CIGARETTE smoking increased cardiovascular risks at 2–5 cigarettes daily; cessation rapidly lowered risk within ten years, overall.
In a pooled analysis of 22 prospective cohorts, investigators modeled how smoking status, cigarettes per day, pack-years, and years since cessation related to nine long-term cardiovascular and mortality outcomes. The study included 323,826 adults and used Cox proportional hazards models adjusted for demographic, socioeconomic, and cardiovascular risk factors. Median follow-up was roughly 14 to 19 years across endpoints, with substantial event counts for myocardial infarction, coronary heart disease, cardiovascular disease, and mortality outcomes.
Compared with never-smokers, current smoking was associated with higher risk of cardiovascular disease in both men (hazard ratio 1.74) and women (hazard ratio 2.07). All-cause mortality risk was also higher in men (hazard ratio 2.17) and women (hazard ratio 2.43). Notably, low-intensity cigarette smoking still carried measurable risk. Participants reporting 2 to 5 cigarettes per day had elevated hazards across outcomes, ranging from 1.26 for atrial fibrillation to 1.57 for heart failure, and showed higher cardiovascular disease mortality (hazard ratio 1.57) and all-cause mortality (hazard ratio 1.60) versus never-smokers.
Smoking Cessation Duration and Risk Reduction
When exposure was modeled continuously, the smoking-outcome curves rose steeply early, with sharper increases across the first 20 pack-years and first 20 cigarettes per day than with additional exposure beyond those levels. In parallel, smoking cessation duration showed the largest relative risk reductions within the first 10 years after quitting across outcomes, followed by continued improvements over longer time horizons. By 20 years after cessation, former smokers demonstrated over 80% lower relative risk than current smokers.
Clinical Takeaway for Counseling
These findings support a clear counseling priority: for current smokers, early and complete smoking cessation is likely to yield the greatest cardiovascular and mortality risk reductions, rather than focusing solely on cutting down cigarettes per day.
Key limitations included reliance on a single baseline, self-reported smoking measure over long follow-up, which could underestimate true associations, and lack of data on other tobacco products and electronic nicotine delivery systems.
Reference: Tasdighi E 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 Med. 2025;22(11):e1004561.
