Two identical twins can share nearly the same DNA and still reach later life with different arteries. One may carry more coronary plaque; the other less. That difference is not proof that lifestyle caused everything — but it is a powerful scientific question.
Modern twin imaging makes the story even more interesting: atherosclerosis is not one single material. Calcified and noncalcified plaque can show very different genetic and environmental patterns.
Quick answer
Is atherosclerosis genetic or environmental?
Both. Twin studies show substantial genetic influence for several atherosclerotic traits, especially calcified plaque, while a modern coronary CT twin study modelled noncalcified plaque volume predominantly through shared and individual environmental factors. The balance depends on the phenotype being measured.
Key takeaways
- Atherosclerosis means plaque accumulation in artery walls; arterial calcification and arterial stiffness are related but not identical processes.
- In the 196-person BUDAPEST-GLOBAL twin study, CAC score had estimated genetic heritability of 58% and calcified plaque volume 78%.
- In the same study, noncalcified plaque volume was modelled predominantly by shared and unique environmental factors.
- An international carotid twin study also found strong genetic influence on plaque presence and several plaque characteristics.
- Heritability describes variation in a population; it cannot tell an individual that a fixed percentage of their plaque is genetic.
First: what do we mean by atherosclerosis?
Atherosclerosis is a long-term process in which lipids, inflammatory cells, connective tissue and other material accumulate within the arterial wall. Plaques can contain different proportions of lipid-rich, fibrous and calcified components.
Calcification is therefore one feature of some atherosclerotic plaques, not a synonym for the entire disease. Arterial stiffness is another related vascular trait and can be influenced by calcification, blood pressure, ageing and structural change.
CT let researchers look inside the plaque
The BUDAPEST-GLOBAL study examined 196 adult twins without known coronary artery disease using coronary CT angiography. The sample included 120 monozygotic and 76 same-sex dizygotic twins, with women making up 63.3%.
Rather than asking only whether disease was present, the researchers quantified coronary calcium, calcified plaque volume and noncalcified plaque volume. That separation produced the study’s most striking result.
The genetic signal depended on the plaque type
In structural-equation models, coronary calcium score had an additive genetic estimate of 58%, while calcified plaque volume had an estimate of 78%.
Noncalcified plaque volume looked very different: 63% of the modelled variation was attributed to common environment and 37% to unique environment. The study does not prove that changing lifestyle will erase noncalcified plaque, but it strongly argues against treating every plaque phenotype as the same genetic entity.
Carotid studies point in the same broad direction — with important nuance
An international study of 275 twin pairs used ultrasound to study carotid plaque. It reported high heritability estimates for plaque presence, echogenicity and size.
Those numbers reinforce a genetic contribution to atherosclerotic biology, but different arteries, imaging methods and populations should not be collapsed into one universal percentage.
TwinPare perspective: the interesting question is where twins diverge
Twin studies are not valuable because identical twins are expected to be identical. They are valuable because similarities help control part of the background while differences expose where biology and lived experience can diverge.
For cardiovascular research, that makes the pair itself a natural experiment: similar genetic starting points, different lifetime exposures, and an opportunity to ask which vascular traits remain similar — and which do not.
Source notes
The sources have been verified and editorially reviewed for this article. The limitations below show which level of conclusion the sources support.
- [drobni-2022] Heritability of Coronary Artery Disease: Insights From a Classical Twin Study Zsofia D Drobni et al.. Circulation: Cardiovascular Imaging, 2022. Evidence type: Prospective coronary CT angiography twin study of 196 adult twins Limitation: Model estimates differed sharply by plaque phenotype: calcified measures had stronger genetic components, while noncalcified plaque volume was modelled predominantly by shared and unique environmental factors. These are population-level variance estimates. PubMed PMC DOI
- [tarnoki-2012] Evidence for a strong genetic influence on carotid plaque characteristics: an international twin study Ádám D Tarnoki et al.. Stroke, 2012. Evidence type: International ultrasound twin study of 275 twin pairs Limitation: High heritability estimates were reported for plaque presence and several plaque characteristics, but estimates depend on the studied populations, measurements and model assumptions. PubMed DOI
Editorial source review
This section shows how the article's key factual claims are linked to the source.
Phrasings that require caution
- Do not say an individual’s plaque is 58% or 78% genetic.
- Do not treat calcification, noncalcified plaque and arterial stiffness as interchangeable.
- The study design identifies variance patterns and associations; it does not assign a single cause to one person’s plaque.
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