LDL cholesterol

LDL cholesterol is often nicknamed the "bad" cholesterol. Picture it as delivery trucks carrying cholesterol through the bloodstream; when there are too many of them, some unload their cargo into artery walls, where it gradually builds up and narrows the vessel.

LDL stands for low-density lipoprotein, a particle that ferries cholesterol from the liver to the rest of the body. Its cholesterol cargo is a central driver of atherosclerosis, the slow plaque-forming process behind most heart attacks and many strokes. Lowering LDL with diet, exercise, and medications such as statins is one of the best-proven ways to reduce cardiovascular risk.

The relationship is causal and dose-dependent: across large studies, the lower the LDL, the lower the risk, and there is no clear threshold below which lowering stops helping high-risk patients. LDL is usually calculated from the other lipid values, though it can be measured directly when triglycerides are very high or the calculation is unreliable.