Association of serum bilirubin concentration with risk of coronary artery disease

Background: Lipid oxidation and formation of oxygen radicals are important elements of arterial plaque formation and atherosclerosis, and are involved in the pathophysiology of coronary artery disease (CAD). Because bilirubin has antioxidant properties, it has been suggested that it may have a protective role in the atherosclerotic process. Approach: This review examines in vitro and in vivo studies indicating that bilirubin inhibits lipid oxidation and oxygen radical formation. Experimental and epidemiological evidence is presented that suggests that bilirubin may serve as a physiological antioxidant providing protection against atherosclerosis and CAD. Special attention is focused on studies that noted an inverse relationship between plasma bilirubin concentration and cardiovascular morbidity. Content: Serum bilirubin concentrations in the upper portion of the reference interval reportedly reduce atherogenic risk and provide protection against CAD. In contrast, serum bilirubin concentrations in the lower portion of the reference interval may be associated with increased risk of ischemic heart disease. Summary: Taken together, the evidence presented in this review supports the concept that bilirubin, via its antioxidant potential, has antiatherogenic properties and that an inverse relationship exists between circulating bilirubin concentrations and risk of CAD. (C) 2000 American Association for Clinical Chemistry.