Table 2.
Association of Baseline Tobacco Product Use With Ever Disposable E-Cigarette Use at Follow-up
| Ever disposable e-cigarette use at follow-up | |||||
|---|---|---|---|---|---|
| Prevalence, n (row %) | OR (95% CI)a | p | AOR (95% CI)b | p | |
| Overall sample (n = 1903) | 273 (14.3) | ||||
| Baseline regressorsc | |||||
| Rechargeable e-cigarette used | |||||
| Never (n = 1391) | 87 (6.3) | Reference | Reference | ||
| Former (n = 253) | 56 (22.1) | 4.3 (2.9–6.2) | <.001 | 3.1 (2.1–4.8) | <.001 |
| Current (n = 259) | 130 (50.2) | 15.1 (10.9–20.9) | <.001 | 11.9 (8.3–16.9) | <.001 |
| Combustible tobacco used,e | |||||
| Never (n = 1562) | 154 (9.9) | Reference | Reference | ||
| Former (n = 234) | 76 (32.5) | 4.4 (3.2–6.1) | <.001 | 2.3 (1.5–3.5) | <.001 |
| Current (n = 107) | 43 (40.2) | 6.1 (4.0–9.4) | <.001 | 1.9 (1.2–3.0) | .01 |
| Baseline combustible tobacco use regressors, stratified by baseline rechargeable e-cigarette use | |||||
| Never rechargeable e-cigarette users (n = 1391) | |||||
| Never combustible tobacco use (n = 1289) | 73 (5.7) | Reference | Reference | ||
| Former combustible tobacco use (n = 77) | 14 (18.2) | 3.7 (2.0–6.9) | <.0001 | 3.9 (2.1–7.5) | <.0001 |
| Current combustible tobacco usef (n = 25) | 0 (0) | N/A | N/A | N/A | N/A |
| Former rechargeable e-cigarette users (n = 253) | |||||
| Never combustible tobacco use (n = 138) | 24 (17.4) | Reference | Reference | ||
| Former combustible tobacco use (n = 77) | 27 (28.4) | 1.9 (1.0–3.6) | .0496 | 1.8 (0.950–3.49) | .07 |
| Current combustible tobacco use (n = 20) | 5 (25.0) | 1.6 (0.5–4.8) | .42 | 1.6 (0.5–5.2) | .47 |
| Current rechargeable e-cigarette users (n = 259) | |||||
| Never combustible tobacco use (n = 135) | 57 (42.2) | Reference | Reference | ||
| Former combustible tobacco use (n = 62) | 35 (56.5) | 1.8 (1.0–3.3) | .07 | 2.2 (1.1–4.4) | .02 |
| Current combustible tobacco use (n = 62) | 38 (61.3) | 2.2 (1.2–4.0) | .01 | 3.0 (1.5–6.0) | .003 |
Significant associations are depicted in bold. AOR = adjusted odds ratios, CI = confidence interval, N/A = not applicable, OR = odds ratio.
aUnadjusted univariable model.
bMultivariable models adjusted for all covariates listed in Table 1. Missing covariate data (Ns missing range: 0–81) were managed with multi-imputation using 20 multiply-imputed data sets.
cCombustible tobacco use and rechargeable tobacco entered as simultaneous regressors in multivariable model.
dFormer: ever use, but not use in the past 30 days. Current: used ≥1 day in the past 30 days.
eUse of cigarettes, big cigars, little cigars or cigarillos, or hookah water pipe.
fAmong baseline never rechargeable e-cigarette users, associations for baseline current tobacco use could not be calculated because no current baseline combustible tobacco/never rechargeable e-cigarette users became ever disposable users by follow-up.