The study, led by Michael Blaha of Johns Hopkins, analyzes long-term data to clarify the dose–response relationship between smoking intensity and cardiovascular outcomes.

Public health context: U.S. adult smoking fell from about 42% in 1965 to ~12% in 2022, though there was a rise in people smoking fewer than 15 cigarettes per day.

A large-scale 20-year study of over 320,000 U.S. adults shows that smoking as few as 2–5 cigarettes daily more than doubles the risk of any cardiovascular disease and raises overall death risk by about 60% compared with never-smokers.

Risk remains elevated for former smokers, potentially for up to three decades after quitting, with the strongest risk reductions occurring in the first decade; time since quitting is a key factor in lowering risk.

Researchers emphasize that no level of smoking is risk-free, and even low-intensity smoking carries substantial cardiovascular and mortality risks, underscoring quitting as the most effective long-term strategy.

A disclaimer notes the information is educational and not medical advice, advising consultation with healthcare professionals for medical decisions.

Experts stress that quitting entirely is the best course of action; immediate risk reductions begin after cessation, and ongoing support and cessation therapies help those who struggle to quit.

Quitting at younger ages yields greater risk reductions than merely cutting back, reinforcing public health guidance to quit as early as possible.

The findings reinforce that quitting entirely is more beneficial than reducing cigarette use, highlighting the importance of smoking prevention, especially among youth.

Cutting back without stopping does not meaningfully reduce cardiovascular risk; the timing of cessation is crucial for maximizing benefits.

The study, funded by the American Heart Association’s Tobacco Center for Regulatory Science and published in PLOS Medicine, notes limitations including not assessing cancer causes of death, not accounting for changes in smoking over time, and lacking data on other tobacco products.

Broader context from WHO and CDC shows tobacco kills millions annually, with substantial health benefits from reducing or quitting smoking over time.