Healthy Subjects, TrainedNCT02599675
Vitamin D Supplementation and Muscle Characteristics in Trained Subjects
A study testing Vitamin D3 in people with Healthy Subjects, Trained, run by Inland Norway University of Applied Sciences at 1 site in Norway.
Trial summary
This study evaluates the effect of vitamin D supplementation on outcomes muscle performance and characteristics in 70 trained healthy individuals (18-40 years of age). Subjects will be allocated to ingest either vitamin D (35) or placebo (35) in a double-blinded fashion Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Subjects, Trained
- What is being tested?
- Vitamin D3
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 71 participants
- Where
- 1 siteNorway
- Study dates
- Nov 2015to 28 Feb 2017
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Individuals that have performed strength and / or endurance exercise training at least 3 X week for at least 6 months prior to the study
Who cannot join
None listed.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effects of 12 Weeks of Vitamin D Supplementation on Muscle Characteristics in Trained Subjects
This study evaluates the effect of vitamin D supplementation on outcomes muscle performance and characteristics in 70 trained healthy individuals (18-40 years of age). Subjects will be allocated to ingest either vitamin D (35) or placebo (35) in a double-blinded fashion
Read the detailed description
Vitamin D insufficiency compromises muscle functionality, leading to changes in muscle mass and strength, manifested at the cellular level. While this is increasingly recognized as a problem for individuals with vitamin D deficiency (typically 25(OH)D < 25 nmol/l), there is no general consensus for the remainder of the vitamin D-spectra. This lack of knowledge is probably linked to the variation in protocols of studies that have investigated the physiological role of vitamin D. These variations vary from aspects such as interventional vs observational studies to aspects related to subject characteristics such as age, health and training status. In this project, we will evaluate the effects of 12 weeks of vitamin D supplementation (2000 IU/day) on muscle performance and characteristics in 70 trained healthy individuals (18-40 years of age). Subjects will be allocated to either a vitamin D (35) or a placebo group (35) in a double-blinded manner. They will be instructed to continue their ordinary modes and frequency of training.
We anticipate baseline vitamin D levels in blood (and hence changes in vitamin D obtained through supplementation), measured as 25(OH)D, to be a major determinant of the efficacy of the intervention. This means that we expect individuals with low baseline levels of 25(OH)D to display more pronounced changes in functional and biological outcome measures than those with high baseline values. Such a scenario could be related to an inability of our protocol to increase blood levels of 25(OH)D in individuals with higher physiological levels of vitamin D (which essentially means that ingestion of vitamin D3 is leveled out or exceeded by elimination of vitamin D derivatives). Alternatively, it may be related to inabilities of tissues to respond to the resulting elevation in vitamin D levels. To study the individual variation in vitamin D responses, data on both functional and biological variables will be divided into quartiles based on baseline 25(OH)D-levels, whereupon comparisons will be made between the low-end and high-end quartile. Individual variation will also be assessed using a mixed model approach.
- Conditions
- Healthy Subjects, Trained
- Being tested
- Vitamin D3, Placebo
- Keywords
- Muscle, Vitamin D, Strength, Endurance, Muscle fiber
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Vitamin D3Dietary supplement
Also called cholecalciferol
Vitamin D3 dissolved in olive oil, encapsuled
PlaceboDietary supplement
Olive oil, encapsuled
| Study group | Role | What they receive |
|---|---|---|
| Vitamin D3 | Experimental | Vitamin D3 capsules for 12 weeks (2000 IU daily, equivalent to 50 ug) Receives: Dietary Supplement: Vitamin D3 |
| Placebo | Placebo comparator | Placebo capsules for 12 weeks (the number of daily capsules will match that of the vitamin D-group) Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Lower body maximal dynamic strength
Changes in the ability of lower body muscles to exert maximal force during a dynamic movement
Measured: wk 0, wk12
Muscle fiber composition
Changes of the muscle fiber composition of musculus vastus lateralis in a 2X to 2A direction, measured using mRNA profiling
Measured: wk0, wk12
Secondary outcomes (5)
Gene expression in muscle
Changes in RNA abundances in musculus vastus lateralis, measured at the level of single genes
Measured: wk0, wk12
Vitamin D in blood
Changes in levels of 25(OH)D in blood
Measured: wk0, wk12
Steroid hormones in blood
Changes in levels of steroid hormones in blood
Measured: wk0, wk12
Muscular endurance
Changes in the ability of muscles to perform repeated dynamic contractions at submaximal loads (50% of 1 repetition maximum)
Measured: wk0, wk12
Upper body maximal dynamic strength
Changes in the ability of upper body muscles to exert maximal force during dynamic movements
Measured: wk0, wk12
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Nov 2015 (estimated)
- Study startNov 2015
- Primary completion28 Feb 2017
- Study completion28 Feb 2017
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy Subjects, TrainedStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 71 participants (actual)
Sponsor and investigators
- Lead sponsor
- Inland Norway University of Applied Sciences
- Sponsor type
- University, hospital or other
- Collaborators
- Sykehuset Innlandet HF
- Responsible party
- Sponsor
- Investigators
- Håvard Nygaard, MSc, Principal investigator, Inland Norway University of Applied Sciences
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02599675
- Sponsor's protocol ID
- Trainsome 2015#006
- Status last verified
- Mar 2017
- First submitted
- 5 Nov 2015
- Last updated
- 8 Sep 2017
- Results posted
- No
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 8 Sep 2017. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of 12 Weeks of Vitamin D Supplementation on Muscle Characteristics in Trained Subjects
- ClinicalTrials.gov ID
- NCT02599675
- Acronym / sponsor ID
- Trainsome 2015#006
- Conditions
- Healthy Subjects, Trained
- Keywords
- Muscle, Vitamin D, Strength, Endurance, Muscle fiber
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 71 participants (actual)
- Lead sponsor
- Inland Norway University of Applied SciencesUniversity, hospital or other
- Collaborators
- Sykehuset Innlandet HF
- Study start
- Nov 2015
- Primary completion
- 28 Feb 2017 (actual)
- Study completion
- 28 Feb 2017 (actual)
- First posted
- 6 Nov 2015 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study evaluates the effect of vitamin D supplementation on outcomes muscle performance and characteristics in 70 trained healthy individuals (18-40 years of age). Subjects will be allocated to ingest either vitamin D (35) or placebo (35) in a double-blinded fashion
Detailed description
Vitamin D insufficiency compromises muscle functionality, leading to changes in muscle mass and strength, manifested at the cellular level. While this is increasingly recognized as a problem for individuals with vitamin D deficiency (typically 25(OH)D < 25 nmol/l), there is no general consensus for the remainder of the vitamin D-spectra. This lack of knowledge is probably linked to the variation in protocols of studies that have investigated the physiological role of vitamin D. These variations vary from aspects such as interventional vs observational studies to aspects related to subject characteristics such as age, health and training status. In this project, we will evaluate the effects of 12 weeks of vitamin D supplementation (2000 IU/day) on muscle performance and characteristics in 70 trained healthy individuals (18-40 years of age). Subjects will be allocated to either a vitamin D (35) or a placebo group (35) in a double-blinded manner. They will be instructed to continue their ordinary modes and frequency of training.
We anticipate baseline vitamin D levels in blood (and hence changes in vitamin D obtained through supplementation), measured as 25(OH)D, to be a major determinant of the efficacy of the intervention. This means that we expect individuals with low baseline levels of 25(OH)D to display more pronounced changes in functional and biological outcome measures than those with high baseline values. Such a scenario could be related to an inability of our protocol to increase blood levels of 25(OH)D in individuals with higher physiological levels of vitamin D (which essentially means that ingestion of vitamin D3 is leveled out or exceeded by elimination of vitamin D derivatives). Alternatively, it may be related to inabilities of tissues to respond to the resulting elevation in vitamin D levels. To study the individual variation in vitamin D responses, data on both functional and biological variables will be divided into quartiles based on baseline 25(OH)D-levels, whereupon comparisons will be made between the low-end and high-end quartile. Individual variation will also be assessed using a mixed model approach.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Vitamin D3 | Experimental | Dietary Supplement: Vitamin D3Vitamin D3 capsules for 12 weeks (2000 IU daily, equivalent to 50 ug) |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboPlacebo capsules for 12 weeks (the number of daily capsules will match that of the vitamin D-group) |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Individuals that have performed strength and / or endurance exercise training at least 3 X week for at least 6 months prior to the study
Key exclusion criteria (0 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Vitamin D3Also: cholecalciferolVitamin D3 dissolved in olive oil, encapsuled | Dietary supplement | Vitamin D3 |
| PlaceboOlive oil, encapsuled | Dietary supplement | Placebo |
Primary outcome
Lower body maximal dynamic strength
Time frame: wk 0, wk12
Changes in the ability of lower body muscles to exert maximal force during a dynamic movement
Muscle fiber composition
Time frame: wk0, wk12
Changes of the muscle fiber composition of musculus vastus lateralis in a 2X to 2A direction, measured using mRNA profiling
5 secondary outcomes
Gene expression in muscle
Time frame: wk0, wk12
Vitamin D in blood
Time frame: wk0, wk12
Steroid hormones in blood
Time frame: wk0, wk12
Muscular endurance
Time frame: wk0, wk12
Upper body maximal dynamic strength
Time frame: wk0, wk12
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Sep 2017.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Håvard Nygaard, MSc principal investigator
Inland Norway University of Applied Sciences
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Vitamin D3 in people with Healthy Subjects, Trained, run by Inland Norway University of Applied Sciences at 1 site in Norway.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 8 Sep 2017. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Norway. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Lower body maximal dynamic strength (time frame: wk 0, wk12). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Sep 2017.