Messages matter: The Tobacco Products Directive nicotine addiction health warning versus an alternative relative risk message on smokers' willingness to use and purchase an electronic cigarette.

Introduction: Many countries have now mandated warning labels on e-cigarette products. One example, the EU TPD health warning states, "This product contains nicotine which is a highly addictive substance. [It is not recommended for use by non-smokers]". The impact of the EU TPD warning message on intentions to use, has not been explored within an EU population.

Aims: Examine the effect of i) the TPD e-cigarette health warning and ii) an alternative relative risk message, on smokers' willingness to use, likelihood of purchase, and intention to use as a quit aid.

Methods: Cross-sectional online study. Ninety-five smokers (55 males; 18-55 years old) were randomly allocated to one of three conditions and viewed ten individually presented e-cigarettes images with either no message, TPD message, or relative risk message. Participants rated i) willingness to use, and likelihood of: ii) purchase, iii) using in the next month, and iv) using in a quit attempt, before and after viewing the images.

Results: For willingness to use and likelihood of purchase, ANCOVAs showed a significant main effect of Message Type ( p s, <.05); ratings were lower in the TPD condition. Message type, however did not significantly change likelihood of using in the next month or using in a quit attempt.

Conclusions: Preliminary findings suggest that the TPD e-cigarette health warning may reduce smokers' willingness to use and likelihood of purchasing an e-cigarette. Messages conveying reduced harm or indeed, no message at all, may be more effective in encouraging smokers to switch to these lower risk products.