DEAR DR. ROACH: Can you please explain what is cholesterol/high-density lipoprotein and the significance of a high HDL cholesterol value? What about non-HDL cholesterol? I have had cholesterol tests for the past 30 years with HDL readings that had a low of 68 mg/dL and a high of 117 mg/dL. Two first-degree relatives also have high HDL cholesterol levels, and although they have high blood pressure, neither has had any blockages in their arteries.

For the past nine years, my average total cholesterol is 206 mg/dL, my HDL is 104 mg/dL, and my LDL is 89 mg/dL. My triglyceride count is 70 mg/dL, my cholesterol/high-density lipoprotein is 2.2 mmol/L, and my non-HDL cholesterol is 101 mg/dL.

I have a diagnosis of hyperlipidemia because of my total cholesterol being over 200 mg/dL, and one doctor suggested starting a statin. I don’t understand the hyperlipidemia diagnosis. As taken individually, each lab value is within normal range, but the high HDL pushes the total over 200 mg/dL. — S.B.

ANSWER: High HDL cholesterol is generally protective against heart disease, so it is often called the “healthy” cholesterol. Unfortunately, few things in medicine are absolute, and there is a subset of people with high HDL cholesterol who have an increased risk for heart disease. (Here, I mean the type of heart disease that causes blockages in the arteries and leads to heart attacks.)

In these cases, a high HDL cholesterol is not normal. For this reason, I pay attention to a patient’s family history, and yours suggests that your HDL is probably associated with a lower risk of heart disease.

Total cholesterol divided by HDL cholesterol is one attempt to give a single number to express a person’s risk, and in this case, the lower the number, the better. However, I don’t find this particularly helpful and consider both the absolute LDL cholesterol and HDL cholesterol.

Non-HDL cholesterol is simply the total cholesterol minus the HDL cholesterol. Non-HDL cholesterol gives similar information about the risk of heart disease as LDL cholesterol, but the non-HDL cholesterol is typically about 30 mg/dL higher than the LDL.

Although “hyperlipidemia” is sometimes defined by a total cholesterol above 200 mg/dL, it doesn’t make any sense in your case (just as you suggest) because your LDL cholesterol and HDL cholesterol are both in the desirable range.

The decision to start a statin should be made by taking a holistic look at your heart disease risk. Traditional risk factors like cholesterol, blood pressure, age, and sex should be considered along with other risk factors like diet, exercise, stress and family history that are not often used by calculators.

In addition, people with inflammatory diseases like rheumatoid arthritis are at a much higher risk for heart disease than what would be expected by their cholesterol alone. Additional tests such as Lp(a) and a high-sensitivity C-reactive protein test can give additional information on your risk. A look at coronary artery calcification gives even more information and may be appropriate in cases where the decision to start a statin isn’t clear.

I don’t think of statin drugs as cholesterol drugs. Instead, they are better thought of as ways to reduce your risk of heart disease. Not everybody with high cholesterol needs a statin, but just as important, not everyone who would benefit from a statin has high cholesterol. This is why a holistic view is so critical since all of a person’s risks get considered.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.