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The Effects of Vitamin D Supplementation on Aerobic Fitness in Athletes (VDAF)

24 mei 2016 bijgewerkt door: Dr Pamela Magee, University of Ulster

The Effects of Vitamin D Supplementation on VO2max in Athletes: a Randomised, Double-blind, Placebo-controlled Trial

The primary aim of the study is to identify if vitamin D3 supplementation influences VO2max in athletes.

Secondary aims are to determine if vitamin D3 supplementation impacts on measures of muscle function, lung function, body composition, immune function and the self-reported incidence of upper respiratory tract infection.

This double-blind, randomised, placebo-controlled trial is of parallel design and will aim to recruit a total of 50 athletes randomised into either a placebo or treatment group for a 12-week intervention.

Studie Overzicht

Toestand

Voltooid

Conditie

Interventie / Behandeling

Studietype

Ingrijpend

Inschrijving (Werkelijk)

44

Fase

  • Fase 4

Contacten en locaties

In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.

Studie Locaties

  • Verenigd Koninkrijk
    • Londonderry
      • Coleraine, Londonderry, Verenigd Koninkrijk, BT52 1SA
        • Human Intervention Studies Unit (HISU), University of Ulster

Deelname Criteria

Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.

Geschiktheidscriteria

Leeftijden die in aanmerking komen voor studie

18 jaar en ouder (Volwassen, Oudere volwassene)

Accepteert gezonde vrijwilligers

Ja

Geslachten die in aanmerking komen voor studie

Allemaal

Beschrijving

Inclusion Criteria:

  • Athletes whose sport does not primarily consist of an anaerobic component
  • Apparently healthy
  • Over the age of 18

Exclusion Criteria:

  • Resting arterial hypertension
  • Individuals who are not an athlete at a University/local sports team
  • Athletes who predominantly utilise anaerobic energy systems
  • Athletes under the age of 18
  • Those that have consumed a supplement containing vitamin D (greater than 400IU/day) or iron supplements for up to 30 days prior to starting the study
  • Those with health conditions identified by the screening questionnaire
  • Individuals that are on prescribed medication that is known to affect vitamin D metabolism
  • Those following a vegan diet
  • Those with a physical disability that would prevent successful completion of the exercise test
  • Those who have either had a sun holiday in the 4 weeks prior to starting the study
  • Those planning a sun holiday during the intervention period

Studie plan

Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.

Hoe is de studie opgezet?

Ontwerpdetails

  • Primair doel: Fundamentele wetenschap
  • Toewijzing: Gerandomiseerd
  • Interventioneel model: Parallelle opdracht
  • Masker: Verdrievoudigen

Wapens en interventies

Deelnemersgroep / Arm
Interventie / Behandeling
Actieve vergelijker: Vitamin D3 3000IU (75μg)
Treatment solution delivered via oral spray once daily for 12-weeks
Voedingssupplement: Vitamin D
3000IU (75 μg) vitamin D in a commercially available oral spray solution
Andere namen:
  • cholecalciferol
  • vitamine D3
Placebo-vergelijker: Placebo
Placebo solution delivered via oral spray once daily for 12-weeks
Voedingssupplement: Placebo
Placebo oral spray solution manufactured to mimic the vitamin D oral spray

Wat meet het onderzoek?

Primaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Aerobic fitness (VO2max)
Tijdsspanne: At baseline and at 12-weeks

A medical screening questionnaire will be completed prior to the test. Athletes resting blood pressure will be measured twice to rule out resting hypertension. After a standardised warm-up, starting speed will be 8/km/hr at 1% incline, until 17/km/hr, after which incline will increase by 1% every minute until VO2max is met. A metabolic cart (Metalyzer 3B) will measure the athlete's ventilation (oxygen uptake and carbon dioxide output) throughout the test.

The test will be terminated when two of the following criterion are met*:

Respiratory exchange ratio reaches/exceeds 1.15 AND VO2 plateau observed OR Heart rate within 10bpm of age-predicted maximum

* Except when volitional exhaustion occurs Athletes will be asked to refrain from strenuous activity for 24 hours prior to VO2max testing in order to control for last bout effects.

Post-exercise lactate concentration (age and gender adjusted) will further-verify that VO2max was attained using a Lactate Pro device.
At baseline and at 12-weeks

Secundaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Hand grip strength
Tijdsspanne: At baseline and at 12-weeks
Hand grip dynamometry will be used to assess athletes grip strength. This will be measured on both dominant and non-dominant hands three times. The athlete will be asked to hold the device and grip as tightly as possible whilst holding the device alongside their body. There will be a 10 second rest period between measurements.
At baseline and at 12-weeks
Vertical jump height
Tijdsspanne: At baseline and at 12-weeks
Athletes will be asked to reach upwards as far as possible, from a standing position and mark this point on a wall. After this they will be asked to perform a counter-movement jump a total of 3 times with a 10 second rest-period between jumps, reaching as high as possible and making a mark each time. Vertical jump height is calculated from the difference between standing reach height and the best height reached when performing a counter-movement jump.
At baseline and at 12-weeks
Lung function
Tijdsspanne: At baseline and at 12-weeks

Forced expiratory volume at 1 second (FEV1) and forced vital capacity (FVC) will be measured. A calibrated Carefusion® MicroLab portable spirometer will be used to measure these variables.The athletes will need to take a maximal inhalation and then perform a full exhalation as fast as possible into a disposable mouthpiece.

This procedure will be repeated three times and an average taken at each time-point. The timing of repeats will be at the athletes discretion.
At baseline and at 12-weeks
Nutrient intake
Tijdsspanne: At baseline only/ at baseline and at 12-weeks

Dietary vitamin D and calcium intake will be estimated using a validated food frequency questionnaire at one time point (baseline only). This is due to studies highlighting equivocal variation in dietary vitamin D intake throughout the year.

24hr recalls will be completed at baseline and at 12-weeks in order to derive mean nutrient intakes for the vitamin D and placebo treatment groups respectively.
At baseline only/ at baseline and at 12-weeks
Self-reported upper respiratory illness
Tijdsspanne: Once per week up to week 12
An online questionnaire will allow athletes to record if they have any symptoms that are associated with upper respiratory infections. The athlete will be asked to mark a series of boxes to indicate how many symptom(s) if any that they have had each week.
Once per week up to week 12
Physical activity levels
Tijdsspanne: At baseline and at 12-weeks
The 'Modified Recent Physical Activity Questionnaire' produced by the Medical Research Council (a validated physical activity questionnaire) will be completed on two occasions to estimate physical activity levels.
At baseline and at 12-weeks
Body composition
Tijdsspanne: At baseline and at 12-weeks
Body composition will be measured using the BodPod, employing air plethysmography (displacement of air) to accurately measure percentage fat mass and percentage fat-free mass.
At baseline and at 12-weeks
Vitamin D status
Tijdsspanne: At baseline and at 12-weeks
25-hydroxyvitamin D (25(OH)D) will be quantified, in serum, using liquid chromatography-tandem mass spectrometry (LCMS/MS). Other biomarkers of vitamin D metabolism (adjusted calcium and parathyroid hormone) will be quantified using a clinical chemistry analyser and commercially available enzyme-linked immunosorbent assay.
At baseline and at 12-weeks
Immune function
Tijdsspanne: At baseline and at 12-weeks
A range of immune markers such as interleukin-6, cathelicidin (LL-37) and C-reactive protein will be measured using a commercially available multiplex immunoassay.
At baseline and at 12-weeks

Medewerkers en onderzoekers

Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.

Sponsor

University of Ulster

Medewerkers

Northern Ireland Executive

Onderzoekers

  • Hoofdonderzoeker: Pamela J Magee, PhD, University of Ulster

Studie record data

Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.

Bestudeer belangrijke data

Studie start

1 oktober 2014

Primaire voltooiing (Werkelijk)

1 april 2015

Studie voltooiing (Werkelijk)

1 april 2015

Studieregistratiedata

Eerst ingediend

27 oktober 2014

Eerst ingediend dat voldeed aan de QC-criteria

27 oktober 2014

Eerst geplaatst (Schatting)

29 oktober 2014

Updates van studierecords

Laatste update geplaatst (Schatting)

25 mei 2016

Laatste update ingediend die voldeed aan QC-criteria

24 mei 2016

Laatst geverifieerd

1 mei 2016

Meer informatie

Termen gerelateerd aan deze studie

Trefwoorden

Aanvullende relevante MeSH-voorwaarden

Andere studie-ID-nummers

  • REC14.0087

Deze informatie is zonder wijzigingen rechtstreeks van de website clinicaltrials.gov gehaald. Als u verzoeken heeft om uw onderzoeksgegevens te wijzigen, te verwijderen of bij te werken, neem dan contact op met register@clinicaltrials.gov. Zodra er een wijziging wordt doorgevoerd op clinicaltrials.gov, wordt deze ook automatisch bijgewerkt op onze website .

Klinische onderzoeken op Aerobic Fitness (VO2max)

Klinische onderzoeken op Vitamin D

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