Everyone โ€” everyone โ€” knows that smoking is terrible for you. But damn, according to a massive new study published in Circulation (a journal of the American Heart Association), even one cigarette a day could be very harmful to your health.

Says the BBC's Michelle Roberts:

[Dr. Roopinder Sandhu and colleagues and colleagues at the University of Alberta Canada] tracked the health of 101,000 US nurses over three decades.

[The researchers] 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.

If it's any consolation, recent research has found that women who give up smoking before the age of 40 can significantly reduce their risk of tobacco related death.

"Stopping before age 40 years (and preferably well before age 40 years) avoids more than 90% of the excess mortality caused by continuing smoking," concludes this study, published earlier this year in The Lancet. "Stopping before age 30 years avoids more than 97% of it."