What does a high Lp(a) mean?

The EAS, the NLA and the 2026 ACC/AHA guideline use 125 nmol/L as the line for high risk [2][7][8]. The ESC/EAS 2025 update says risk becomes clinically relevant above 50 mg/dL (105 nmol/L) and estimates that at least 20% of people are above it [5]. HEART UK grades risk as moderate from 90 nmol/L, high from 200 and very high above 400 [9].

Risk does not switch on at one number. It climbs steadily, by about 11% for every 50 nmol/L [10], and the ACC/AHA summary links levels above 250 nmol/L to at least twice the risk [8]. See the full chart on what is a good Lp(a) level.

Inherited causes

Each person carries two copies of the LPA gene, one from each parent. Copies with fewer kringle IV type 2 repeats make smaller apo(a), which the liver releases more readily. In Copenhagen, the quarter of people with the fewest repeats averaged 56 mg/dL, against 15 mg/dL in the quarter with the most [11]. Common variants such as rs10455872 and rs3798220 mark high-Lp(a) versions of the gene [12].

Why Lp(a) can increase later in life

Some conditions push Lp(a) up from your genetic baseline [2][5]:

• Kidney disease. Nephrotic syndrome raises Lp(a) 3 to 5 times; peritoneal dialysis roughly doubles it.
• Low thyroid function. Hypothyroidism raises it; thyroid treatment lowers it by 5% to 20%. See TSH.
• Menopause and pregnancy. Levels can rise after menopause and roughly double in pregnancy.
• Some medicines. Growth hormone therapy and some HIV medicines raise it.
• Inflammation. Lp(a) rises only slightly with inflammation, for example from a median 18.0 to 21.1 mg/dL as CRP rose from below 1 to above 10 mg/L [13].

Diet, weight and exercise are not major causes. Changing them moves Lp(a) far less than it moves LDL cholesterol [2].

High Lp(a) does its damage silently, over decades, in the arteries and the aortic valve [2]. Clues that it might run in your family include:

• a heart attack, stroke or stent in a close relative at a young age
• heart disease in someone without the usual risk factors
• aortic valve stenosis in a relative
• a relative already known to have high Lp(a)

These are the same reasons HEART UK and the NLA give for testing [9][14]. The only way to know your level is the Lp(a) test.

Population and genetic studies agree on the size of the effect:

• Per unit. Risk rose 11% for every 50 nmol/L in 460,506 UK Biobank adults [10].
• At thresholds. The 2026 ACC/AHA guideline summary links above 125 nmol/L to 1.4 times and above 250 nmol/L to at least 2 times the risk [8].
• At the extremes. Women and men at or above 120 mg/dL had 3.6 and 3.7 times the heart attack risk of people below 5 mg/dL [3].
• Stroke. Each 3.5-fold higher Lp(a) raised ischemic stroke risk by 10% [15].
• On treatment. Among statin users, Lp(a) of 50 mg/dL or more carried a 43% higher risk of events [16].

Absolute risk matters more than relative risk. The EAS notes that an Lp(a) of about 250 nmol/L roughly doubles risk whatever a person's starting point, so the same Lp(a) adds far more absolute risk to someone who smokes or has high blood pressure [2].

A genome-wide study found that one LPA variant doubled the odds of aortic valve calcium per copy (odds ratio 2.05) and raised the risk of aortic stenosis by 68% per copy [17]. In 77,680 Danes followed for up to 20 years, Lp(a) above 90 mg/dL carried 2.9 times the risk of aortic stenosis, and genetic analysis supported a causal role [18]. HEART UK recommends Lp(a) testing in anyone with calcific aortic stenosis [9]. No treatment has yet been shown to slow valve disease by lowering Lp(a) [2].

In UK Biobank, 47.0% of first-degree relatives and 31.8% of second-degree relatives of someone with Lp(a) of 125 nmol/L or more also had a high level, against 16.4% of unrelated pairs. First-degree relatives were 7.4 times as likely to be high [6]. The EAS, NLA and ACC/AHA all support testing relatives [2][7][8].

Because each child gets one LPA copy from each parent, high Lp(a) can appear in one generation and not the next, depending on which copy was passed on.

Without a proven Lp(a)-lowering treatment, the EAS recommends early, intensive management of overall risk, matched to both overall risk and Lp(a) level [2]. The ESC/EAS 2025 update says people with high Lp(a) should be strongly encouraged to take high-intensity statins and that more intensive LDL lowering is reasonable [5]. HEART UK suggests non-HDL cholesterol below 100 mg/dL (2.5 mmol/L)2.5 mmol/L (100 mg/dL) [9].

Practical steps to discuss with a clinician:

1. Test ApoB and LDL cholesterol and agree on a target.
2. Check blood pressure, HbA1c and smoking status.
3. Ask whether a coronary calcium scan would change your plan.
4. Test first-degree relatives.
5. Ask about clinical trials if you already have heart disease.

Treatment options and their effect sizes are compared on can you lower Lp(a). Protocols such as longevity focus track the LDL and ApoB side of this plan.