How Heart Disease Can Start as Early as Your 20s

For most of our lives, heart disease feels like a problem for the future.

A healthy 25-year-old can visit the doctor, hear that their blood pressure looks fine, their cholesterol isn’t alarming, and their odds of having a heart attack anytime soon are extremely low. Prevention can feel like something reserved for later, when the numbers start drifting in the wrong direction.

But what if that’s the wrong way to think about heart disease?

A growing body of research suggests that the process leading to heart attacks and strokes often begins decades before anyone would be considered at significant risk. A new study published in the New England Journal of Medicine found evidence of artery-clogging plaque even among some adults in their 20s. The finding adds to an unsettling consensus in cardiovascular research: heart disease may be less a condition that develops in middle age than a lifelong process that becomes visible later.

“We’ve thought of this as a middle-aged person’s issue, and that’s been a problem,” says Amit Khera, director of preventive cardiology at UT Southwestern Medical Center. “The prevention of heart disease starts in childhood.”

That doesn’t mean healthy young adults should worry about imminent heart attacks, he says. What it does mean is that the timeline many people use to think about prevention may not match the timeline their arteries are following.

The new REACT study examined 16,808 adults in Denmark and Spain aged 18 to 70 with no known heart disease.

Researchers used imaging to look for plaque throughout the arterial system, including arteries supplying the heart and major blood vessels in the neck and legs. More than half of participants had evidence of atherosclerosis in at least one of the areas examined.

The study found plaque in even some of the youngest participants—8.7 percent of men and 6.7 percent of women aged 18 to 29.

Among younger adults, plaque was typically limited to a single part of the arterial system. As people aged, both the amount of plaque and the number of affected arteries increased significantly.

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The findings provide one of the clearest snapshots yet of how atherosclerosis accumulates across adulthood, often before traditional measures signal significant risk.

For decades, doctors have used risk calculators that incorporate age, cholesterol levels, blood pressure, diabetes, and smoking history to estimate a person’s likelihood of experiencing a cardiovascular event during the next decade.

Those tools work well for predicting short-term risk. But they can tell a very different story than what is actually happening inside a person’s arteries.

Age carries enormous weight in those calculations. That means a 30-year-old with elevated LDL cholesterol can still appear relatively low risk simply because heart attacks are uncommon at that age.

Yet arteries are exposed to that cholesterol every day. Khera compares the process to compound interest.

“When you have gene traits that lower your cholesterol modestly from birth, you have a dramatically lower risk of heart disease,” he says. “When we start late, it’s much harder to put the horse back in the barn.”

Increasingly, researchers believe those accumulated years matter.

A 2025 analysis of more than 4,300 people found that people who spent more years exposed to unhealthy cholesterol were more likely to develop heart disease after age 40, even when researchers accounted for other risk factors.

New U.S. cholesterol guidelines released this year reflect this shift in thinking. Rather than focusing only on who is at highest short-term risk, they emphasize reducing years of exposure to unhealthy cholesterol levels, particularly among adults ages 18 to 39.

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It is a subtle but important change.

The goal, Khera says, is to help people retain the health they’re born with.

“We can’t just assume kids do whatever they do and we’ll change course later,” Khera says. “We’re missing an opportunity.”

The obvious question raised by findings like REACT is whether doctors should start looking for plaque much earlier.

That’s where the story becomes more complicated.

“The clinical implications of these plaques are not 100 percent clear,” says Goodarz Danaei, the Bernard Lown Professor of Cardiovascular Health at Harvard T.H. Chan School of Public Health.

Some plaques remain relatively stable for years. Others continue growing until they restrict blood flow. Some become unstable and rupture, triggering blood clots that can cause heart attacks.

Researchers are getting better at distinguishing among them.

A 2020 analysis examined 1,769 patients with stable chest pain who underwent coronary CT angiography. Researchers found that a specific type of noncalcified plaque, known as low-attenuation plaque, was especially predictive of future heart attacks. Patients with a low-attenuation plaque burden above 4 percent had nearly five times the risk of heart attack during follow-up.

But Danaei cautions against extending those findings too far.

The average participant was about 58 years old and had already sought medical care for chest pain. Finding a tiny plaque in an otherwise healthy 20-something is a very different clinical situation.

REACT does not answer what will eventually happen to the plaques detected.

“There’s plaque, and then there’s what we call high-risk plaque or plaque vulnerability,” Danaei says. “Without knowing what they’ll do, it’s hard to rely on these scans alone.”

For now, experts view imaging as another piece of information rather than a replacement for traditional risk factors such as cholesterol, blood pressure, smoking, exercise, and family history.

“Maybe it becomes part of the conversation, but not the whole conversation,” Danaei says. “It’s not a one-size-fits-all approach.”

If arteries keep time, women may follow a different clock.

Men accumulated plaque earlier. Women started lower, but plaque levels rose more steeply as they entered midlife.

The pattern raises questions about the role of menopause, which is associated with significant changes in cardiovascular risk factors.

One study showed women began gaining more deep abdominal fat about two years before their final menstrual period. Those with larger increases were also more likely to show early signs of plaque buildup in their arteries.

Those changes have fueled growing interest in what happens to cardiovascular health during the menopause transition and whether hormone therapy influences that trajectory.

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An analysis of two decades of data from the Study of Women’s Health Across the Nation found that, among women with hot flashes or night sweats, starting hormone therapy during perimenopause or early postmenopause was associated with fewer cardiovascular events than not starting it. The association was strongest among Black women and among women who began treatment within 10 years of menopause.

The findings are consistent with what some researchers call the “timing hypothesis,” the idea that when hormone therapy is started may matter as much as whether it is used at all. Even so,  Danaei cautions that decisions about hormone therapy should remain highly individualized, shaped by a woman’s symptoms, age, medical history, risk factors, and personal goals.

A paradox lies at the center of all this research.

We can see more than ever before, yet the most important lesson may have little to do with scanning technology.

REACT does not show that everyone with early plaque needs medication. It does not tell a healthy 25-year-old whether a tiny lesion will someday cause a heart attack.

Instead, it makes the long arc of heart disease harder to ignore.

“This study shows that even in low-risk populations, people have substantial underlying pathology with these plaques,” Danaei says. “What we have in the general knowledge sphere is, ‘Don’t worry about heart disease until you're 40 or 50.'”

That may be the assumption most in need of updating.

Heart disease often announces itself with chest pain, a heart attack, or an emergency room visit. But its biology is usually far less dramatic.

By the time prevention feels urgent, the story may already be decades old.