Understanding Lipoprotein(a): Why This Hidden Heart Risk Factor Matters
You've probably heard about cholesterol as a cardiovascular risk factor, and you may be aware of the difference between the "good" kind (HDL) and the "bad" kind (LDL). Your doctor may have talked to you about keeping your LDL cholesterol low to protect your heart. But there is another player in the cholesterol story that is an important risk factor for heart disease : Lipoprotein (a), or Lp(a) for short.
Think of Lp(a) as LDL cholesterol's troublesome cousin. It's similar in many ways, but it comes with some extra baggage that makes it particularly risky for your heart and blood vessels.
What Exactly is Lp(a)?
Lp(a) is a particle that floats around in your bloodstream carrying cholesterol, just like LDL does. But Lp(a) has an additional protein attached to it called apolipoprotein(a). This extra protein is what makes Lp(a) different—and more dangerous.
Here's what makes Lp(a) unique: your Lp(a) level is almost entirely determined by your genes. More than 90% of your Lp(a) level comes from the DNA you inherited from your parents. Unlike LDL cholesterol, which you can lower by eating better, exercising, or taking medications like statins, Lp(a) doesn't budge much with lifestyle changes. You are essentially born with a certain Lp(a) level, and it stays relatively stable throughout your life.
Why Should You Care About Lp(a)?
High levels of Lp(a) significantly increase your risk of heart disease, stroke, and other cardiovascular problems, even if your regular cholesterol numbers look perfectly fine. This is what doctors call "residual cardiovascular risk"—the risk that remains even when everything else seems under control.
Research has shown that Lp(a) contributes to heart disease in several harmful ways:
- It builds up in artery walls. Like LDL cholesterol, Lp(a) can accumulate in the walls of your arteries, contributing to the formation of plaques that narrow blood vessels and restrict blood flow.
- It promotes inflammation. Lp(a) carries oxidized fats that trigger inflammation in your blood vessels, which accelerates the development of atherosclerosis (hardening of the arteries).[
- It may increase blood clotting. The apolipoprotein(a) part of Lp(a) looks similar to a protein involved in breaking down blood clots. This similarity can interfere with your body's natural clot-dissolving processes, potentially making dangerous clots more likely to form.
- It can damage heart valves. Beyond affecting your arteries, high Lp(a) is also linked to calcific aortic valve stenosis—a condition where the aortic valve in your heart becomes stiff and narrowed.
Studies involving hundreds of thousands of people have confirmed that elevated Lp(a) independently raises the risk of heart attacks, strokes, and peripheral artery disease. The evidence is strong enough that scientists now consider high Lp(a) a causal risk factor for cardiovascular disease, meaning it doesn't just correlate with heart problems, it actually helps cause them.
What's Considered "High"?
Generally, an Lp(a) level of 50 mg/dL or higher (or 125 nmol/L or higher) is considered elevated and may increase cardiovascular risk. You might see Lp(a) reported in different units (mg/dL or nmol/L) depending on which lab does the test—the nmol/L number is roughly 2 to 3 times higher than the mg/dL number.
Who Should Get Tested?
Because Lp(a) is so strongly genetic, you only need to have it measured once in your lifetime—it won't change significantly over time. Testing is particularly important if you:
- Have a family history of early heart disease (heart attacks or strokes at a young age)
- Have had a heart attack or stroke yourself, especially if your other risk factors don't fully explain why
- Have a close family member with high Lp(a)
- Have familial hypercholesterolemia (an inherited condition causing very high cholesterol)
- Have calcific aortic valve disease
Some experts believe everyone should have their Lp(a) checked at least once, perhaps during routine cholesterol screening in young adulthood.
What Can You Do If Your Lp(a) Is High?
There are currently no approved medications specifically designed to lower Lp(a), though new medications targeting Lp(a) are being developed. Statins, the most common cholesterol drugs, do not lower Lp(a) but are often used in people with elevated Lp(a). Research suggests that though statins may actually raise Lp(a) slightly, the cardiovascular risk reduction they supply by lowering LDL outweighs the small increase in Lp(a). Other medications called PCSK9 inhibitors can reduce Lp(a) by about 25-30%, but it remains unclear whether this reduction is enough to meaningfully lower cardiovascular risk. Targeting modifable risk factors by not smoking, exercising regularly, maintaining a healthy body weight and normal blood pressure, and following a mediterranean diet continue to be the foundation to reducing cardiovascular risk.
