Intimal Thickening and Antioxidants in Hispanics and Anglos (Los Angeles Atherosclerosis Study)

This study has been completed.
Sponsor:
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)
ClinicalTrials.gov Identifier:
NCT00005372
First received: May 25, 2000
Last updated: June 26, 2005
Last verified: June 2005
  Purpose

To investigate the role of serum and dietary antioxidants, serum pro-oxidants, and smoking on the progression/regression of carotid intima-media thickness (IMT).


Condition
Atherosclerosis
Cardiovascular Diseases
Heart Diseases

Study Type: Observational

Resource links provided by NLM:


Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

Study Start Date: January 1994
Estimated Study Completion Date: February 2005
Detailed Description:

BACKGROUND:

A finding from the Cholesterol Lowering Atherosclerosis Study (CLAS), a clinical trial, indicated that common carotid intima-media thickness responded more rapidly and more markedly to LDL-C lowering treatment than angiographic coronary stenosis or carotid roughness. New data from a primate model also showed ultrasound detection of intimal thickening in response to a hypercholesterolemic diet within twelve months. These findings suggest that carotid IMT is a reliable and rapidly responding marker of extent of atherosclerosis. However, less than a third of the observed therapeutic benefit on carotid IMT found in CLAS was explained by change in LDL-C and HDL-C, suggesting that related (or other) factors are more directly linked to atherogenic mechanisms. In addition, a Finnish epidemiologic study found that LDL-C was predicative of rate of progression in carotid IMT only in persons with high serum levels of (pro-oxidant) copper. . These and other data support a model of atherosclerosis in which intracellular accumulation of modified LDL is promoted/retarded by serum pro-oxidants/antioxidants.

DESIGN NARRATIVE:

The study tested the specific hypotheses that the positive association between rate of increase in carotid IMT and low density lipoprotein cholesterol (beta deltaIMT/LDL) was greater in persons with [1] higher levels of serum pro-oxidants (relative to persons with lower levels of serum pro-oxidants), [2] lower levels of serum antioxidants, [3] lower levels of dietary antioxidants; and [4] that regression of carotid IMT associated with smoking cessation would be detected in 30 months. Hypothesis were tested with the longitudinal observation of carotid IMT in Hispanic and non-Hispanic white women and men. The inclusion of Hispanics and women was motivated by their prevalence in the study population (18 percent Hispanic, 40 percent women), and by the then recent report that incidence of hospitalization for myocardial infarction was elevated in Hispanics. Seventy three persons from each of four ethnicity-sex groups aged 40-60 years (n-292), and 83 smokers and recent quitters (n-166) were recruited from employees in an ongoing study. Baseline blood, diet and potential confounder variables were related to 18 and 36 month (6, 12, 18, 24 and 30 month in smoker(s) changes in carotid IMT. Levels of antioxidant vitamins, including alpha-tocopherol, ascorbate, and beta carotene, in the plasma were measured at baseline. Plasma levels of negatively charged LDL were measured in a sub-sample of subjects with the most rapidly progressing common carotid intima-media thickness and in an age-sex matched subsample with the least rapidly progressing common carotid intima-media thickness. Finally, an ultrasound measurement of carotid arterial stiffness, another indicator of early atherosclerosis, was developed to address the role of blood pressure.

The Los Angeles Atherosclerosis Study (LAAS) has been renewed through February, 2004 to continue follow-up of the cohort for a total of seven years with two additional measures of arterial dysfunction, including endothelial function of the brachial artery and distensibility or stiffness of the common carotid artery.

  Eligibility

Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   No
Criteria

No eligibility criteria

  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00005372

Sponsors and Collaborators
Investigators
Investigator: James Dwyer University of Southern California
  More Information

Publications:

ClinicalTrials.gov Identifier: NCT00005372     History of Changes
Other Study ID Numbers: 4264
Study First Received: May 25, 2000
Last Updated: June 26, 2005
Health Authority: United States: Federal Government

Additional relevant MeSH terms:
Atherosclerosis
Arteriosclerosis
Cardiovascular Diseases
Heart Diseases
Arterial Occlusive Diseases
Vascular Diseases

ClinicalTrials.gov processed this record on August 28, 2014