Most people expect a heart attack to announce itself, perhaps with chest tightening during a workout or a few months of warning signs. The REACT study, published in the New England Journal of Medicine and presented simultaneously at ESC Congress 2026, found something that challenges that assumption completely. Among adults in their 30s with no diagnosis of heart disease and no symptoms of any kind, more than one in three men already had detectable arterial plaque building silently inside them.
That figure came from direct imaging, including ultrasound scans and CT angiography, performed on more than 16,000 adults across Denmark and Spain. If a third of men in their 30s are already affected, conventional approaches to identifying who is and isn’t at risk may be missing a substantial amount of hidden disease. Atherosclerosis typically causes no symptoms in its early stages, and by the time warning signs do appear, plaque may have been accumulating for years.
The REACT findings reveal just how early this process can begin, how differently it progresses with age, and how much disease may be present long before symptoms appear. Together with what researchers already know about atherosclerosis, the results raise important questions about how we recognize and prevent cardiovascular disease. Here are eight things to know about this often silent condition.
1. The disease starts far earlier than most people realize
Atherosclerosis may begin in early adulthood and remain clinically silent for decades before manifesting as a heart attack, stroke, or sudden cardiac death. That’s been understood in general terms for years. What the REACT study did was put hard numbers on it for the first time across the full adult lifespan.
The results show that 57.1% of the more than 16,000 participants had atherosclerotic plaques, despite having no symptoms or previous diagnosis of cardiovascular disease. Silent plaque was the statistical norm, not the exception, across the full 18-to-70 age range studied.
The disease showed sex-specific patterns of growth with age, detectable from early adulthood. According to Johns Hopkins Medicine, atherosclerosis is a slow, progressive disease that may start as early as childhood and can progress rapidly. For anyone in their 20s or 30s who assumes they’re too young to worry about arterial health, the REACT data tells a different story. The disease doesn’t wait for middle age to begin.
2. Even teenagers and young adults in their 20s aren’t immune
One of the most striking findings from the REACT study was the prevalence of atherosclerosis in its youngest participants. Prevalence rose in an S-shaped curve with age, detectable in roughly 1 in 13 participants who were 18 to 29 years old. These were adults who, by any standard clinical measure, would have been considered at negligible cardiovascular risk.
Researchers conducted a cross-sectional analysis of 16,808 adults aged 18 to 70 years without known atherosclerotic cardiovascular disease. Participants from Denmark and Spain underwent multimodal imaging to assess the presence of atherosclerosis in the carotid, femoral, and coronary arteries. Examining three separate vascular territories in the neck, legs, and heart is more comprehensive than almost anything attempted in previous population studies of subclinical (below-the-surface, not yet causing symptoms) disease.
The fact that roughly 7 or 8 percent of people under 30 already carry detectable plaque – silently, with no warning – gives the clinical reality of atherosclerosis symptoms a far sharper edge than it had before. Most will never feel a thing until the disease has progressed significantly further.
3. The atherosclerosis symptoms gap: why standard risk tools fall short
The REACT study found silent atherosclerosis in 57.1% of adults without known cardiovascular disease – a burden largely missed by the SCORE2 risk tool. SCORE2 is a standard European calculator that estimates a person’s 10-year risk of a cardiovascular event based on age, sex, blood pressure, cholesterol, and smoking status. It’s widely used in clinical practice, and in the REACT population, it failed to flag the vast majority of people who actually had detectable plaque.
Among participants aged 40 or older without diabetes, SCORE2 classified only 1.9% of those with subclinical atherosclerosis as being at high risk. That gap is enormous. The tool that clinicians depend on for primary prevention decisions was functionally blind to the disease in more than 98 of every 100 affected people in that age group.
These findings suggest that reliance on risk factor-based assessment alone may fail to detect substantial subclinical disease. The researchers proposed that earlier identification and treatment of silent atherosclerosis through imaging could help reduce the burden of atherosclerotic cardiovascular disease. The question isn’t just who has the disease, but whether the tools used to identify it are up to the task.
4. Men develop plaque earlier — but women catch up fast
In the REACT data, sex-specific patterns were stark. Among adults in their 30s, 34.6% of men had detectable plaque compared to 21.3% of women, according to findings published in the NEJM. That’s roughly a one-in-three versus one-in-five split – a meaningful gap at an age when most people aren’t thinking about arterial health at all.
Professor Henning Bundgaard from Denmark’s Rigshospitalet – Copenhagen University Hospital, who co-led the REACT study, noted that “these data from multiple locations support the concept of silent atherosclerosis as a systemic, progressive disease process with men showing an approximately 5-to-10-year earlier atherosclerotic trajectory than women.” For much of adulthood, that head start defines the gap. But the data also showed a later, steeper rise in women through middle age – likely linked to hormonal changes around menopause – that begins to close the difference.
By ages 60 to 70, the sex gap narrows considerably. In that age group, 9 in 10 participants had detectable atherosclerosis. At that point, the distinction between men and women matters far less than the near-universal presence of the disease itself.
5. Plaque doesn’t just spread to more people — it spreads to more of the body
The REACT study didn’t just track how many people had atherosclerosis – it tracked where in the body plaque was present and how extensively it had spread. Researchers used three-dimensional vascular ultrasound to assess atherosclerosis in the carotid and femoral arteries, and CT angiography for the coronary arteries. Examining all three vascular territories in each participant gave the researchers a picture of systemic disease burden that single-artery studies simply can’t provide.
The results showed a dramatic shift in how widely plaque had spread as people aged. Among adults in their 30s, plaque confined to two or three vascular territories was found in just 6% of men and 2.6% of women. By ages 60 to 70, according to the New England Journal of Medicine study, all three territories contained plaque in 56.3% of men and 30.7% of women. The disease doesn’t just become more common with age – it becomes more extensive, moving through the body’s arterial network over time.
Atherosclerosis in one spot, like the coronary arteries, is often a clue that plaque is building up elsewhere. All arteries are connected, like a network of pipes. The things that cause atherosclerosis – high cholesterol, high blood pressure, smoking – don’t discriminate. Once plaque takes hold in one territory, the systemic risk factors that drove it there continue acting on the entire vascular system.
6. The atherosclerosis symptoms that appear — and when
Symptoms of atherosclerosis may not appear until an artery is more than 70% blocked. Most of the damage happens in silence, long before pain or discomfort signals anything is wrong. Many people don’t know they have plaque buildup until they have a medical emergency like a heart attack or stroke.
When atherosclerosis symptoms do appear, they vary by location. Chest pain during activity that goes away at rest is a sign of coronary disease. Deep, aching pain in the abdomen or back can be an early sign of an abdominal aortic aneurysm. Painful muscle cramps in the hips or legs when walking, which stop at rest, may indicate peripheral artery disease – plaque buildup in the leg arteries restricting blood flow.
In the brain’s arteries, the warning signs can be more acute. A transient ischemic attack (TIA), sometimes called a “mini stroke,” is a warning sign that a full stroke may follow. Symptoms appear then go away after a few minutes, and include severe sudden headache, difficulty moving or thinking, and numbness or weakness on one side of the body. The National Heart, Lung, and Blood Institute also flags erectile dysfunction as an early warning signal in men – a sign worth discussing with a doctor, since it can indicate reduced blood flow well before more obvious symptoms emerge.
Erectile dysfunction is an early warning sign that a man may be at higher risk for atherosclerosis and its complications. If you have it, talking with a healthcare team about your risk of plaque buildup is recommended.
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7. The risk factors that drive silent plaque growth
Understanding what accelerates atherosclerosis matters because the disease itself is invisible for so long. Risk factors may include high cholesterol and triglyceride levels, high blood pressure, smoking, diabetes, obesity, physical inactivity, and eating saturated fats. None of these cause symptoms on their own – they act quietly, driving plaque accumulation in artery walls before any clinical event occurs.
Atherosclerosis develops when a sticky plaque builds up inside arteries. In some cardiovascular diseases, plaque builds up and hardens. Plaque buildup reduces blood flow and makes it more likely that blood clots will form in the arteries – the mechanism behind most heart attacks and strokes.
What makes atherosclerosis particularly dangerous is what happens when plaque becomes unstable. Millions of patients who take cholesterol medications faithfully still suffer heart attacks, not because the drugs aren’t working, but because existing plaques can rupture before they’re controlled. When a plaque ruptures, its contents are exposed to the bloodstream, triggering a clot that can block a coronary artery or a vessel supplying the brain within minutes.
8. What the REACT findings mean for prevention going forward
Professor Henning Bundgaard of Rigshospitalet – Copenhagen University Hospital, who led the REACT initiative, concluded that “identifying and treating silent atherosclerosis as early as possible could help reduce the global burden of CVD.” The findings support further prospective studies to investigate whether imaging-guided treatment of those with early evidence of disease – detected using a handheld ultrasound scanner – can improve current standards. If successful, this could support a precision medicine approach to atherosclerotic cardiovascular disease.
Future prospective studies will examine whether imaging-guided treatment strategies, including those using handheld ultrasound devices, can improve prevention and support a more personalized approach to cardiovascular care. A large, randomized trial is planned as the next phase of the REACT initiative. That trial – the second phase of REACT – will test whether catching silent plaque early and treating it changes long-term outcomes. The cross-sectional data proves the disease is there. The trial will tell us whether earlier detection actually saves lives.
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The biology doesn’t wait
The REACT study establishes, with more comprehensive data than any previous study of its kind, that silent atherosclerosis is widespread far earlier in life than conventional risk tools suggest. Cardiovascular diseases are the leading cause of death globally. An estimated 19.8 million people died from CVDs in 2022, representing approximately 32% of all global deaths, with 85% of those deaths due to heart attack and stroke – almost all driven by the same arterial plaque process the REACT study found present in more than half of healthy adults.
The practical upshot is concrete. If you’re in your 30s or 40s and have any of the known risk factors – elevated LDL cholesterol (the “bad” kind that deposits in artery walls), high blood pressure, a history of smoking, diabetes, or a family history of early heart disease – ask your doctor whether imaging beyond a standard risk calculator is worth considering. The European Society of Cardiology has indicated that conventional risk assessment identifies only a small fraction of those with silent disease, meaning many people currently told they’re “low risk” may already have detectable plaque that no one has looked for. Statins won’t fix a plaque that hasn’t been found. A scan might.
Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.
AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.
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