Nearly Every First Heart Attack and Stroke Was Preceded by a Known Risk Factor

CATEGORY: HEART & CIRCULATION

Heart attacks that arrive out of nowhere, in people whose basic numbers were all fine, turn out to be close to nonexistent. Across more than 9.3 million adults, over 99% of first heart attacks and other coronary events, strokes and episodes of heart failure occurred in someone who already had at least one elevated risk factor: blood pressure, cholesterol, blood sugar or tobacco use.¹ Heart failure means the heart cannot pump well enough to meet the body’s needs. The authors say the results also cut against recent work suggesting heart disease often shows up without traditional risk factors.¹

The Bar for Elevated Was Set Low on Purpose

Researchers used stricter cutoffs than the ones that define a disease. Blood pressure counted as elevated at 120/80 mm Hg or higher. That sits below the level at which high blood pressure is diagnosed. Taking blood pressure medication counted too. Total cholesterol counted from 200 mg/dL. Blood sugar counted at the prediabetes level, meaning above normal but short of diabetes. Any past or current smoking counted as tobacco exposure. Plenty of adults would call those numbers unremarkable. That is part of what the study documents. Risk begins accumulating below the lines where diagnoses get drawn.

Korean Insurance Records and American Clinic Exams

Two populations on opposite sides of the world were followed. About 9.3 million South Korean adults were tracked through national health screenings and insurance records from 2009 to 2022. Another 6,800 or so American adults had detailed periodic exams from 2000 to 2019. When someone had a first heart attack, stroke or new heart failure, researchers looked back at the measurements already on file from the years before. The analysis rested on 601,025 cardiovascular events in the Korean records and 1,188 in the American group.¹ Both countries gave the same picture. Over 99% of these events happened in people with at least one elevated factor beforehand, and more than 9 in 10 had two or more. Elevated blood pressure led the list, present in roughly 96% of cases.¹

The Finding Does Not Run Backward

This is observational work. Association is what it can show, not proof that any one factor caused any one event. And it does not reverse. Elevated risk factors are extremely common. Most people who have one will never have a heart attack. A reading above 120/80 is neither a diagnosis nor a prediction. What the data document is how seldom the opposite happens: cardiovascular events in people whose blood pressure, cholesterol, blood sugar and smoking history were all optimal were vanishingly rare. Even among women under 60, where elevated factors were least common, more than 95% of heart failure and stroke cases still followed at least one. Earlier research landed in the same territory with smaller figures. Two large 2003 analyses used the thresholds at which conditions are formally diagnosed, not the stricter cutoffs here. They found at least one major risk factor beforehand in 87% to 94% of fatal coronary events. Among people who already had heart disease, the figures were roughly 81% of men and 85% of women.²³ Where a number like this lands depends heavily on how low the bar is set.

Key Takeaways

• More than 9.3 million adults in two countries gave the same result: over 99% of first heart attacks, strokes and heart failure cases occurred in people who already had at least one elevated risk factor.
• Elevated blood pressure was the most common, present in roughly 96% of cases. More than 9 in 10 people had two or more factors before their event.
• The study is observational and looks backward from events. It shows these events almost never happen without prior risk factors. Having an elevated factor does not make an event likely; most people with one never have a cardiovascular event.

References

1. Lee H, Huang X, Khan SS, et al. Very High Prevalence of Nonoptimally Controlled Traditional Risk Factors at the Onset of Cardiovascular Disease. Journal of the American College of Cardiology. 2025;86(14):1017–1029. link
2. Greenland P, Knoll MD, Stamler J, et al. Major risk factors as antecedents of fatal and nonfatal coronary heart disease events. JAMA. 2003;290(7):891–897. link.
3. Khot UN, Khot MB, Bajzer CT, et al. Prevalence of conventional risk factors in patients with coronary heart disease. JAMA. 2003;290(7):898–904. link.