A large study led by researchers at the University of Toronto shows a clear message: quitting smoking before hitting age 40 can align life expectancy with that of people who never smoked. The findings, reported in NEJM Evidence, come from an extensive observational analysis spanning four countries and millions of adults, underscoring how early cessation translates into meaningful longevity benefits for people in Canada, the United States, the UK, and beyond.
The study pooled data from about 1.5 million adults, including long-term smokers and those who had never smoked. Participants were monitored for health status over a period that revealed stark differences in risk. Specifically, smokers between 40 and 79 faced nearly three times the likelihood of dying from any cause compared with non-smokers. The analysis further estimated that the average lifespan of ongoing smokers was shortened by roughly 12 to 13 years. The message is loud and direct: smoking takes years off life, and those years are not guaranteed to return without change.
After following the same cohort for about 15 years, researchers observed a meaningful shift in risk patterns among individuals who quit. The data showed that the overall risk of death from various causes dropped by about 1.3 times for quitters, compared with those who continued smoking. Put simply, stopping smoking at any age contributes to longer survival, a claim that holds across diverse populations and health profiles. The practical takeaway is that cessation yields benefits that accumulate over time, reinforcing the value of quitting as a public health priority.
Crucially, the investigation found that people who quit before age 40 reach a life expectancy that matches that of non-smokers. The benefits of quitting appear relatively quickly, with a notable portion of lost life years regaining earlier than many expect. In fact, staying smoke-free for around three years can recoup roughly half of the estimated lifetime loss associated with prior tobacco use. This rapid improvement highlights how dynamic health advantages can be when cessation takes place early in adulthood, and it offers a hopeful message for individuals weighing quitting as a serious lifestyle choice.
Beyond the main findings, the research team also touches on broader questions about vaping and its risks relative to traditional smoking. While the study centers on cigarette smoking and quitting, it invites readers to consider how new nicotine delivery methods may influence health outcomes in the long term. These questions are essential for individuals and policymakers seeking clearer guidance on the comparative dangers of vaping versus smoking, and they frame ongoing discussions about harm reduction and public health strategies.