What are the Four Major Factors that Cause 99% of Heart Attacks and Strokes? The Importance of Prevention and Early Detection: Most Heart Attacks and Strokes Were Forewarned

Why "99%" is a Hot Topic Now

An international collaborative study published in the Journal of the American College of Cardiology (JACC) on September 29, 2025, combined data from Korea's National Health Insurance and the U.S. Multi-Ethnic Study of Atherosclerosis (MESA) to present conclusions derived from tracking millions of people over up to 20 years. The results are clear: over 99% of those who developed myocardial infarction, stroke, or heart failure had at least one of blood pressure, lipids, blood sugar, or smoking not at "optimal" levels before onset. The research group, led by Northwestern University and Yonsei University, emphasized in their press release that "almost all events are preceded by 'warnings'."PubMed

The Four Red Flags: Which is Most Prevalent?

According to a report by WELT, the most frequent was hypertension, with over 93% of event experiencers in both U.S. and Korean groups having had hypertension before onset. Furthermore, even among women under 60, over 95% fell into one of the four factors. This data dispels the myth that "young women are safe."DIE WELT

The Pitfall of "Nonoptimal" — Don't Be Complacent Even Below Diagnostic Levels

The keyword of this study is "nonoptimal." Even if not at "disease level" exceeding diagnostic criteria, if a state deviates from optimal values for a long time, the risk quietly accumulates. The JACC commentary thus advocates for early risk management as crucial.PubMed

"Classics" Reinforced by Big Data

In fact, the trend that "most can be explained by preventable factors" is not a new discovery. INTERHEART (2004) showed that nine modifiable factors explain >90% of the risk of first myocardial infarction, and INTERSTROKE (2010/2016) demonstrated that ten factors explain about 90% of stroke risk. The current JACC study updates the subjects and era, visualizing the reality by adding the "modern gradient of nonoptimal levels."PubMed

Three Practical Points from the Study

1. Manage blood pressure from "high normal." Measure home blood pressure morning and evening, record the average. Consider lifestyle improvements and medical consultation if it is around 130mmHg (risk-based management is recommended by hypertension treatment guidelines and JACC reviews).Japan American Heart Association

2. "Fixed-point observation" of LDL-C and HbA1c. Not just annual health checkups, but follow-up every 3–6 months if under treatment.

3. "Complete smoking cessation." Even heated tobacco products have been reported to worsen vascular endothelial function. Use smoking cessation clinics and nicotine replacement therapy.

※This text provides general information and should not replace individual medical advice. Always consult a doctor for medical decisions.

Visualizing Social Media Reactions

• Proponents: "The myth of 'sudden' was debunked. Home blood pressure and 1-2 blood tests a year can significantly reduce risks."

• Skeptics: "'99%' is too strong. How were genetics, chronic stress, socioeconomic factors handled?"

• Practitioners: "It's important not to overlook 'nonoptimal below diagnostic levels.' Insurance and health checkup designs should be changed."

• Policy Advocates: "Normalize blood pressure measurement at workplaces and schools, support smoking cessation, and create environments for salt reduction and exercise."

These discussions resonate with the authors' emphasis that "intervention is valuable even at nonoptimal levels," while also serving as a caution against misreading "99% = all preventable."STAT

Common Misunderstandings and Limitations

• "99% is not completely preventable." The study indicates **association (precursor presence)**, not guaranteeing causation and complete prevention.PubMed

• Other factors are not unnecessary. Diet, exercise, obesity, stress, and social determinants also contribute to cardiovascular risk in existing studies.PubMed

• Issues with measurement and diagnostic thresholds. For example, home blood pressure vs. clinic blood pressure, white coat effect, and measurement bias remain.

• Be cautious with extrapolation. The data is primarily from Korea and the U.S. In other regions, ethnic differences and healthcare access disparities could affect outcomes.

Still, "What Can Be Done Now"

• Start a home blood pressure log for a week

• Check recent LDL-C/HbA1c values and schedule a blood test if not measured

• Declare your intention to quit smoking to those around you and seek support

• Incorporate "a little extra exercise" (walk an extra 10 minutes during your commute, choose stairs) and reduce salt together

Summary

This study reaffirms the harsh yet hopeful fact that "almost all cardiovascular events come with 'warnings'." If action is taken at the nonoptimal stage, the 99% 'warnings' can be turned into opportunities for treatment and lifestyle improvement. The issue is not whether there is a problem, but "when you notice it and how you act."American College of Cardiology