Vitamin D Supplementation in Conscripts

Fitness and Health Characteristics in Conscripts With Supplementation of Vitamin D


Lead Sponsor: Leho Rips

Collaborator: Estonian Defence Forces
University of Tartu

Source Tartu University Hospital
Brief Summary

A longitudinal, triple-blinded, randomized, placebo-controlled trial, with a 7-month follow-up period is conducted between October 2016 to April 2017.

Detailed Description

Body mass (kg) and height (cm) is measured by the same person at the medical center using standardized equipment and the body mass index (BMI) is calculated in kg/m2. Computed randomization is used to divide conscripts into two groups; either the intervention group or the control group. Both types of capsules are administered once per day in the morning before breakfast for 7 months. Standardized coded packages (3 per conscript) and capsules (100 per package) are manufactured on a special order by Innopharma A/S (Denmark). No commercial sponsoring is involved. The key of the package code is stored in the computer database until unblinding of the results. Laboratory measurements Serum samples for clinical chemistry analysis are collected into serum clot activator tubes. Calcium measurements are performed using spectrophotometry method. Ionized calcium measurements are performed using ion selective electrodes. The direct chemiluminescent immunoassay method is used for measurement of PTH. 25(OH)D is measured using direct chemiluminescent immunoassay method. Power calculation The primary variable of the study is the level of 25 (OH)D in the serum. In the power analysis a difference of 20 nmol/L between the intervention and the control group is considered to be meaningful to detect. If the SD would be 25 nmol/L, then 26 participants would be needed in each group to reach a power of 80%. Statistical analysis The distribution of blood serum values in the study groups is described by means and standard deviations (SD). Differences in mean values of the variables of interest between the groups are evaluated using Welch t-test. The within group comparisons over time are performed using paired t-test with Bonferroni correction. Distributions of categorical variables are described by absolute numbers and percentages and compared between groups using the Fisher exact test. Statistical significance is set at the 0.05 probability level.

Overall Status Completed
Start Date 2016-10-01
Completion Date 2017-04-25
Primary Completion Date 2017-04-20
Phase N/A
Study Type Interventional
Primary Outcome
Measure Time Frame
Prevalence of vitamin D deficence 0, 2, 5 and 7 months of recruitment
Enrollment 63

Intervention Type: Dietary Supplement

Intervention Name: Vitamin D3 (1200 IU/30µg)

Arm Group Label: Intervention

Intervention Type: Dietary Supplement

Intervention Name: Placebo

Description: Placebo oil capsule

Arm Group Label: Control



Inclusion Criteria: - participating in military service at the Estonian Defence Forces - voluntarity to participate in the study Exclusion Criteria: - inability to continue military service for any reason, during the 7 month follow-up period



Minimum Age:

19 Years

Maximum Age:

27 Years

Healthy Volunteers:

Accepts Healthy Volunteers

Overall Official
Last Name Role Affiliation
Helena Gapeyeva, MD, PhD Study Director University of Tartu
Facility: Kuperjanov Infantry Battalion, Estonian Defence Forces
Location Countries


Verification Date


Responsible Party

Type: Sponsor-Investigator

Investigator Affiliation: Tartu University Hospital

Investigator Full Name: Leho Rips

Investigator Title: Head of department

Has Expanded Access No
Condition Browse
Number Of Arms 2
Arm Group

Label: Intervention

Type: Active Comparator

Description: Received vitamin D3 capsules (1200 IU/30µg).

Label: Control

Type: Placebo Comparator

Description: Received placebo (oil capsules).

Study Design Info

Allocation: Randomized

Intervention Model: Parallel Assignment

Intervention Model Description: Triple blinded randomized placebo-controlled study

Primary Purpose: Prevention

Masking: Triple (Participant, Care Provider, Investigator)

Masking Description: Computed randomization was used to divide conscripts into two groups; either the intervention group, who received vitamin D3 capsules (1200 IU/30µg) or the control group, who received placebo (oil capsules).

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