Credit: CC0 Public domain
Credit: CC0 Public domain
People who quit smoking see significant improvements in their life expectancy after just a few years, according to a new study by researchers at Unity Health Toronto at the University of Toronto.
The study, published in NEJM Evidence, shows that smokers who quit before age 40 can expect to live almost as long as those who never smoked. Those who quit smoking at any age return to survival close to that of those who have never smoked 10 years after quitting, and about half of that benefit occurs in just three years.
“Quitting smoking is ridiculously effective at reducing the risk of death, and people can reap those benefits remarkably quickly,” said Prabhat Jha, a professor at U of T’s Dalla Lana School of Public Health and Temerty School of Medicine. , who is executive director of the Global Health Research Center at Unity Health Toronto.
The observational study included 1.5 million adults in four countries (US, UK, Canada and Norway), followed for 15 years. Smokers aged 40 to 79 had almost three times the risk of dying compared to those who never smoked, meaning that on average they lost between 12 and 13 years of life.
Ex-smokers reduced their risk of death by 1.3 times (or 30 percent more) compared to never smokers. Quitting smoking at any age was associated with longer survival, and even those who quit smoking for less than three years gained up to six years of life expectancy.
“Many people think it’s too late to quit smoking, especially in middle age,” Jha said. “But these results contradict that line of thinking. It is never too late, the impact is rapid, and the risk of major diseases can be reduced, which means a longer and better quality of life.”
Researchers found that quitting smoking reduced the risk of dying from vascular diseases and cancer, in particular. Ex-smokers also reduced their risk of death from respiratory diseases, but slightly less, probably due to residual lung damage.
There are currently around 60 million smokers in the four countries participating in the study and more than one billion worldwide. The global smoking rate has decreased by more than 25 percent since 1990, but tobacco remains a leading cause of preventable death.
Jha said the findings should add urgency to governments’ efforts to support people who want to quit smoking. “Helping smokers quit is one of the most effective ways to substantially improve health. And we know how to do it by increasing taxes on cigarettes and improving support for quitting.”
Canada is long overdue for raising the federal excise tax on cigarettes, and many other countries could reduce smoking rates by raising taxes, Jha said. Smoking cessation supports may include clinical guidelines and patient resources such as helplinesbut also a health system-wide approach.
“When smokers interact with the health care system in any way, doctors and health professionals can encourage them to quit smoking by pointing out how well it works,” Jha said. “This can be done with concern and without judgment or stigma, recognizing that cigarettes are designed to be highly addictive.”
Eo Rin Cho et al, Smoking cessation and short- and long-term mortality, NEJM Evidence (2024). DOI: 10.1056/EVIDoa2300272