Background Although the smoking rate among Japanese men has been the highest in developed countries, the epidemiological evidence about whether smoking cessation can extend their lifespan is not well established.

Methods A total of 1083 Japanese men aged ≥40 years were classified by their smoking status and followed up prospectively for 18 years (1988–2006).

Results Current smoking was a significant risk factor for all-cause death: the multivariate-adjusted HRs of all-cause death for current smokers of 1–19, 20–39 and ≥40 cigarettes per day were 1.61 (95% CI 1.16 to 2.22), 1.56 (95% CI 1.08 to 2.23) and 3.15 (95% CI 1.59 to 6.24), respectively. Former smokers did not have an increased risk of all-cause death compared with never smokers. The excess risk of all-cause death for current smokers tended to decrease within 5 years after smoking cessation, eventually reaching a level almost equivalent to that of never smokers. The risk of cancer death decreased by 53% in subjects who had quit smoking for ≥10 years, while the risk of cardiovascular death decreased by 56% in subjects with the cessation period of <10 years.

Conclusions Our findings suggest that even a modest smoking habit significantly increases the risk of death among Japanese men, and the risk of death diminishes soon after cessation of smoking. These results imply the importance of smoking cessation to extend life in Japanese men.