Smoking cessation improves mortality in Japanese men: the Hisayama study.

Plain-language summary

This study set out to see if quitting smoking helps Japanese men live longer, given that Japan has had high smoking rates among men. Researchers followed 1,083 Japanese men aged 40 and older for 18 years, tracking their smoking habits and deaths. They found that current smokers had a higher risk of death, with heavier smokers facing the greatest risk, while former smokers saw their risk drop to nearly that of never smokers. The benefits of quitting appeared within 5 years, with cancer death risk falling by half after 10 years smoke-free and heart-related deaths dropping by more than half even sooner.

Key findings

• Current smoking increased the risk of all-cause death, with heavier smoking (≥40 cigarettes/day) tripling the risk.
• Former smokers had no increased risk of death compared to never smokers.
• The excess risk of death for current smokers decreased within 5 years after quitting.
• Quitting for ≥10 years cut cancer death risk by 53%, and quitting for <10 years reduced cardiovascular death risk by 56%.