Low-density lipoprotein (LDL) is a lipoprotein that carries cholesterol around the body, for use by various cells.
Because LDL transports cholesterol to the arteries, increased levels are associated with atherosclerosis, and thus myocardial infarctions and strokes. This is why cholesterol inside LDL lipoproteins is called bad cholesterol.
LDL is formed as VLDL lipoproteins lose triglyceride, and become smaller and denser containing a higher proportion of cholesterol.
The American Heart Association provides a set of guidelines for fasting LDL levels and risk for heart disease.
; Less than 100 mg/dL : Optimal LDL cholesterol, corresponding to reduced risk for heart disease
; 100 to 129 mg/dL : Near optimal LDL level
; 130 to 159 mg/dL : Borderline high LDL level
; 160 to 189 mg/dL : High LDL level
; 190 mg/dL and above : Very high LDL level, increased risk of heart disease