Skip to content

Optimizing Vitamin D Status During Initial Military Training

Optimizing Vitamin D Status During Initial Military Training: A Randomized, Double-blind, Placebo-controlled Trial

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT01617109
Enrollment
342
Registered
2012-06-12
Start date
2012-06-30
Completion date
2018-05-02
Last updated
2018-10-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Bone Health, Nutrition Status

Keywords

Vitamin D, Calcium, Parathyroid hormone, Bone, Bone formation, Bone resorption, Micronutrients, Trace Elements

Brief summary

The primary objective of this randomized, double-blind, placebo-controlled trial is to determine the effect of vitamin D and calcium supplementation (800IU and 2000mg, respectively) on biochemical indicators of nutritional status and bone health in military personnel during Army basic combat training (BCT) and Air Force basic military training (BMT). The investigators hypothesize that daily supplementation with vitamin D and calcium during military training will improve vitamin D status, stabilize PTH levels, and result in improvements in markers of bone health. As a result of the investigators study design, the findings will provide critically important data regarding the concentration of vitamin D in blood necessary to stabilize PTH levels and to optimize bone formation during initial military training.

Detailed description

Vitamin D is an essential nutrient for maintaining bone health. Previous work from our laboratory indicates that vitamin D status may decline in Soldiers during BCT, even during the summer months in the Southeastern United States. Stress fractures may affect up to 5% of male and 21% of female Soldiers during training, resulting in attrition in up to 60% of affected personnel, but a recent report indicates that vitamin D and calcium supplementation may attenuate stress fracture risk by up to 20% in female Navy recruits. However, biochemical measures of nutritional status and associated markers of bone health were not collected in that study, leaving questions regarding the vitamin D and calcium requirements for military personnel during periods of elevated bone turnover.

Interventions

DIETARY_SUPPLEMENTCa/Vit D

800IU vitamin D3 and 2000mg elemental calcium (as calcium carbonate); administered as 5 pills daily or 2 snack bars

OTHERPlacebo

administered as 5 pills daily or as 2 snack bars

Sponsors

United States Army Research Institute of Environmental Medicine
Lead SponsorFED

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
17 Years to 42 Years
Healthy volunteers
Yes

Inclusion criteria

* Female or male US Army or US Air Force Recruits * Participating in Basic Combat Training or Basic Military Training, respectively

Exclusion criteria

* Pregnant or breastfeeding * History of kidney stones or kidney disease

Design outcomes

Primary

MeasureTime frame
Serum PTH pg/mlParticipants will be followed for the duration of basic combat training or basic military training, which are 7-9 weeks

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 19, 2026