Dyslipidemia

What it is and why it matters

Cholesterol is a fat the body needs: it forms cell membranes, hormones and vitamin D. The problem arises when there is too much LDL cholesterol (called “bad cholesterol”) in the blood. LDL particles settle in artery walls, join with inflammatory cells and form plaques (atherosclerosis). Over the years these plaques can narrow the artery or rupture, causing a heart attack, stroke or peripheral artery disease.

The risk depends on the LDL level and on how long you are exposed to it: a mildly raised LDL for decades can do as much harm as a very high LDL for a few years. High cholesterol causes no symptoms; the only way to find it is a blood test, which is why occasional checks matter, especially after age 40 or earlier if there are risk factors.

What the lipid profile measures

• Total cholesterol.
• LDL cholesterol, the main treatment target.
• HDL cholesterol (“good cholesterol”): a high HDL does not cancel the risk of a high LDL and is not a treatment target.
• Triglycerides, fats that rise with excess sugar, alcohol, overweight and diabetes.
• In selected cases Lp(a) is added, a genetically determined fat that needs to be measured only once in a lifetime, or apolipoprotein B.

Fasting is not necessary for most lipid profiles. It may be requested when triglycerides are very high or when other tests that require it are taken at the same time.

Why it rises

• Heredity: accounts for a large share of cases.
• A diet rich in saturated fat (fatty meat, full-fat cheese, butter, commercial pastries and processed foods with trans fats).
• Overweight and inactivity.
• Other conditions: hypothyroidism, diabetes, kidney or liver disease (see also fatty liver), nephrotic syndrome.
• Certain medicines, such as some diuretics, corticosteroids and some hormonal treatments.

A very high LDL (for example above 190 mg/dL), especially with a family history of early heart attack, may suggest familial hypercholesterolemia: an inherited, relatively common condition in which LDL is high from birth. It calls for early treatment and for testing relatives, because it affects about one person in 250 and often goes undetected.

What your LDL should be

There is no “normal” value for everyone. The target depends on your overall cardiovascular risk:

• a person at low risk: the target is milder;
• a person at high risk, such as someone with diabetes, chronic kidney disease or several risk factors: the target is lower, around 70 mg/dL or less depending on the case;
• a person who has had a heart attack or stroke, has a stent, or is at very high risk: the target is very low, usually below 55 mg/dL, together with a reduction of at least 50% from the starting level.

The doctor calculates risk considering age, sex, blood pressure, smoking, diabetes, other conditions and family history, and updates this over time. In practice, the higher the risk, the lower the target and the stronger the treatment.

Treatment

Diet and lifestyle. These are the foundation for everyone:

• more vegetables, fruit, legumes, whole grains and fiber;
• unsaturated fats (olive oil, nuts, fish) in place of saturated and trans fats;
• regular physical activity, weight control, stopping smoking.

These measures improve cardiovascular risk even when the effect on LDL is limited, and they lower triglycerides considerably.

Medicines. Statins are the basis of treatment for most patients: they lower LDL by roughly 30–50% depending on the dose and have been shown to reduce heart attacks, strokes and deaths. Ezetimibe is added when a statin is not enough or cannot be taken at a full dose. For patients at very high risk or with familial hypercholesterolemia there are other drugs, such as PCSK9 inhibitors, that lower LDL much further. Diet does not replace medication in patients at high risk. Do not stop or change medicines because of a single test: LDL is low precisely because you take them.

The fear that statins “damage the liver” or “cause muscle pain” is widespread. A significant rise in liver enzymes is rare; muscle pain affects a minority and often resolves with a change of dose or drug. If you notice problems, talk to your doctor rather than stopping treatment yourself.

Follow-up and special care

The lipid profile is repeated 6–8 weeks after starting or changing treatment, then usually once a year, or less often when it is stable. Tell your doctor about new muscle pain or if you are planning a pregnancy, because statins are not recommended during pregnancy. Very high triglycerides (above 500 mg/dL) call for separate assessment because of the risk of acute pancreatitis.

This information is educational and does not replace a medical visit.