Study Links 99% of Heart Attacks and Strokes to Four Common Risk Factors

Heart attacks and strokes rarely occur without warning, according to new research. An analysis of health records from more than 9 million adults in the United States and South Korea found that nearly all major cardiovascular events were preceded by at least one of four well-established risk factors.

The study, published in 2025 in the Journal of the American College of Cardiology, linked 99 percent of heart attacks, strokes, and heart failure cases to high blood pressure, elevated cholesterol, abnormal blood sugar, or tobacco use. Both current and former smokers were included, highlighting that cardiovascular risk can persist even after smoking cessation.

Even among women younger than 60, who generally have a lower risk of cardiovascular disease, more than 95 percent of major cardiovascular events were associated with at least one of these conditions. The findings challenge the notion that unexplained heart attacks or strokes in people without identifiable risk factors are becoming increasingly common.

Main Drivers of Cardiovascular Risk

High blood pressure emerged as the most common precursor to serious cardiovascular disease. Across both countries included in the study, more than 93 percent of individuals who experienced a heart attack, stroke, or heart failure had previously been diagnosed with hypertension.

Elevated low-density lipoprotein (LDL) cholesterol and abnormal blood sugar levels, including both prediabetes and diabetes, were also common among people who later developed cardiovascular disease. Having multiple risk factors substantially increased the likelihood of experiencing a major cardiovascular event.

Lead author Philip Greenland, a cardiologist at Northwestern University, said the findings indicate that nearly every cardiovascular event was associated with at least one modifiable risk factor. He argued that prevention strategies should prioritize identifying and controlling these measurable conditions rather than focusing on rare or unproven causes.

Reassessing "Heart Attacks Without Warning"

The researchers say their findings contrast with recent reports suggesting that heart attacks and strokes are becoming more common among people without known cardiovascular risk factors. They propose that earlier studies may have overlooked mild hypertension, borderline cholesterol levels, or early metabolic abnormalities that had not yet been formally diagnosed.

In an accompanying editorial, Duke University cardiologist Neha Pagidipati wrote that the findings demonstrate how much opportunity remains to improve the detection and management of high blood pressure, elevated cholesterol, and diabetes. She also emphasized the importance of expanding screening efforts, particularly among younger adults and populations with limited access to preventive healthcare.

Public health experts note that lifestyle measures—including a healthy diet, regular physical activity, and smoking cessation—can substantially reduce these common cardiovascular risks. At the same time, they stress that many people will also require medication and that long-term adherence to treatment remains essential.

Different Heart Attack Patterns in Women

The new analysis coincides with separate research showing that the underlying causes of heart attacks often differ between men and women. A Mayo Clinic study examined 1,474 heart attacks among adults aged 65 years or younger that occurred in Minnesota between 2003 and 2018, focusing on the biological mechanisms responsible for each event.

Among men, approximately 75 percent of heart attacks resulted from atherothrombosis, a process in which a cholesterol plaque ruptures and a blood clot blocks a coronary artery. Among women, however, this classic mechanism accounted for only 47 percent of cases, indicating that more than half were caused by other processes.

Approximately 34 percent of heart attacks in women were classified as supply-demand mismatch events, also known as type 2 or secondary myocardial infarctions. These occur when the heart's oxygen requirements temporarily exceed the available blood supply during conditions such as severe infection, significant anemia, or rapid heart rhythm disturbances.

Underrecognized Causes and Treatment Gaps

The Mayo Clinic researchers also identified important contributions from spontaneous coronary artery dissection, in which a tear develops within the wall of a coronary artery, and coronary embolism, in which blood clots travel from another part of the body to the coronary circulation. Both conditions are diagnosed more frequently in women and younger patients.

Cardiologist Claire Raphael said the findings demonstrate that several heart attack mechanisms, particularly those affecting women, have historically been underrecognized. She noted that identifying the wrong cause may lead to treatments that are less effective or, in some cases, potentially harmful, such as performing aggressive coronary stenting when spontaneous coronary artery dissection is the underlying problem.

Experts suggest that more individualized diagnostic approaches, including advanced cardiac imaging and greater attention to sex-specific symptoms and risk profiles, are needed. Improved awareness among healthcare professionals could help ensure that patients receive treatment tailored to the specific cause of their heart attack.

Implications for Prevention and Public Health

Taken together, these two studies reinforce two important messages about cardiovascular disease. First, traditional risk factors continue to account for nearly all heart attacks and strokes, underscoring the importance of routine blood pressure measurement, cholesterol testing, blood sugar management, and tobacco control across the population.

Second, once a cardiovascular event occurs, accurately identifying its underlying mechanism is essential for guiding treatment and improving long-term outcomes. Researchers are calling for updated clinical guidelines that better reflect sex-specific differences in heart attack mechanisms and for greater representation of diverse patient populations in cardiovascular research.

Public health experts also advocate expanding early prevention initiatives, including community blood pressure screening programs and accessible smoking cessation services. With cardiovascular disease remaining the leading cause of death worldwide, they argue that identifying and managing these four common risk factors remains one of the most effective strategies for reducing the global burden of heart disease.