Women who quit smoking by the age of 40 can gain ten years of extra life, a study has found.
A survey of 1.3million women found that quitting before middle age avoids more than 90 percent of the increased risk of dying caused by continuing to smoke, the Daily Mail reported.
The benefits also apply to men, scientists said.
Most of the increased death rate resulted from smoking-related diseases such as lung cancer, chronic lung disease, heart disease or stroke.
The risk rose steeply with the quantity of tobacco smoked, but even light smokers who puffed fewer than 10 cigarettes a day doubled their chances of dying early.
Smokers who kicked the habit around age 30 avoided 97 percent of their excess risk of premature death.
In the UK almost half of the 10 million smokers are women.
Although smoking is falling among both sexes, the decline has been less rapid in women.
The study recruited women aged 50 to 65 from 1996 to 2001.
They completed a questionnaire about living habits, medical and social factors and re-surveyed three years later.
Women were monitored for a total of 12 years on average, during which there were 66,000 deaths.
Although the serious risk of ill health remained among those who smoked until age 40, the excess hazards among those who continued smoking after 40 were ten times bigger
Initially, 20 percent of the women were smokers, 28 percent ex-smokers, and 52 per cent had never smoked.
"Smokers lose at least ten years of lifespan. Although the hazards of smoking until age 40 years and then stopping are substantial, the hazards of continuing are ten times greater," the study report said.
The study is published in The Lancet medical journal. (ANI)