Many people believe that heart attacks, strokes, and heart failure happen suddenly without any warning.
While these events often seem unexpected, a huge new international study suggests that this is rarely true.
The research found that almost every person who later developed one of these serious heart and blood vessel conditions already had at least one well-known health risk before becoming sick.
The findings show that many of these life-threatening illnesses could potentially be prevented if those warning signs are found and treated early.
The study was led by researchers from Northwestern Medicine in the United States and Yonsei University in South Korea. Scientists examined health information from more than 9 million adults in South Korea and nearly 7,000 adults in the United States.
Some participants were followed for as long as 20 years, allowing researchers to see which health problems appeared before heart disease developed. The research was published in the Journal of the American College of Cardiology.
Cardiovascular disease, which includes heart attacks, strokes, and heart failure, remains the leading cause of death around the world. Every year, millions of people die from these conditions.
Doctors have spent decades searching for hidden causes, but this study suggests that the biggest opportunity to save lives may be much simpler: identify and control the common risk factors that are already well known.
The researchers focused on four major risk factors. These were high blood pressure, high cholesterol, high blood sugar or diabetes, and tobacco use. They used the American Heart Association’s recommended levels to decide whether each risk factor was healthy or unhealthy.
Blood pressure of 120/80 mm Hg or higher, total cholesterol of 200 mg/dL or higher, fasting blood sugar of 100 mg/dL or higher, or current or previous tobacco use were all considered risk factors.
They also performed another analysis using higher levels that doctors commonly use to diagnose disease, such as blood pressure of 140/90 mm Hg or above and fasting blood sugar of 126 mg/dL or above.
The results were remarkably consistent. More than 99% of people who later experienced a heart attack, stroke, or heart failure already had at least one of these risk factors before the event occurred. More than 93% had two or more risk factors, showing that many people were living with several health problems at the same time.
High blood pressure was by far the most common warning sign. It was found in more than 95% of participants in South Korea and more than 93% of participants in the United States who later developed cardiovascular disease.
Even women younger than 60 years, a group often thought to have a lower risk of heart disease, showed the same pattern. More than 95% already had at least one important risk factor before becoming ill.
When the researchers looked only at people with the more severe levels used to diagnose disease, the results barely changed. At least 90% still had one or more major risk factors before developing serious heart problems. This means that most cases did not appear without warning.
Professor Philip Greenland, one of the senior authors of the study and a cardiologist at Northwestern University, said the findings show that doctors should place even greater emphasis on controlling the risk factors that can be treated.
Instead of searching for rare or difficult-to-change causes, improving blood pressure, cholesterol, blood sugar, and smoking habits may prevent many future heart attacks and strokes.
The findings also provide an important reminder for the public. Many people feel perfectly healthy even when they have high blood pressure or high cholesterol because these conditions often cause no symptoms.
That is why they are sometimes called “silent” risk factors. Regular health check-ups can identify these problems long before they lead to permanent heart damage.
Simple lifestyle changes can make a big difference. Eating a balanced diet, exercising regularly, maintaining a healthy weight, avoiding smoking, limiting alcohol, and taking prescribed medicines when needed can all reduce cardiovascular risk. Early treatment can help lower the chances of developing life-threatening complications later in life.
Although no study can prevent every heart attack or stroke, this research shows that most people receive warning signs years in advance. Recognizing those signs and taking action early could save countless lives.
If you care about heart disease, please read studies that herbal supplements could harm your heart rhythm, and how eating eggs can help reduce heart disease risk.
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The research was published in the Journal of the American College of Cardiology.
