Abstract: Income and Normative Influence on E-cigarette Use among Smokers, Former Smokers, and Non-Smokers: A Multilevel Modeling Perspective

◆ Junhan Chen, University of Maryland
◆ Yuan Wang, University of Maryland

Objectives of this study:
Vaping is becoming an emerging risk that threatens individuals’ health. However, we still have a limited understanding of why people use e-cigarettes, and who are more likely to use e-cigarettes. In addition, it is important to consider both individual-level and community-level risk factors in order to inform interventions on risky health behaviors (Thrul, Lipperman-Kreda, Grube, & Friend. 2014), which did not get enough attention in health communication literature. Therefore, based on a multilevel modeling approach, this study explored both individual-level factors (i.e., income and perceived harmfulness of e-cigarettes) and community-level factors (i.e., collective norms) in predicting individuals’ possibility of vaping. Besides, from a multivariate perspective, this study explored whether the underlying factors predicting vaping differ based on individuals’ smoking status of traditional cigarettes (i.e., smokers, former smokers, non-smokers).

Research questions:
RQ1: How does income affect e-cigarette usage?
RQ2: How does the effect of income on e-cigarette usage vary across areas with different social norms against e-cigarette use?
RQ3: How do the above relationships different for current smokers, former smokers, and non-smokers?

Data from the 2018 Health information National Trends Survey (HINTS) second cycle were employed in the current study. In total, 3504 participants were recruited, including 12.8% smokers, 24.7% former smokers, and 60.8% non-smokers.

Logistic multilevel regression (i.e., a random intercept random slope model) was used to analyze the data. Income was entered as an individual-level predictor (level1). Collective norm was entered as the cluster-level factor (level2) which predicted the intercept of the model and the slope of income. Perceived harmfulness of e-cigarettes, age, gender, and race were controlled. The result showed that income, collective norm, and their interactions were not significant predictors for smokers and non-smokers. However, for former smokers, higher income was associated with a lower probability of ever using e-cigarettes. And stronger collective norm (i.e., people think that e-cig is more harmful than traditional cigarettes) was associated with a lower probability of ever using e-cigarettes. The interaction between collective norm and income was significant (β = 2.86, p<0.05) such that as collective norm increases, the negative relationship between income and e-cigarette usage attenuated.

This study suggested that Individual income and the area-level social norms against e-cigarette use can significantly influence former smokers’ e-cigarettes usage, but the effect does not hold for non-smokers and current smokers. For former smokers, as social norm increases (i.e., the higher perceived harmfulness of e-cigarettes at the community level), the positive effect of income on e-cigarette use becomes larger.