Lipoprotein(a): Understanding Your Genetic Cardiovascular Risk

Lp(a) is one of the lipoproteins: the particles that carry fat and cholesterol through your blood. It does not, however, appear on a standard cholesterol panel. Your total cholesterol, your HDL, your LDL and your triglycerides can all be perfectly tidy while your lipoprotein(a) is substantially raised, because this one particle is not counted separately in any of those tests. Only a dedicated lp(a) blood test brings it to light. That, in one sentence, is why the test exists.

An Lp(a) particle is built around the same core as LDL: a cargo of cholesterol wrapped in exactly one molecule of apolipoprotein B. What sets it apart is a second protein firmly attached to it: apolipoprotein(a), or apo(a) for short. In its structure that protein resembles plasminogen, the protein your body uses to break clots down again. An Lp(a) particle can therefore not only lodge in the artery wall the way LDL does, it also interferes with clotting. That dual role makes it less favourable than an ordinary LDL particle.

How much Lp(a) you produce is inherited. The value is set by the LPA gene, and above all by the number of so-called KIV-2 repeats within it. Fewer repeats means a smaller apo(a) protein and a higher output of Lp(a) from your liver. You inherited that predisposition from a parent, it was fixed before you were born, and it accounts for more than 90 percent of the difference between two people. It is also precisely why this value behaves unlike almost everything else you meet on a women's panel: FSH, oestradiol and AMH say something about the stage you are in now, while Lp(a) says something about the cards you were dealt at birth.

One practical point, because it causes a great deal of confusion. Your result is reported in g/l. Foreign leaflets and studies often use mg/dl, which amounts to the same thing (0.30 g/l is 30 mg/dl), or nmol/l, which is something else: that unit counts particles rather than weighing them. Because the apo(a) protein is far larger in one person than in another, the same number of particles does not weigh the same in everyone. No reliable fixed conversion factor exists. So do not line up results in different units as though they said the same thing.

Cardiovascular disease still counts as a man's problem, and that picture costs women time. Symptoms are more often put down to stress, to a busy life or to the menopause, further investigation follows later, and risk factors are asked about less consistently. Within that picture Lp(a) has a welcome property: it is hard, measurable and established from a single tube of blood. No estimate, no interpretation of symptoms, simply a number.

And that number matters. Genetic research shows that people who naturally carry a high Lp(a) suffer heart attacks more often and develop narrowed coronary arteries more often, even when the rest of their lipid profile is fine. Risk climbs gradually with the level: there is no line below which you are safe and above which you suddenly are not. Roughly one in five people sits above the value that counts as raised, which makes this one of the most common inherited risk factors for cardiovascular disease. At very high results the lifetime risk is of the same order as inherited high cholesterol.

Which brings us to the situation where this test earns its keep. Picture a woman in her fifties: an LDL cholesterol comfortably within the reference range, a decent blood pressure, never smoked. And yet a father who had a heart attack at 54 and a brother stented at 49. On paper none of that story adds up, and that is exactly what a raised Lp(a) does: it sits invisibly in the family, it appears on no standard panel, and it produces no symptoms at all. For many women it is the missing link between a clean lipid profile and a family history that says something else entirely.

Lp(a) is also not only linked to furring arteries. It is independently associated with calcification and narrowing of the aortic valve, a connection mentioned on almost no patient page.

One misconception about the menopause needs clearing up. After the menopause, Lp(a) usually rises slightly. That rise is modest and can push a value that sat just below a boundary just above it, but it changes nothing about your genetic starting point and it does not make the menopause the cause of a high Lp(a). A markedly raised result is not something the menopause gave you; the predisposition was already there.

What you do with the result is what it really comes down to. A statin does not lower Lp(a) and in fact raises it slightly, so anyone hoping a cholesterol-lowering drug will fix this is hoping for the wrong drug. Medicines that specifically suppress Lp(a) production are in development; they lower the number steeply, but whether that actually prevents heart attacks has not been shown. Those outcome trials are still running: promising, not proven. The sensible response to a raised value today is therefore that everything you can influence gets watched more strictly. In concrete terms: the number of atherogenic particles in your blood, read from ApoB and non-HDL cholesterol, your blood pressure, smoking and your blood sugar regulation. Your doctor decides with you how strict that has to be.

Finally, the family. Lp(a) is passed on through a single gene, so every first-degree relative, your parents, your siblings and your children, has roughly a 50 percent chance of carrying the same predisposition. That is not an instruction to have your family tested. It is a reason to discuss a raised result with your doctor and to look together at what it means for the people close to you.

There is no good or bad cycle day on which to draw Lp(a), and that takes some getting used to if you are accustomed to having hormone values taken on day 3 or in the luteal phase. Lp(a) is not a hormone: the value is genetically fixed and stays much the same across your whole adult life. Nor do you need to fast. The 2022 European consensus therefore advises something you will meet with almost no other blood value: measure Lp(a) at least once in every adult, and with that it is done.

There is extra reason to have it measured when cardiovascular disease occurs at a young age in your family, when you already have cardiovascular disease yourself, when inherited high cholesterol runs in the family, or when a first-degree relative has been found to have a raised Lp(a). If you want a concrete peg to hang it on: the period around the menopause is a logical one, because your doctor is looking at your cholesterol and blood pressure anyway and the lp(a) blood test can simply run alongside that check.

The only reason to postpone is during or shortly after acute inflammation, an infection or surgery. Lp(a) behaves partly as an acute-phase protein and can then read temporarily higher; a CRP in the same tube shows whether that is the case. Two conditions can lift the value structurally: reduced kidney function or nephrotic syndrome, and an underactive thyroid. With an unexpectedly high result it is therefore worth having your TSH looked at as well.

The table below sets out, per life stage, what happens to Lp(a) and what that means for the measurement.

The categories below come from the European consensus. They are meant as orientation and emphatically not as a cut-off, because risk climbs gradually.

Finally, weigh your ancestry. The median Lp(a) is considerably higher in people of African descent than in people of European or South Asian descent, so the same result need not mean the same thing in two women. Always have your doctor place the value within your full risk profile.