Evaluation of Calcium and Vitamin D Supplementation During Marine Corps Training

Study Overview
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Brief Summary
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The primary objective of this randomized, double-blind, placebo-controlled trial is to determine the efficacy and effectiveness of Ca and vitamin D supplementation provided daily throughout Marine Corps recruit training on maintenance of PTH and indices of bone strength in Marine Corps recruits. The investigators hypothesize that Ca+D will prevent elevations in PTH and result in greater increases in indices of bone strength compared to placebo.

Detailed Description
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Military recruits undergoing initial military training (IMT) are 17 times more likely to develop stress fractures compared to active duty service members. Up to 800 male and female recruits will be enrolled at the MCRD, Parris Island, SC over two seasons (summer/fall and winter/spring) in order to account for seasonal variation in vitamin D status. Ca (2000 mg/d) and vitamin D (1000 IU/d) will be supplied as either capsules or a fortified food product daily throughout training. This study will provide novel data for the military, medical and scientific communities regarding the relationship between Ca and vitamin D supplementation and biomarkers of immune function, and the requirements for calcium and vitamin D to support bone health during IMT.

Official Title
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Evaluation of Calcium and Vitamin D Supplementation for Optimizing Bone Health During Marine Corps Recruit Training

Conditions
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Nutrition Status, Bone Health

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


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female Marine Corps recruit at least 17 years of age. Exclusion Criteria: Pregnant or breastfeeding History of kidney stones or kidney disease History of endocrine disorders Allergies to any component of the food product bar

Ages Eligible for Study
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Minimum Age: 17 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: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Calcium/Vitamin D Bar<br>Dietary supplement consumed as 2 calcium and vitamin D fortified snack bars per day | Dietary Supplement: Calcium/Vitamin D<br>* 2000 mg calcium and 1000 IU vitamin D administered daily as 8 pills or 2 fortified snack bars.<br>|
| Experimental: Calcium/Vitamin D Pill<br>Dietary supplement consumed as several capsules per day | Dietary Supplement: Calcium/Vitamin D<br>* 2000 mg calcium and 1000 IU vitamin D administered daily as 8 pills or 2 fortified snack bars.<br>|
| Placebo Comparator: Placebo Bar<br>Placebo consumed as 2 isocaloric, unfortified snack bars per day | Dietary Supplement: Placebo<br>* Administered daily as 8 placebo pills or 2 unfortified snack bars.<br>|
| Placebo Comparator: Placebo Pill<br>Placebo consumed as several capsules per day | Dietary Supplement: Placebo<br>* Administered daily as 8 placebo pills or 2 unfortified snack bars.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum Bone Health Biomarkers (Composite) | Effect of calcium/vitamin D on the following serum biomarkers: 25(OH)D (ng/ml), parathyroid hormone (PTH) (pg/ml), C-telopeptide cross-links of type 1 collagen (CTX) (ng/ml), tartrate-resistant acid phosphatase (TRAP) (U/L), bone alkaline phosphatase (BAP) (ug/L), procollagen I N-terminal peptide (P1NP) (ug/L) | Measures will be taken at the beginning and end of Initial Military Training (IMT) which is approximately 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bone Strength Indices (Composite) | Effect of calcium/vitamin D on the following indices of bone strength as assessed by peripheral quantitative computed tomography (pQCT): volumetric bone mineral density (vBMD) (mg/cm3), bone strength index (BSI) (mg/mm4), cortical bone mineral content (Crt BMC) (mg/mm), cortical volumetric bone mineral density (Crt vBMD) (mg/cm3), strength strain index (SSI) (no units) | Measures will be taken at the beginning and end of Initial Military Training (IMT) which is approximately 12 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Calcium, Vitamin D