Circulation published an article from Sweden on the profound effect of cessation of smokeless tobacco on post-MI mortality (see DOI: 10.1161/CIRCULATIONAHA.113.007252). they assessed all patients who were <75 years old and admitted to CCUs for MI between 2005-9 (the database included the vast majority of Swedish hospitals). They followed patients for 2.1 years post-MI to assess the relative difference in mortality in the 675 who quit snus (their form of oral snuff) vs 1799 who continued using.
Results:
–83 people died in the 2.1 years of follow-up
–Mortality rate in those who quit snus was 9.7/1000 person-years; Mortality rate in those who continued snus was 18.7/1000 person-years
–Adjusted for age and gender, the mortality rate HR was 0.51 (0.29-0.91) for quitters; In multivariable-adjusted model, the HR was 0.57 (0.32-1.02)
–these results were remarkably similar to those who quit smoking, with HR 0.54 (0.42-0.69)
Sweden has the highest prevalence of snuff use, though the overall snuff market is highest in the US (1.7 billion cans/yr, and growing at 5%/yr). Nicotine levels in Swedish snuff is similar to US (though, they do pasteurize it and lower the carcinogenic nitrosamines). Snuff (and snus) is associated with endothelial dysfunction, and increased blood pressure, heart rate and adrenaline, and perhaps increased risk of heart failure. Animal studies suggest an increase in ventricular arrhythmias post-MI.
There are caveats to the study:
–All patients were recruited 2 months post-MI (ie, we do not have data on nonsurvivors, though prior data suggest that snus users have a higher MI mortality)
–Many patients used both snus and smoked (though above controlled mathematically for smoking status, but the actual % of patients who never smoked but used snus was small)
–This was not an intervention study but a prospective observational one
–Those who continued to use snus were less likely to participate in a cardiac rehab program.
Nonetheless, this study highlights the potential cardiotoxicity and mortality associated with smokeless tobacco and the potential to halve the risk of subsequent mortality through cessation and reinforces the importance for us to be as aggressive in helping patients quit smokeless tobacco as we are with smokers.
Geoff