Coronary artery calcium, exercise tests, and CHD outcome

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DESCRIPTION (provided by applicant): Our goal is to evaluate coronary artery calcium (CAC) and exercise test results (cardiorespiratory fitness [CRF] and abnormal exercise tests) as predictors of coronary heart disease (CHD). We also will have nearly 5,000 persons who received 2 electron beam tomography (EBT) scans, which will allow us to evaluate change in CAC as a predictor of incident CHD. Finally, we will evaluate abdominal adiposity (visceral and subcutaneous fat) as predictors of CHD and diabetes. CAC and abdominal adiposity will be assessed by EBT, and exercise test results will be derived from a maximal treadmill exercise test. The study group is approximately 35,000 women (n=12,250) and men (n=22,750) who had or will have had at least 1 EBT evaluation during 1995-2002. Follow-up will be for an average of 3.1 yrs., with 38,548 woman-yrs. and 70,654 man-yrs. of observation by the end of the study. Primary outcomes are combined fatal and nonfatal CHD (Ml, fatal CHD, and revascularization procedures) and diabetes. We estimate there will be 139 CHD deaths, 1183 nonfatal CHD events, and 906 cases of diabetes. Secondary outcomes (# of expected events) include all-cause mortality (424) and stroke (318). All participants will have CAC, abdominal adiposity, and outcome ascertainment, as mentioned above. An additional strength of the study is the more than 19,000 of the participants who received a comprehensive medical evaluation. This exam provides an extensive database of medical history, health habits, physical examination, and clinical variables including blood pressure, cholesterol, HDL-C, triglyceride, plasma glucose, and resting and exercise ECGs. We will determine if medical history or measured conventional risk factors for CHD affect the association between the primary exposures and CHD or diabetes. This unique database allows us to investigate the disease outcome implications of 1) CAC as an indicator of compromised coronary artery anatomy, 2) results from a maximal exercise test as an indicator of compromised coronary artery physiology, and 3) assessments of abdominal adiposity. We will evaluate the independent predictive value of CAC, CRF, abnormal exercise test results, and the combination of these in relation to incident CHD. This study will make important contributions as to the role of the primary exposures as predictors of CHD and diabetes. and implications for the prevention of these diseases.