Each year, 443,000 people in the U.S. die from smoking-related illnesses. Cigarette smoking is known to be the major single cause of cancer deaths in the nation. According to the Centers for Disease Control and Prevention’s latest statistics, 69 percent of smokers want to quit, and 52 percent of smokers attempted to quit in 2010. While kicking the habit could be difficult and feel nearly impossible, those who need an incentive to quit should look no further than their health. Quitting smoking can reduce an individual’s risk of heart attack and death to the risk levels of never-smokers, according to recent research.

Findings — presented at the European Society of Cardiology 2013 by Dr. James K. Min and Dr. Rine Nakanishi — show the impact that quitting smoking can have on a person’s risk of cardiovascular events, coronary artery disease (CAD), and even death. The CONFIRM (Coronary CT Evaluation for Clinical Outcomes: An International Multicenter Study) registry of 13,372 patients from nine countries in Europe, North America, and East Asia investigated the risk of severe harmful cardiac events in three groups: 2,853 active smokers, 3,175 past smokers, and 7,344 never smokers.

To evaluate the prevalence of severely blocked coronary arteries in all three groups, researchers used a coronary computed tomographic angiography (CCTA), a non-invasive imaging technique that allows examiners to see the coronary arteries clearly, reports Science Daily. Researchers found that active smokers, like past smokers, had a one-and-a-half-fold higher probability of severe stenoses in one or two major heart arteries, and a two-fold increased probability of severe stenoses in all three major heart arteries.

Stenoses in heart arteries occur when the heart’s aortic valve gets narrow, preventing the valve from opening to its full capacity, says Mayo Clinic. An aortic valve stenosis blocks blood flow from the victim’s heart into the aorta and to the rest of the body, which causes the heart to work extra hard to pump blood into the body. The heart muscle can weaken in the presence of stenoses and, ultimately, lead to serious heart problems, if left untreated.

While kicking the cigarette habit was not found to reduce the presence or severity of coronary blockages in the study, the risk of heart attack and death was lowered to levels of never-smokers. After the two-year study, researchers found that 2.1 percent of participants experienced heart attacks or death. Active smokers had rates of heart attack or death approximately two-fold higher compared to never-smokers. However, past smokers were found to have the same rates of heart attack or death as those of never-smokers, despite having a higher prevalence of severe CAD. The researchers noted that their findings for active smokers and past smokers remained consistent after being matched with never-smokers who had similar demographics, such as age, gender, and CAD risk factors.

“Our study aimed to find out what impact stopping smoking had on the risk of cardiovascular events, death and the severity of CAD,” said Min. At the European Society of Cardiology 2013, Min said that future studies are taking shape to examine how this protective effect may occur for past smokers.

"Numerous questions remain and require further study. For example, will the severe blockages observed in patients who have quit smoking provoke adverse events after 2 years (the duration of the present study)?” he said. “Further, does the duration of smoking or the number of cigarettes smoked per day affect the severity of CAD or the prognosis related to quitting smoking?”

Smoking accounts for almost 20 percent of all heart disease-related deaths in the United States.

Past smokers can lower their risk of coronary heart disease to the risk levels of a non-smokers after 15 years of quitting, says the American Cancer Society.