An interventional study of Vitamin C and Placebo in Cardiovascular Risk Factor, sponsored by Oregon Health and Science University. Completed at 1 site in United States. Open to participants aged 40 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2023-03-23.
Sponsored by Oregon Health and Science University · Not applicable, Interventional, and Supportive care
This study will test the efficacy of Vitamin C to counteract morning cardiovascular (CV) risk markers in a randomized, double blind, placebo controlled crossover pilot study. The participants will also perform morning typical behaviors such as arousal from sleep, change in posture (getting out of bed) and mild intensity physical activity; identical to the stressors encountered in everyday life. Primary dependent variables are markers of cardiovascular risk including vascular endothelial function and oxidative stress.
The investigators plan to test the efficacy of Vitamin C to counteract morning cardiovascular (CV) risk markers in a randomized, double blind, placebo controlled crossover pilot study. The participants will also perform morning typical behaviors such as arousal from sleep, change in posture (getting out of bed) and mild intensity physical activity; identical to the stressors encountered in everyday life. This pilot study is in healthy middle aged adults without a history of CV disease.
Participants will spend two nights in an inpatient hospital suite at Hatfield Research Center. Upon awakening in the morning, they will either ingest Vitamin C or placebo in a randomized order. This will be followed by moderate intensity exercise, recovery, and discharge.
Oregon Health and Science University is the lead sponsor of 696 studies on the registry; 131 are open to participants now.
Of its 52 completed or terminated interventional studies of FDA-regulated products, 39 (75%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive a 1.5g dose of Ascorbic Acid upon wake for the first visit, and a placebo tablet on the second visit.
Dietary Supplement: Vitamin C · Other: Placebo
Participants will receive a placebo tablet upon wake for the first visit, and a 1.5g dose of Ascorbic Acid on the second visit.
Dietary Supplement: Vitamin C · Other: Placebo
1.5g Ascorbic Acid
Also known as: Ascorbic Acid
Inactive placebo to mimic 1.5g ascorbic acid.
Vascular Endothelial Function
Vascular endothelial function will be measured as flow-mediated dilation (FMD). We will measure brachial artery FMD immediately upon awakening in a constant posture following an overnight fast using the standard guidelines and protocol.
Time frame: Approximately three months
Oxidative stress
Oxidative stress will be measured as malondialdehyde (MDA) adducts from Ethylenediaminetetraacetic acid (EDTA) plasma. Higher values may indicate increased oxidative stress.
Time frame: Approximately three months
Plasma Vitamin C and Tetrahydrobiopterin
We will measure Vitamin C levels in the plasma to ensure that the levels are increased after supplementation, and to control for baseline levels. We will measure tetrahydrobiopterin (BH4) from plasma to test if levels are increased upon administration of Vitamin C.
Time frame: Approximately three months
Platelet aggregation
Platelet aggregation will be measured using Chronolog 560 VS Platelet aggregometer as an indicator of how well blood clots or clumps together. Higher values may indicate increased cardiovascular risk.
Time frame: Approximately three months
Plasminogen activator inhibitor -1
Plasminogen activator inhibitor-1 (PAI-1) will be measured from plasma as a blood inflammatory marker. Higher values may indicate increased cardiovascular risk.
Time frame: Approximately three months
Plan to share: No
No publications or documents are linked to this record.
Ran from Feb 2018 to primary completion in Mar 2022, 48 months.
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This study is completed, as verified in Mar 2023. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Ascorbic Acid
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