury in collegiate athletes. Fasting vitamin D concentrations will be measured and athletes will be supplemented daily with Vitamin D for 8-12 weeks. The amount of supplementation will depend on whether the athlete is categorized as sufficient (>30ng/ml), insufficient (20-35ng/ml), or deficient (<20ng/ml). Vitamin D concentrations, strength, bone density, and injury risk will be assessed before and after the intervention period.

Official Title
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Vitamin D, Strength, and Bone Density in Collegiate Athletes

Conditions
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Vitamin D Deficiency

Intervention / Treatment
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* Drug: Vitamin D 10000 UNT
* Drug: Vitamin D 5000 UNT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: athlete for a sanctioned Virginia Tech sport Exclusion Criteria: pregnant or trying to become pregnant, currently taking vitamin D (>600IU/day), calcium (>1000mg/dl), taking any performance enhancing supplements (example, creatine), or any other medication or nutritional supplements that might influence the study variables, cardiac or thyroid problems, have diabetes, or epilepsy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 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

Primary Purpose: Prevention
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Subjects will either receive placebo, 5000IU, or 10000IU per day of Vitamin D for 8-12 weeks.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Vitamin D - 10000IU<br>These individuals have been categorized as Vitamin D deficient and will receive 10000IU of Vitamin D per day. | Drug: Vitamin D 10000 UNT<br>* 10000 IU Vitamin D per day<br>|
| Experimental: Vitamin D - 5000IU<br>These individuals have been categorized as Vitamin D insufficient and will receive 5000IU of Vitamin D per day. | Drug: Vitamin D 5000 UNT<br>* 5000 IU Vitamin D per day<br>|
| No Intervention: Placebo<br>These individuals have been categorized as Vitamin D sufficient and will receive placebo. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Strength | Overall strength assessed via maximal strength testing. The specific tests may include the following, 1) one repetition max bench press (lbs) -, 2) one repetition max squat (lbs), 3) vertical jump test (feet), 4) broad jump test (feet), 5) dead lifts (lbs and repetition), 6) pull ups (repetition), 7) dips (repetition), and 8) shuttle time (test involving repeated sprints to and from marked points or lines - minutes/ seconds). | Up to 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Femur Bone Density | Bone Density will be assessed in spine using Dual Energy X-ray Absorptiometry. T-scores will be determined. | Up to 12 weeks | 
| Spine Bone Density | Bone Density will be assessed in the hip (proximal femur) using Dual Energy X-ray Absorptiometry. T-scores will be determined. | Up to 12 weeks | 
| Injury Occurence | New and current Injuries including bone breaks, muscle strains and sprains will be tracked via a questionnaire that will be filled out weekly. Subjects will report whether they had an injury, where the injury occurred on the body, the type of injury, as well as the date/ time of the injury and how the injury occurred. Number of injury | Every week for up to 12 weeks |