LDL cholesterol refers to the cholesterol that is packaged within low-density lipoprotein particles. It is considered “bad” cholesterol because LDL deposits excess cholesterol in blood vessel walls, where it accumulates, leading to hardening of the arteries, atherosclerosis, and blood clots. LDL cholesterol levels are often considered to be the best predictor of the risk of heart disease.
LDL cholesterol levels below 100 mg/dL are considered optimal for adults. Individuals at a very high risk of heart disease due to other risk factors (e.g. obesity, family history, smoking) should keep their LDL cholesterol levels below 70 mg/dL. LDL cholesterol levels above 160 mg/dL in adults are considered high and contribute to an increased risk of cardiovascular disease. Diet, lifestyle, and genetic variation can influence LDL cholesterol levels.