۱- Introduction

۲- Materials and methods

۳- Results

۴- Discussion

References

Abstract

Family history of tobacco use and use of e-cigarettes have both been associated with increased tobacco use among young adults. However, to our knowledge, these variables have not been considered simultaneously. This study was designed to evaluate the hypothesis that family history of tobacco use would predict tobacco product use over time among young adult e-cigarette users with limited combustible tobacco use experience. A sample of 124 participants were recruited online from across the United States, completed five surveys over 12 months, and reported use of nicotine and tobacco products over the previous two weeks at each survey. Family history of nicotine and tobacco use was reported at the 6-month assessment, and data were collected in 2017 and 2018. Regression models indicated that family history was associated with likelihood of cigarette use (odds ratio = 1.02 [95% confidence interval = [1.00, 1.04]). Significant interactions between family history and linear (OR = 1.05 [1.01, 1.10]) and quadratic (OR = 0.99 (0.98, 1.00)] time terms indicated that the association between family history and likelihood of combustible product use shifted over time. In both cases, more extensive family histories predicted greater use frequency, and follow-up analyses showed that more extensive family history was associated with greater combustible tobacco product use 3, 6, and 9 months following baseline. Family history of nicotine/tobacco use may promote initiation of tobacco use among e-cigarette users. These results suggest family history of tobacco use may comprise a risk factor for combustible tobacco use within the evolving tobacco product landscape.

Introduction

Recent research has indicated that e-cigarette use is becoming increasingly common among young adults (Ramo et al., 2015). Although long-term health consequences of using e-cigarettes remain uncertain, some studies suggest that using e-cigarettes is associated with respiratory disorders and exposure to chemicals that can promote respiratory disease (Farsalinos et al., 2015; Wills et al., 2019). Although some data characterize e-cigarettes as a healthier alternative to tobacco cigarettes (Choi and Forster, 2013; Sutfin et al., 2013), other findings suggest that e-cigarette use could promote tobacco use, especially within younger populations (Leventhal et al., 2015; Primack et al., 2015). Research has also shown that individuals with a family history of smoking tobacco cigarettes are more likely to smoke cigarettes themselves (Peterson et al., 2006). However, little is known about whether family history of nicotine and tobacco product use is associated with subsequent combustible tobacco use among young adults. It is possible that e-cigarette use and family history of combustible tobacco use might work synergistically to promote transitions to use of combustible tobacco products. This analysis was intended to evaluate the hypothesis of an association between family history of using nicotine/tobacco products and transitions to use of combustible tobacco products among young adult e-cigarette users. More specifically, we expected that participants with more family members with histories of nicotine/tobacco use would be more likely to begin using cigarettes and other combustible tobacco products.