According to a new study by researchers at the University of Toronto at Unity Health Toronto, people who quit smoking experience a significant increase in life expectancy in just a few years.
The study, published in NEJM Evidence, shows that smokers who quit before the age of 40 can expect a life expectancy almost as long as those who have never smoked. Those who quit smoking at any age reach almost the chance of non-smoker survival 10 years after quitting, with about half of this benefit occurring within just three years.
„Quitting smoking is incredibly effective in lowering the risk of death, and people can reap these benefits remarkably quickly,“ said Prabhat Jha, Professor at the Dalla Lana School of Public Health and Temerty Faculty of Medicine at U of T. and Executive Director of the Center for Global Health Research at Unity Health Toronto.
The observational study included 1.5 million adults in four countries (USA, UK, Canada, and Norway) and was observed over a period of 15 years. Smokers aged 40-79 had nearly triple the risk of dying compared to non-smokers, resulting in an average loss of 12-13 years of life.
Former smokers reduced their risk of death by 1.3 times (or 30% higher) 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 extended life expectancy by up to six years.
Many people think it’s too late to quit smoking, especially in middle age. But these results contradict that belief. It’s never too late, the effect is quick, and one can reduce the risk of serious diseases, leading to longer and better quality of life,“
-Prabhat Jha, Professor at the Dalla Lana School of Public Health at U of T and the Temerty Faculty of Medicine
The researchers found that smoking cessation specifically reduced the risk of dying from vascular disease and cancer. Former smokers also reduced the risk of dying from a respiratory disease, albeit to a lesser extent, likely due to remaining lung damage.
Currently, there are approximately 60 million smokers in the four countries involved in the study, and over a billion worldwide. The global smoking rate has decreased by more than 25% since 1990, but tobacco is still one of the most common preventable causes of death.
Jha said the findings should give urgency to governments‘ efforts to support people who want to quit smoking. „Helping smokers quit smoking is one of the most effective ways to significantly improve their health. And we know how to achieve that by increasing cigarette taxes and improving support for smoking cessation.“ In Canada, an increase in federal sales taxes on cigarettes is long overdue, and many other countries could reduce smoking rates through tax hikes. Clinical guidelines and patient resources such as hotlines, as well as a whole-of-health-system approach, may be part of smoking cessation support.
„When smokers interact with the health system in any way, doctors and health experts can encourage them to quit and show them how effective quitting is,“ said Jha. „This can be done with care and without judgment or stigma, recognizing that cigarettes are designed to be highly addictive.“
Cho, ER, et al. (2024) Smoking cessation and short- and long-term mortality. NEJM Evidence. doi.org/10.1056/EVIDoa2300272.