An extensive review of nearly two dozen long-term studies shows that people who smoke only a small number of cigarettes still face a much higher chance of heart disease and early death than those who have never smoked. This elevated risk remains for years after quitting. Michael Blaha of the Johns Hopkins Ciccarone Center for Prevention of Cardiovascular Disease, USA, and his team published the findings on November 18th in the open-access journal PLOS Medicine.
Previous research has already established that smoking raises the likelihood of cardiovascular disease, but the connection between smoking intensity and specific health consequences has been harder to clarify, particularly for light smokers. As more individuals smoke fewer cigarettes than in past decades, understanding both the risks tied to low-intensity smoking and the long-term benefits of quitting has become increasingly important, even for people who do not consider themselves heavy smokers.
Large Multi-Study Review Reveals Long-Term Damage
Blaha's group examined information from more than 300,000 adults who participated in 22 longitudinal studies (which follow individuals over extended periods) for as long as 19.9 years. During that time, more than 125,000 deaths and 54,000 cardiovascular events were recorded, including heart attacks, strokes and heart failure. The results showed that smoking only two to five cigarettes per day was linked to a 50 percent higher risk of heart failure and a 60 percent higher risk of death from any cause compared with people who had never smoked. The greatest reduction in cardiovascular risk occurred within the first 10 years after quitting and continued to improve the longer a person remained smoke-free. Even so, former smokers still had higher risk levels than lifelong non-smokers for as long as three decades after they quit.
Quitting Completely Offers the Strongest Protection
Because even occasional or low-level smoking can sharply increase the chance of heart disease and premature death, the researchers emphasize that stopping entirely at a younger age is the most effective way to reduce long-term harm. Simply cutting back on the number of cigarettes smoked each day does not provide the same protective benefits. These findings support long-standing public health recommendations that encourage early and complete cessation and highlight the need for robust smoking prevention efforts.
Researchers Stress the Impact of Early Cessation
The authors add, "This is one of the largest studies of cigarette smoking to date using the highest quality data in the cardiovascular epidemiology literature. It is remarkable how harmful smoking is -- even low doses of smoking confer large cardiovascular risks. As far as behavior change, it is imperative to quit smoking as early in life as possible, as the among of time passed since complete cessation from cigarettes is more important prolonged exposure to a lower quantity of cigarettes each day."