Epidemiology of Cardiac Structure and Function in African Caribbeans: The Tobago Heart Study

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PROJECT SUMMARY Abnormalities in cardiac structure and function, such as left ventricular hypertrophy (LVH) and reduced ejection fraction (EF), are associated with increased risk of heart failure (HF) and other cardiovascular morbidity and mortality. Echocardiography provides an in-depth and low-cost assessment of multiple aspects of cardiac structure and function. Both clinical and epidemiologic studies have demonstrated that African Americans are at higher risk for hypertensive related cardiac abnormalities than Whites; however, there have been no population-based studies to assess cardiac structure and function in African Caribbeans. Risk factors for cardiac dysfunction, such as hypertension and obesity, are more common in African Caribbeans than African Americans, suggesting that African Caribbeans may have even greater cardiac dysfunction than African Americans. Over the past 20 years, we have been studying population-based cohorts of African Caribbean men and women from Tobago in whom we have extensive measures of medical history, blood pressure, subclinical cardiovascular measures, adiposity distribution, and biospecimens. We noted an exceptionally high rate of uncontrolled hypertension and elevated blood pressure in Tobago men and women, which puts them at high-risk for further CVD comorbidities. We have strong evidence that these participants have a high burden of non-atherosclerotic vascular disease; however, to this point, we have not assessed cardiac muscle health, which is a major limitation in comparing them to African American or White U.S. epidemiologic cohorts. Therefore, we propose to expand our cardiovascular research in Tobago by performing an echocardiography exam in participants aged 50 and older from the Tobago Men’s Study and the Tobago Women’s Study (N=500 each, 1000 total: The Tobago Heart Study [THS]), in order to describe the burden of and identify risk factors for cardiac dysfunction and structural abnormalities in African Caribbeans. Specifically, we aim to 1) characterize and describe the cardiac structure and function of the THS; 2) use the wealth of existing data in the Tobago Men and Women’s Studies to identify traditional and unique correlates of cardiac structure and function in African Caribbeans, including measures of demography, medical history, behaviors/lifestyle, adiposity distribution, and subclinical cardiovascular disease; and 3) comprehensively assay circulating cardiac biomarkers to identify which facets of cardiac biology are most strongly associated with cardiac structure and function measures in African Caribbeans. Completion of these Specific Aims will provide the first assessment of cardiac structure and function in African Caribbean men and women, add to the existing cardiovascular assessments in the Tobago studies, and allow for future comparison to U.S.-based CVD cohorts that include African Americans. Importantly, this will yield unique insight into the underlying biologic process(es) associated with cardiac structure and function in Tobago, which can be harnessed in future efforts to improve prediction, prevention, and treatment of cardiac disease in these high-risk individuals.