Women who smoke are at two times higher risk of a sudden cardiac death than women who don't smoke, a new study has found. For every five years of continued smoking, the risk of sudden cardiac death climbed by 8 percent. However, quitting smoking can help women cut down this risk.

According to American Lung Association, in 2008, 21.1 million (18.3%) women smoked in the United States compared to 24.8 million (23.1%) men.

"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 from the University of Alberta, Canada, in a press release.

The study included 101,000 U.S. women who had participated in the Nurses' Health Study. Most of the participants were white, and all were between 30 to 55 years old at the study's start. On average, women reported that they had started smoking when they were in their late teens.

Nurses' Health Study has collected biannual health questionnaires from female nurses nationwide since 1976. During the study, 351 participants died of sudden cardiac death.

The study found that women who smoked one to 14 cigarettes daily were at two times higher risk of suffering a sudden cardiac death than women who didn't smoke.

Women smokers who had no other health complications like stroke, heart disease or cancer were still at two and half times higher cardiac death risk.

In women who were diagnosed with heart disease, the risk of sudden cardiac death risk dropped to that of nonsmokers within 15 to years if they quit smoking. But, in women with no history of heart disease, the risk of sudden cardiac death dropped quickly.

"Sudden cardiac death is often the first sign of heart disease among women, so lifestyle changes that reduce that risk are particularly important. 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," said Sandhu.

Smoking causes 87 percent of all deaths associated with lung-cancer. Apart from lung cancers, smokers are at risk for diseases associated with heart and blood vessels, stroke and cataracts. In women, smoking causes pregnancy-related complications.

The study is published in the journal Circulation: Arrhythmia & Electrophysiology.

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