Researchers from the American Heart Association’s Tobacco Regulation and Addiction Center have published a study in PLOS Medicine, revealing that smoking just two to five cigarettes daily can double the risk of heart disease and increase the risk of death by 60%. The study, which analyzed data from over 320,000 adults participating in 22 long-term health studies, challenges the common belief that smoking in smaller quantities is less harmful.
Cardiovascular damage from even low levels of smoking is significant, according to the study. Researchers divided participants into never smokers, current smokers, and former smokers, with a focus on measuring smoke exposure in ‘pack-years’ and cigarettes per day. The findings show that current smokers had more than double the risk of dying from any cause compared to never smokers. Notably, those who smoked two to five cigarettes a day had double the risk of developing heart disease.
Quitting smoking entirely is the only way to reverse the harmful effects, the study concludes. Former smokers saw a marked reduction in health risks within 10 years, and after 20 years, their risk levels were over 80% lower than current smokers. However, the full recovery of health may take up to 30 years. The authors emphasized that low-intensity smoking is not safer and that the primary recommendation for current smokers is to quit entirely rather than reduce their smoking habits.
Despite the findings, the study admitted a few limitations, including self-reported smoking habits which could lead to underreporting, particularly among women. Additionally, data on e-cigarettes and other tobacco products were not included in the analysis. The researchers stressed that the study’s main message is clear: the only safe level of smoking is not smoking at all.