Health warning labels describing snus as less harmful than smoking: effects on perceptions of risk

Using snus (Swedish moist snuff) is less harmful than smoking, but health warning labels (HWLs) on snus products do not reflect this relation. There are few studies on the effects of comparative risk information in snus warning labels. The purpose of this experiment is to examine whether risk perceptions differ after exposure to non-comparative vs. comparative risk information in snus warning labels.

A total of 254 Norwegians aged 19-69 were exposed to pictures of snus packages in one of four HWL conditions: non-comparative EU-based ("Snus is damaging to your health"), control (the text "Snus" only), general comparative risk ("Snus is less damaging to your health than smoking"), or percentage comparative risk ("Snus is 90% less damaging to your health than smoking"). Perceptions of risk from snus use and smoking were measured before (pre) and during (post) exposure to the HWL. Changes from pre to post in (1) perceptions of risk from snus use and (2) perceptions of risk differences from snus use versus smoking were tested in repeated measures ANOVAs with current snus and cigarette use as covariates.

Both the perceived risks from snus use and its perceived risk difference to smoking decreased more in the control and the percentage HWL conditions than in the EU-based HWL condition. When comparing the general comparative risk and the EU-based HWL, a similar difference was found for the perceived risk difference, but not for the separate measure of snus risk. Both the snus risk and risk difference perception decreased more for the percentage than for the general relative risk HWL.

The non-comparative EU-based HWL claiming that "Snus is health damaging" maintains a high level of perceived risk from snus use, while no HWL and the suggested comparative HWLs adjust perceptions of risk in the direction of lower harm from snus use. An HWL describing snus as 90% less harmful than smoking was more effective than a general claim.