Overview
- Researchers report that low-intensity smoking of two to five cigarettes per day is linked to about a 50% higher risk of heart failure and roughly a 60% higher risk of death compared with never-smokers.
- Even those who smoke one or fewer cigarettes per day face elevated risks for most cardiovascular outcomes compared with never-smokers, with the exception of stroke and atrial fibrillation.
- Risk rises with cumulative exposure, increasing 2.4% to 4.6% for every 10 pack-years, with a high-risk threshold around five pack-years and the steepest increases occurring early in exposure.
- Quitting delivers the largest cardiovascular risk drop within the first decade and continues to confer benefits for decades, with former smokers after 20 years having roughly an 80% lower risk than current smokers yet remaining above never-smoker levels.
- The findings draw on 22 cohorts tracking about 323,826 adults over roughly 25 million person-years, though smoking was self-reported at baseline and use of other tobacco products or e-cigarettes was not fully captured.