Clinical Research Office. A partnership between Sheffield Teaching Hospitals NHS Foundation Trust and the University of Sheffield

More than 8-fold higher risk of major heart attack for under 50s who smoke

All smokers at risk, but younger ones are particularly vulnerable, study shows

Smokers under the age of 50 are more than eight times as likely as non-smokers to suffer a major heart attack, making them the most vulnerable of any age group of smokers, reveals research published online in the journal Heart.

All smokers have a significantly higher risk of having a heart attack than non-smokers of the same age, but it’s not clear what the magnitude of that risk is among different age groups.

The research, which was led by Sheffield Teaching Hospitals NHS Foundation in partnership with the University of Sheffield, drew on data for 1727 adults undergoing treatment for a classic type of heart attack known as a STEMI at South Yorkshire’s regional specialist cardiothoracic centre in Sheffield, northern England, between 2009 and 2012.

A STEMI, or ST-segment elevation myocardial infarction, refers to the typical pattern seen on an electrocardiogram (ECG), indicating that a large portion of the heart muscle is dying.

The researchers also used data from the Office for National Statistics Integrated Household Survey (ONS-IHS), for the South Yorkshire region. Among other things, this collects information on smoking prevalence and other aspects of perceived health.

Almost half of the 1727 patients (48.5%) were current smokers, with roughly a quarter (just over 27%) former smokers, and a quarter (just over 24%) non-smokers.

Current smokers tended to be 10-11 years younger than ex or non-smokers when they had their STEMI. And along with ex-smokers, were twice as likely as non-smokers to have had previous episodes of coronary artery disease.

They were also three times as likely as non-smokers to have peripheral vascular disease, a condition in which a build-up of fatty deposits in the blood vessels restricts blood supply to the legs.

Dr Ever Grech, Consultant Cardiologist at Sheffield Teaching NHS Foundation Trust, said: “This important study, carried out at the South Yorkshire Cardiothoracic Centre, Sheffield is the first time that the increased risk of a major and life-threatening heart attack due to smoking has been quantified. All smokers are at much greater risk, but younger smokers are particularly vulnerable and are over eight times more likely to have a major heart attack than their non-smoking peers. An awareness of this strikingly higher risk is an essential public health message and could allow effective targeted intervention.” 

The researchers say that the much higher risk of STEMI in younger smokers is not easy to explain as this age group typically don’t have many of the other contributory risk factors that might be seen in older smokers, such as high blood pressure, high cholesterol or diabetes.

Smoking may therefore be the most important risk factor, they suggest, adding that other research shows that the fatty deposits furring up the arteries of smokers differ from those of non-smokers and seem to be more vulnerable to rupture.

Greater efforts are needed to help younger smokers stub out their habit, say the researchers.

“All current smokers must be encouraged into smoking cessation therapy to reduce their risk of acute STEMI, with a focus on the youngest smokers whose increased risk is often unrecognised,” Dr Grech added.


Photo: Dr Grech at the South Yorkshire Cardiothoracic Centre, Northern General Hospital