Antioxidants and Prevention of Early Atherosclerosis
This study will evaluate the effects of vitamin E supplementation in retarding the progression of common carotid artery intima-media thickening in African Americans.
Description
BACKGROUND:
Evidence from epidemiologic studies, and from one unpublished study, suggests that greater intake of antioxidant vitamins is associated with reduced risk of coronary heart disease and stroke. Findings from an animal model indicate that increased intake of antioxidant vitamins prevents progression of aortic fatty streaks induced by an atherogenic diet, but not from more advanced injury-induced lesions. These observations suggest the hypothesis that increased antioxidant vitamin intake may prevent further progression of early atherosclerosis, possibly by means of reduced susceptibility of low density lipoprotein to oxidative modification and consequent cytotoxic, chemotactic, chemostatic, and unregulated uptake effects.
A new, automated, low-cost, portable ultrasound system for determining intima-media thickness of the common carotid artery makes it feasible to test the primary prevention impact of antioxidant vitamins on early atherosclerosis. Results of two studies at the University of Southern California suggest that the low-density lipoprotein effects on common carotid artery intima-media thickness can be detected by automated methods within 12 to 24 months in small patient samples. Retardation of intima-media thickness progression was achieved in both studies without significant changes in average vessel diameter, which suggests effects on early atherosclerotic lesions.
DESIGN NARRATIVE:
Patients will be screened for carotid intima-media thickness at home or at schools in mobile vans equipped with portable ultrasound equipment. After 12 months, those patients above the age and sex-adjusted 66th percentile at Screen I will be re-screened (Screen II), and those showing the greatest progression in intima-media thickness will be invited to participate in a trial run-in to assess vitamin E compliance. Patients will be randomized to the following four groups: 1) vitamin E (573 mg/day); 2) vitamin C; 3) Vitamin E and C combined; and 4) placebo. Common carotid artery intima-media thickness will be observed by ultrasound at 12- and 24-month follow-ups. The primary outcome is 24-month rate of change in average common carotid artery intima-media thickness.
Status: Terminated (Phase 2). Started on June 1st, 1995.
Enrollment: subjects
Study Type: Interventional
Study Design:
- Prevention
- Randomized
- Placebo Control
Conditions:
- Cardiovascular Diseases
- Carotid Artery Diseases
- Intracranial Arteriosclerosis
- Cerebrovascular Disorders
- Heart Diseases
- Vascular Diseases
- Atherosclerosis
Interventions:
- Drug: Vitamin E
- Drug: Vitamin C
Eligibility
Inclusion Criteria:
- African American
- Gender
Both
- Mininum Age
35 Years
- Maximum Age
59 Years
- Healthy Volunteers
No
Resources
Source: National Heart, Lung, and Blood Institute (NHLBI)
Authority: United States: Federal Government
Officials
James H. Dwyer, III (Principal Investigator, University of Southern California)
Sponsors
National Heart, Lung, and Blood Institute (NHLBI) (Lead Sponsor)
References
None.
Links
None.
- Date Verified
- October 1st, 2006
- First Received
- October 25th, 2006
- Last Changed
- October 25th, 2006
Information obtained from ClinicalTrials.gov on July 15, 2008. Link to the current ClinicalTrials.gov record.
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