Sample characteristics by baseline ever e-cigarette use status among baseline never smokers
| Outcome | Baseline e-cigarette use | Contrast by ever e-cigarette use P value | ||
| Overall (n=2185) | Never use (n=1994) | Ever use (n=191) | ||
| Sociodemographics | ||||
| Sex, n (%) | <0.001* | |||
| Girls | 1160 (53.1) | 1097 (55.0) | 63 (33.0) | |
| Boys | 1025 (46.9) | 897 (45.0) | 128 (67.0) | |
| Age, M (95% CI) | 13.62 (13.56 to 13.67) | 13.57 (13.51 to 13.62) | 14.16 (13.99 to 14.34) | <0.001† |
| Ethnicity, n (%) | 0.063* | |||
| Dutch | 1978 (90.5) | 1816 (91.1) | 162 (84.8) | |
| Belgian | 76 (3.5) | 65 (3.3) | 11 (5.8) | |
| Polish | 8 (0.4) | 7 (0.4) | 1 (0.5) | |
| Turkish | 30 (1.4) | 24 (1.2) | 6 (3.1) | |
| German | 5 (0.2) | 5 (0.3) | 0 | |
| British | 4 (0.2) | 4 (0.2) | 0 | |
| Moroccan | 16 (0.7) | 13 (0.7) | 3 (1.6) | |
| Chinese | 6 (0.3) | 4 (0.2) | 2 (1.0) | |
| Italian | 5 (0.2) | 5 (0.3) | 0 | |
| Spanish | 5 (0.2) | 5 (0.3) | 0 | |
| Other, don’t want to say or unknown | 52 (2.4) | 47 (0.2) | 1 (0.5) | |
| Highest parental education, n (%) | 0.029‡ | |||
| Graduate degree | 271 (12.4) | 248 (12.4) | 23 (12.0) | |
| College graduate | 478 (21.9) | 426 (21.4) | 52 (27.2) | |
| Secondary higher education | 368 (16.8) | 347 (17.4) | 21 (11.0) | |
| Vocational education | 301 (13.8) | 267 (13.4) | 34 (17.8) | |
| Secondary vocational education | 211 (9.7) | 189 (9.5) | 22 (11.5) | |
| Lower vocational education | 42 (1.9) | 34 (1.7) | 8 (4.2) | |
| Primary school | 14 (0.6) | 13 (0.7) | 1 (0.5) | |
| None | 23 (1.1) | 22 (1.1) | 1 (0.5) | |
| Don’t know | 477 (21.8) | 448 (22.5) | 29 (15.2) | |
| Environmental factors | ||||
| Lives with both biological parents, n (%) | 1729 (79.1) | 1606 (80.5) | 123 (64.4) | <0.001* |
| Family history of smoking, n (%) | 1522 (69.7) | 1364 (68.4) | 158 (82.7) | <0.001* |
| Peer smoking, M (95% CI) | 1.32 (1.29 to 1.36) | 1.27 (1.24 to 1.31) | 1.84 (1.64 to 2.04) | <0.001† |
| Intrapersonal factors | ||||
| CESD-Depressive symptoms, M (95% CI) | 9.91 (9.55 to 10.27) | 9.69 (9.32 to 10.07) | 12.19 (10.84 to 13.55) | <0.001† |
| TCI-Impulsivity, M (95% CI) | 7.99 (7.87 to 8.10) | 8.08 (7.97 to 8.20) | 6.97 (6.55 to 7.39) | <0.001† |
| Ever substance use, n (%) | 757 (34.6) | 617 (30.9) | 140 (73.3) | <0.001* |
| Delinquent behaviour, M (95% CI) | 14.39 (14.23 to 14.55) | 14.13 (13.97 to 14.29) | 17.08 (16.32 to 17.85) | <0.001† |
| Smoking susceptibility, M (95% CI) | 3.47 (3.43 to 3.51) | 3.40 (3.36 to 3.44) | 4.20 (4.00 to 4.41) | <0.001† |
| Smoking expectancies, M (95% CI) | 6.90 (6.85 to 6.95) | 6.93 (6.88 to 6.98) | 6.53 (6.36 to 6.71) | <0.001† |
*χ2 test.
†Independent samples t-test.
‡Spearman’s r test.
CESD, Center for Epidemiologic Studies Depression Scale; M, mean; TCI, Temperament and Character Inventory.