An interventional study of Vitamin C and Placebo in Exercise-induced Bronchospasm, sponsored by University of Kansas Medical Center. Withdrawn at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2019-12-13.
Sponsored by University of Kansas Medical Center · Not applicable, Interventional, and Basic science
The purpose of this research is to assess the association between diet and pulmonary function during standardized EIB testing. Determine the effect of Vitamin C supplementation on airway inflammatory markers and bronchoconstriction after a standardized EIB test compared to usual diet and placebo control.
This study will use a double-blind, randomized, cross-over design with subjects serving as their own controls. This study will be conducted over a consecutive five-week period.
All subjects will be asked to discontinue taking their short- and long-acting beta-agonist medication 12 and 24 hours respectively prior to data collection. Also, all subjects will be asked to refrain from caffeine, physical activity, and NSAID use 24 hours prior to testing. In addition all subjects will be asked to abstain from taking any vitamin supplement during the course of the study.
52 studies on the registry are indexed under Asthma, Exercise-Induced; 3 are open to participants now.
Browse Asthma, Exercise-Induced studies →University of Kansas Medical Center is the lead sponsor of 492 studies on the registry; 110 are open to participants now.
Of its 38 completed or terminated interventional studies of FDA-regulated products, 24 (63%) 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.
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
FEV1
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will ingest 3 (500 mg) capsules of Vitamin C each day for 2 weeks.
Dietary Supplement: Vitamin C
Participants will ingest a matched capsule for size and color to the Vitamin C supplement.
Other: Placebo
Taken as 3 500mg capsules.
Taken as 3 500mg capsules.
Change in airway inflammatory biomarkers
Urinary concentrations of cysteine leukotrienes (LTC4-LTE4), prostaglandin (9α,11β-PGF2), and creatinine will be measured.
Time frame: Change from Baseline to End of Week 5
Change in quality of life: asthma quality of life questionnaire (AQLQ)
Asthma specific quality of life will be measured by the validated asthma quality of life questionnaire (AQLQ). The AQLQ includes 32 separate responses within 4 domains: activity limitation (11 items), symptoms (12 items), emotional function (5 items), and environmental stimuli (4 items). Each response option is based on a 7-point scale, where 1 represents maximal impairment and 7 indicates no impairment. Scores for the four domains and overall score are computed as averages of the item scores. The minimal important difference for overall and each domain, has been determined to be a change in score of 0.5 per item.
Time frame: Change from Baseline to End of Week 5
Dietary Intake Questionnaire
Baseline dietary intake will be assessed by the National Cancer Institute's Diet Health Questionnaire II (DHQ II). It consists of 134 food items and 8 dietary supplement questions. It calculates the Healthy Eating Index (HEI) that is a measure of diet quality. Scores range from 0 to 100. The higher the score the healthier the diet.
Time frame: Change from Baseline to End of Week 5
Cardiorespiratory Fitness
Cardiorespiratory fitness will be assessed during the EIB test by an integrated metabolic measurement system that will be used for measurement of oxygen consumption. The metabolic cart will be set to produce a 15-second average of the data collected during gas analyses for all tests.
Time frame: Baseline
Pulmonary function testing
The outcome will measure the change in the first second of forced expiration (FEV1).
Time frame: Change from Baseline to End of Week 5
Ran from Jul 2018 to primary completion in May 2019, 10 months.
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This study is withdrawn, as verified in Dec 2019. You cannot join it, but the record below documents what was studied.
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