Do Heart Attacks Really Strike Without Warning, or Are We Just Missing Signs? Study Sheds Light - Video

A large-scale international study published in The Journal of the American College of Cardiology has found that more than 99% of people who experience heart attacks, strokes, or heart failure had at least one cardiovascular risk factor above optimal levels before their event. The study challenges the long-standing belief that heart disease often strikes without warning.

Cardiovascular disease remains the leading cause of death globally, and this new research offers strong evidence that nearly all major cardiac events are preceded by identifiable and modifiable risk factors.

The study examined over a decade of health data from more than 9.3 million adults in South Korea and nearly 7,000 adults in the United States. Researchers focused on four key cardiovascular risk factors: high blood pressure, elevated cholesterol, high blood sugar, and tobacco use, as defined by the American Heart Association’s thresholds for ideal cardiovascular health. Secondary analysis used even stricter clinical definitions.

The findings were consistent across both countries. More than 99% of individuals who later developed coronary heart disease, stroke, or heart failure had at least one nonoptimal risk factor prior to the event. Additionally, over 93% had two or more risk factors, with high blood pressure being the most common. Even in groups traditionally considered lower risk—such as women under 60—the pattern held.

“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 author Dr. Philip Greenland, 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.”

The study underscores the urgent need for early detection and proactive management of cardiovascular risk factors. The authors stress that controlling blood pressure, cholesterol, glucose levels, and eliminating tobacco use could drastically reduce the global burden of heart disease.

Reference: Lee, H., et al. (2025) Very High Prevalence of Nonoptimally Controlled Traditional Risk Factors at the Onset of Cardiovascular Disease. Journal of the American College of Cardiology. doi.org/10.1016/j.jacc.2025.07.014