| Audrain-McGovern et al,7 2018 |
Age, sex, race/ethnicity, parental education, family history of combustible cigarette and drug use, peer combustible cigarette and marijuana use, Temperament and Character Inventory impulsivity subscale, and Center for Epidemiologic Studies Depression Scale |
3 |
1 |
2 |
6 |
3.67 (2.51-5.36) |
| Azagba,32 2018 |
Sex, grade level, socioeconomic status, living area, and region of residence |
2 |
1 |
0 |
3 |
7.05 (4.95-10.03) |
| Bluestein,33 2017 |
Sex, race, education level, household income, and the total number of tobacco products used |
3 |
2 |
0 |
5 |
1.91 (1.13-3.22) |
| Camenga et al,34 2014 |
Sex, grade, and race |
2 |
1 |
0 |
3 |
29.14 (9.54-88.92) |
| Cohn et al,35 2015 |
Age, sex, race/ethnicity, and educational attainment |
2 |
1 |
0 |
3 |
3.30 (1.61-6.73) |
| Conway et al,36 2018 |
Age, sex, race/ethnicity, lifetime mental health (internalizing and externalizing) symptoms, and sensation seeking |
3 |
1 |
0 |
4 |
9.70 (8.31-11.31) |
| Curran et al,5 2018 |
Age, sex, and race/ethnicity |
2 |
2 |
0 |
4 |
6.90 (5.55-8.57) |
| Dai et al,6 2018 |
Sensation seeking, ever use of cigarettes, drinking, nonmedical use of prescription drugs and other illicit drugs, and demographic characteristics (sex, race and/or ethnicity, grade performance, parental education, and region) |
4 |
2 |
2 |
8 |
1.90 (1.42-2.53) |
| Dautzenberg et al,37 2015 |
Age, smoking status of best friend, smoking status of sibling, ever smoked a cigarette, ever smoked shisha, smoking status, private school vs public, and parental message of prohibition |
2 |
2 |
0 |
4 |
1.90 (1.32-2.72) |
| Dunbar et al,23 2017 |
Age, sex, mother's education level, nuclear family status, intervention group, and smokeless tobacco use |
2 |
2 |
0 |
4 |
6.95 (5.36-9.01) |
| Fotiou et al,38 2015 |
Sex, life satisfaction, cigarette smoking, cannabis use, and presence of peers who smoke tobacco |
2 |
2 |
0 |
4 |
2.20 (1.37-3.53) |
| Kong et al,39 2017 |
Age, sex, ethnicity, family structure, highest degree of mother and father, substance use, antisocial behaviors, stress coping scale, and school clustering |
2 |
2 |
0 |
4 |
0.98 (0.24-3.26) |
| Kristjansson et al,40 2017 |
Age, sex, family structure, race, and each parent education |
2 |
2 |
0 |
4 |
3.85 (2.54-5.84) |
| McCabe et al,31 2017 |
Age, sex, race/ethnicity, parental education, college plans, urbanicity, and geographical region |
2 |
1 |
0 |
3 |
4.97 (4.09-6.04) |
| Milicic and Leatherdale,41 2017 |
Sex and school clustering |
2 |
2 |
0 |
4 |
5.55 (4.96-6.20) |
| Saddleson et al,42 2015 |
Age, sex, race/ethnicity, institution, tobacco smoking, school ability, other tobacco use in the past 30 d, and beliefs about e-cigarette harm |
1 |
2 |
0 |
3 |
2.37 (1.69-3.32) |
| Sutfin et al,43 2013 |
Sex, sensation seeking, current binge drinking, current marijuana use, lifetime illegal drug use, and e-cigarette harm perception |
1 |
2 |
0 |
3 |
0.94 (0.64-1.38) |
| Tavolacci et al,44 2016 |
Age, university, student job holder, study grant holder, curriculum, and academic year |
1 |
2 |
0 |
3 |
2.44 (1.70 -3.51) |
| Unger et al,45 2016 |
Age, sex, and other substance abuse |
3 |
2 |
2 |
7 |
1.97 (1.01-3.85) |
| White et al,46 2015 |
Age, sex, school deprivation, income/allowance, smoking status, parental smoking behavior, close friends’ smoking behavior, use of tobacco products other than cigarettes (eg, chewing tobacco and cigars) in the past 30 d, ever use of marijuana, and ever engagement in binge drinking |
2 |
2 |
0 |
4 |
2.24 (1.46-3.43) |
| Williams and White,47 2018 |
Age, sex, socioeconomic status, school level clustering, and education sector |
2 |
2 |
0 |
4 |
9.00 (1.72-13.89) |
