<qa>  What is the primary specific aims of the project?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. 