Q: After having a heart attack five months ago, I stopped smoking and started on a diet and exercise program to lose weight and control my cholesterol level. My doctor seems satisfied with my cholesterol of 220, but I wonder if it should be lower.
A: A cholesterol of 220 mg/dl is too high for anyone who has had a heart attack or any other evidence of coronary artery disease, such as angina or a history of bypass surgery or angioplasty to open a blocked coronary artery. This opinion is based on several types of information.
First, population studies have shown that a high cholesterol is associated with a much greater risk of dying of coronary artery disease in people who have had a heart attack than in those who have never had a heart attack. Next, more than 10 studies have demonstrated clear benefits from aggressive reduction of the serum cholesterol in people with known coronary artery disease. In these studies, the subjects first had the anatomy of their coronary arteries evaluated by angiography. Half of the participants were then placed randomly into groups that had their cholesterol levels substantially lowered by one of several methods: a single medication, a combination of medications, a strict diet or a surgical procedure. No special effort was made to lower the cholesterol in the remaining participants who served as the control groups. When angiography was repeated two to four years later, members of the groups that had their cholesterol lowered by any of the methods has less additional narrowing of their coronary arteries than the members of the control groups.
In several of these studies, there was a significant widening of partially blocked arteries and a reduction in the recurrence of heart attacks in the cholesterol-lowering groups, compared with the controls.
The National Cholesterol Education Program has recommended that the level of the low-density cholesterol, or LDL (the atherogenic lipoprotein or "bad" cholesterol), should be reduced to less than 100 in anyone with known coronary artery disease or atherosclerotic disease involving arteries to the brain or legs.
Total cholesterol must be in the range of 160 to 180 mg/dl in order to achieve an LDL cholesterol less than 100 mg/dl. You should speak to your doctor about lowering your cholesterol even further with a more strict diet or the use of a medication.
Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine.