Table 3.
Changes in PSECDI Over Time by E-Cigarette Use Behaviors
| Baseline/follow-up | PSECDI |
p-valueb | |||
|---|---|---|---|---|---|
| Baseline, mean (SD) | Follow-up, mean (SD) | p-valuea | Pearson correlation coefficient | ||
| Exclusive e-cigarette users (n=402) | |||||
| Exclusive e-cigarette users (n=355) | 8.6 (3.4) | 8.3 (3.7) | 0.25 | 0.52 | <0.0001 |
| Poly users: e-cigarette and other nicotine (n=5) | 7.6 (3.0) | 6.4 (4.0) | 0.46 | 0.60 | 0.28 |
| Poly users: e-cigarette and other tobacco (n=37) | 7.4 (3.1) | 8.0 (3.4) | 0.39 | 0.33 | 0.045 |
| Ex–e-cigarette users (n=5) | 5.2 (4.2) | 5.4 (4.5) | 0.81 | 0.92 | 0.03 |
| Poly users (e-cigarette and other nicotine products) (n=17) | |||||
| Exclusive e-cigarette users (n=12) | 8.2 (4.0) | 8.8 (4.4) | 0.43 | 0.83 | 0.0008 |
| Poly users: e-cigarette and other nicotine (n=4) | 9.5 (4.2) | 8.8 (6.3) | 0.76 | NA | NA |
| Poly users: e-cigarette and other tobacco (n=1) | 14.0 | 11.0 | NA | NA | NA |
| Ex–e-cigarette users (n=0) | — | — | — | — | — |
| Poly users (e-cigarette and other tobacco products) (n=71) | |||||
| Exclusive e-cigarette users (n=43) | 8.3 (3.6) | 8.5 (3.7) | 0.82 | 0.36 | 0.02 |
| Poly users: e-cigarette and other nicotine (n=5) | 10.8 (5.9) | 8.4 (5.9) | 0.40 | 0.53 | 0.36 |
| Poly users: e-cigarette and other tobacco (n=20) | 7.5 (4.8) | 7.7 (4.8) | 0.86 | 0.14 | 0.56 |
| Ex–e-cigarette users (n=3) | 7.3 (4.7) | 12.0 (7.1) | 0.06 | NA | NA |
| Ex-e-cigarette users (n=4) | |||||
| Exclusive e-cigarette users (n=2) | 9.0 (0) | 6.0 (2.8) | 0.37 | NA | NA |
| Poly users: e-cigarette and other tobacco (n=1) | 5.0 | 10.0 | NA | NA | NA |
| Ex-e-cigarette users (n=1) | 4.0 | 0 | NA | NA | NA |
| Total study subjects (n=494) | 8.4 (3.5) | 8.3 (3.9) | 0.49 | 0.49 | <0.0001 |
Note: The PSECDI was calculated according to the individuals’ responses to 10 e-cigarette-related dependence questions. Boldface indicates statistical significance (p<0.05).
a
Paired t-test p-values were used to examine changes in the mean PSECDI between baseline and follow-up.
b
Pearson correlation coefficient p-values were used to assess the correlation between the baseline PSECDI and the follow-up PSECDI. Pearson correlation coefficients were not calculated for cells with <5 subjects.
NA, not applicable; PSECDI, Penn State Electronic Cigarette Dependence Index.