Smokers who quit while still young can live almost as long as people who never smoked, new Canadian research has found.
While it’s estimated that smoking cuts at least 10 years off a person’s lifespan, new analysis from researchers at Toronto’s St. Michael’s Hospital finds that people who quit smoking before the age of 40 regain almost all of those potentially lost years.
“The most important message is that quitting works,” lead researcher Dr. Prabhat Jha told CTV News. “Cessation of smoking at an early age -- even up to age 40 -- avoids about 90 per cent of the risk of continuing to smoke.
“And the risk is big. Smokers are looking at a decade of life lost, a decade of good life lost.”
Jha -- head of the Centre for Global Health Research at St. Michael’s -- led a team who examined health records from the U.S. National Health Interview Survey. They also looked at data from the National Death Index, narrowing in on 16,000 people who had died but who had reported smoking earlier in life.
They found that people who never smoked were about twice as likely to live to age 80 than those who did.
But they also found that people who quit smoking between 35 and 44 years of age gained about nine years life back. Those who quit between ages 45-54 and 55-64 gained six and four years of life, respectively.
Jha stresses his team’s findings shouldn’t be interpreted as saying it’s safe to smoke until 40 and then stop. Former smokers still have a greater risk of dying sooner than non-smokers, he says.
But the risk is small compared to the huge risk taken by those who continue to smoke.
Many smokers have the belief that if they’ve been smoking for a decade or more already, it’s too late to quit.
Jha says that’s simply not true.
“Quitting at any age will have benefits, but particularly if you quit before age 40, you get close to never-smoker death rates,” he says.
Jha explains some of the effects of a smoker’s past history linger while others don’t. For example, ex-smokers still have a higher risk of developing lung cancer than those who never smoked, though of course their risk not as high as for those who continue to smoke.
But for other causes of death -- such as a sudden heart attack -- the effects of smoking can be erased with time.
“You can get a sudden narrowing of your artery if you’re a smoker and that leads to a heart attack. But if you quit smoking, that risk pretty much disappears. So it does vary by disease,” Jha says.
The study is also among the first to examine the death rates of the generation of women who started smoking when they were young and kept smoking through their adult lives.
Studies in the 1980s suggested the risks of smoking in these women were low, but this new research suggests they too lose about 10 years of life by continuing to smoke.
“Basically, if women smoke like men, they die like men,” says Jha. “That means about a decade of life lost. Not a few years, but a full decade -- a healthy decade of life lost.”
The research was funded by the National Institutes of Health, the Canadian Institutes of Health Research, and the Disease Control Priorities-3 project of the Bill and Melinda Gates Foundation.
All the findings appear in the most recent edition of New England Journal of Medicine.
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