(NaturalNews) Being a smoker cuts about 10 years off your life expectancy - but if you quit before you hit 40, you can get nearly all those years back, according to a study conducted by researchers from the University of Toronto, the Centre for Global Health Research at St. Michael's Hospital, and published in the New England Journal of Medicine.
In fact, at every age studied, quitting smoking increased a person's life expectancy by several years.
"Quitting smoking before age 40, and preferably well before 40, gives back almost all of the decade of lost life from continued smoking," researcher Dr. Prabhat Jha said.
"That's not to say; however, that it is safe to smoke until you are 40 and then stop. Former smokers still have a greater risk of dying sooner than people who never smoked. But the risk is small compared to the huge risk for those who continue to smoke."
The study is the first to examine the risks of smoking and the benefits of quitting in a large representative sample of the U.S. population. In contrast, many prior studies have focused on nurses or other groups that tend to be healthier than average.
Numbers show toll of smoking
The researchers cross-referenced information on 200,000 people who had participated in the U.S. National Health Interview Survey with information from the National Death Index. The Health Interview Survey is conducted every year on a representative cross-section of the U.S. population, while the Death Index includes every death certificate issued in the United States since 1986.
Among both men and women, smoking cut an average of 10 years off a person's life span. Put another way, smokers between the ages of 25 and 79 were three times more likely to die than people who had never smoked, and only half as likely to live until the age of 80.
Previous studies, conducted in the 1980s, contained very little information on women smokers, because smoking rates among women were so much lower when the adult participants in those studies were young. In contrast, the current study was able to track the mortality outcomes of many more lifelong female smokers. Strikingly, women were 50 percent more likely to die from smoking-related causes in the current study than in comparable studies conducted in the 1980s.
"Women who smoke like men, die like men," Jha said.
The good news was that quitting smoking dramatically increased life expectancy at all ages. Of the 10 years lost from being a smoker, people who quit smoking between the ages of 35 and 44 gained nine of those back. People who quit between the ages of 45 and 54 gained back six years, while people who quit between the ages of 55 and 64 recovered four.
There are now 1.3 billion smokers worldwide, and smoking is estimated to kill about one billion people in the 21st century, compared with the 100 million killed by smoking in the 20th century. The vast majority of smokers today live in low and middle-income countries, where quitting rates are also much lower.