Quitting smoking reduces heart attack risk by 50 percent, study finds

Give up smoking can significantly reduce the risk of a myocardial infarction For people diagnosed with coronary artery disease, as highlighted in a recent study, researchers warn that simply cutting back on smoking does not substantially reduce this risk. Interestingly, people who have never smoked still have a lower overall risk of major cardiovascular events compared to those who have quit smoking, even if they have been smoke-free for many years.

These findings were presented at ESC Congress 2024 in London, the annual meeting of the European Society of Cardiology. Although the research has not yet been published in a peer-reviewed journal, experts believe it carries a vital message.

“This analysis reinforces what’s been known from previous, smaller studies over the years: There is no safe level of cigarette smoking,” said Dr. Richard Wright, a cardiologist at Providence Saint John’s Health Center in Santa Monica, Calif. Wright noted that the harmful components of cigarette smoke immediately trigger a cascade of damaging events, regardless of the amount smoked, and that even minimal exposure can increase heart risk, even for those exposed to secondhand smoke.

The study analyzed data from the CLARIFY registry, which has been pivotal in previous cardiovascular research. Researchers examined 32,378 people with coronary artery disease, with an average follow-up of about six years after diagnosis. At the start of the study, 41 percent of participants had never smoked, 46 percent were former smokers, and 12 percent were current smokers. Among former smokers, 73 percent had quit smoking within a year of their diagnosis, while 27 percent quit in the years since.

The study found that quitting smoking after a diagnosis of coronary heart disease reduced the risk of a major cardiovascular event by 44 percent, regardless of when one quit. However, each additional year of continuous smoking increased the risk by 8 percent. Notably, reducing the amount smoked did not significantly reduce the risk compared with those who continued to smoke. Former smokers also did not achieve the lower cardiovascular risk level of those who had never smoked, even after years of quitting.

“I often tell my patients that it is never too early or too late to quit smoking, but the sooner a patient does so, the better it will be to reduce cardiovascular risk,” explains Dr Jules Mesnier, a cardiologist at Bichat-Claude Bernard Hospital in Paris and one of the authors of the study. He stresses that reducing smoking is not enough and that clear messages about the importance of quitting smoking should be included in all medical consultations.

Dr. Robert Page, professor of clinical pharmacy and a member of the American Heart Association’s Council on Lifestyle and Cardiometabolic Health, stressed the importance of the study’s findings. “Even after quitting smoking, patients do not return to their baseline cardiovascular risk status,” he noted. Although the study is based on registry data, Page highlighted the substantial evidence on the cardiovascular effects of smoking, reinforcing the importance of patient education.

Dr. Cheng-Han Chen, an interventional cardiologist and medical director of the Structural Cardiology Program at MemorialCare Saddleback Medical Center in California, echoed the study’s findings. “This study confirms that quitting smoking, not just cutting back, can cut the risk of major cardiovascular events in half. This is consistent with our current knowledge and recommendations,” he said.

Dr. Jayne Morgan, a cardiologist and vice president of medical affairs at Hello Heart, who attended the ESC conference, highlighted that smoking causes irreversible damage to the endothelial lining of the coronary arteries, leading to atherosclerosis, which can lead to heart attacks and heart failure. Smoking also accelerates the progression of existing atherosclerosis, narrowing the coronary arteries and reducing blood flow to the heart. In addition, smoking increases levels of blood clotting factors, which increases the risk of cardiovascular events.

Health experts like Page and Morgan agree that quitting smoking should include counseling, guidance, behavioral interventions, and drug therapy when necessary. Quitting smoking is challenging, but setting a quit date and having the support of health professionals can be crucial steps toward success.

For nonsmokers, the advice is clear: “Don’t start. If you’ve already started, now is the best time to quit,” Morgan said. Wright added: “If you smoke, quit now. You’ll see the benefits within a month, and within a decade or so, the excess risk will be gone — but only if you abstain from cigarettes altogether.”