Heavy smokers may need 25 years for heart disease risk to match that of non-smokers after quitting

A new study from South Korea has revealed that heavy smokers may take up to 25 years after quitting for their cardiovascular system to resemble that of someone who has never smoked. The research indicates that heavy smokers who have smoked for at least eight years have a similar risk of heart attack or stroke as those who still smoke, highlighting the long-term heart health risks for smokers even after quitting.

The study, published on JAMA Network, examined health data from over 5 million people in South Korea, including more than 100,000 ex-smokers and over 4 million people who have never smoked. The participants were tracked for an average of 4.2 years. The researchers noted the age of the ex-smokers, how old they were when they started smoking, how many cigarettes they smoked a day, and the age they quit. Their smoking history was also recorded, including the number of cigarettes smoked daily and when they quit smoking. Their health conditions were monitored, including heart attacks, strokes, and heart failure.

The study defined eight pack-years as the median that separated light smokers from heavy smokers. A pack-year is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years smoked. This threshold is reached by someone who has smoked one pack per day for eight years or two packs per day for four years. The quantity of tobacco consumed before quitting and the duration of smoking cessation are important factors in measuring the subsequent risk of cardiovascular diseases.

Researchers found that heavy smokers who have smoked for more than eight years have a similar risk of impending heart attack or stroke as those who continue to smoke. For these individuals, it could take 25 years for the risk of heart attack and stroke to lower to the level of someone who has never smoked. "Heavy ex-smokers should be considered to have a cardiovascular disease risk equivalent to that of patients who continue to smoke," the study authors said, according to The Sun.

In contrast, those who were light smokers saw their risk of cardiovascular disease plummet soon after stopping. Five to ten years after quitting, the cardiovascular risk of these former smokers becomes almost identical to that of a person who has never smoked. The researchers emphasized that the best approach is to never start smoking or to quit as soon as possible, ideally before accumulating eight pack-years, in order to enjoy the most significant health benefits.

"This is in tune with what has been observed and studied in the past. The residual effects of smoking are just as risky till the body gets rid of them," said Dr. Ambuj Roy, professor of cardiology at AIIMS, Delhi, according to The Indian Express. He added that former smokers need to take care of other co-morbidities after quitting smoking. "The former smokers must eat right, avoid preventable risk factors like obesity, keep the blood pressure, blood sugar and cholesterol levels down. This is the only way to lower the cumulative risk score for cardiovascular diseases," Dr. Roy said.

Smoking is known to trigger body inflammation, which can lead to plaque build-up in arteries. "Smoking can damage blood vessel walls, constricting them. It raises your heart rate and blood pressure, stressing your heart out in the process," said Dr. Balbir Singh, from Cardiac Sciences, Cardiology at Max Hospital, Saket, New Delhi, according to The Indian Express. He explained that smoking can thicken the blood, creating conditions for a heart attack. "Smoking can lower high-density lipoprotein (HDL) or good cholesterol and raise your low-density lipoprotein (LDL) or bad cholesterol along with triglycerides, which are a type of fat in your blood," Dr. Singh added.

The chemicals in cigarettes make the walls of arteries sticky, and fatty material sticks to the walls. This fatty material can begin to clog arteries and reduce the space for blood to flow properly. If the arteries that carry blood to the heart get clogged, this can lead to a heart attack. If the arteries that carry blood to the brain get clogged, it can lead to a stroke.

Dr. Singh noted that it takes almost five years for the heart to experience the benefits of quitting smoking. "You may take a couple of months or more for the lungs to heal, remove mucus, tar and dust and tend to feel short of breath or wheezing," he said. "This usually settles within a year and you can feel yourself breathing easy," Dr. Singh said, according to The Indian Express.

According to the British Heart Foundation, after just 20 minutes of quitting smoking, the heart rate and blood pressure will begin to return to normal. After two to three days, the sense of smell and taste will begin to improve. After a year of quitting smoking, the risk of a heart attack is half of that of a smoker. On average, smokers who quit in their 30s will add ten years to their life, while even quitting at 60 can add three years.

The study highlighted that the history of smoking is not equal for everyone; individuals take different amounts of time to heal after quitting smoking. For some, recovery may take years, while for others, it may take decades. The researchers emphasized that quitting smoking as soon as possible is advised, as it could take more than two decades for heart health to return to normal after an individual gives up smoking.

Sources: The Sun, Femme Actuelle, The Indian Express, The Scottish Sun, Youm7 (Entertainment)

This article was written in collaboration with generative AI company Alchemiq