Lipoprotein(a) or Lp(a): The Hidden, Inherited Heart Risk Most People Have Never Tested

Most of the risk factors I talk to patients about can be changed. You can lower your cholesterol, treat your blood pressure, stop smoking, and improve your blood sugar. Lipoprotein(a), usually written as Lp(a) and said out loud as “L-P-little-a”, is different. It is set largely by the genes you were born with, it stays fairly steady for life, and roughly one in five people walking around has a level high enough to matter. Yet most of them have never had it measured, and many doctors still do not test for it routinely.

In this article I will explain what Lp(a) is, why it raises the risk of heart attack and stroke, who should be tested and when, what counts as a high level, and what you can sensibly do about it today. The honest summary is this: knowing your number is genuinely worth doing, even though our direct treatment options are still limited.

What is Lp(a)?

To understand Lp(a), it helps to start with the particles that carry fat around your body. Cholesterol and fat do not dissolve in blood, so they have to be wrapped in a protein shell to travel. That protein is apolipoprotein B (apoB), and the best known of these particles is LDL, the so-called “bad cholesterol”. (If you want the full picture of apoB, I have written about it separately in understanding apoB.)

Lp(a) is essentially an LDL-style particle with one extra component bolted on: a looping protein called apolipoprotein(a), or apo(a). So picture a standard LDL particle, then add a distinctive tail, and you have Lp(a).

That extra protein is what makes Lp(a) troublesome. It drives the build-up of fatty plaque in artery walls, the process we call atherosclerosis, and it is thought to be 6x more atherogenic than a standard LDL particle.

How much Lp(a) you make is decided almost entirely by your genes. Diet, exercise and weight, which strongly influence ordinary cholesterol, have very little effect on Lp(a). Your level is largely fixed by early childhood and tends to stay roughly the same throughout your life. In other words, this is inherited risk, not lifestyle risk.

Why is high Lp(a) dangerous?

A large body of evidence now shows that elevated Lp(a) is an independent, causal risk factor for cardiovascular disease. “Independent” means it adds to your risk even when your LDL cholesterol, blood pressure and everything else look fine. “Causal” means the genetics strongly suggest Lp(a) does not just travel alongside heart disease, it helps to cause it.

A high Lp(a) has been linked with a higher risk of several conditions:

• Coronary artery disease and heart attack, from plaque building up in the arteries that feed the heart.
• Ischaemic stroke, when a clot blocks blood flow to part of the brain.
• Peripheral artery disease, narrowing of the arteries supplying the legs.
• Aortic stenosis, a stiffening and narrowing of the heart’s main outflow valve, which is one of the more distinctive associations with Lp(a).

The effect is also dose-dependent. Broadly speaking, the higher your Lp(a), the higher your risk, and the risk climbs steadily rather than switching on at a single point. Large studies suggest that at very high levels the lifetime risk of a heart attack may be roughly double that of someone with a low level. What matters is that this is a risk you carry for decades, so it adds up over a lifetime.

I want to keep this in proportion. A high Lp(a) does not mean you are destined to have a heart attack. It means you start with a head-start of risk that you did not choose, which is all the more reason to be tight on everything else you can control.

Who should get tested for Lp(a), and when?

This is the part I most want people to take away, because it is simple and actionable. Current European guidance recommends that every adult should have their Lp(a) measured at least once in their lifetime.

The logic is straightforward. Because your level is largely genetic and stays fairly stable, a single test usually tells you what you need to know for life. You do not need to repeat it every year the way you might monitor LDL or blood pressure. It is, in most cases, a once-in-a-lifetime test.

I would particularly encourage testing if any of the following apply to you:

• A family history of early heart attack or stroke, especially in parents or siblings before about age 55 in men or 65 in women.
• A personal history of heart attack, stroke or other vascular disease, particularly if it happened young or without an obvious cause.
• A family history of raised Lp(a) itself.
• South Asian or African ancestry, which I will come back to below.

The test itself is a straightforward blood test, widely available and inexpensive. The practical snag is that it is often not included in a standard lipid panel, and some doctors are still not in the habit of ordering it. If you are arranging blood tests, it is worth asking specifically for Lp(a) to be added. We routinely include it in our assessments here, and you can read about what is covered in our heart screening packages.

What level of Lp(a) is high?

The first thing to know is that Lp(a) is reported in two different units, which causes endless confusion. Some labs use nmol/L (nanomoles per litre), which counts particles, and some use mg/dL (milligrams per decilitre), which measures mass. The nmol/L unit is generally preferred. There is no exact conversion between the two, but as a rough guide 50 mg/dL corresponds to somewhere around 125 nmol/L.

As a broad framework that I find useful in clinic:

• Below about 75 nmol/L (around 30 mg/dL): generally considered low risk.
• Around 125 nmol/L (around 50 mg/dL) and above: commonly regarded as elevated, and a level at which I take note.
• Around 250 nmol/L (around 100 mg/dL) and above: clearly high, with studies suggesting the risk may be roughly doubled.
• Very high inherited levels (in the region of 430 nmol/L, around 180 mg/dL): carry a risk that some guidelines compare to inherited high-cholesterol conditions.

Please treat these as guide-posts rather than hard lines. Risk rises in a continuous fashion, and your Lp(a) number always has to be read alongside your overall picture, your age, blood pressure, LDL, diabetes status, smoking history and family history. A number on its own is not a diagnosis.

Can you lower Lp(a)?

This is where I have to be straight with you, because it is the area where there is the most hype and the least proof.

The everyday tools that lower ordinary cholesterol do not do much for Lp(a):

• Diet, exercise and weight loss have little meaningful effect on Lp(a). They remain essential for your heart for many other reasons, but they will not move this particular number much.
• Statins, the mainstay of cholesterol treatment, do not lower Lp(a) and may even nudge it up slightly. That is not a reason to stop a statin if you need one, since the overall benefit on LDL is what counts.
• PCSK9 inhibitors, a newer class of injectable cholesterol-lowering drugs, do reduce Lp(a) modestly, by roughly a fifth to a quarter. They are generally prescribed to lower LDL rather than for Lp(a) specifically. I have written more about this class in PCSK9 inhibitors.
• Lipoprotein apheresis, a procedure that physically filters lipoproteins out of the blood, can lower Lp(a) substantially, but it is intensive and reserved for a small number of severe cases.

Crucially, here is the point that I think is most often misunderstood: we do not yet have proof that lowering Lp(a) itself reduces heart attacks and strokes. A treatment can lower a number on a blood test without lowering real-world risk, and until the trials report, we cannot assume the two are the same thing. For now, chasing the Lp(a) number directly is not the priority.

What should I do if my Lp(a) is high?

If your level comes back high, the first thing is not to panic. A high Lp(a) is information, and information you can act on, just not in the way most people expect.

Since we cannot reliably lower Lp(a) itself yet, the strategy in most cases is to manage every other risk factor aggressively, so that your total cardiovascular risk is pulled down as far as possible. In practice that means:

1. Get your LDL and apoB as low as appropriate for your overall risk, usually with a statin and other agents if needed. If you start with extra inherited risk, it makes sense to be firmer about the risk you can control.
2. Treat blood pressure properly and keep it in a healthy range.
3. Do not smoke, and get help to stop if you do.
4. Manage blood sugar and weight, and stay physically active.
5. Know your family. Because Lp(a) is inherited, a high result in you is a prompt to suggest your close relatives consider testing too.

This is a sensible, evidence-based plan rather than a counsel of despair. Think of a high Lp(a) as a reason to take the rest of your prevention seriously, not a sentence you can do nothing about. A first step, if you have not had a full assessment, is a proper comprehensive heart check-up so that we can see the whole picture and set the right targets.

It is also worth knowing that the treatment horizon is genuinely promising. Several drugs designed to target Lp(a) directly, including antisense and RNA-based agents, are in late-stage clinical trials and can lower Lp(a) dramatically, by up to around 80 to 90 percent. The large outcome trials testing whether this actually prevents heart attacks and strokes are underway, with first results from the pelacarsen Lp(a)HORIZON study expected around 2026 and others following after. If those trials are positive, the way we manage high Lp(a) could change within a few years.

Lp(a) and ethnicity

Average Lp(a) levels differ markedly between ethnic groups, and this is highly relevant in a diverse society like Singapore. People of African and South Asian ancestry tend to have higher Lp(a) on average, while those of East Asian (including Chinese) and European ancestry tend to have lower levels.

This is not an abstract point. A Singapore study comparing newborns of Chinese, Malay and Indian background found that Indian babies had the highest Lp(a) levels and Chinese babies the lowest, and that ranking mirrored the differences in coronary heart disease mortality between those communities in adulthood. South Asian populations carry a well-documented excess of early heart disease, and elevated Lp(a) appears to be one of the contributing threads.

The practical message is that ancestry can be a useful flag for who should make sure they are tested. If you are of South Asian or African background, particularly with any family history of early heart disease, I would be especially keen to know your Lp(a) number.

The bottom line

Lp(a) is a common, largely inherited risk factor for heart attack and stroke that most people have never had measured. The good news is that finding out is easy and, in most cases, only needs doing once. While we cannot yet lower Lp(a) itself with proven benefit, a high level is a strong reason to control everything else, your LDL and apoB, blood pressure, smoking and blood sugar, as tightly as possible. Know your number, then act on the rest.

If you would like to have your Lp(a) checked and your overall heart risk properly assessed, I offer comprehensive cardiac evaluation at the Harley Street Heart and Vascular Centre in Singapore. Call +65 6235 5300 to arrange an appointment.

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Written by Dr Michael Ross MacDonald MB ChB, BSc (Hons), FRCP (UK), MD (Research), FESC (Europe) Senior Consultant Cardiologist at the Harley Street Heart and Vascular Centre, Singapore.

This article is general information, not a substitute for individual medical advice. If you are worried about your heart, seek medical care, and in an emergency in Singapore, call 995.

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