Artery plaque already shows up in 1 in 13 adults under 30, before any symptom

Fatty plaque was already sitting inside the arteries of about 1 in 13 adults aged 18 to 29, none of whom had a diagnosis or a single symptom. Among people in their thirties, it turned up in a third of the men and a fifth of the women. By 60 to 70, nine in ten carried it.

Those numbers come from the REACT study, which scanned the arteries of 16,808 apparently healthy adults in Denmark and Spain. More than half of them, 57.1 percent, had atherosclerosis, the slow build-up of fat, cholesterol and calcium in artery walls that eventually causes most heart attacks and many strokes. The finding matters because the tools doctors use to decide who needs prevention, a risk score built from blood pressure, cholesterol, age and smoking, flagged almost none of those people as high risk.

The study was led by cardiologist Henning Bundgaard of Rigshospitalet in Copenhagen and Borja Ibáñez, scientific director of Spain’s National Centre for Cardiovascular Research (CNIC) in Madrid, and appeared in the New England Journal of Medicine. “Until now, preventive decisions have been based on an estimate of risk, but we did not know whether the disease was already present,” Bundgaard said.

How they looked inside 16,808 healthy arteries

Most population studies of heart disease start in middle age, because that is when heart attacks start. REACT started at 18. The team recruited adults up to 70 with no known atherosclerotic disease and split them into five age bands of roughly equal size, with a balance of men and women in each. The average participant was 45, and 51 percent were women.

Every volunteer went through two kinds of imaging. A three-dimensional ultrasound swept the carotid arteries in the neck and the femoral arteries in the groin, where plaque often appears first. A coronary CT angiogram, an X-ray scan with injected contrast dye, mapped the arteries that feed the heart muscle itself. The researchers also collected blood biomarkers, retinal images and samples for genetic and molecular analysis, which later phases of the project will use.

Scanning three arterial territories instead of one is the design choice that changes the result. Plaque in young people tends to be small, peripheral and confined to a single spot. A heart scan alone would have missed much of it, and isolated plaque in the coronary arteries turned out to be rare, at no more than 9.3 percent of men and 5.0 percent of women in any age band.

The numbers by age and sex

In the youngest group, plaque showed up in 8.7 percent of men and 6.7 percent of women. In the thirties it jumped to 34.6 percent of men and 21.3 percent of women. Among those aged 60 to 70, only 1.9 percent of men and 8.1 percent of women had clean arteries on every scan.

Men ran roughly five to ten years ahead of women. Women caught up fast in midlife: their sharpest rise came between 40 and 60, around the usual age of menopause, when oestrogen levels fall. Plaque volume did not grow in a straight line either. It rose exponentially with age, and older participants tended to have disease in two or three territories at once.

That spread matters for how plaque is found. Most people with coronary plaque also had it in the neck or legs, which supports the idea that atherosclerosis is a body-wide disease rather than a heart problem. It also suggests that a cheaper, radiation-free ultrasound of the carotid and femoral arteries could catch many cases without a CT scan, although the study did not test ultrasound as a stand-alone screen.

The risk score that missed almost everyone

European doctors estimate heart risk with a calculator called SCORE2, which predicts a person’s chance of a heart attack or stroke over ten years. In REACT, a high-risk SCORE2 result was almost always right when it appeared, with 99.8 percent specificity. But it appeared for very few of the people who actually had disease: its sensitivity was 1.9 percent. Put plainly, for every 100 people with plaque, the calculator labelled fewer than two as high risk.

There was a second blind spot. Doctors often use a coronary calcium score, a quick CT measure of hardened plaque, as a tiebreaker. Among people in their thirties who had coronary plaque on the angiogram, 41.8 percent of the men and 48.4 percent of the women had a calcium score of zero. Young plaque is often soft and not yet calcified, so a zero score can mean “nothing visible yet” rather than “nothing there”.

“In this model, preventive interventions and the treatment of risk factors could be guided by the actual presence of silent atherosclerosis rather than relying solely on an indirect estimate of risk,” Ibáñez said.

What the study doesn’t settle

REACT shows how common plaque is. It does not show that finding it saves lives. Nobody has yet tested whether scanning healthy adults and treating those with plaque prevents more heart attacks than current care, and that is the question the project’s next phase was designed to answer.

The design also has limits. It is cross-sectional: it compares different people at different ages rather than following the same people over time, so it cannot say how fast an individual’s plaque grows or how much of it will ever cause harm. Many small plaques in young adults may stay stable for decades. Volunteers for a heart-scanning study may also differ from the general population, and the participants came from two European countries, so the percentages may not transfer directly to other regions or ethnic groups.

Coronary CT angiography carries a dose of radiation and requires contrast dye, which is why cardiologists do not order it casually for healthy people. Screening millions would bring costs, incidental findings and the risk of overtreatment with statins in people whose plaque would never have caused trouble. The authors frame their results as a reason to test imaging-guided prevention, not as a recommendation to scan everyone today.

Common questions about artery plaque in young adults

Can you have plaque in your arteries at 25?

Yes. In REACT, about 1 in 13 adults aged 18 to 29 had detectable plaque in the neck, leg or heart arteries, with no symptoms and no diagnosis. Early plaque is usually small and limited to one artery.

What is silent atherosclerosis?

It is plaque that has built up in artery walls without causing chest pain, a heart attack or a stroke. It can only be found with imaging such as ultrasound or a CT scan, so most people who have it do not know.

Does a normal heart risk score mean my arteries are clear?

Not necessarily. The SCORE2 calculator flagged as high risk fewer than 2 in 100 of the REACT participants who had plaque. Risk scores estimate the odds of a future event; they do not look at the arteries.

Should healthy young adults ask for an artery scan?

The study does not recommend it. There is no evidence yet that scanning healthy people prevents heart attacks, and coronary CT involves radiation and contrast dye. The established steps still apply: blood pressure, cholesterol, not smoking and exercise.

What comes next

The first phase, REACT-DETECT, began in 2024 and was funded with up to 23 million euros from the Novo Nordisk Foundation. The results were presented at the European Society of Cardiology Congress in Munich and published in the New England Journal of Medicine on 29 August 2026. A second phase, REACT-PROTECT, is planned for 2027 to 2032 if funding is approved. It would randomise participants to imaging-guided prevention or standard care and extend recruitment to India, Singapore, Tanzania and Mexico. That trial is the one that can show whether seeing plaque early changes who has a heart attack.

Reference: Bundgaard H, García-Lunar I, Kofoed KF, et al., “Prevalence of Silent Atherosclerosis across Adult Life,” New England Journal of Medicine, 2026. DOI: 10.1056/NEJMoa2609059

Tags: medicine, artery plaque, atherosclerosis, cardiovascular disease, CNIC, REACT study