Oct. 26, 2012 -- Smoking cigarettes can shave 10 years off of a woman's life, a large new study shows.
But quitting before her 40th birthday (preferably well before it) avoids more than 90% of this increased risk of dying, and stopping before 30 avoids more than 97% of it.
These are the main findings of the Million Women Study, which appears online in The Lancet.
The study included 1.2 million women aged 50 to 69. Participants answered questions about their lifestyle, including whether or not they smoked cigarettes. They were asked these questions again three years later. During about 12 years of follow-up, 66,000 of these women died.
When the study started:
20% of the women were smokers
28% were ex-smokers
52% had never smoked
Women who were still smoking at the 3-year mark were close to three times as likely to die during the next nine years, when compared with their non-smoking counterparts, the study shows.
This threefold increase means that two-thirds of all deaths of female smokers in their 50s, 60s, and 70s are caused by smoking-related diseases such as lung cancer, chronic lung disease, heart disease, or stroke.
The more the women smoked, the greater their risk of dying. That said, even “light smokers” who smoked one to nine cigarettes per day at the start of the study were twice as likely to die as non-smokers.
Previous studies have examined risks of smoking in men, but women born around 1940 were the first generation of female smokers to take up the habit on a large scale. As such, this study is among the first to have the data to look at the effects of prolonged smoking, quitting, and the risk of dying among women who smoke.
“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,” says researcher Kirstin Pirie of the University of Oxford in the U.K.
Rachel R. Huxley co-wrote an editorial accompanying the new study. She is an epidemiologist at the University of Minnesota in Minneapolis. “This is the first study to be able to assess the full effects of smoking in women,” she says. “It is as harmful in women as in men.”
The message is clear: “Don’t start smoking, and if you do smoke, quit,” Huxley says. “If you quit in your late 30s or 40s, your risk of dying from serious chronic illness is substantially reduced. [But] it’s never too late to quit.”