London, United Kingdom – Heart attacks and strokes are widely perceived as sudden and unpredictable medical emergencies. While they do require immediate treatment, new large-scale scientific evidence suggests that these cardiovascular events are far less abrupt than commonly believed. A major international study indicates that the human body often sends clear warning signals long before the first episode occurs.
The findings were published in the Journal of the American College of Cardiology and are based on an extensive analysis of more than nine million medical records from South Korea, alongside nearly 7,000 patient histories from the United States. Researchers identified a consistent pattern across populations, revealing that the vast majority of myocardial infarctions and cerebrovascular accidents occur in individuals who already exhibit at least one well-known cardiovascular risk factor.
According to the study, approximately 99% of heart attacks and strokes were associated with pre-existing conditions that could, in principle, have been detected and managed earlier. Professor Philip Greenland of Northwestern University, the study’s lead author in the United States, noted that these results challenge the idea of cardiovascular events as entirely unforeseen. Instead, they underline the importance of early identification and preventive care.
Early biological signals not to be ignored
The research highlights that elevated blood pressure, high cholesterol levels, abnormal blood glucose and exposure to tobacco are the most common precursors. These factors were present years before diagnosis in many cases, indicating a prolonged period during which preventive interventions could have reduced risk.
Cardiovascular specialists emphasise that these findings reflect established biological mechanisms rather than simple statistical associations. Chronic exposure to high levels of low-density lipoprotein (LDL) cholesterol and apolipoprotein B contributes to atherosclerosis, the underlying cause of most cardiovascular events. Hypertension accelerates damage to arterial walls, high blood sugar promotes inflammation and endothelial dysfunction, and smoking intensifies all of these processes.
Hypertension emerges as the leading factor
Among all risk indicators, high blood pressure was the most prevalent. More than 93% of individuals who later experienced a heart attack, stroke or heart failure already had elevated blood pressure. Furthermore, up to 97% had at least two uncontrolled risk factors at the same time, significantly increasing their vulnerability.
Importantly, the study found that even values below the thresholds traditionally used for clinical diagnosis were associated with future events. Many patients had blood pressure, cholesterol or glucose levels that were considered “borderline”, yet these levels still contributed to long-term vascular damage.
Women and younger adults also affected
The analysis also dispelled the notion that younger or middle-aged adults are largely protected. Among women under the age of 60, more than 95% of cardiovascular events were linked to at least one prior risk factor. This reinforces the need for early screening and lifestyle guidance across all adult age groups.
Guidelines from organisations such as the American Heart Association define risk thresholds including blood pressure at or above 120/80 mmHg, total cholesterol above 200 mg/dL, fasting glucose levels of 100 mg/dL or higher, and any history of smoking. The study demonstrates that risk accumulates even before these limits are reached.
Implications for public health
Health authorities in the United Kingdom stress that these findings strengthen the case for prevention-focused healthcare. Regular monitoring of blood pressure, cholesterol and glucose, combined with smoking cessation, balanced nutrition and physical activity, remains central to reducing cardiovascular mortality.
While heart attacks and strokes may appear sudden, the evidence shows they are usually the result of long-standing, modifiable conditions. Early detection and sustained management of these risk factors could prevent a substantial proportion of events, transforming cardiovascular care from emergency response to proactive prevention.