Overview
- The study pooled 22 longitudinal cohorts with more than 320,000 adults followed for roughly two decades, documenting over 125,000 deaths and more than 54,000 cardiovascular events.
- A clear dose–response emerged, with the steepest risk jump at smoking initiation and a roughly 50–60% higher overall and cardiovascular mortality at just two to five cigarettes per day versus never smoking.
- Compared with never-smokers, current smokers showed markedly higher risks across outcomes, including heart attack, stroke, reduced heart pump function, and atrial fibrillation.
- Risk falls after quitting, with noticeable cardiovascular improvement within 3–5 years and many coronary and stroke risks approaching never-smoker levels by about 10 years.
- Authors note limits from baseline self-reported exposure and lack of updates on behavior changes, flag a possible higher relative risk for women, and public-health groups such as the American Heart Association reinforce that there is no safe level of tobacco use.