8 times risk of major heart attack in under-50 smokers

London, November 30  

Smokers under the age of 50 are over eight times more likely to suffer a major heart attack compared to peers who do not smoke or gave it up, according to a new study.

Researchers including those from the University of Sheffield in the UK drew on data for 1,727 adults undergoing treatment for a classic type of heart attack known as a STEMI 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.

Among other things, this collects information on smoking prevalence and other aspects of perceived health.

Almost half of the 1,727 patients (48.5 per cent) were current smokers, with roughly a quarter (just over 27 per cent) former smokers, and a quarter (just over 24 per cent) 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.

Based on the ONS-IHS data, the overall prevalence of smoking in South Yorkshire was 22.4 per cent, with the highest prevalence among those under the age of 50 (just over 27 per cent).

However among STEMI patients under the age of 50, smoking prevalence was almost 75 per cent.

Overall, the data analysis showed that smokers were more than three times more likely to have a STEMI than ex- and non-smokers combined.

The highest risk was among the under-50s who were nearly 8.5 times as likely to do so as former and non-smokers of the same age.

This risk fell with increasing age, dropping to a five-fold difference among 50-65 year olds, and a three-fold difference among the over 65s.

The researchers said that the much higher risk of STEMI in younger smokers is not easy to explain as this age group typically do not 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.

“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,” said researchers. The study was published in the journal Heart. — PTI