In a groundbreaking study spanning decades and continents, researchers sought to unravel the mysteries surrounding smoking cessation and its impact on health outcomes.

For the study, investigators pooled data from four national cohorts across the United States, United Kingdom, Norway, and Canada, and tracked the health trajectories of 1.48 million adults between the ages of 20 to 79 from 1974 to 2018. By examining the hazard ratios of current, former, and never smokers, they aimed to understand how smoking cessation influences mortality rates from smoking-related illnesses.

They found that current smokers faced significantly higher hazard ratios for death compared to never smokers, with women and men both experiencing almost 3 times higher risks. Moreover, smokers lived, on average, 12 to 13 years less than their non-smokers.

They also found former smokers exhibited lower hazard ratios, indicating a reduction in mortality risk after quitting. Even short-term cessation, spanning fewer than 3 years, was associated with a remarkable decrease in excess mortality – up to 95% for women and 90% for men under 40 years of age.

The most striking results from the study was the transformative power of quitting early. Cessation before 40 years of age was linked to notably longer survival, with those who quit for 10 or more years experiencing life expectancies similar to never smokers.

Smoking is perhaps one of the single most easily modifiable factor in improving one’s health no matter what health ailments you are experiencing.

The study was published in NEJM Evidence.

ER Cho et al. Smoking cessation and short- and longer- term mortality. NEJM Evidence (2024). DOI: 10.1056/EVIDoa230027