Quitting Smoking Earlier Went With Living Longer

CATEGORY: DISEASE PREVENTION

People who had quit smoking 10 or more years earlier lived about as long as those who never smoked, regaining roughly 10 of the 12 to 13 years of life that continued smoking was linked to losing.¹ The figures come from 1.48 million adults across four countries, published in NEJM Evidence. The differences showed up fast. Quitting was associated with measurably lower death rates within three years.

122,697 Deaths, Counted by National Registries

Four large national health studies were pooled: the United States, the United Kingdom, Norway and Canada, covering 1.48 million adults aged 20 to 79. Each study was linked to its country’s death registry, the official government record of every death, so participants could be followed for 15 years with no death missed. There were 122,697 of them. Death rates were then compared across current smokers, never smokers and former smokers, the former smokers sorted by time since quitting: under 3 years, 3 to 9, or 10 or more. The comparisons were adjusted for age, education, alcohol use and obesity.

Twelve Fewer Years for Women, Thirteen for Men

Current smokers were close to three times as likely as never smokers to die during follow-up, 2.8 times as likely for women and 2.7 times for men. Averaged over the group, that worked out to 12 fewer years of life for women and 13 for men between the ages of 40 and 79, with the excess deaths driven mostly by heart and blood-vessel disease, lung disease and cancer.¹ That average blends two very different fates. It combines about 24 to 26 years of life lost by the smokers who died from smoking with no loss at all for those who did not.¹

Under 40, Nearly All the Extra Risk Was Gone

Former smokers as a whole were 1.3 times as likely to die as never smokers, down from nearly threefold. Time since quitting mattered most. Quitting within the previous 3 years was associated with averting about 5 of the lost years of life; 10 or more smoke-free years with averting about 10, which is survival close to that of people who never smoked. Age at quitting mattered too. Among people under 40 who had quit within the previous 3 years, 95% of the extra death risk in women and 90% in men had already disappeared. Even at ages 50 to 59, more than half of it was gone within that same short window. Quitting at every age studied was associated with longer survival.¹

Group Averages, Not Personal Forecasts

This was observational work. It tracked what people did rather than assigning anyone to quit. Proven cause and effect is beyond what that design can deliver. People who quit may also differ from those who keep smoking in ways the adjustments cannot reach. The size of the study, the matching pattern across four countries and the steady gradient still point one way: the longer since quitting, the closer to never-smoker survival. These are group averages. No individual is promised them.

Other large studies land nearby. Among more than 200,000 U.S. adults, those who quit between ages 25 and 34 lived about 10 years longer on average than those who kept smoking.² A 2025 pooling of 22 cohorts adds a qualification: even 21 to 30 years after quitting, former smokers still carried a 4% higher risk of death from heart and blood-vessel disease than never smokers.³

Key Takeaways

• Across 1.48 million adults followed for 15 years, smoking was linked to 12 to 13 fewer years of life between ages 40 and 79, while quitting for 10 or more years was linked to survival close to that of never smokers.¹
• Benefits appeared early. Death rates were measurably lower within 3 years, and quitting within the previous 3 years was linked to averting about 5 years of the projected loss.
• Quitting before age 40 was linked to avoiding nearly all of smoking’s excess death risk, and every age group that quit showed longer survival than those who continued.

References

1. Cho ER, Brill IK, Gram IT, Brown PE, Jha P. Smoking Cessation and Short- and Longer-Term Mortality. NEJM Evidence. 2024;3(3):EVIDoa2300272. link
2. Jha P, Ramasundarahettige C, Landsman V, et al. 21st-century hazards of smoking and benefits of cessation in the United States. The New England Journal of Medicine. 2013;368(4):341–350. link.
3. Tasdighi E, Yao Z, Dardari ZA, et al. Association between cigarette smoking status, intensity, and cessation duration with long-term incidence of nine cardiovascular and mortality outcomes: the Cross-Cohort Collaboration (CCC). PLOS Medicine. 2025;22(11):e1004561. link.