Quitting smoking at any age has big health benefits, fast: Unity Health Toronto study

Dr. Prabhat Jha

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According to a new study by researchers at Unity Health Toronto at the University of Toronto, people who quit smoking experience a significant increase in life expectancy after just a few years.

A study published in Evidence from the NEJM, shows that smokers who quit before age 40 live as long as those who never smoked. Those who quit smoking at any age return to a lifetime of never smoking 10 years after quitting, and about half of these gains occur within three years.

“Quitting smoking is ridiculously effective at reducing the risk of death, and people can reap those rewards quickly,” said Prabhat Jha, executive director of the T Dalla Lana School of Public Health and Temerthy School of Medicine. Unity Health is a global health research center in Toronto.

The observational study involved 1.5 million adults in four countries (the United States, Great Britain, Canada, and Norway) over 15 years. Smokers between the ages of 40 and 79 had nearly three times the risk of dying compared to never smokers, meaning they lost an average of 12 to 13 years of life.

Former smokers had a 1.3-fold (or 30 percent higher) risk of death compared to never-smokers. Quitting smoking at any age was associated with longer life, and even those who had quit smoking for less than three years increased their life expectancy by up to six years.

“A lot of people think it's too late to quit, especially in middle age,” Jha said. “But these results challenge that idea. It's never too late, the effect is fast and you can reduce the risk of major diseases, which means a longer and better quality of life.

Researchers have found that quitting smoking reduces the risk of dying from cardiovascular disease and cancer in particular. Former smokers also had a reduced risk of dying from respiratory disease, but slightly less from residual lung damage.

Currently, there are about 60 million smokers in the four countries that participated in the study, and there are more than a billion people worldwide. Global smoking rates have fallen by more than 25 percent since 1990, but tobacco is still the leading cause of preventable death.

Jha said the findings should accelerate efforts by governments to support people who want to quit smoking. “Helping smokers quit is one of the most effective ways to significantly improve their health. We know how to do this, by raising tobacco taxes and improving support for cessation.”

Canada is long overdue to increase the federal excise tax on cigarettes, and many other countries could reduce smoking rates by raising taxes, Jha said. Cessation support may include clinical guidelines and patient resources such as helplines, as well as a health system approach.

“When smokers interact with the health care system in any way, doctors and health professionals can encourage them to quit by showing them how well quitting works,” Jha said. “This can be done with concern and without judgment or stigma, recognizing that tobacco is designed to be highly addictive.”

The study was funded by the Canadian Institutes of Health Research.

By Jim Oldfield, University of Toronto Temerty Faculty of Medicine