Probability of smoking onset (ever use) at T2 among T1 never-smokers as a function of level of e-cigarette use at T1, with ORs and 95% CIs
| Level of T1 e-cigarette use | Probability of (T2 smoker) (%) | OR | CI | p Value |
|---|---|---|---|---|
| Never | 5 | 1.00 | ||
| 1–2 times | 14 | 2.88 | 1.96 to 4.22 | <0.0001 |
| 3–4 times | 11 | 2.29 | 1.35 to 3.87 | 0.002 |
| Yearly/monthly | 19 | 4.17 | 2.03 to 8.57 | 0.0001 |
| Weekly/daily | 19 | 4.09 | 2.43 to 6.88 | <0.0001 |
Analysis conducted for T1 never-smokers, analytic N=1070. Criterion variable is never smoked versus ever smoked at T2. Cells for the highest levels of use are collapsed to avoid small cell sizes. Results are adjusted for demographics, parenting and personality variables, and for clustering within school.