A new snus study from Sweden, the largest ever conducted, reports that snus use is not associated with heart attacks. Researchers crunched data for 130,361 men never smokers followed for a total of 2.3 million years in eight separate Swedish cohort studies.
Lead author Jenny Hansson, a research assistant at the Karolinska Institute in Stockholm (here), worked with 15 collaborators from the Institute, Sweden’s Umeå, Uppsala and Lund Universities, and the University of Milano-Bicocca in Italy. The study was published in the European Journal of Epidemiology (abstract here).
Compared with never users of tobacco, the hazard ratio (HR, similar to relative risk, adjusted for age and body mass index, BMI) for heart attack among current snus users was 1.03 (95% Confidence Interval = 0.92 – 1.15).
Hansson and colleagues also reported that HRs were not elevated with higher levels of snus consumption or longer duration. These are important findings, as they confirm that even a high consumption level (1 can per day) or a long history of snus use (20+ years) does not confer heart attack risk.
|Risk of Heart Attack Among Snus Users, According to Consumption Level and Duration|
|Group||Hazard Ratio (95% CI)|
|Non-Current Users (Referent)||1.00|
|Current Snus Users|
|< 4 cans per week||1.02 (0.90 – 1.16)|
|4-6 cans per week||0.94 (0.64 – 1.38)|
|7+ cans per week||1.17 (0.79 – 1.72)|
|< 20 years||0.96 (0.80 – 1.14)|
|20+ years||1.10 (0.95 – 1.27)|
The researchers also collected information on subjects who died within one year of a heart attack. They observed, “Current snus users had a higher probability of dying as compared to non-users (p < 0.05), and this excess occurred during the first 24 h[ours].” However, they did not provide any other information on this point (e.g. number of deaths), so it’s significance is unclear. In addition, they wrote, “The 28-day case fatality among snus users was 1.28 ([CI] = 0.99 – 1.68), adjusted for age and BMI, based on 97 cases.” This was not statistically significant, and the authors note that “…this relationship may be due to confounding by socioeconomic or life style factors.” Other than the 24-hour and 28-day points, there appears to be no difference in the death rate among snus users versus nonusers for the year following a heart attack.
Hansson and colleagues conclude: “These findings, based on the largest sample to date, do not support any relationship between use of snus and development of [heart attacks].”