Smoking Cessation Benefits and Time-Course of Health Improvements

Immediate Benefits (Within Days to Weeks)

Blood carbon monoxide levels normalize within hours to days of cessation, according to the National Comprehensive Cancer Network 1
Respiratory symptoms improve rapidly, including reduction in cough and shortness of breath within the first few weeks, as reported by the National Comprehensive Cancer Network 1, 2
Lung function begins to improve measurably within the first weeks of cessation, as stated by the National Comprehensive Cancer Network 1

14 days of preoperative cessation reduces pulmonary complications and in-hospital mortality, as found by the National Comprehensive Cancer Network 2, 3
3 weeks of cessation before reconstructive surgery significantly lowers wound healing complications, according to the National Comprehensive Cancer Network 2
Risk-adjusted mortality and complication rates progressively decrease as cessation duration increases from 14 days to 1 month, to 1-12 months, and beyond 12 months, as reported by the National Comprehensive Cancer Network 2

Recent quitters demonstrate survival outcomes intermediate between never-smokers and current smokers, as found by the National Comprehensive Cancer Network 2, 3
Performance status improves at 6 and 12 months post-diagnosis compared to continued smokers, even after adjusting for disease stage, demographics, therapy, and comorbidity, according to the National Comprehensive Cancer Network 2, 3
Overall symptom burden decreases significantly by 6 months after cessation, as reported by the National Comprehensive Cancer Network 2, 5

1 year quit: Adjusted HR 1.04 (minimal benefit yet), as found by Chest 4
1-5 years quit: Adjusted HR 0.93 (7% risk reduction), according to Chest 4
5-10 years quit: Adjusted HR 0.84 (16% risk reduction), as reported by Chest 4
10+ years quit: Adjusted HR 0.65 (35% risk reduction, linear trend P < .001), according to Chest 4

Reduced recurrence rates compared to continued smokers, as found by the National Comprehensive Cancer Network 2, 3
Lower rates of second primary cancers in lung and head/neck cancer patients, according to the National Comprehensive Cancer Network 2, 3
Former smokers approach never-smoker risk levels for metastasis in colon cancer, as reported by the National Comprehensive Cancer Network 2, 3

Even quitting after a cancer diagnosis or in middle age provides substantial mortality and morbidity benefits, as stated by the National Comprehensive Cancer Network 1, 2
The benefit curve is continuous and progressive—there is no threshold effect, according to Chest 4
Stopping smoking after an MI is potentially the most effective of all preventive measures, with benefits that are almost immediate, as found by the European Heart Journal 6