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Calcium and Vitamin D Supplementation Decreases Incidence of Stress Fractures in Female Navy Recruits

This study has been completed.
United States Department of Defense
Information provided by:
Creighton University Identifier:
First received: May 18, 2007
Last updated: March 24, 2015
Last verified: August 2008

We conducted a double-blind, placebo-controlled randomized clinical trial of calcium and vitamin D supplementation in 5201 female Naval recruits. During 8 weeks of basic training, supplementation with 2000 mg calcium and 800 IU vitamin D/day decreased incidence of stress fracture by 25%. The hypothesis was:

Supplementation with calcium 2000 mg/d and vitamin D 800 IU/d will significantly reduce the incidence of stress fractures in female Navy recruits during 8 weeks of basic training.

Condition Intervention
Stress Fracture
Dietary Supplement: Calcium & Vitamin D

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Calcium and Vitamin D Supplementation Decreases Incidence of Stress Fractures in Female Navy Recruits

Resource links provided by NLM:

Further study details as provided by Creighton University:

Primary Outcome Measures:
  • individuals with stress fracture [ Time Frame: one year ]

Enrollment: 5201
Study Start Date: May 2002
Study Completion Date: March 2006
Arms Assigned Interventions
Active Comparator: Calcium
Daily calcium supplementation Intervention: Calcium 2000mg / daily
Dietary Supplement: Calcium & Vitamin D
Calcium 2000mg / daily Vitamin D 800IU / daily
Experimental: Vitamin D
Daily Calcium and Vitamin D supplementation Intervention: Vitamin D 800IU / daily
Dietary Supplement: Calcium & Vitamin D
Calcium 2000mg / daily Vitamin D 800IU / daily

Detailed Description:

Introduction: Stress fractures (SFx) are one of the most common and debilitating overuse injuries seen in military recruits, and they are also problematic for non-military athletic populations. The goal of this randomized double-blind, placebo-controlled study was to determine if a calcium and vitamin D intervention could reduce the incidence of SFx in female recruits during basic training.

Methods: We recruited 5201 female Navy recruit volunteers and randomized them to a 2000 mg calcium and 800 IU vitamin D supplement/day or placebo. SFx were ascertained when recruits reported to the Great Lakes clinic with symptoms. All SFx were confirmed with radiography or technetium scan according to the usual Navy protocol.

Results: A total of 309 subjects were diagnosed with a SFx resulting in an incidence of 5.9% per eight weeks. Using "intention-to-treat" analysis by including all enrolled subjects, Fisher's Exact test found that the calcium and vitamin D group had a 25% lower incidence of SFx than the control group (6.6% vs 5.3%, respectively, p=0.03). The per protocol analysis, including only the 3700 recruits who completed the study, found a 27% lower incidence of fractures in the supplemented vs the control group (8.6% vs 6.8%, respectively, p=0.02).

Conclusions: Generalizing the findings to the population of 14,416 females who entered basic training at the Great Lakes during the 24 months of recruitment, calcium and vitamin D supplementation for the entire cohort would have prevented about 130 persons per year from fracturing. Such a decrease in SFx would be associated with a significant decrease in morbidity and financial costs.


Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Female entering basic recruit training at the Great Lakes Naval Station
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Please refer to this study by its identifier: NCT00476346

United States, Nebraska
Creighton University
Omaha, Nebraska, United States, 68131
Sponsors and Collaborators
Creighton University
United States Department of Defense
Principal Investigator: Joan M Lappe, Ph.D. Creighton University
  More Information

Responsible Party: Joan M. Lappe, Creighton University Identifier: NCT00476346     History of Changes
Other Study ID Numbers: DAMD-17-01-1-0807
Study First Received: May 18, 2007
Last Updated: March 24, 2015

Keywords provided by Creighton University:
physical training
military training
fracture prevention
young adult

Additional relevant MeSH terms:
Fractures, Bone
Fractures, Stress
Wounds and Injuries
Vitamin D
Calcium, Dietary
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents processed this record on April 28, 2017