A study published recently in the journal Circulation: Arrhythmia & Electrophysiology has shown that even light-to-moderate female smokers were more likely than nonsmokers to sudden cardiac death. Long-term smokers are at even greater risk, though the risks subside over time after quitting.

“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 Dr. Roopinder Sandhu, lead author of the study and a cardiac electrophysiologist at the University of Alberta.

Sandhu and her colleagues looked at more than 101,000 incidences of cardiac death among healthy women in the Nurses’ Health Study, a biannual health survey of registered female nurses in the U.S. The women were between the ages of 20 and 55 years old at the start of the study and most of them were white. 351 of them died of sudden cardiac death during the study.

Those who smoked one to 14 cigarettes daily (light-to-moderate smokers) had almost double the risk of sudden cardiac death as those who did not smoke. Every five years of continued smoking added 8% to the risk, but the risk dropped to the same as a nonsmoker within 5 years for women without heart disease who quit smoking. For those with heart disease, it took 15 to 20 years to fully reduce the risk.

“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. “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.”