(HealthDay News) -- Smoking takes at least 10 years off women's lives but they can significantly reduce that risk if they quit smoking early enough, a new study suggests.
Researchers looked at more than 1 million women in the United Kingdom who were recruited when they were aged 50 to 65 and followed for 12 years. Initially, 20 percent of the women were smokers, 28 percent ex-smokers, and 52 percent had never smoked.
Women who still smoked three years into the study were nearly three times more likely to die in the following nine years than nonsmokers. This threefold increased risk of death means that two-thirds of all deaths of female smokers in their 50s, 60s and 70s are caused by smoking, the researchers said.
The death risk among smokers increased sharply with the amount smoked, but even those who were light smokers (1 to 9 cigarettes a day) at the start of the study were twice as likely to die as nonsmokers, according to the report published online Oct. 27 in The Lancet.
The investigators also found that women who had stopped smoking before the age of 40 avoided more than 90 percent of the increased risk of dying associated with continuing to smoke, while those who quit before 30 avoided more than 97 percent of that increased risk.
"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 10 years of life," study co-author Sir Richard Peto, of the University of Oxford in England, said in a journal news release.
The authors of a commentary accompanying the study agreed that the findings are "simple and unequivocal."
"That we had to wait until the 21st century to observe the full consequences in women of a habit that was already widespread in the mid-20th century, when tobacco smoking pervaded much of the developed world, might seem paradoxical," wrote Rachel Huxley, of the University of Minnesota, and her co-author.
"But this is because, in most of Europe and the U.S.A., the popularity of smoking among young women reached its peak in the 1960s, decades later than for men," the editorialists explained. "Hence, previous studies have underestimated the full eventual impact of smoking on mortality in women, simply because of the lengthy time lag between smoking uptake by young women and disease onset in middle and old age."
The U.S. National Cancer Institute has more about women and smoking.
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