Vitamin D Supplementation and Immunity/Physical Performance

Not Applicable

• Conditions: Vitamin D Status
• Interventions: Radiation: Placebo SSR; Dietary Supplement: Oral Vitamin D3; Radiation: Solar simulated radiation (SSR); Dietary Supplement: Placebo Oral Vitamin D3

• Registration Number: NCT03132103
• Lead Sponsor: Bangor University

Brief Summary

The purpose of this study is to examine the effect of vitamin D supplementation on vitamin D status, immunity and physical performance.

Detailed Description

Vitamin D plays a key role in bone mineralisation and has been linked to immune defence maintenance and muscle function. Vitamin D is primarily obtained from endogenous synthesis in response to skin sunlight exposure and follows a seasonal pattern; whereby, vitamin D levels peak at the end of the summer and fall to a trough during winter. If winter vitamin D levels can be increased to match those found in summer using supplementation, it is proposed sufficient vitamin D levels will improve physical performance and reduce susceptibility to illness in military recruits.

Study Timeline

• Study Start: 2016-01-06
• Study First Submitted: 2017-03-30
• Status Verified: 2017-04
• Study First Submitted QC: 2017-04-24
• Last Update Submitted: 2017-04-24
• Study First Posted: 2017-04-27
• Last Update Posted: 2017-04-27
• Primary Completion: 2017-04-28
• Study Completion: 2017-08-31

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: Male
• Target Recruitment: 260

Inclusion Criteria

• Passed medical assessment by medical doctor

Exclusion Criteria

• Medically deferred by medical doctor
• Regular sun bed use
• Holiday in a hot sunny climate in <3 months
• Regular vitamin D supplementation

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo SSR	Placebo SSR	Placebo SSR
Oral Vitamin D3	Oral Vitamin D3	Oral Vitamin D3
Solar simulated radiation (SSR)	Solar simulated radiation (SSR)	Solar simulated radiation (SSR)
Placebo Oral Vitamin D3	Placebo Oral Vitamin D3	Placebo Oral Vitamin D3

Primary Outcome Measures

Name	Time	Method
Vitamin D status	Up to 20 months	Circulating 25-hydroxy-vitamin D, 1,25-d OH(OH)D

Secondary Outcome Measures

Name	Time	Method
Physical performance 1	Up to 20 months	Vertical Jump height (cm) and peak power output (watts)
Physical performance 2	Up to 20 months	Maximal dynamic lift strength (kg)
Physical performance 3	Up to 20 months	Multi-stage fitness test predicted VO2max (mL/kg/min)
Hepatitis B antibody	Up to 20 months	Antibody produced in response to the presence of Hepatitis B antigen (e.g. Hepatitis B vaccine)
Mucosal immunity	Up to 20 months	Secretory Immunoglobulin A levels

Trial Locations

Locations (1)

Infantry Training Centre; 🇬🇧 Catterick, North Yorkshire, United Kingdom