Aortic Calcium: Epidemiology and Progression

BACKGROUND:

Aortic calcium measured by computed tomography occurs earlier in life than other subclinical (that is, asymptomatic) markers of cardiovascular disease (CVD), shows a wide range, and is common in women. The large size of the aorta and relative lack of image artifact from motion make it ideal for radiographic quantitative imaging. This study is ancillary to and coordinated with the Multi-Ethnic Study of Atherosclerosis (MESA), a large prospective epidemiologic study investigating multiple subclinical CVD measures and CVD risk factors. Subclinical measures in MESA include coronary calcium, carotid ultrasound, cardiac magnetic resonance imaging, and the ankle/brachial blood pressure index. The extensive CVD risk factor measurements include both traditional risk factors and newer measures such as inflammatory and genetic markers.

DESIGN NARRATIVE:

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 and/or aortic calcium progression independently predict subsequent myocardial infarction, stroke, and other CVD events.