Giving up smoking can add 10 years to life, says a new study that is based on a large-scale research done on more than a million women. Researchers say that quitting smoking before age 30 can cut the risk of dying early.
A recent study from Japan had found that smoking shortens life by ten years and quitting before age 35 can help people live longer.
According to American Lung Association, in 2008, 21.1 million (18.3%) women smoked in the United States compared to 24.8 million (23.1%) men.
"If women smoke like men, they die like men - but, whether they are men or women, smokers who stop before reaching middle age will on average gain about an extra ten years of life," said Sir Richard Peto, at the University of Oxford, UK and co-author of the study.
Smoking causes 87 percent of all deaths associated with lung-cancer. Apart from lung cancers, smokers are at risk for diseases associated with heart and blood vessels, stroke and cataracts. In women, smoking causes pregnancy-related complications.
The present study involved 1.3 million women at ages 50 to 65 years between 1996 and 2001. Study participants were required to fill a questionnaire about their lifestyle, social and medical details. Participants were re-interviewed three years after they joined the study. All the women were tracked for about 12 years, at the end of which about 66,000 women had died.
"Both in the UK and in the USA, women born around 1940 were the first generation in which many smoked substantial numbers of cigarettes throughout adult life. Hence, only in the 21st century could we observe directly the full effects of prolonged smoking, and of prolonged cessation, on premature mortality among women," said Peto.
After analyzing the study data, researchers found that women who smoked had a three-fold greater chance of dying in their 50s or 60s than women who never smoked. They found that even a cigarette a day can increase the risk of early death twofold.
Researchers also found that by quitting smoking before age 30, women can reduce the risk of dying early by as much as 97 percent.
Professor Rachel Huxley, from the University of Minnesota, said that it is only now that researchers are getting to understand the full consequence of smoking. Smoking among women in Europe and USA became very popular only during the 1960s, much later than among men, said Huxley. That's one of the reasons why previous studies have underestimated the effects of smoking in women "simply because of the lengthy time lag between smoking uptake by young women and disease onset in middle and old age," Huxley added.