Background:
It is important to know why individuals use electronic cigarettes (e-cigarettes) compared to tobacco cigarettes. This comparison provides policy makers with opportunities to target different types of users. This study examined behavioral determinants associated with both tobacco and e-cigarette use. Differences between non-users (neither e-cigarette users nor smokers), smokers, e-cigarette users, and dual users were assessed for tobacco use versus e-cigarette use among adults (>18 years).

Methods:
A cross-sectional survey (n=726) among 223 non-users, 287 smokers, and 216 e-cigarette users was conducted in the Netherlands. The questionnaire assessed demographics, tobacco and e-cigarette behavior, knowledge, attitudes, social ties, risk perception, intention, and deliberation.

Results:
Health benefits was the most frequently reported reason for e-cigarette use. Overall, 30.8% of the respondents were non-users, 39.5% smokers, 29.7% e-cigarette users, and 15.4% dual users. Ever use of e-cigarettes was 29.6 %. Of the ever users, 45.6 % used e-cigarettes daily, 20.9% weekly, and 10.7 % on a monthly basis. A low socio-economic status was associated with ever use of e-cigarettes, and older participants were less likely to have used e-cigarettes. Participants knew more about tobacco cigarettes than e-cigarettes. Furthermore, non-users perceived the social environment to be more negative towards e-cigarette and tobacco use. Additionally, non-users and smokers perceived e-cigarettes as more harmful than e-cigarette users. Smokers were significantly more likely to have an intention to start vaping compared to non-users. Finally, e-cigarette users made a deliberate choice to vape.

Conclusions:
Determinants of smoking and vaping behavior differ between non-users, smokers, e-cigarette users, and dual users. Using the determinants of behavior assessed, we are able to predict e-cigarette use among non-users and smokers. Policy makers could use these determinants, such as e-cigarette attractiveness, to specifically target dual users, smokers, e-cigarette users or non-users.