Swedish researchers from several institutions document that snus use is not associated with atrial fibrillation (commonly known as AFib), the most common heart arrhythmia (irregular timing of the heart beat) and a risk factor for stroke (abstract here). The same group previously reported that snus use conferred no significant risk for heart attack (discussed here) and stroke (here).
Led by Maria-Pia Hergens, researchers analyzed data on Swedish men who were subjects in several studies. While snus users had no risks for Afib, smokers had a small but significantly elevated risk (Hazard ratio = 1.16, 95% confidence interval = 1.01-1.33).
Although smokeless tobacco cannot be proven to be absolutely safe, this study adds important evidence that any cardiovascular effect is very minor.
Given the number of institutions represented by its authors, the report is an important development for tobacco harm reduction. In contrast are the biased 1990s and 2000s studies from the Karolinska Institute. There, a small group of KI researchers had access to the construction workers’ cohort and refused to share the data. Instead, they manipulated the information to fabricate some health risks and amplify others in snus users, a fact which I documented in numerous blog posts (examples here, here, and here) and in letters to journal editors.