Cholesterol is a fatty, waxy substance that occurs naturally throughout the body and is also carried through the bloodstream in the form of spherical particles called lipoproteins. Two of these are commonly known as LDL (low-density lipoproteins) and HDL (high-density lipoproteins).

For many people, high cholesterol can be the result of an unhealthy diet, being overweight or smoking. In others, the problem runs in their family. Often it is a combination of genes and environment.

Cholesterol plays an important role in normal bodily function, such as helping the body make cell membranes, vitamin D and various types of hormones. However, when too much LDL cholesterol builds up in the blood, it can narrow or clog the arteries, raising a person’s risk of having a heart attack, developing heart disease, or having a stroke.

For people who have plaque in their arteries, cardiovascular events or other factors that put them at risk for cardiovascular disease, doctors recommend an LDL level below 70 milligrams per deciliter (mg/dl). For those without risk factors who have an LDL level at or above 190 mg/dl, the recommendation is to get this level below 100 mg/dl promptly with medication or lifestyle changes. People age 40 to 75 who are living with diabetes and whose LDL is at 70 or above may need medication.

Every person is different, and those with elevated cholesterol should work with their care team to discuss treatment. Many factors figure into the decision, including the person’s age, blood pressure, diet and ethnic background. Another test, called a coronary artery calcium scan, can detect heart disease and help the patient and clinician decide on treatment.

Sometimes, lifestyle changes alone can lower cholesterol or maintain healthy numbers. Examples include avoiding foods that are high in saturated fat, exercising more, quitting smoking and losing weight.

Clinicians may also prescribe a cholesterol-lowering drug. These include statins, ezetimibe and a new class of drugs called PSCK9 inhibitors.

Prevention is key for heart health. Adults over age 20 should have their cholesterol tested every five years, and individuals with a family history should be especially diligent.