• Posted September 30, 2025

Heart Attack, Stroke Almost Always Foreshadowed, Study Says

Nearly everyone who suffers a heart attack, stroke or heart failure had at least one warning sign that cropped up years before, a new study says.

More than 99% of patients had one or more risk factors prior to their heart emergency, including high blood pressure, elevated cholesterol, poor blood sugar control or smoking, researchers reported Sept. 29 in the Journal of the American College of Cardiology.

The study refutes the common belief that heart disease often strikes without warning, researchers said.

“We think the study shows very convincingly that exposure to one or more nonoptimal risk factors before these cardiovascular outcomes is nearly 100%,” said senior researcher Dr. Philip Greenland, a professor of cardiology at Northwestern University Feinberg School of Medicine.

“The goal now is to work harder on finding ways to control these modifiable risk factors rather than to get off track in pursuing other factors that are not easily treatable and not causal,” he added in a news release.

For the study, researchers analyzed health records for more than a decade for more than 9 million adults in South Korea and nearly 7,000 people in the United States.

The team looked for four major heart risk factors — blood pressure, cholesterol, blood sugar and tobacco use.

The team used the American Heart Association’s guidelines for heart health, which included as risk factors:

• Blood pressure 120/80 mmHG or greater, or being treated

• Total cholesterol 200 mg/dL or higher, or being treated

• Fasting blood sugar 100 mg/dL or higher, or a diagnosis of diabetes

• Past or current tobacco use

Not only did nearly everyone have at least one of these risk factors, more than 93% had two or more, the study showed.

High blood pressure was the most common problem, affecting more than 95% of patients in the South Korea cohort and more than 93% of the U.S. group.

Even among women younger than 60 — the group assumed to have the lowest heart health risk — more than 95% had at least one risk factor before having heart failure or a stroke.

“Taken together, our results challenge claims recently appearing in the medical literature that (heart attack) and coronary heart disease events occurring in the absence of antecedent major risk factors are increasingly common,” researchers concluded.

Even when researchers looked at higher levels of these risk factors — for example, clinical high blood pressure as opposed to elevated blood pressure — the pattern still held. At least 90% still had at least one major risk factor before their heart emergency, researchers said.

“Each risk factor, particularly blood pressure, cholesterol and smoking, has a continuous, dose-dependent and cumulative effect on cardiovascular disease risk even below clinical diagnostic thresholds,” researchers wrote.

More information

The American Heart Association has more on Life’s Essential 8 for good heart health.

SOURCES: Northwestern Medicine, news release, Sept. 29, 2025; Journal of the American College of Cardiology, Sept. 29, 2025