Understanding Cholesterol – Doctor Interview
We’ve all seen headlines that the National Heart, Lung, and Blood Institute (NHLBI) has revised its guidelines. How do the new guidelines differ from the old?
Dr. Howard: We are now emphasizing looking at people who are at very high risk who don’t have heart disease, trying to identify those who would benefit from very aggressive or from cholesterol modification treatment.
What is now being considered, in terms of looking at cholesterol, that may have not been before? Are the levels higher?
Dr. Howard: Several things. Number one, we no longer say that total cholesterol and an HDL are enough. We would like people to get a total lipoprotein profile, which includes total cholesterol, HDL, triglycerides and LDL, and if you can get that fasting, that’s preferable. Secondly, we have identified certain people who we think have the same risk as somebody who already has heart disease, and that’s people with diabetes, people that have arteriosclerosis that is not cardiac in origin — that would be peripheral vessel disease, disease of the carotid artery. Thirdly, we have a way of looking at what we call global risk assessment. We use an algorithm developed by the very famous Framingham Epidemiologic Study and by looking at the totality of their risk factors, and rating them, we can tell you what your risk of having a heart attack in the next ten years might be. We look at that. If it’s greater than 20 percent for the next 10 years, then you also have CHD equivalent, as we say.
What about metabolic syndrome?
Dr. Howard: Metabolic syndrome is the predecessor to diabetes and it’s very, very prevalent in Western countries. It’s featured by central obesity, and that’s the giveaway. It’s a waist circumference in males greater than 40 and in females greater than 35 inches if taken at the umbilicus, the belly button. It also includes some other factors, such as it’s common to have hypertension and it’s common to have abnormalities of not only the LDL cholesterol but also of triglycerides and HDL.
Why was it important to change the guidelines?
Dr. Howard: We have very, very convincing data since the last report, ATP II, in 1993. There have been five large clinical trials using a statin drug to lower cholesterol, both in people who have heart disease and in people who do not have heart disease. We’ve shown significant benefit in reducing heart attacks, death from heart disease, strokes and all of the various manifestations of arteriosclerosis. We know we can do something. We want to identify those people on whom we should focus our efforts.
Are you saying more people would need more drug therapy? Why the need to change the numbers or the way you look at it?
Dr. Howard: The number of people in the United States who need drug therapy moved from about 13 million up to over 35 million. Yes, we have proven since the last report that intervening in people with cholesterol levels that were formally thought not to be terribly dangerous can benefit them and we’re trying to identify who are those people that we should intervene by lowering their cholesterol.
Are you evaluating more things now?
Dr. Howard: We’re looking at more things and we’re grading them. We used to say, ‘You’ve either got hypertension or you don’t. You’ve either got diabetes of you don’t.’ We now take your age and give it a certain number of points. We take your total cholesterol and give it a certain number of points. Your HDL, and when you add up the points and we have a scale that we can read off and the number of points determines whether you have a 20-percent risk, a 15-percent risk, a 10-percent risk. Less than 10 percent is low risk. Greater than 20 percent is the same as if you already had heart disease.
So the total cholesterol number above something is not enough anymore?
Dr. Howard: Not enough, because we are also very concerned about the HDL. We now are beginning to look at the triglycerides as contributors. So for a total risk assessment, we really need to know multiple risk factors and a gradation of how severe are they. In fact, even one risk factor that is very severe, like very bad hypertension, heavy cigarette smoking, a very high LDL will give you a significant lifetime risk of having a heart attack. We also want to identify those individuals.
As you mentioned, NHLBI recommends everyone get a lipid profile done every five years. Why is this important for someone without heart disease and less than two risk factors?
Dr. Howard: We know at the present time about 45 percent to 50 percent of men will die of a heart attack and women are very, very close to that same number, so we have a tremendous problem of heart disease. We know that as you age, your cholesterol level generally increases and your risk of a heart attack increases. We would like to pick out those people at risk early, intervene early to try to lower their risk, and to prevent them from ever having that first heart attack or from ever developing the other problems with arteriosclerosis in their cerebral circulation or in their peripheral circulation.
I talked to a couple of people who said they don’t even know their risk. Do you consider that dangerous?
Dr. Howard: That’s dangerous. You should know several numbers. You should know your blood pressure, you should know your blood sugar, you should know your cholesterol level, and as I’ve already said, now we want to go even further in really assessing risk and know your complete lipid profile because all of those numbers are important in really determining what your risk may be.
Explain what you can do to determine your own risk for a heart attack based on gender and lifestyle, and this is referring to this. How can somebody go about it if they’re curious?
Dr. Howard: There is a NHLBI Web site at http://www.nhlbi.nih.gov. On that, you can get this information. You can calculate your own risk. Your physician probably has this available. I have it on my Palm Pilot now so I can sit with a patient and discuss it with them on my Palm and change the numbers and show them how much that will improve their risk.
How can someone assess their risk for heart disease if they do not have it?
Dr. Howard: The same way — you want to look at your age, you want to look at what your total cholesterol is, you want to look at your HDL, your blood pressure, do you smoke or not smoke, are you sedentary, do you have a bad family history. These are the kinds of things you want to look for. If those are all positive, you are at a higher risk.
What are some tips to help consumers take control of their cholesterol?
Dr. Howard: The best tip is to eat a healthy diet, low fat, and low cholesterol diet. The particular fat is saturated fat, and that is animal fat, dairy fat. Exercise. Inactivity is one of the major contributors in the United States. Good activity levels, even if it’s just increasing your activity of daily living. Go upstairs instead of taking elevators or escalators. Park away from the supermarket and walk those extra few minutes or so. Don’t use the clicker — get up and down. And, if you can develop a program of aerobic exercise, that’s even better. So, those are the two most important things, and don’t smoke cigarettes — absolutely a no-no.