It could take more than two decades before heart disease risk drops back to average after a person quits smoking, a new study suggests.
For decades, experts have known that cigarette smoking can cause significant damage to the heart.
According to the British Heart Foundation, at least 15,000 deaths from heart disease in the UK are attributed to smoking each year.
Now, researchers in South Korea have discovered exactly how long it takes for an ex-smoker’s cardiovascular system to resemble that of someone who has never smoked: 25 years.
What’s more, the findings revealed that former heavy smokers who have smoked for more than eight years have a similar risk of having an impending heart attack or stroke as those who still smoke.
In it studyPublished in the journal JAMA, researchers examined health data from more than 100,000 former smokers and more than 4 million people who never smoked.
The ex-smokers were followed a decade after they stopped smoking.
Other details were noted, including age, how old they were when they started smoking, how many cigarettes they smoked a day, and their age when they stopped smoking.
According to the British Heart Foundation, at least 15,000 deaths from heart and circulatory diseases in the UK are attributed to smoking each year.
The study found that the link between smoking and cardiovascular disease risk was dose-dependent, meaning those who were light smokers saw their risk drop relatively soon after quitting.
But for former heavy smokers, who had smoked for at least eight years, the researchers concluded that it could take 25 years before the risk of heart attack and stroke was reduced to that of someone who has never smoked.
The study authors said: “Former heavy smokers should be considered to have an equivalent risk of cardiovascular disease as patients who continue to smoke.”
Smoking kills around 78,000 people in the UK each year, and many more suffer from illness due to their habit.
Half of all smoking-related diseases in the UK are cardiovascular, such as heart problems and strokes.
Dozens of studies have shown that smoking is linked to heart failure, when the heart muscle does not pump blood through the body as well as it should, usually because it is too weak or stiff.
As a result, the heart is unable to supply the body’s organs and tissues with the vital oxygen and nutrients they need to function normally.
The 7,000 chemicals in tobacco (including tar and others) can damage the blood vessels that supply the heart, which is believed to be the cause of some of the damage that smoking inflicts on the organ.
Meanwhile, nicotine (a highly addictive toxin found in tobacco) is strongly linked to dangerous increases in heart rate and blood pressure.
Smoking also releases poisonous gases such as carbon monoxide into the body, further reducing our oxygen supply.
Around one in eight Britons and Americans smoke now, compared with almost half of the adult population in the 1970s.