Coronary heart disease (CHD), as the leading cause of death in the United States, is of significant public health concern. Despite the knowledge that atherosclerosis is the underlying cause of CHD, the recognition that both genetic and environmental factors contribute to the occurrence of disease, and the identification of a large number of genetic and environmental factors that have been found to be associated with disease risk, the etiology of atherosclerosis with the later development CHD continues to be not very well understood.