A recent longitudinal study of over one million females in the United Kingdom has uncovered some interesting facts. The study, published yesterday in The Lancet has discovered that a woman who smokes her entire adult life will, on average, cut ten years from that life.
However, if she stops before she turns 40, the life expectancy is reduced by just one year and there was no discernable difference between those who stopped before the age of 30 and those who never smoked.
There was no opinion offered as to the magnitude of changes to a woman's quality of life (or her bank balance!).
According to the study, "For this prospective study, 1.3 million UK women were recruited in 1996—2001 and resurveyed postally about 3 and 8 years later. All were followed to Jan 1, 2011, through national mortality records (mean 12 woman-years, SD 2). Participants were asked at entry whether they were current or ex-smokers, and how many cigarettes they currently smoked.
"Those who were ex-smokers at both entry and the 3-year resurvey and had stopped before the age of 55 years were categorised by the age they had stopped smoking. We used Cox regression models to obtain adjusted relative risks that compared categories of smokers or ex-smokers with otherwise similar never-smokers." Around 100,000 women were excluded from the summarised results due to prior diseases.
The study concluded, "Among UK women, two-thirds of all deaths of smokers in their 50s, 60s, and 70s are caused by smoking; smokers lose at least 10 years of lifespan. Although the hazards of smoking until age 40 years and then stopping are substantial, the hazards of continuing are ten times greater. Stopping before age 40 years (and preferably well before age 40 years) avoids more than 90% of the excess mortality caused by continuing smoking; stopping before age 30 years avoids more than 97% of it."
"Stopping works, amazingly well actually. Smoking kills, stopping works and the earlier you stop the better."
Of interest, Professor Peto noted that the crucial risk factor was time spent smoking, rather than amount. "If you smoke 10 cigarettes a day for 40 years it's a lot more dangerous than smoking 20 cigarettes a day for 20 years," he said.
In a moment of clarity, Peto said, ""What we've shown is that if women smoke like men, they die like men."
And they smell just as bad.