Table 3 Study characteristics - adolescents
Study | Study design | Population | Follow-up and loss to follow-up | Definition: use neither product | Definition: exclusive ST user | Definition: exclusive smoker | Definition: dual use | How transitions calculated |
|---|---|---|---|---|---|---|---|---|
Tomar et al. (2003) | • The Teenage Attitudes and Practices Survey (TAPS-I and II), nationally representative cohort study, in 1988–1989 and 1993 | • n = 3,996 | • Four-year follow-up between 1989 and 1993 | Non-user = Not ST user + Not current smoker | ST user = self-identification as regular user of chewing tobacco or snuff | Current smoker = smoked ≥ 100 cigarettes in lifetime and smoked at least 1 day in 30 days preceding interview | Dual user = ST user + current smoker | percentages are weighted by survey weights |
• Young males | ||||||||
• Telephone interviews and self-administered questionnaires by mail (TAPS-I) or in-person contact (TAPS-II) | • Ages 11-19 | • 87.1% of baseline sample completed follow-up | adjusted odds ratios for other analyses (not presented here) | |||||
• Nationally representative | ||||||||
Severson et al. (2007) | • Cohort study conducted between 1994 and 1999 | • n = 2263 | • Two-year follow-up in 9th or 11th grade | Non-user = Non-smoker + Not ST user | ST user = any smokeless tobacco use in the past 30 days | Current smoker = WSI score is ≥ 1 | Dual user = ST user + cigarette smoker (only included at follow-up) | percentages are unadjusted |
• Young males | ||||||||
• Baseline survey completed once in 7th or 9th grade | • 7th and 9th-graders at baseline | Non-smoker = Has never smoked and Weekly Smoking Index (WSI) score is 0. WSI score averages answers to four questions about current smoking during past month | adjusted odds ratios for other analyses (not presented here) | |||||
• Evaluation of a randomized community intervention to prevent adolescent use | • Small rural communities in Oregon | |||||||
O’Hegarty et al. (2012) | • National Longitudinal Study of Adolescent Health (Add Health), a nationally representative school-based sample with Wave I conducted during the 1994–1995 school year | • n = 3284 | • Wave II conducted in 1996, approximately 1–2 years after Wave I (1994–1995) |  | ST user = reported using smokeless tobacco during the past 30 days | Current smoker = smoked on at least 1 of the past 30 days | Dual user = smoked on at least 1 of the past 30 days and used reported using smokeless during the past 30 days |  |
• Male and female | ||||||||
• Grades 7–11 when interviewed in Wave I | ||||||||
• Nationally representative sample |  |