Vitamin C & Exercise Induced Bronchoconstriction (EIB)

University of Kansas Medical Center

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Conditions

Exercise-induced Bronchospasm

Interventions

Vitamin CDIETARY_SUPPLEMENT

Taken as 3 500mg capsules.

PlaceboOTHER

Taken as 3 500mg capsules.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Student or student-athlete who has tested positive for EIB * Able to communicate in English Exclusion Criteria: * Forced expiratory volume in 1 second (FEV1) \< 70% of predicted, cardiac history, * Current respiratory infection * \> 10 pack year history of smoking * Pregnancy.

Locations (1)

University of Kansas Medical Center

Kansas City, Kansas, United States

Outcomes

Primary Outcomes

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

Secondary Outcomes

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).

Data from ClinicalTrials.gov

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