Larry, California It is confusing, but I’ll try to clarify. The problem is that what’s considered “normal” or average cholesterol in our society is not biologically normal for our arteries. So when I hear people say heart attacks occur when cholesterol is normal (e.g., 180 to 200 mg/dL), I cringe. Total cholesterol is made up of good and bad cholesterol. You can have a total cholesterol level of less than 200 mg/dL but that may be because your good (HDL) cholesterol is low, which may put you at risk of heart disease. That’s why I like to look at all the numbers, the good (HDL) cholesterol, the bad (LDL) cholesterol, and the “ugly” (triglycerides) in addition to the total cholesterol. The goal for total cholesterol is less than 200 mg/dL, the goal for bad (LDL) cholesterol is less than 100 mg/dL, the goal for good (HDL) cholesterol is 40 mg/dL or higher in men and 50 mg/dL or higher in women, and the goal for triglycerides is less than 150 mg/dL. The higher your cholesterol levels (total and LDL), the greater the likelihood of heart disease. The Multiple Risk Factor Intervention Trial (a national heart-disease prevention study conducted from 1973 to 1982) showed that the likelihood of heart attack in people with cholesterol levels in the highest 20 percent was three times that of people whose levels were in the lowest 20 percent. Another well-known survey, the Framingham study, also illustrated the link between high cholesterol levels and heart disease. In both studies, however, a significant number of heart attacks still occurred in people with low or “normal” cholesterol values. In the Framingham study, four of five people fell into a large middle range of cholesterol levels, whether or not they developed heart disease. Those with extremely low total cholesterol (less than 50 mg/dL) had low (though not zero) risk for heart attack; those with extremely high cholesterol (over 300 mg/dL) had a threefold higher risk for heart attack. But the great majority of people fell in between these extremes, and the greatest number of heart attacks developed in people with cholesterol levels in this middle range. Why? Because people with low or middle-range cholesterol values vastly outnumber those with high cholesterol levels. As a result, there are at least as many heart attack victims with low and intermediate cholesterol levels as there are those with high cholesterol. The bottom line: The higher the cholesterol, the higher the statistical risk of heart attack, yet a surprising number of heart attacks still occur in people who have “normal” cholesterol levels because “normal” in our society is too high. I hope that helps. Q2. I just got cholesterol test results and the TC/HDL ratio is 3.5. What is the risk factor and what does the number mean? – Kathi, Oregon I’m glad you asked this question since deciphering your results can be confusing. The total cholesterol to HDL cholesterol ratio is a number that is helpful in predicting atherosclerosis, the process of fatty buildup in the walls of the arteries. The number is obtained by dividing total cholesterol by HDL (good) cholesterol. For example, if a person has a total cholesterol of 200 mg/dL and an HDL cholesterol level of 50 mg/dL, the ratio would be 4.0. A high ratio indicates a higher risk of heart attack while a low ratio indicates a lower risk. High total cholesterol (an indicator that your body has a lot of the lipoproteins that contribute to atherosclerosis) and low HDL cholesterol increases the ratio, so that scenario is undesirable. Conversely, low total cholesterol and high HDL cholesterol lowers the ratio and is good news. The goal is to keep the ratio below 5.0; the optimum ratio is 3.5. But even though this ratio can be a powerful predictor of heart disease risk, it is not used as a sole indicator for therapy. So while this ratio will help you understand your risk, keep in mind that your physician will be making treatment choices based upon your other lipoprotein numbers, specifically your LDL and HDL levels. Q3. I’m already taking a statin — shouldn’t this protect me from a heart attack? — Chris, Indiana Possibly, but most of the time, the answer is no! Statins are not a magic bullet. They reduce the number of cardiovascular events, including heart attacks, by about 30 percent over five years. This means that 70 percent of individuals who were destined for a cardiac event without the statin will still have one, which is why we need to get more aggressive and consider other therapies, like taking niacin to increase high-density lipoprotein(HDL) — the good cholesterol. Other medications, such as metformin (Glucophage) and insulin sensitizers (the thiazolidinediones, or TZDs), are typically used to treat insulin resistance in patients with type 2 diabetes, but some have been found to have beneficial effects on blood fats as well. The TZD troglitazone, for example, can have a lipid-lowering effect and increases HDL levels. Another TZD, pioglitazone, can also decrease triglycerides. Bottom line: Don’t assume that a statin is going to do all the work. You still need to adopt a healthy lifestyle with a proper diet and regular exercise (and no smoking, of course!) to give yourself the greatest protection against heart disease. Learn more in the Everyday Health Heart Health Center.
