The most common warning sign that occurs before a heart attack

Almost everyone who suffers a heart attack, stroke or heart failure experiences warning signs years before the event, according to landmark research.

The study, which tracked millions of people across two continents, found that more than 99 per cent of patients had at least one major risk factor, long before their first cardiac emergency.

However, high blood pressure – also known as hypertension – was by far the most common culprit, affecting more than nine in ten of participants. 

The findings overturn the widespread belief that heart disease can strike ‘out of the blue’, affecting people with no obvious health problems.

In fact, the research suggests that the warning signs are there in almost every case – but often go unrecognised or untreated.

Scientists from Northwestern University in Chicago and Yonsei University in Seoul analysed medical records for more than 9.3 million adults in South Korea and almost 7,000 in the U.S.

They were able to follow participants for up to two decades, thanks to routine health screenings that recorded blood pressure, cholesterol, glucose and smoking history.

By comparing these records with subsequent diagnoses of heart attack, stroke or heart failure, the researchers could see what health problems were already present years before disaster struck.

Across both groups, the results were striking: more than 99 per cent of people who later developed cardiovascular disease had at least one ‘non–optimal’ risk factor beforehand, while more than 93 per cent had two or more.

Alongside high blood pressure, factors included raised blood sugar or a diabetes diagnosis, high cholesterol and past tobacco use.

Even among younger women, who are typically assumed to be at lower risk, more than 95 per cent had at least one red flag before experiencing stroke or heart failure.

‘These findings show very convincingly that exposure to one or more nonoptimal risk factors before cardiovascular outcomes is nearly 100 per cent,’ said senior author Dr Philip Greenland, professor of cardiology at Northwestern University Feinberg School of Medicine.

‘The goal now is to work harder on controlling these modifiable risk factors, rather than being distracted by other factors that are not easily treated and not causal.’

Cardiovascular disease remains the world’s leading cause of death, killing an estimated 18 million people every year.

In the UK alone, it accounts for a quarter of all deaths. Experts say the new findings underscore the importance of early detection and prevention.

NHS figures show that while most cardiac events still occur in older age, hospital admissions for heart attacks among people in their 30s and 40s have risen in recent years.

Experts say the trend is being driven by obesity, high blood pressure and type 2 diabetes, all increasingly common at younger ages in the UK.

Cardiologists also point to poor diet, lack of exercise and high levels of stress as fuelling a new generation of patients who once would have been considered too young for heart disease.

In the US, heart attacks among adults under 40 have been rising by around two per cent a year, according to the American College of Cardiology.

National survey data show that strokes in adults aged 18 to 44 increased by roughly 15 per cent in the past decade, even as rates in older people declined.

American researchers blame the same culprits seen in the UK: obesity, smoking, poorly controlled blood pressure and cholesterol, and soaring rates of type 2 diabetes in younger age groups.

Doctors warn that younger patients are often overlooked because heart disease is still seen as an ‘older person’s’ problem, meaning opportunities for early intervention are missed.

Raised blood pressure, cholesterol and blood sugar can often be controlled through lifestyle changes such as diet, exercise and stopping smoking, as well as with medication.

The problem, doctors warn, is that many people either don’t know they have these conditions, or fail to keep them under control.

High blood pressure, for example, is sometimes called the ‘silent killer’ because it rarely causes symptoms until it has already damaged the heart or blood vessels.

Lead investigators argue that health services should put greater emphasis on identifying risk factors in middle age, before they cause irreversible harm.

Routine screening, particularly for blood pressure and cholesterol, could help spot problems in people who feel otherwise healthy.

The study, funded by the National Research Foundation of Korea, is published in the Journal of the American College of Cardiology.