Vitamin D Supplementation and Muscle Characteristics in Trained Subjects
Effects of 12 Weeks of Vitamin D Supplementation on Muscle Characteristics in Trained Subjects
調査の概要
詳細な説明
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.
研究の種類
入学 (実際)
段階
- 適用できない
連絡先と場所
研究場所
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Lillehammer、ノルウェー
- Lillehammer University College
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参加基準
適格基準
就学可能な年齢
健康ボランティアの受け入れ
受講資格のある性別
説明
Inclusion Criteria:
- Individuals that have performed strength and / or endurance exercise training at least 3 X week for at least 6 months prior to the study
研究計画
研究はどのように設計されていますか?
デザインの詳細
- 主な目的:処理
- 割り当て:ランダム化
- 介入モデル:並列代入
- マスキング:トリプル
武器と介入
参加者グループ / アーム |
介入・治療 |
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実験的:Vitamin D3
Vitamin D3 capsules for 12 weeks (2000 IU daily, equivalent to 50 ug)
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ビタミンD3をオリーブオイルに溶かしカプセル化
他の名前:
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プラセボコンパレーター:Placebo
Placebo capsules for 12 weeks (the number of daily capsules will match that of the vitamin D-group)
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オリーブオイル、カプセル化
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この研究は何を測定していますか?
主要な結果の測定
結果測定 |
メジャーの説明 |
時間枠 |
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Lower body maximal dynamic strength
時間枠:wk 0, wk12
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Changes in the ability of lower body muscles to exert maximal force during a dynamic movement
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wk 0, wk12
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Muscle fiber composition
時間枠:wk0, wk12
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Changes of the muscle fiber composition of musculus vastus lateralis in a 2X to 2A direction, measured using mRNA profiling
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wk0, wk12
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二次結果の測定
結果測定 |
メジャーの説明 |
時間枠 |
---|---|---|
Gene expression in muscle
時間枠:wk0, wk12
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Changes in RNA abundances in musculus vastus lateralis, measured at the level of single genes
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wk0, wk12
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Vitamin D in blood
時間枠:wk0, wk12
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Changes in levels of 25(OH)D in blood
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wk0, wk12
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Steroid hormones in blood
時間枠:wk0, wk12
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Changes in levels of steroid hormones in blood
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wk0, wk12
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Muscular endurance
時間枠:wk0, wk12
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Changes in the ability of muscles to perform repeated dynamic contractions at submaximal loads (50% of 1 repetition maximum)
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wk0, wk12
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Upper body maximal dynamic strength
時間枠:wk0, wk12
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Changes in the ability of upper body muscles to exert maximal force during dynamic movements
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wk0, wk12
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その他の成果指標
結果測定 |
メジャーの説明 |
時間枠 |
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Training diary
時間枠:From 1 month prior to study to post test (w12)
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Diary that includes information on type of training, duration and intensity performed
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From 1 month prior to study to post test (w12)
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Vitamin D-intake diary
時間枠:From 1 month prior to study to post test (w12)
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Diary withthat includes information on approximate intake of vitamin D from sources other than the study-specific supplement, including ingestion of fish, seafood and vitamin D-supplement
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From 1 month prior to study to post test (w12)
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Sun exposure diary
時間枠:From 1 month prior to study to post test (w12)
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Diary that includes information on exposure to solarium or sun in countries south of Norway
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From 1 month prior to study to post test (w12)
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協力者と研究者
捜査官
- 主任研究者:Håvard Nygaard, MSc、Inland Norway University of Applied Sciences
研究記録日
主要日程の研究
研究開始
一次修了 (実際)
研究の完了 (実際)
試験登録日
最初に提出
QC基準を満たした最初の提出物
最初の投稿 (見積もり)
学習記録の更新
投稿された最後の更新 (実際)
QC基準を満たした最後の更新が送信されました
最終確認日
詳しくは
この情報は、Web サイト clinicaltrials.gov から変更なしで直接取得したものです。研究の詳細を変更、削除、または更新するリクエストがある場合は、register@clinicaltrials.gov。 までご連絡ください。 clinicaltrials.gov に変更が加えられるとすぐに、ウェブサイトでも自動的に更新されます。
ビタミンD3の臨床試験
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