Women who are even light-to-moderate cigarette smokers may be significantly more likely than nonsmokers to suffer sudden cardiac death, according to new research in Circulation: Arrhythmia & Electrophysiology, an American Heart Association journal.
The findings indicate long-term smokers may be at even greater risk. But 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 study's lead author and a cardiac electrophysiologist at the University of Alberta's Mazankowski Heart Institute in Edmonton, Alberta, Canada.
Researchers examined the incidence of sudden cardiac death among more than 101,000 healthy women in the Nurses' Health Study, 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 include:
- 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 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."