What Your Cholesterol Numbers Mean

Susan O’Leary, M.D., Ph.D., F.A.C.C.

The majority of heart attacks and strokes are caused by cholesterol build up in the blood vessels. Specifically, LDL (bad) cholesterol enters and is taken up in the blood vessels to form plaque (e.g. coronary artery disease). Thus, a lot of attention is focused on controlling LDL cholesterol.

The Adult Treatment Panel (ATP) III of the National Cholesterol Education Program (NCEP), recommends that the LDL cholesterol be less than 130 mg/dL for individuals without known heart disease or less than 100 mg/dL for those with known coronary artery disease.

Since the publication of the last ATP guidelines, data has emerged to support a lower LDL cholesterol goal in the highest risk patients. The highest risk patients include those with known coronary artery disease, diabetes, metabolic syndrome, poorly controlled risk factors such as continued tobacco use, and those who have had an unstable heart episode (e.g. heart attack). For these individuals, the target LDL goal is less than 70 mg/dL.

Unfortunately, the total LDL cholesterol does not tell the whole story. Two people may have the same LDL cholesterol value, but have very different risks of developing heart disease. This is because there are two major LDL particles types that are associated with different risks of having heart disease. The small, dense, “pattern B” LDL cholesterol particles are more likely to enter the blood vessel and develop plaque compared with the large, less dense, “pattern A” LDL cholesterol particles. Thus, the smaller the LDL cholesterol particles are, the greater the risk of vascular plaque development. Cardiac events, such as heart attacks are also more likely to occur in individuals with small dense LDL cholesterol. It is possible to modify the density and size of the LDL cholesterol to a more protective form with a healthy lifestyle (e.g. diet, regular exercise, strict control of diabetes) and with medical therapy.

It is also now possible to measure the total number of LDL particles, the number of small dense LDL and the number of large less dense LDL particles. This allows the prediction of plaque risk with greater accuracy in select individuals. Medical therapy may be beneficial in reducing the total number and the small dense LDL particles.

Despite the significant focus on LDL cholesterol, the other components of the cholesterol panel are also important in determining overall risk of developing heart disease. The total cholesterol, which is a measure of all of the different lipid components, should be less than 200 mg/dL. The HDL (good) cholesterol has a protective effect and should be greater than 40 mg/dL. If the HDL cholesterol falls below 40 mg/dL, it also is a risk factor for the development of plaque. Conversely, if the HDL is greater than 60 mg/dL, this confers a protective effect with a lower likelihood of developing heart disease. The NCEP also recommends that the ratio of the total cholesterol to the HDL cholesterol be less than 4.5. Exercise, tobacco cessation, consumption of low amounts of alcohol, and medical therapy can help raise the HDL cholesterol.

Elevated triglycerides are also a risk factor for developing heart disease. Triglycerides should be less than 150 mg/dL. Decreasing carbohydrates in your diet, strict control of diabetes, and increasing dietary alpha omega-3- fatty acids (e.g. fish and flax seed oil) can help decrease triglyceride levels. Medication therapy may also be beneficial.

There is a multitude of information derived from cholesterol testing that can help determine the risk of developing heart disease, as well as, preventing cardiovascular events in patients with high risk or known heart disease. It is recommended that you talk and work with your physician to achieve all of your cholesterol goals. In addition, it is important to quit smoking, maintain a healthy diet and weight, as well as, work with your doctor to control blood pressure and diabetes.

Dr. O’Leary is a board certified Cardiologist with Carson Tahoe Cardiology