Smoking a pack a day starting in their teens reduced their life expectancy by an average of 11 years, tripling the chances of a premature death, a number even higher than the risk for men. This means if you're a smoker your whole life, the chances you're going to die directly of smoking are greater than the chances of dying of everything else put together.
The study also found that even women who smoked a few cigarettes a day doubled their chances of dying younger, but the news from the study is not all bad. It reinforces the idea that quitting does cut risk enormously, and the sooner the better.
The research found if a woman who starts smoking as a teen quits before age 40, her increased chances of dying drop by 90%. Even if a woman stops by age 50, her extra risk drops by about 66%. For those 30 or younger who manage to quit, their excess risk disappears almost completely.