There is much confusion, in the lay press, between cholesterol itself, and the lipoproteins that carry it in the blood. References to "bad cholesterol" are misleading because cholesterol is cholesterol, but cholesterol carried by low-density lipoproteins (LDL) tend to increase atherosclerosis while cholesterol carried by high-density lipoproteins (HDL) tend to decrease it.
Disorders of cholesterol
Hypoalphalipoproteinemia is abnormally low levels of alpha-lipoproteins (high-density lipoproteins or HDL) in the blood. Low levels of high-density lipoproteins in the blood is a component of the metabolic syndrome.