Your cholesterol levels are one factor that affects your risk of developing cardiovascular problems. Some of the cholesterol in your body is used to make bile, steroid hormones and cell membranes. Too much cholesterol, on the other hand, can increase your risk of having a heart attack or stroke. Your cholesterol levels and LDL-HDL ratio can predict your risk of developing cardiovascular disease.
Cholesterol and Atherosclerosis
The reason why your cholesterol levels are important is that high levels of cholesterol in your blood result in atherosclerosis. Atherosclerosis is caused by cholesterol building up in the walls of the arteries in masses called plaques. Atherosclerotic plaques make the arteries stiff and narrow, raising blood pressure and restricting blood flow. These plaques can break off and form clots, known as emboli, which block other arteries. If the coronary or cerebral arteries are affected, your risk of a heart attack or stroke increases.
Lipoproteins
Cholesterol in the blood is not found on its own but instead is transported in complexes known as lipoproteins, which the liver makes. Increased levels of one kind of lipoprotein, known as low-density lipoprotein, or LDL cholesterol is associated with an increased risk of atherosclerosis. Not all lipoproteins increase your risk of atherosclerosis, however. High-density lipoprotein, or HDL, cholesterol protects you from atherosclerosis.
Cholesterol Ratios
To determine your risk for developing atherosclerosis, a blood test, known as a lipid profile, will measure the levels of cholesterol and the different kinds of lipoprotein in your blood. One way of evaluating your lipoprotein levels is to look at your ratio of LDL to HDL cholesterol. This is measured by dividing your LDL cholesterol levels by your HDL concentration. Your goal should be to have a ratio of less than 3.5:1, and a ratio of 2.5:1 or lower is better.
Cholesterol Levels
Your absolute cholesterol numbers may be more important than your ratios. Ideally, your total cholesterol levels will be lower than 200 mg/dL; between 200 and 239 mg/dL is borderline high and concentrations higher than 240 mg/dL are high. Optimal LDL levels are below 100 mg/dL, with between 100 and 129 mg/dL near optimal and 130 to 159 mg/dL classified as borderline high. Levels 160 mg/dL and higher are considered high. For HDL cholesterol, average levels for women are between 50 and 59 mg/dL and for men are between 40 and 49 mg/dL. Ideal levels are over 60 mg/dL.
