How cholesterol becomes plaque

Atherosclerosis starts when LDL particles cross the inner lining of an artery and become trapped and chemically modified. Immune cells move in to clear them, become engulfed with lipid, and die, leaving a fatty core. Over years this builds a plaque with a fibrous cap.

The critical event usually is not gradual narrowing. It is plaque rupture: the cap tears, blood is exposed to the plaque contents, and a clot forms rapidly. If that clot blocks a coronary artery, the result is a heart attack; in a brain artery, an ischaemic stroke.

  • The process begins in early adulthood and progresses silently for decades.
  • Plaques that rupture are often not the largest ones, which is why symptoms can be absent beforehand.
  • Inflammation, high blood pressure, smoking, and diabetes accelerate the process alongside LDL.

Which numbers matter and why

LDL cholesterol is the standard target because it is the best-studied measure and reducing it reduces events. But it has limits, particularly when triglycerides are high, when calculated LDL becomes less reliable.

  • Non-HDL cholesterol — total minus HDL. Captures all atherogenic particles and needs no fasting.
  • ApoB — one apoB molecule per atherogenic particle, so it counts particles directly. Increasingly recommended when triglycerides are raised or metabolic syndrome is present.
  • Lipoprotein(a) — largely genetically determined, not much affected by lifestyle, and an independent risk factor. Many guidelines suggest measuring it at least once in adulthood.
  • Triglycerides — high levels reflect metabolic problems and respond to alcohol, refined carbohydrate, weight, and activity.

Ask for non-HDL alongside LDL; it is calculated from the same panel at no extra cost.

Interpreting cholesterol within overall risk

An LDL of 140 mg/dL (3.6 mmol/L) means something different in a 30-year-old non-smoker with normal blood pressure than in a 62-year-old with diabetes and hypertension. That is why guidelines use a risk calculator combining age, sex, blood pressure, smoking, diabetes, and lipids to estimate ten-year risk.

Additional factors can shift the decision when risk is borderline — family history of premature heart disease, chronic inflammatory conditions, chronic kidney disease, high lipoprotein(a), and pregnancy-related conditions such as pre-eclampsia. A coronary artery calcium score is sometimes used to clarify risk in intermediate-risk adults; it measures calcified plaque and can move a decision either way.

The practical question for a consultation is: what is my estimated risk, what would change it, and what is the target we are aiming for?

Lowering LDL: diet, activity, and medication

Dietary changes with measurable LDL effects are consistent: replace saturated fat with unsaturated fat, add soluble fibre from oats, barley, beans, and psyllium, include nuts, and consider plant sterol-fortified foods. Together these can produce a meaningful reduction, though typically smaller than medication achieves in people who need it.

Exercise affects triglycerides and HDL more than LDL, but it lowers overall cardiovascular risk through blood pressure, weight, insulin sensitivity, and vascular function. Stopping smoking is the highest-value single change for anyone who smokes.

Statins remain the best-evidenced medication class for reducing cardiovascular events. Ezetimibe and injectable agents are used in addition or as alternatives in specific situations. All decisions about starting, changing, or stopping — and all dosing — are individualised with a prescriber.

Familial hypercholesterolaemia and family history

Some people have genetically high cholesterol from birth. Familial hypercholesterolaemia is more common than often assumed and substantially raises the risk of early heart disease because LDL has been high for a lifetime rather than a few years.

Features that raise suspicion include very high LDL, cholesterol problems in multiple family members, heart attacks in relatives at young ages, and physical signs such as tendon thickening or cholesterol deposits around the eyes at a young age. It is treatable, and identifying one person usually means screening close relatives.

  • Ask relatives about heart attacks or strokes before age 55 in men and 65 in women.
  • Very high LDL in a young adult deserves specific evaluation rather than general advice.
  • Cascade screening of first-degree relatives is recommended when it is identified.