The goal of the work proposed in this application is to investigate coronary artery calcium (CAC), detected by electron beam computed tomography (EBCT), as a predictor of coronary heart disease (CHD) mortality and morbidity, stroke, and all-cause mortality in a historical cohort epidemiological study. The study population includes 5,400 and 12,600 men who had or will have had at least one evaluation of the presence of CAC by EBCT examination at a preventive medicine clinical during the interval 1995 to 1999. Follow-up of these individuals will be for an average of about 2.75 years with approximately 15,000 woman-years and 35,000 man-years of observations being available for analyses by June 30, 2000. We expect 248 deaths including 94 from CHD, 364 non-fatal myocardial infarctions (MI), and 84 non-fatal strokes. An important strength of the proposed study is the self-reported key health variables at baseline for all study participants. In addition, objective measures of blood pressure, total cholesterol, HDL- cholesterol, triglyceride, plasma glucose, resting and exercise electrocardiograms (ECG), maximal health rates, cardiorespiratory fitness, and other clinical and biochemical measurements are available for about half of the participants. CAC by EBCT has been associated with prevalent CHD and with incident CHD in recent small prospective studies. However, it is unclear whether CAC is predictive of MI or CHD deaths, because currently available studies had few individuals with evidence of hard CVD endpoints. In this proposed study, the large cohort morbidity, stroke, and all- cause mortality in terms of thresholds or dose-response effects. An additional strength of this proposed study is that exercise test results and measures of conventional CHD risk factors, including several health behaviors and biochemical markers, are available for about 50% of the participants. This will allow us to evaluate the separate and independent predictive value of CAC and exercise test results and the combination of these two exposures in relation to study outcomes. Furthermore, we will use CAC scores, exercise test results, and the presence of conventional risk factors together to identify participants at the highest risk of developing CHD outcomes. This study has the potential to make important contributions to the assess of subclinical CHD, and may have implications for prevention of CHD.
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