A new study of over a million women reports smokers more than triple their risk of dying early compared with nonsmokers , and that kicking the habit can virtually eliminate this increased risk of premature death . Smoking remains the leading causes of preventable death in both the United States and the United Kingdom . Lead study author Richard Peto , a professor at the University of Oxford in the U.K. , and his colleagues conducted one of the largest studies looking at the hazards of smoking and the benefits of quitting among women born around the 1940s . These women were among the first generation of females to smoke regularly throughout their lifetimes , and tracking these women into the 21st century provided the most comprehensive look at the prolonged effects of smoking , as well as the benefits of quitting . TIME.com : Largest ever survey on global tobacco use issues dire warnings . `` 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 in a statement . Between 1996 and 2001 , the researchers recruited 1.3 million female participants ages 50 to 65 . The women filled out questionnaires detailing their lifestyles , medical status and sociodemographic factors . The researchers followed up and resurveyed the women three and eight years later . At the start of the study , published in the journal Lancet , 20 % of the women were smokers , 28 % were former smokers and 52 % never smoked . Each of the women was registered in the U.K. 's national health system , so their deaths and cause of death were recorded . By 2011 , 66,000 had passed away . The researchers found that women who smoked cigarettes throughout their adult years had three times a greater risk of dying compared with nonsmokers and women who quit well before middle age . They were much more likely to die of smoking-related causes like lung cancer , heart disease and stroke . Even light smokers who smoked one to nine cigarettes per day had two times the mortality rate of nonsmokers . TIME.com : 5 smartphone apps that promote smoking . More encouraging , however , was the positive effect that quitting seemed to have on the women 's life span . Those who quit smoking before they reached 40 avoided more than 90 % of the increased risk of premature death from cigarettes , while women who stopped even earlier -- before age 30 -- avoided 97 % of the added risk . And it 's never too late , the authors write , to stub out those cigarettes . `` Even cessation at about 50 years of age avoids at least two-thirds of the continuing smoker 's excess mortality in later middle age , '' they write . The hazards of smoking on health and mortality for women who continued to smoke past 40 , for example , were 10 times greater than among women who quit before age 40 . Rachel Huxley , a professor at the University of Minnesota who wrote an accompanying editorial to the study , says that the latest data on women are a welcome addition to existing knowledge , which have underestimated the full impact of smoking on women . `` Unlike in men , we have had to wait until now to fully understand the hazards of smoking and the associated benefits of quitting in women , '' she says . `` This is because smoking only first became popular among women born in the 1960s -- decades later than men -- and because of the long time lag between smoking and disease onset , we 've had to wait until these women were in their 50s to really see the damage to health that smoking has . '' TIME.com : The major toll of secondhand smoke . Huxley and the study authors note that compared with those who do n't smoke , women who smoke are at greater risk of heart disease than male smokers . Although the underlying mechanisms are largely unknown , researchers speculate that smoking 's effect on dampening the potentially protective effects of estrogen on the heart might put women smokers at a higher risk for heart disease than men who light up . Behavioral factors , like the fact that women tend to inhale more deeply than men , may also play a role . `` We just do n't know , but it 's intriguing and warrants further study , '' says Huxley . Although smoking rates have largely declined in the West since the 1940s , new evidence suggests the practice may be on the rise in developing countries . In August , the World Health Organization released a report showing global smoking rates remain strong , with 1 in 10 women picking up the habit . More people from middle-income countries are smoking , and women are starting at younger ages . Given these trends , data on the long-term health effects of smoking are desperately needed , says Huxley . `` The main message is that quitting smoking works , and the sooner the better . '' TIME.com : How much weight will you gain after you quit smoking ? TIME.com : Teens and tobacco use : Why declines in youth have stalled . This story was initially published on TIME.com . Women who give up smoking extend lives by 10 years .
A new study found more than a million women in the United States . Women who smoke throughout adult years have three times the risk of dying . Female smokers are also at a greater risk of heart disease than male smokers . Quitting smoking before middle age can virtually eliminate this risk .