Most of us picture clogged arteries as a problem for later in life.
The gray hair, the first prescription, the chat about cholesterol.
For most people in their 20s, heart disease still feels like a problem for someone much older.
A new imaging study is challenging that picture. Researchers scanned 16,808 adults aged 18 to 70 in Denmark and Spain.
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None had any known heart disease.
The REACT study was published in the New England Journal of Medicine on August 29, 2026.
More than half of the participants turned out to have atherosclerotic plaque in their arteries.
In the 18 to 29 age group, roughly 1 in 13 already did.
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Atherosclerosis is the slow build-up of fatty, fibrous plaque in the walls of the arteries.
It is the main driver of heart attacks and strokes. The disease can grow for years without any warning sign.
Already carrying plaque in their twenties
The researchers used imaging to look for silent disease in three different arteries.
A 3D ultrasound scanned the arteries in the neck and legs. A CT scan checked the coronary arteries that feed the heart.
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Overall, 57 percent of participants had plaque in at least one of these areas. By age 60 to 70, roughly 9 in 10 did.
Men showed up with plaque earlier than women. Across the whole study, their atherosclerotic trajectory ran about 5 to 10 years ahead.
Women caught up quickly between 40 and 60, the years that span the menopausal transition.
In the youngest group, the plaque was usually small and limited to a single region.
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It most often sat in the arteries of the neck or legs, not the heart itself. Pure coronary plaque was uncommon at every age.
Standard risk scores missed most of them
Doctors today estimate cardiovascular risk with tools like SCORE2.
These combine age, blood pressure, cholesterol and smoking status to flag the people most likely to have a heart attack.
In REACT, the standard scores flagged only a small share of participants who already had silent plaque.
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They almost never flagged younger adults with it.
What this does not mean is that a 25-year-old with early plaque is on the verge of a heart attack.
Small, isolated plaques in a young person usually sit quietly for years, often decades.
The practical point, the researchers argue, is that habits that slow plaque start to matter earlier than most people assume.
That means not smoking, keeping blood pressure and cholesterol in a healthy range, and staying active.
Anyone with chest pain, breathlessness on light exertion, or a strong family history of early heart attacks should talk to their doctor.
A planned follow-up called REACT-PROTECT will run from 2027 to 2032.
It will test whether finding early plaque with imaging, and acting on it, actually prevents heart attacks and strokes in younger adults.
This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.