In this pooled analysis of four national cohorts in the US, UK, Canada and Norway (total of about 1.5 million adults followed for 15 years, in whom about 123,000 deaths occurred), current smokers had significantly higher death risks compared with never smokers (2.8-fold higher for women, 2.7-fold higher for men). Survival between 40 and 79 years of age was 12 and 13 years less in women and men, respectively, who smoked compared with never smokers.
Former smokers showed lower death risks (1.3-fold in both sexes). Cessation at every age was associated with longer survival. Long-term quitters (10 or more years) had survival close to never smokers. Importantly, the benefits of quitting were evident as early as 3 years after cessation.
The results demonstrating the large and rapid benefits of quitting are relevant not only to the 60 million current smokers in these four countries, but to the 1 billion smokers worldwide.