The REACT study found silent artery plaque in one in 13 adults under 30. Here is what the research means in plain terms.

Atherosclerosis is the slow buildup of plaque inside artery walls. It causes most heart attacks and strokes. The damage usually builds quietly for decades before any symptoms appear.

REACT is one of the largest efforts to map this hidden disease across adult life. Phase one examined more than 16,000 people with no symptoms or heart disease history.

Researchers found plaques in 57.1 per cent of participants. The study was presented at the ESC Congress 2026 and published in the New England Journal of Medicine.

Men developed plaque five to 10 years earlier than women. Women saw the steepest rise between ages 40 and 60.

Common risk calculators missed many cases. Knowing the disease is actually present, rather than estimating risk, changes the picture for prevention.

Professor Henning Bundgaard, who led the study, says the goal is early detection through vascular imaging. Portable ultrasound could one day spot hidden plaque more widely.

The study does not say everyone needs scans. It says heart health starts earlier than we thought.