Vitamin D Supplementation in Conscripts

NCT ID: NCT04359524

Last Updated: 2021-09-17

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 63 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2016-10-01
• Study Completion Date: 2017-04-25

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.

Conditions

Vitamin D Deficiency; Military Activity

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: TRIPLE

Study Groups

Intervention

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

Group Type: ACTIVE_COMPARATOR

Vitamin D3 (1200 IU/30µg)

Intervention Type: DIETARY_SUPPLEMENT

Control

Received placebo (oil capsules).

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DIETARY_SUPPLEMENT

Placebo oil capsule

Interventions

Vitamin D3 (1200 IU/30µg)

Intervention Type: DIETARY_SUPPLEMENT

Placebo

Placebo oil capsule

Intervention Type: DIETARY_SUPPLEMENT

Eligibility Criteria

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 Eligible Age: 19 Years
• Maximum Eligible Age: 27 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

Estonian Defence Forces

UNKNOWN

Sponsor Role: collaborator

University of Tartu

OTHER

Sponsor Role: collaborator

Leho Rips

OTHER

Sponsor Role: lead

Responsible Party

Leho Rips

Head of department

Responsibility Role: SPONSOR_INVESTIGATOR

Principal Investigators

Helena Gapeyeva, MD, PhD

Role: STUDY_DIRECTOR

University of Tartu

Locations

Kuperjanov Infantry Battalion, Estonian Defence Forces

Võru, Võrumaa, Estonia

Countries

Estonia

Other Identifiers

R-002

Identifier Type: -

Identifier Source: org_study_id