Evaluating the Effectiveness of a Community Exercise Program to Reduce the Risk of Metabolic Syndrome Among Black Americans

Community Exercise and Metabolic Syndrome in Black Families

Black Americans with a family history of early heart disease tend to have a group of risk factors that can contribute to heart disease. These risk factors, which include excess body weight, high blood pressure, and high cholesterol, are known collectively as metabolic syndrome. This study will compare a community-based, coach-led exercise program to an individual, self-led home-based exercise program to determine which program is more effective at reducing the metabolic syndrome risk factors that can lead to heart disease.

Metabolic syndrome is a term that is used to describe a group of risk factors for coronary artery disease (CAD). The risk factors include abdominal obesity, insulin resistance, high cholesterol, and high blood pressure. People who live a sedentary lifestyle and do not get enough exercise are at risk of developing metabolic syndrome and CAD. Black Americans also have an increased risk of metabolic syndrome and CAD, particularly if they have a sibling younger than 60 years old who has premature CAD. Studies have shown that people who engage in regular, moderate intensity exercise can eliminate metabolic syndrome risk factors that can lead to CAD; however, many high-risk Black Americans do not take part in regular exercise. The purpose of this study is to compare a community-based, coach-led exercise program to an individual, self-led home-based exercise program to examine which program is more effective at reducing the metabolic syndrome risk factors that can lead to CAD in Black Americans.

This study will enroll Black Americans with metabolic syndrome who have a sibling with premature CAD. Participants will be randomly assigned (by individual) to either a community-based exercise program (C-FIT) or a self-help home-based exercise program (HOME). Participants in the C-FIT group will do 1 hour of exercise two to three times each week in a community setting and will be supervised by a personal coach or trainer for 1 year. Participants in the SELF group will undergo a fitness evaluation and will be instructed on how to exercise on their own. They also will be expected to do 1 hour of exercise two to three times each week for 1 year. Study visits will occur at baseline, Month 6, and Years 1 and 2. At all study visits, participants will undergo the following: a medical history review; physical examination; blood pressure measurements; blood collection; body measurements, including height, weight, and waist circumference; a treadmill stress test; a strength test; a dual-energy x-ray absorptiometry (DEXA) scan to measure body fat; an echocardiogram to examine the heart; a flow-mediated vasodilatation test for brachial reactivity to measure vascular function; and questionnaires on diet, exercise habits, and self-efficacy.

Inclusion Criteria:

• Participating in the Johns Hopkins Sibling and Family Heart Studies
• Has metabolic syndrome components
• Self-identifies as Black American

Exclusion Criteria:

• Any clinical CAD
• Diabetes
• Major co-morbidity that precludes exercise (e.g., stroke, AIDS, cancer, neurological disorder, serious emphysema or exercise asthma, disabling arthritis)
• Resting systolic blood pressure greater than or equal to 160 mm Hg, resting diastolic blood pressure greater than or equal to 100 mm Hg, or exercise peak blood pressure greater than or equal to 250/115 mm Hg
• Known ejection fraction less than 40%
• Already participating in regular exercise, defined as 90 minutes per week of activities of greater than 5 metabolic equivalents (METS)
• Cardiac arrhythmias, including supraventricular tachycardia in the 5 years before study entry, any ventricular tachycardia, or greater than 4-beat runs of nonsustained premature ventricular contractions on baseline screening exercise testing
• Body mass index (BMI) greater than 45 kg/m2
• Alcohol or substance abuse in the 12 months before study entry
• A known abnormal exercise electrocardiogram and an abnormal thallium scan (double abnormal), a moderate to severe defect on thallium scan, or a coronary calcium score greater than 500 on a prior screening
• An abnormal exercise screening test supervised by a physician as part of this study
• Pregnant
• Current smokers if they have stated evidence of shortness of breath with normal exercises or a diagnosis of chronic obstructive pulmonary disease by their physician, as verified by medical records