Dr Min in his presentation at the ESC congress in 2013 said: “Smoking is an established risk factor for cardiovascular disease. Studies have identified that quitting smoking can reduce heart attacks and death but have not examined the relationship of this salutary effect on the presence and severity of coronary artery disease (CAD). Our study aimed to find out what impact stopping smoking had on the risk of cardiovascular events, death and the severity of CAD.”
The researchers examined 13,372 patients from 9 countries in Europe, North America and East Asia and looked at the risk of major adverse cardiac events in 2,853 active smokers, 3,175 past smokers and 7,344 never smokers.
Both active smokers and past smokers had a higher prevalence of severely blocked coronary arteries compared to non-smokers. This was determined using coronary computed tomographic angiography (CCTA), a non-invasive imaging technique that enables direct visualization of the coronary arteries. Active and past smokers had a 1.5-fold higher probability of severe stenoses in 1 and 2 major heart arteries, and a 2-fold increased probability of severe stenoses in all 3 major heart arteries.
Dr Min, who is director of the Institute of Cardiovascular Imaging at the New York-Presbyterian Hospital and the Weill Cornell Medical College, said: “Our results show that quitting smoking does not reduce the amount of disease smoking causes in the coronary arteries, but it does reduce the risk of heart attack and death to the levels of non-smokers.”
After 2.0 years of follow-up, 2.1% of the patients experienced heart attacks or death. Rates of heart attack or death were almost 2-fold higher in active smokers compared to never smokers. Past smokers had the same rates or heart attack or death as never smokers, despite having a higher prevalence, extent and severity of CAD (see figure). The findings in both active and past smokers persisted even when they were matched with non smokers who were similar in age, gender and CAD risk factors.
Dr Min said: “Our study was the first to demonstrate that the presence and severity of coronary blockages do not go away with quitting smoking, but that the risk of heart attack and death does. Future studies are being pursued to determine how this protective effect may occur.”
He continued: “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). 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. Our team and several others are pursuing such investigations.”
Dr Min concluded: “It’s never too late to quit smoking. This study clearly shows that stopping smoking lowers the risk of heart attacks and death to the level of never smokers.
In women even light-to-moderate cigarette smoking is associated with a significant increase in the risk of sudden cardiac death. A prior risk study found that the risk of sudden cardiac death rose 8 percent for each five years of smoking and the effects of smoking and risk of sudden cardiac death was reduced within 15-20 years to that of a nonsmoker. The findings published in the journal of Circulation: Arrhythmia & Electrophysiology, an American Heart Association journal, specify that long-term smokers may be at even greater risk. Quitting smoking can reduce and eliminate the risk over time.
“Cigarette smoking is a known risk factor for sudden cardiac death, but until now, we didn’t know how the quantity and duration of smoking effected the risk among apparently healthy women, nor did we have long-term follow-up,” said Roopinder K. Sandhu, M.D., M.P.H., the lead author and a cardiac electrophysiologist at the University of Alberta’s Mazankowski Heart Institute in Edmonton, Alberta, Canada.
Researchers investigated the occurrence of sudden cardiac death among more than 101,000 healthy women in the Nurses’ Health, which has collected biannual health questionnaires from female nurses nationwide since 1976. They included records dating back to 1980 with 30 years of follow-up. Most of the participants were white, and all were between 30 to 55 years old at the study’s start. On average, those who smoked reported that they started in their late teens.
During the study, 351 participants died of sudden cardiac death.
Other findings demonstrated:
Light-to-moderate smokers, defined in this study as those who smoked one to 14 cigarettes daily, had nearly two times the risk of sudden cardiac death as their nonsmoking counterparts.
Women with no history of heart disease, cancer, or stroke who smoked had almost two and a half times the risk of sudden cardiac death compared with healthy women who never smoked.
For every five years of continued smoking, the risk climbed by 8 percent.
Among women with heart disease, the risk of sudden cardiac death dropped to that of a nonsmoker within 15 to 20 years after smoking cessation. In the absence of heart disease, there was an immediate reduction in sudden cardiac death risk, occurring in fewer than five years.
Sudden cardiac death accounts for between 300,000-400,000 deaths in the Unites States annually and results from the abrupt loss of heart function, usually within minutes after the heart stops.
“Sudden cardiac death is often the first sign of heart disease among women, so lifestyle changes that reduce that risk are particularly important,” said Sandhu, who is also a visiting scientist at Brigham and Women’s Hospital in Boston, Mass. “Our study shows that cigarette smoking is an important modifiable risk factor for sudden cardiac death among all women. Quitting smoking before heart disease develops is critical.”
Sandhu et al. >Smoking, Smoking Cessation and Risk of Sudden Cardiac Death in Women. Circulation: Arrhythmia & Electrophysiology, 2012
European Society of Cardiology (2013, September 1). Quitting smoking drops heart attack risk to levels of never smokers.