Treatment guidelines for low HDL cholesterol
In clinical trials involving lowering LDL cholesterol, scientists also studied the effect of HDL cholesterol on atherosclerosis and heart attack rates. They found that even small increases in HDL cholesterol could reduce the frequency of heart attacks.
For each 1 mg/dl increase in HDL cholesterol, there is a 2 to 4% reduction in the risk of coronary heart disease. An HDL level of <40 mg/dl is considered undesirable and measures should be taken to increase it.