Study finds significant and rapid health benefits from quitting smoking at any age

A recent study by University of Toronto researchers reveals that individuals who quit smoking experience substantial increases in life expectancy within a few years.

The study, published in NEJM Evidence, showed that people who quit smoking before age 40 can expect to live almost as long as those who never smoked whereas those who quit at any age return close to never-smoker survival 10 years after quitting, and about half that benefit occurs within just three years.

“Quitting smoking is ridiculously effective in reducing the risk of death, and people can reap those rewards remarkably quickly,” said Prabhat Jha, a professor at the University of Toronto’s Dalla Lana School of Public Health and Temerty Faculty of Medicine, and executive director of the Centre for Global Health Research at Unity Health Toronto.

An observational study of 1.5 million adults across the U.S., UK, Canada, and Norway tracked over 15 years revealed that smokers aged 40 to 79 faced nearly three times the risk of death compared to non-smokers, resulting in an average loss of 12 to 13 years of life. However, former smokers reduced their risk of death to 1.3 times higher than non-smokers. Quitting smoking at any age was linked to increased survival, with those abstaining for less than three years gaining up to six years in life expectancy.

“Many people think it’s too late to quit smoking, especially in middle age,” said Jha. “But these results counter that line of thought. It’s never too late, the impact is fast and you can reduce risk across major diseases, meaning a longer and better quality of life.”

The findings suggest that quitting smoking reduces the risk of dying from vascular disease and cancer, in particular. Former smokers also reduced their risk of death from respiratory disease, but slightly less so, likely due to residual lung damage.

Reference: DOI: 10.1056/EVIDoa2300272