Heart disease is usually imagined as a problem for the over-fifties. A major new study suggests that picture is badly out of date. Advanced imaging of nearly 17,000 adults in Denmark and Spain has found silent atherosclerosis — the fatty build-up inside arteries that narrows them and restricts blood flow — in a meaningful share of people in their twenties, with roughly one in ten younger adults affected. The findings, published in the New England Journal of Medicine, reframe artery disease not as a condition of old age but as a lifelong process that can be under way decades before any symptom appears.
The study is the first phase of the ongoing international REACT project, led by Dr Borja Ibáñez, scientific director of the Spanish National Centre for Cardiovascular Research in Madrid. Researchers recruited more than 16,800 adults aged 18 to 70 across Denmark and Spain — none of whom had any known cardiovascular disease — and divided them into five age groups, starting at 18 to 29. The cohort was roughly evenly split between men and women.
How the arteries were mapped
To detect plaque, the team used two imaging techniques. For the arteries supplying the heart, they used CT angiography, which produces detailed three-dimensional images of blood vessels. For arteries in the neck and legs, they used ultrasound. The combination allowed the researchers to build what one cardiologist described as the most comprehensive atlas yet of how atherosclerosis evolves across adult life, spanning multiple arterial beds rather than a single site.
Previous studies had already hinted that artery disease arrives early. In 2025, a team led by Olli Raitakari at the University of Turku in Finland found plaque in the carotid arteries — the vessels supplying the head, face and neck — of about 5 per cent of Finnish adults under 30. But no large-scale investigation had spanned multiple adult age categories while examining several artery locations at once. The REACT study was designed to fill precisely that gap.
What the scans revealed
The headline numbers are striking. Across the full study population, silent atherosclerosis — defined as plaque that causes no symptoms but may lead to cardiovascular problems later — was detected in 57.1 per cent of participants: 63 per cent of men and 51 per cent of women. Prevalence rose steadily with age, from about one in 13 adults aged 18 to 29 — roughly 7 to 8 per cent — to approximately nine in 10 adults between 60 and 70.
The sex differences were notable. Men tended to develop plaque five to ten years earlier than women, while women experienced their sharpest increase in prevalence between the ages of 40 and 60 — a pattern consistent with the protective cardiovascular effects of oestrogen before menopause. Atherosclerosis itself develops when cholesterol, fatty deposits and other substances accumulate inside artery walls, gradually narrowing the passage through which blood flows. It can progress silently for years before a heart attack or stroke announces its presence.
The blind spot in standard risk scores
Perhaps the most consequential finding is not the prevalence itself but what conventional medicine misses. Common cardiovascular risk scores — which estimate danger from factors such as age, blood pressure, cholesterol and lifestyle — identified only a small share of the participants who already had silent atherosclerosis. That was particularly true of the younger adults, the very group whose risk profiles look cleanest on paper.
"For decades, we have estimated cardiovascular risk using factors such as age, blood pressure and cholesterol," said Ibáñez. "This study shows that we can now go one step further and detect the disease directly before it causes a heart attack or stroke." The shift he is describing is philosophically significant: moving from estimating the probability of disease to imaging whether the disease is already there.
Why experts say this is not a reason to panic
Researchers were careful to temper the findings with context. "Finding plaque doesn't mean someone is about to have a heart attack, but finding it gives us an opportunity to address a patient's risk factors," said Dr Sirisha Vadali, a cardiologist at HonorHealth Women's Heart Health in Arizona, who was not involved in the research. "We shouldn't wait for symptoms to start paying attention to heart health. Feeling healthy doesn't necessarily mean your arteries are free of plaque."
Crucially, the experts said the results do not justify screening every person under 30. The study does not establish that broad imaging would prevent heart attacks or strokes — that question belongs to the trial planned for REACT's next phase, which will test whether earlier detection actually improves prevention. As Raitakari summarised the core message: "Atherosclerosis is a lifelong process, not a disease of old age." The takeaway, the researchers say, should be motivation rather than alarm: decisions about additional testing should be based on each person's individual risk factors, not on age alone.
What drives plaque in the young
Atherosclerosis is not a single-cause condition, and its appearance in young adults reflects the familiar catalogue of cardiovascular risk factors arriving earlier in life. High levels of LDL cholesterol, smoking, high blood pressure, poor diet, physical inactivity, excess weight and diabetes all accelerate plaque formation, and family history can add a genetic component. Rising rates of obesity and metabolic problems among younger adults are widely suspected of pulling the onset of artery disease forward in time, though the study itself did not assign individual causes.
The researchers believe portable, handheld ultrasound scanners could eventually help identify hidden plaque in people whose risk scores look reassuring — but they stress that clinical trials are needed first. Until such tools are validated, the proven levers remain unglamorous: avoiding tobacco, staying active, eating a balanced diet, and knowing your blood pressure and cholesterol numbers so problems can be addressed before symptoms arrive.
Why it matters
Cardiovascular disease remains the leading cause of death worldwide, and most prevention strategies are still aimed at middle-aged patients whose risk scores have finally turned red. This study suggests that by the time those scores sound the alarm, the disease may have been progressing quietly for twenty years or more. If the planned trial confirms that finding plaque early — and acting on it early — changes outcomes, the entire logic of cardiovascular prevention could shift toward youth. The arteries of the twenty-something, it turns out, are not a blank slate. They are a work in progress — and the earlier that work is noticed, the more can be done about it.
🤖 This article was rewritten by Feed and Figures' editorial AI from a report originally published by New Scientist. Facts and quotes are preserved from the original; the rewrite focuses on clarity and structure. For the unedited original, see the source link below.
