APOA1 and coronary artery disorder: HDL cholesterol plays a protective role and low HDL is an independent risk factor for CAD.[16] This protective effect of HDL is related to its role as an antiatherogenic, antioxidant, and anti-inflammatory agent that prevents low-density lipoprotein (LDL) oxidation, primarily through Apolipoprotein A-I (Apo A-I), the main protein of HDL.