Table 2.
Relationships between e-cigarette use at baseline (aged 13–14 years) and smoking cigarettes or any combustible tobacco 24 months later (aged 15–16 years) among those who were never smokers at baseline (n=3994)
| Smoking at age 15–16 years | Baseline e-cigarette use | |||
| Never | Tried | Infrequent | Frequent | |
| (1–2 times) | (1/month–1/week) | (>1/week) | ||
| n (%) | n (%) | n (%) | n (%) | |
| Cigarette smoking | ||||
| Never | 2743 (68.7) | 405 (10.1) | 30 (0.8) | 2 (0.1) |
| Once | 285 (7.2) | 147 (3.7) | 11 (0.3) | 1 (0.0) |
| Used to smoke | 89 (2.2) | 63 (1.6) | 8 (0.2) | 5 (0.1) |
| Rarely (<1/week) | 72 (1.8) | 44 (1.1) | 5 (0.1) | 1 (0.0) |
| Occasional (1–6/week) | 21 (0.5) | 18 (0.5) | 1 (0.0) | 0 (0.0) |
| Frequent (>6/week) | 25 (0.6) | 12 (0.3) | 6 (0.2) | 0 (0.0) |
| Any recent tobacco smoking | ||||
| None | 3010 (75.4) | 556 (13.9) | 37 (0.9) | 4 (0.1) |
| One or more days | 226 (5.7) | 133 (3.3) | 23 (0.6) | 5 (0.1) |