The first report to establish the inverse relationship between CEC and CAD was done in a study by Khera et al. where (ATP-binding cassette transporter-dependent cholesterol efflux capacity (ABCA1-CEC) was measured in 203 healthy volunteers studied for subclinical atherosclerosis (assessed by carotid intima-media thickness) and 793 patients who underwent cardiac catheterization (442 case and 351 controls). This evidence concerns the gene ABCA1 and coronary artery disorder.