What Lp(a) is
Lipoprotein(a) — written as Lp(a) and pronounced "L-P-little-a" — is a lipoprotein particle structurally similar to LDL, with an additional protein called apolipoprotein(a) [apo(a)] attached via a disulfide bond. This structural addition gives Lp(a) properties that distinguish it from LDL in important ways.
Lp(a) is:
- More inflammatory than LDL — apo(a) contains sequences similar to plasminogen (a clot-dissolving protein), and Lp(a) competes with plasminogen for binding sites, potentially promoting thrombosis
- More atherogenic — it penetrates the arterial wall more readily than LDL and promotes the formation of atherosclerotic plaques
- Responsible for a type of cardiovascular risk that does not respond to standard lipid management — statins do not substantially lower Lp(a), and dietary changes have minimal effect
Why it is largely genetic
Approximately 80–90% of the variance in Lp(a) levels between individuals is determined by the LPA gene, which encodes apo(a). Variations in the number of repeating sequences (called kringle IV type 2 repeats) in this gene drive individual Lp(a) levels, and this genetic determination is largely set at birth.
Several practical consequences follow from this genetic architecture:
Lp(a) needs to be tested only once. Unlike LDL-C or triglycerides, which respond to diet, exercise, and medication, Lp(a) levels remain essentially stable throughout adult life in the absence of specific Lp(a)-lowering therapy. A single measurement provides a lifetime risk estimate.
Lifestyle interventions do not substantially lower Lp(a). A patient who discovers an elevated Lp(a) cannot meaningfully reduce it through diet or exercise. This is clinically important: it means that elevated Lp(a) represents an additional, additive cardiovascular risk that requires risk-based management of other modifiable factors.
Family history is informative. Because Lp(a) is genetically determined, first-degree relatives of patients with elevated Lp(a) are more likely to have elevated levels themselves. A parent who had premature cardiovascular disease with a normal LDL-C may have had elevated Lp(a) as the unrecognised driver.
What "elevated" means
Population Lp(a) levels follow a skewed distribution: most people have relatively low levels, and a subset has very high levels. The commonly cited threshold for elevated Lp(a) in cardiovascular risk guidelines is 50 mg/dL (or approximately 125 nmol/L, depending on assay type). Approximately 20% of the population exceeds this threshold.
Above 50 mg/dL, the association with cardiovascular risk becomes substantial. In the Kamstrup et al. 2008 JAMA study, patients in the top 20% of Lp(a) distribution had a 1.6-fold increased risk of myocardial infarction; those in the top 5% had a 2.6-fold increased risk — comparable to the risk associated with carrying one copy of the APOE4 allele.
Very high Lp(a) (above 180 mg/dL) is associated with cardiovascular risk equivalent to familial hypercholesterolaemia.
The Indian context
Systematic Lp(a) data in Indian populations are limited, but available studies suggest that Lp(a) levels in South Asian populations are comparable to or modestly higher than in Western populations. Given India's disproportionately high cardiovascular disease burden at younger ages and lower BMIs, Lp(a) likely accounts for a meaningful proportion of the "unexplained" cardiovascular risk in Indians who have otherwise controlled lipid profiles.
A cardiometabolic assessment that does not include Lp(a) is incomplete for any Indian adult who is evaluating cardiovascular risk — particularly those with a family history of premature heart disease, those who have had a cardiovascular event with otherwise normal lipids, and those who want a full picture of inherited risk.
What to do if your Lp(a) is elevated
There is no approved pharmacological therapy for Lp(a) reduction that is available in India at the time of writing. Several investigational therapies (small interfering RNA approaches, antisense oligonucleotides) have shown substantial Lp(a) reductions in trials and may be available in coming years.
The current clinical approach:
- Treat other modifiable cardiovascular risk factors more aggressively — statin therapy, blood pressure control, diabetes management, smoking cessation, aspirin in appropriate settings
- Consider earlier statin initiation (lower LDL-C targets) to compensate for the elevated Lp(a)-attributable risk
- Cascade screening of first-degree relatives
- Repeat testing not needed (Lp(a) is stable)
- Remain under regular cardiometabolic follow-up with a doctor who understands the risk context
Knowing your Lp(a) does not change what you can do about Lp(a) directly — but it changes what you should do about everything else.