The University of Oxford study, published this week in the British medical journal The Lancet, included 1.3 million women between the ages of 50 and 65, making it one of the largest ever conducted on smoking. At the start of the study, in 1996, 20 percent of the women were smokers, 28 percent were former smokers and 52 percent had 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," explains Alexandra Sifferlin of Time magazine. "By 2011, 66,000 had passed away." Researchers found that even smokers who smoked as few as nine cigarettes a day had twice the mortality rate of nonsmokers.
"More encouraging, however," writes Sifferlin, "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 percent of the increased risk of premature death from cigarettes, while women who stopped even earlier -- before age 30 -- avoided 97 percent of the added risk." (Read more)