Scientists reveal warning signs that appear before every heart attack or stroke

High blood pressure is most common culprit

Warning signs like high blood pressure, elevated cholesterol or glucose levels precede almost all cases of heart attack or stroke, according to a new study which debunks the belief that these strike people without warning.

Above optimal levels of blood pressure, cholesterol, glucose, or smoking almost always precede these cardiac events, say researchers from Yonsei University College in South Korea, who call for greater attention to early detection and control of these modifiable risks.

In the study, published in the journal JACC, scientists assessed health records for over nine million people in South Korea and nearly 7,000 in the US and followed the health status of these individuals for up to two decades.

The researchers looked for the presence of four major risk factors before a heart attack, stroke or heart failure – high blood pressure, cholesterol, blood sugar, and smoking.

Non-optimal levels of these factors include past tobacco use, blood pressure over 120/80 mm Hg, total cholesterol of over 200 mg/dL, fasting glucose level over 100 mg/dL, and the diagnosis of diabetes.

The researchers also looked at higher thresholds of these factors posing elevated risk, including blood pressure of over 140/90, cholesterol above 240, glucose levels greater than 126, and current smoking.

A woman uses a blood pressure monitor at her home in Paris, France (AFP via Getty)

They found that 99 per cent of those who had a major heart event during the study had non-optimal levels of at least one of these risk factors, and 93 per cent had two or more risk factors.

“We think the study shows very convincingly that exposure to one or more non-optimal risk factors before these cardiovascular outcomes is nearly 100 per cent,” study co-author Philip Greenland from Northwestern University, US, said.

“The goal now is to work harder on finding ways to control these modifiable risk factors rather than to get off track in pursuing other factors that are not easily treatable and not causal.”

The researchers found that high blood pressure – or hypertension – was the most common culprit, affecting over 95 per cent of patients in South Korea and over 93 per cent in the US.

Even among women under 60 – the group often assumed to be at the lowest risk – more than 95 per cent still had at least one of these factors before heart failure or stroke.

At least 90 per cent of the patients had at least one of the major high-risk factors before their first cardiac event, the study found.