MESA is an ongoing study involving 6,814 participants from six diverse geographic sites across the United States. Participants were recruited between 2000 and 2002 from areas surrounding Wake Forest University, Columbia University, Johns Hopkins University, University of Minnesota, Northwestern University, and University of California Los Angeles. The cohort consists of men and women aged 45-84 years at baseline, free of clinical cardiovascular disease, and includes individuals from White, African-American, Hispanic, and Chinese-American backgrounds. MESA also includes several ancillary studies, such as MESA Mind, MESA Stress, and MESA Sleep, which focus on specific aspects of health and environmental factors. Participants are followed up every 9-12 months to collect ongoing data.