TABLE 2.
E-cigarette Use and Risk of Subsequent Smoking Among Baseline Never Smokers
| E-cigarette Use (Baseline) | Cigarette Use (Follow-up) | |||
|---|---|---|---|---|
| Never | Experimentationa | Infrequentb | Frequentc | |
| Total, N (%) | 4575 (90.8) | 315 (6.2) | 96 (1.9) | 55 (1.1) |
| Never | 3891 (93.3) | 184 (4.4) | 60 (1.4) | 36 (0.9) |
| Ever | 673 (78.5) | 129 (15.1) | 36 (4.2) | 19 (2.2) |
| Versus never use, adjusted OR (95% CI)d | Reference | 4.57 (3.56–5.87) | 4.27 (2.75–6.62) | 3.51 (1.97–6.24) |
| Versus previous use, adjusted OR (95% CI)e | — | Reference | 0.98 (0.60–1.60) | 0.76 (0.41–1.42) |
—, not applicable.
a
Experimentation is initiation between baseline and follow-up but no use in the past 30 days.
b
Infrequent use is initiation and use on 1–2 of the past 30 days.
c
Frequent use is initiation and use on 3–5 or more of the past 30 days.
d
Adjusted for sex, race and/or ethnicity, grade, and study; restricted to never cigarette users at baseline with a random effect for school.
e
Additionally restricted to ever cigarette initiators.