Vitamin D Supplementation in Conscripts

September 12, 2021 updated by: Leho Rips

Fitness and Health Characteristics in Conscripts With Supplementation of Vitamin D

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

Study Overview

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.

Study Type

Interventional

Enrollment (Actual)

63

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Võrumaa
      • Võru, Võrumaa, Estonia, 50400
        • Kuperjanov Infantry Battalion, Estonian Defence Forces

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

19 years to 27 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Male

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: PREVENTION
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: TRIPLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
ACTIVE_COMPARATOR: Intervention
Received vitamin D3 capsules (1200 IU/30µg).
PLACEBO_COMPARATOR: Control
Received placebo (oil capsules).
Placebo oil capsule

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Prevalence of vitamin D deficence
Time Frame: 0, 2, 5 and 7 months of recruitment
Prevalence of vitamin D deficence as measured serum vitamin D 25(OH)D concentration. Vitamin D was considered as sufficient if the se-rum 25(OH)D concentration was ≥75 nmol/L, insufficient if <75 nmol/L, and deficient if <50 nmol/L.
0, 2, 5 and 7 months of recruitment

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
serum parathyroid hormone
Time Frame: 0, 2, 5 and 7 months of recruitment
serum parathyroid hormone concentration (pmol/l)
0, 2, 5 and 7 months of recruitment
serum calcium
Time Frame: 0, 2, 5 and 7 months of recruitment
serum calcium (Ca) concentration (mmol/l)
0, 2, 5 and 7 months of recruitment
serum ionized calcium
Time Frame: 0, 2, 5 and 7 months of recruitment
serum ionized calcium (Ca-i) concentration (mmol/l)
0, 2, 5 and 7 months of recruitment
Hand Grip Strength
Time Frame: 0, 2, 5 and 7 months of recruitment
Hand grip strength is determined by isometric contraction while standing, upper limb away from the body, using a hand dynamometer (Lafayette Instrument Co., USA).
0, 2, 5 and 7 months of recruitment
Testosterone
Time Frame: 0, 2, 5 and 7 months of recruitment
Serum testosterone concentration (nmol/l)
0, 2, 5 and 7 months of recruitment
Cortisol
Time Frame: 0, 2, 5 and 7 months of recruitment
Serum cortisol concentration (nmol/l)
0, 2, 5 and 7 months of recruitment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Study Director: Helena Gapeyeva, MD, PhD, University of Tartu

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

October 1, 2016

Primary Completion (ACTUAL)

April 20, 2017

Study Completion (ACTUAL)

April 25, 2017

Study Registration Dates

First Submitted

April 21, 2020

First Submitted That Met QC Criteria

April 21, 2020

First Posted (ACTUAL)

April 24, 2020

Study Record Updates

Last Update Posted (ACTUAL)

September 17, 2021

Last Update Submitted That Met QC Criteria

September 12, 2021

Last Verified

September 1, 2021

More Information

Terms related to this study

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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