How Smoking Harms Women's Hearts

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 It should come as no surprise to anyone that smoking is bad for health, upping the risk of lung and other cancers as well as heart disease. But a new study pinpoints just how deadly lighting up can be for women's hearts.

Researchers examined the effects of cigarette smoking and smoking cessation on the risk of sudden cardiac death (SCD) over 30 years in 101,018 women enrolled in the Nurses' Health Study. The leading cause of cardiovascular death, SCD causes 300,000 to 400,000 deaths in the U.S. each year.  SCD occurs when the heart suddenly stops beating. Most people die within one hour.

During the course of the study, 351 women died of sudden cardiac death.

After controlling for heart disease, stroke and cancer, the study authors found that women who currently smoked had almost two and one half times the risk for SCD compared with women who never smoked. Former smokers had nearly two times the risk compared with women who never smoked.

None of the women in the study had known coronary heart disease, nor did any of them have a history of stroke or cancer when the study began in 1980. Twenty-nine percent of the women were current smokers; 26.4 percent were former smokers; and 44.5 percent had never smoked. The women ranged in age from 30 to 55 at the study's start.

The number of cigarettes a woman smoked and the length of a time she smoked was directly linked to her risk of SCD. Light to moderate smokers — those who smoked one to 14 cigarettes per day — had nearly two times the risk compared with never smokers. Women who smoked 25 or more cigarettes per day had more than three times the risk. And for every five years a woman smoked, there was an associated 8 percent increase in SCD risk.

Despite the unsettling findings, it is never too late to kick the habit, researchers noted. Women in the study with heart disease who quit smoking lowered their risk of SCD to that of a nonsmoker's within 15 to 20 years. Women who did not have heart disease dropped their risk to that a nonsmoker fewer than five years after quitting.

"Sudden cardiac death is often the first sign of heart disease among women so lifestyle changes that reduce that risk are particularly important," said researcher Roopinder K. Sandhu, M.D., M.P.H., of the University of Alberta's Mazankowski Heart Institute in Edmonton, Alberta, Canada in a statement. "Our study shows that cigarette smoking is an important modifiable risk factor for sudden cardiac death among all women."

The study is published today (Dec. 11) in the American Heart Association's  journal Circulation: Arrhythmia  & Electrophysiology.

Pass It On: Quitting smoking substantially lowers a woman's risk for sudden cardiac death.

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