Women who are light smokers - including those who smoke just one cigarette a day - double their chance of sudden death, a large study suggests.
The research tracked the health of 101,000 U.S. nurses over three decades. Light to moderate smokers were twice as likely to die of sudden heart problems than those who had never smoked.
In people aged 35 or younger, sudden cardiac death is usually because of a heart condition that runs in the family. But in people who are older - as most of the nurses in the study were - it can be the first sign of coronary heart disease, where the heart's arteries become blocked by fatty deposits.
Of the 315 sudden deaths in the study, 75 were among current smokers, 148 were among recent or past smokers and 128 occurred in people who had never smoked. After taking into account other heart risk factors, such as high blood pressure, high cholesterol and family history of heart disease, Dr. Roopinder Sandhu and colleagues found the women who smoked were twice as likely to die suddenly even if they smoked "light-to-moderate" amounts - between one and 14 cigarettes a day.
For every five years of continued smoking, the risk went up by 8%.
"What this study really tells women is how important it is to stop smoking," said Sandhu, of the University of Alberta.
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