 This ancillary study will determine the epidemiology of aortic calcium in 2000 randomly selected from 6500 total MESA participants. Questions to be addressed include predictors of aortic calcium progression; associations of aortic calcium and aortic calcium progression with other subclinical CVD measures, CVD risk factors, and demographics; and the prognostic significance of aortic calcium. The project has three primary specific aims: 1 to predict the cross-sectional aortic calcium burden as a function of other subclinical CVD measures and CVD risk factors; 2 to predict aortic calcium progression as a function of other subclinical CVD measures and CVD risk factors, and 3 to predict aortic calcium progression as a function of progression of selected subclinical CVD measures and CVD risk factors. The two secondary specific aims are 1 to contrast the results of the three primary specific aims for men vs. women, and for four major ethnic groups White, Hispanic, Black, and Asian; and 2 to provide a database for future evaluation of whether aortic calcium andor aortic calcium progression independently predict subsequent myocardial infarction, stroke, and other CVD events. 