The Post Lab is involved in the Multi-Ethnic Study of Atherosclerosis (MESA), a collaborative study of the characteristics of subclinical cardiovascular disease (that is, disease detected non-invasively before it has produced clinical signs and symptoms) and the risk factors that predict progression to clinically overt cardiovascular disease or progression of the subclinical disease. As MESA researchers, we study a diverse, population-based sample of 6,814 asymptomatic men and women aged 45-84. Approximately 38 percent of the recruited participants are white, 28 percent African-American, 22 percent Hispanic, and 12 percent Asian, predominantly of Chinese descent. Participants were recruited from six field centers across the United States, including Johns Hopkins University. Each participant received an extensive physical exam to determine a number of conditions, including coronary calcification, ventricular mass and function, flow-mediated endothelial vasodilation, standard coronary risk factors, sociodemographic factors, lifestyle factors, and psychosocial factors. Selected repetition of subclinical disease measures and risk factors at follow-up visits have allowed study of the progression of disease. Participants are being followed for identification and characterization of cardiovascular disease events, including acute myocardial infarction and other forms of coronary heart disease (CHD), stroke, and congestive heart failure; for cardiovascular disease interventions; and for mortality. Wendy S. Post, MD, MS, is an associate faculty, Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, and a professor of medicine.