"Is a 'Sudden Myocardial Infarction' Really Sudden? Four Common Warning Signs Shared by 99%"

Are Heart Attacks and Strokes Really "Sudden"?

Heart attacks and strokes seem to occur suddenly, without any warning. Many people feel this way. Someone who was working energetically until yesterday collapses the next morning. An acquaintance who seemed healthy is rushed to the hospital. Each time we hear such stories, cardiovascular diseases seem like a matter of "luck."

However, a large-scale study introduced by the German news site FOCUS challenges this view significantly. Research teams from Northwestern University in the United States and Yonsei University in South Korea analyzed long-term health data from over 9 million people in Korea and about 7,000 in the U.S. They found that over 99% of those who experienced heart attacks, strokes, heart failure, etc., had at least one major risk factor before onset.

These four factors are blood pressure, cholesterol, blood sugar, and smoking.

Of course, this study does not conclude that "these four are the only causes." Many factors are involved in cardiovascular diseases, including genetics, age, sleep, stress, kidney function, inflammation, obesity, diet, lack of exercise, and air pollution. However, the important point highlighted by this study is that many heart attacks and strokes leave measurable signs long before they occur, both for the individual and the medical side.

In other words, behind what appears to be a "sudden death" event, there is likely a long-standing burden on the blood vessels.

The Four Risks Examined in the Study

The risk factors the research team focused on are not ones that can only be identified through special tests. They are basic items that can be confirmed in health check-ups or general medical examinations.

The first is blood pressure. The criteria used were 120/80 mmHg or higher, or being under blood pressure treatment. It is notable that this includes stages lower than the general level diagnosed as "hypertension," treating them as "not optimal blood pressure."

The second is total cholesterol. Levels of 200 mg/dL or higher, or being under treatment for dyslipidemia, were included. Cholesterol is related to atherosclerosis, where lipids accumulate inside the blood vessels, and is associated with long-term risks of heart attacks and strokes.

The third is blood sugar. This included fasting blood sugar levels of 100 mg/dL or higher, a diabetes diagnosis, or being under treatment. It considers not only diabetes but also so-called borderline blood sugar levels. Persistently high blood sugar can damage the endothelium of blood vessels, promoting atherosclerosis.

The fourth is smoking. This includes not only current smokers but also those with a history of smoking. Smoking is known to constrict blood vessels and adversely affect blood pressure, clot formation, and atherosclerosis.

Over 99% of people had at least one of these four items. Furthermore, over 93% had two or more risk factors. Among them, the most frequent was blood pressure, with non-optimal blood pressure observed in over 95% of patients in the Korean data and over 93% in the U.S. data before onset.

What is important here is that the study did not only look at "people diagnosed with diseases." Even at stages not reaching formal diagnoses of hypertension, diabetes, or dyslipidemia, it picked up non-ideal states as risks. In other words, the assurance of "I'm fine because the doctor hasn't said I'm sick" does not necessarily mean safety.

The Stage Before Diagnosis is Easily Overlooked

The fear of cardiovascular disease lies in the fact that changes in blood vessels often lack symptoms. Slightly high blood pressure. Slightly high blood sugar. Slightly high cholesterol. Even if there is a small warning mark on the health check-up results, many people do not take it seriously if it doesn't interfere with daily life.

However, for blood vessels, the very fact that "slightly high" continues for years becomes a burden.

Hypertension constantly puts strong pressure on the walls of blood vessels. High blood sugar tends to damage the endothelium of blood vessels. Dyslipidemia tends to create plaques inside blood vessels. Smoking constricts blood vessels and leads to inflammation and blood clot risks. Each change may seem minor, but when multiple factors overlap and time accumulates, it causes significant damage to the heart and brain's blood vessels.

The research team states that even when the diagnostic criteria were raised to stricter "clinically high values" for re-analysis, at least 90% of those who experienced cardiovascular events had major risk factors before onset. This cannot be explained simply by saying that the criteria were broadly set to reach 99%.

Reactions on Social Media: "I Knew It" vs. "Broad Criteria"

Regarding this study, three main types of reactions were observed on social media.

The most common reaction was the realization that "after all, the basics are important." On Instagram and Facebook, there were multiple posts introducing blood pressure, cholesterol, blood sugar, and smoking as "items to review from today." These posts, along with visuals evoking heart images, blood pressure monitors, sugar management, and smoking cessation, emphasized the importance of prevention.

On the other hand, there were somewhat calm reactions on Reddit. Users claiming to be medical professionals commented, questioning whether this is really new information, suggesting that the relationship between cardiovascular disease and blood pressure, lipids, blood sugar, and smoking has been well-known for some time. Indeed, the fact that these are major risk factors for cardiovascular disease is not a new discovery.

However, another user perceived "the 99% figure is new." In other words, while it was known that individual risk factors are dangerous, the impact of this study lies in the fact that they existed at such a high rate before the onset of heart attacks, strokes, and heart failure.

Furthermore, questions arose about how to consider factors other than the four items, such as inflammation markers and genetic risks. This is an important point. For example, inflammation indicators like high-sensitivity CRP, lipid-related risks influenced by genetics like Lp(a), family history, chronic kidney disease, sleep apnea, stress, and autoimmune diseases cannot be ignored in cardiovascular risk assessment.

Therefore, it is dangerous to interpret this study as "only these four are relevant." Rather, it should be read as "these four should not be overlooked first."

Interpreting the "99%" Figure

 

The figure "99%" is indeed a strong number that spreads easily on social media. However, caution is needed to interpret this number correctly.

Firstly, this does not mean "99% of people with risk factors will have a heart attack or stroke." Many people have slightly high blood pressure, high cholesterol, or a history of smoking. Not all of them will experience cardiovascular events.

Secondly, this is about "looking back at those who developed the condition, almost all had one of the four items beforehand." In other words, while the presence of risk factors is an important warning, it does not directly predict an individual's future.

Thirdly, the four factors are not only independent but also overlap to increase risk. There is a significant difference between someone with slightly high blood pressure alone and someone with overlapping high blood pressure, blood sugar, lipids, and a smoking history. The study also highlighted that over 93% had two or more risk factors.

In short, "99%" should be seen not as a number to instill fear but as a number indicating a significant potential for prevention.

Cardiovascular Disease as a Major Global Health Issue

According to the WHO, cardiovascular disease is the leading cause of death worldwide, with an estimated 19.8 million deaths in 2022. This accounts for about 32% of all global deaths, with 85% attributed to heart attacks and strokes.

The FOCUS article also mentioned that in Germany, approximately 300,000 people experience heart attacks and 270,000 experience strokes annually, with cardiovascular disease accounting for a significant portion of deaths. Regardless of the country, the impact of cardiovascular disease on society is enormous.

In Japan, the situation is no different. As the population ages, strokes and heart failure are directly linked to medical expenses, caregiving, and quality of life. While acute medical care to save lives is advancing, preventing onset is less burdensome for both individuals and society than treating it after it occurs.

Focus on "Numbers" Rather Than "Disease Names" from Today

The practical message from this study is very simple: know your blood pressure, lipids, blood sugar, and smoking history. That's all it boils down to.

Blood pressure should be measured not only in the doctor's office but also at home. Some people get high readings due to nervousness at the hospital, while others may appear fine during check-ups but have high readings in daily life. Continuously recording home blood pressure can reveal one's true tendencies.

For lipids, it's important to consider not only total cholesterol but also LDL cholesterol, HDL cholesterol, and triglycerides. If necessary, a doctor may decide on more detailed tests.

Blood sugar can be checked with fasting blood sugar and HbA1c. Instead of ignoring borderline levels, it should be an opportunity to review weight, diet, exercise, and sleep.

Regarding smoking, the benefits of quitting are significant. It's never too late, even if you've been smoking for years. Quitting smoking is one of the most definitive actions to reduce cardiovascular risk.

"Change Your Lifestyle" Alone is Not Enough

However, this article should not end with a simple self-responsibility argument. As the WHO points out, cardiovascular disease risk also involves social and environmental factors such as food environments, city planning conducive to exercise, access to healthcare, income, education, stress, and air pollution.

Even if one wants to eat healthily, there are areas where affordable food is skewed towards high salt, high fat, and high sugar. Long working hours or a lack of safe sidewalks can hinder exercise. Some people find it difficult to undergo health check-ups or continue treatment.

Therefore, it is necessary to not only know one's numbers but also create an environment where prevention is easier for society as a whole. Cardiovascular disease prevention is related not only to individual will but also to healthcare systems, workplaces, education, food policies, and urban design.

Turning "Scary News" into "Useful News"

News about heart attacks and strokes can easily evoke anxiety. Especially the "99%" figure resonates strongly. However, it would be a waste to let this study end as merely a source of anxiety.

What this study shows is that many cardiovascular diseases have signs that can be confirmed in advance. Blood pressure, cholesterol, blood sugar, smoking. Managing all of these perfectly is not easy, but they can be measured. They can be changed. Treatment can be sought if necessary.

As reactions on social media indicate, some people perceive this study as "something they already knew," while others are motivated to "review the basics." The important thing is not to let the numbers that became a topic end as a temporary surprise but to relate them to one's health check-up results and lifestyle.

Heart attacks and strokes cannot be completely eradicated. However, they do not have to be resigned to as "sudden misfortunes." Blood vessels remember daily burdens and respond to daily improvements.

Before putting away the results of your next health check-up, review them once. Measure your blood pressure at home. Look into smoking cessation clinics. Reduce the salt in your meals a little. Increase your walking time slightly.

The message from the large-scale study was not about flashy treatments but rather something very basic. That's why it relates to many people.

Source URL

FOCUS online: Referenced for an overview of the large-scale study, four risk factors, and the scale of heart attacks and strokes in Germany.
https://www.focus.de/gesundheit/ratgeber/mega-studie-bringt-99-prozent-aller-herzinfarkte-und-schlaganfaelle-mit-vier-risikofaktoren-in-verbindung_1cafc430-b3ca-4516-8b86-d18680c04a96.html

Northwestern Now: Introduction to the study by Northwestern University. Referenced for study subjects, four risk factors, results of over 99% and over 93%, and comments by Philip Greenland.
https://news.northwestern.edu/stories/2025/09/nearly-everyone-has-at-least-one-risk-factor-before-a-heart-attack-stroke-or-heart-failure

Journal of the American College of Cardiology: DOI page of the research paper "Very High Prevalence of Nonoptimally Controlled Traditional Risk Factors at the Onset of Cardiovascular Disease." Referenced as primary information for the study.
https://www.jacc.org/doi/10.1016/j.jacc.2025.07.014

PubMed: Bibliographic information of the same research paper. Used to confirm authors, journal, and paper title.
https://pubmed.ncbi.nlm.nih.gov/41033739/

WHO: Referenced for global cardiovascular disease death numbers, main risk factors, and basic information on prevention.
https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-%28cvds%29

Reddit: Posts and comments introducing the study. Referenced for reactions on social media such as "Isn't this known?" "The 99% figure is new," and "How to consider other factors like inflammation."
https://www.reddit.com/r/Nutraceuticalscience/comments/1o1zfsg/huge_study_links_99_of_heart_attacks_and_strokes/

Instagram: Example of posts introducing the study content to the general public. Referenced as an example of spreading interest in "four risk factors" and "knowing your numbers" on social media.
https://www.instagram.com/reel/DVJ_6HljhEw/

Facebook: Example of posts introducing the study content to the general public. Referenced as an example of general user dissemination regarding cardiovascular disease prevention.
https://www.facebook.com/scienceexplorist/photos/%EF%B8%8F-99-of-heart-attacks-strokes-and-heart-failure-cases-are-linked-to-preventable-/847235861194776/