Which type of cholesterol is associated with fatty deposits on artery walls?

The type of cholesterol that is primarily associated with fatty deposits on artery walls is low-density lipoprotein (LDL). LDL is often referred to as "bad" cholesterol because it carries cholesterol from the liver to the cells. When there is an excessive amount of LDL in the bloodstream, it can lead to plaque formation in the arteries, which can contribute to atherosclerosis, a condition characterized by the hardening and narrowing of arteries due to cholesterol buildup.

In contrast, high-density lipoprotein (HDL), commonly known as "good" cholesterol, helps transport cholesterol away from the arteries and back to the liver for excretion or recycling, thereby reducing the risk of cardiovascular diseases. The other options, small-density lipoprotein (SDL) and medium-density lipoprotein (MDL), are not standard classifications widely recognized in lipid profiles and their cholesterol-related health implications are less documented compared to LDL and HDL. Thus, low-density lipoprotein stands out clearly as the type linked to the development of fatty deposits on arterial walls.