- A new study found that most people who experienced major cardiovascular events had modifiable risk factors.
- These findings contradict the claim that heart disease often strikes without warning.
- Over 99% of people had at least one risk factor at a suboptimal level before their illness.
- Experts say the research demonstrates the value of keeping risk factors well within healthy ranges.
A large study from researchers in Korea and the United States has found that virtually everyone who experiences a heart attack, stroke, or other major cardiovascular event had at least one key risk factor beforehand, even if it wasn’t bad enough to trigger a formal medical diagnosis.
The findings, published on September 29 in the Journal of the American College of Cardiology, challenge claims that heart disease often strikes without warning in people with no traditional risk factors such as high blood pressure, high cholesterol, high blood sugar, or smoking history.
Instead, this research shows that more than 99% of people with cardiovascular disease had at least one of these risk factors at suboptimal levels before their illness.
Per the authors, this highlights the importance of keeping these values well within a healthy range.
To uncover just how often cardiovascular disease occurs without warning signs, the researchers analyzed data from two large, long-running health studies that track participants over time.
One was the Korean National Health Insurance Service (KNHIS) database, a nationwide collection of health records that includes nearly every adult in South Korea.
This study followed 9,341,100 adults aged 20 and older who took part in a routine government health screening in 2009.
The screenings measured blood pressure, cholesterol, and blood sugar, and asked people about their smoking history.
The researchers also reviewed prescription records for medications to lower blood pressure, cholesterol, or blood sugar.
Participants were tracked for 13.3 years to see who developed cardiovascular disease, using hospital records and death registries to confirm diagnoses.
The other dataset came from the Multi-Ethnic Study of Atherosclerosis (MESA), a U.S. study of 6,803 adults aged 45 to 84 with no known heart disease at the start.
MESA participants underwent repeated in-person exams to measure the same traditional risk factors — blood pressure, cholesterol, and blood sugar — and reported whether they smoked.
The team tracked them for 17.7 years, recording heart attacks, strokes, heart failure, and related deaths through medical record reviews by physician experts.
It was noted that the researchers didn’t just look for whether someone had been diagnosed with hypertension, diabetes, or high cholesterol. They also included “nonoptimal” levels — readings above the ideal range but below the threshold for a formal diagnosis.
For example, systolic blood pressure of 120–139 mm Hg was counted as nonoptimal even if it wasn’t high enough to be labeled hypertension.
The definition of “nonoptimal” stems from the “ideal cardiovascular health” framework established by the American Heart Association (AHA), which sets stricter targets than most clinical guidelines.
The team examined five types of events separately: coronary heart disease (including fatal and non-fatal heart attacks), heart failure, stroke, myocardial infarction (a specific type of heart attack), and “total cardiovascular disease,” meaning any of those conditions.
The analysis determined the percentage of people who had at least one nonoptimal risk factor before their event and the percentage with two or more such risk factors.
The researchers found that in both countries, and across all types of cardiovascular events, the vast majority — 99% of people — had at least one nonoptimal risk factor before getting sick.
In Korea’s KNHIS data, 99.7% of people who developed coronary heart disease had at least one nonoptimal traditional risk factor.
The numbers were similar for other conditions: 99.8% for myocardial infarction, 99.4% for heart failure, and 99.3% for stroke.
The pattern was nearly identical in the U.S. MESA study, with 99.5% to 99.7% of participants having at least one nonoptimal risk factor before their illness.
When the researchers looked at specific risk factors, elevated blood pressure was the most common. In Korea, 95.6% to 96.1% of people with cardiovascular disease had blood pressure above the ideal range before their event. In the U.S., 93.0% to 96.8% did.
Elevated cholesterol was next most common, affecting 75.8% to 84.7% in Korea and 70.7% to 77.8% in the U.S.
Elevated blood sugar — even if not high enough to qualify as diabetes — was found in 72.8% to 77.7% of Korean participants and 53.8% to 60.3% of Americans.
Past or current smoking was also frequent, ranging from 47.9% to 68.1% in Korea and 54.1% to 63.3% in the U.S.
Having multiple risk factors was the norm. In both studies, more than 93% of participants had two or more nonoptimal risk factors before their event. For example, in the KNHIS cohort, only 0.3% of people with coronary heart disease had none of the four risk factors, while 42.8% had all four: elevated blood pressure, elevated cholesterol, elevated blood sugar, and a history of smoking.
Even when researchers used stricter cutoffs, 90% to 95% of participants still had at least one risk factor. And among those without any clinically high readings, most still had one or more risk factors above the optimal range.
The near-universal presence of risk factors also held true across sexes and ages.
These results suggest that heart disease, strokes, and heart failure rarely strike people who are truly in the healthiest ranges for blood pressure, cholesterol, blood sugar, and smoking status, and that keeping these numbers well within optimal limits may be key.
Yanting Wang, MD, director of both the Women’s Heart Program and the Cardio-Obstetrics Program at Robert Wood Johnson University Hospital, said that lifestyle changes don’t have to be complicated. Wang wasn’t involved in the study.
Wang additionally suggested that staying active — even as little as 30 minutes a day — can help keep blood pressure, cholesterol, and weight in check.
She further noted the value of stress management, explaining that mindfulness, deep breathing, and getting a good night’s sleep can all contribute to a healthy heart.
“Taken together, these small changes can protect your heart and boost overall well-being,” said Wang.
She also stressed the importance of working with your personal physician to keep an eye on your risk factors.
“Remember to schedule regular checkups with your doctor to monitor blood pressure, cholesterol, blood sugar, and other important indicators of heart health,” she said.
If any abnormalities do show up, Bradley Serwer, MD, an interventional cardiologist and chief medical officer at VitalSolution, said it’s necessary to treat them and then continue to keep your blood pressure, cholesterol, and diabetes under control. Serwer wasn’t involved in the new study.
“Work closely with your primary care providers to ensure you are reaching your goals,” Serwer told Healthline, noting that lifestyle modifications like those described by Wang are first-line treatments.
“If these lifestyle modifications don’t adequately treat the risk factors, medication may be required,” he said.
Serwer additionally noted that treatment goals are based on several factors and should be developed with the help of a trained medical professional.
“Lifestyle changes are not meant to be undertaken for a few weeks and then overlooked,” he added. “Making enduring and manageable changes to ensure lifelong health is the key.”
