Table 1.
Sample Demographic, Covariate, and Tobacco Use Variables by Baseline E-cigarette Nicotine Concentration
| Variable | Totala (N=181) | Baseline e-Cigarette Nicotine Concentrationab | P valuec | |||
|---|---|---|---|---|---|---|
|
| ||||||
| None (N=73) | Low (N=52) | Medium (N=35) | High (N=21) | |||
| Sociodemographic characteristics | ||||||
| Male | 96 (53.0) | 39 (53.4) | 24 (46.2) | 20 (57.1) | 13 (61.9) | .60 |
| Age, mean (SD), y (n=180)g | 16.1 (.4) | 16.1 (.4) | 16.0 (.4) | 16.1 (.4) | 16.0 (.3) | .30 |
| Race/ethnicity (n=177)g | .42 | |||||
| Hispanic | 88 (49.7) | 33 (45.8) | 27 (52.9) | 17 (50.0) | 11 (55.0) | |
| White | 38 (21.5) | 12 (16.7) | 12 (23.5) | 11 (32.4) | 3 (15.0) | |
| Asian | 34 (19.2) | 17 (23.6) | 9 (17.6) | 3 (8.8) | 5 (25.0) | |
| Other | 17 (9.6) | 10 (13.9) | 3 (5.9) | 3 (8.8) | 1 (5.0) | |
| Parental college degree or higher (n=154)g | 67 (43.5) | 33 (52.4) | 17 (36.2) | 10 (35.7) | 7 (43.8) | .29 |
| Interpersonal factors | ||||||
| Peer smoking or vaping (n=161)g | 141 (87.6) | 51 (77.3) | 46 (95.8) | 24 (92.3) | 20 (95.2) | .01 |
| Other tobacco product use (n=172)g | 138 (80.2) | 57 (79.2) | 41 (83.7) | 27 (90.0) | 13 (61.9) | .08 |
| Intrapersonal factors | ||||||
| UPPS Impulsive Behavior Scale Sensation Seeking score, mean (SD),d (n=154)g | 33.7 (9.1) | 34.4 (8.9) | 33.0 (7.7) | 33.4 (8.2) | 33.1 (13.6) | .85 |
| CESD score, mean (SD),e (n=176)g | 17.4 (12.7) | 16.0 (11.2) | 17.6 (13.2) | 16.5 (10.8) | 22.9 (17.9) | .18 |
| Delinquent behavior score, mean (SD),f (n=176)g | 19.3 (8.5) | 17.9 (6.1) | 19.1 (8.4) | 19.8 (7.5) | 24.4 (14.9) | .03 |
| Smoking variables | ||||||
| Cigarette smoking in past 30 d | ||||||
| Baseline (n=180)g | .001 | |||||
| 0 d | 117 (65.0) | 57 (79.2) | 34 (65.4) | 17 (48.6) | 9 (42.9) | |
| 1–2 d | 35 (19.4) | 6 (8.3) | 13 (25.0) | 12 (34.3) | 4 (19.0) | |
| ≥ 3 d | 28 (15.6) | 9 (12.5) | 5 (9.6) | 6 (17.1) | 8 (38.1) | |
| Follow-up | .001 | |||||
| 0 d | 138 (76.2) | 62 (84.9) | 42 (80.8) | 24 (68.6) | 10 (47.6) | |
| 1–2 d | 18 (9.9) | 7 (9.6) | 5 (9.6) | 4 (11.4) | 2 (9.5) | |
| ≥ 3 d | 25 (13.8) | 4 (5.5) | 5 (9.6) | 7 (20.0) | 9 (42.9) | |
| No. of cigarettes smoked per d, mean (SD) | ||||||
| Baseline (n=179)g | .6 (1.7) | .2 (.5) | .5 (1.0) | .7 (1.2) | 1.9 (4.5) | .002 |
| Follow-up | .5 (2.2) | .2 (.5) | .4 (1.0) | .3 (.6) | 2.5 (5.9) | <.001 |
| Vaping variables | ||||||
| Use in past 30 d | ||||||
| Baseline | .001 | |||||
| 1–2 d | 83 (45.9) | 43 (58.9) | 26 (50.0) | 10 (28.6) | 4 (19.0) | |
| ≥3 d | 98 (54.1) | 30 (41.1) | 26 (50.0) | 25 (71.4) | 17 (81.0) | |
| Follow-up | .03 | |||||
| 0 d | 92 (50.8) | 45 (61.6) | 24 (46.2) | 16 (45.7) | 7 (33.3) | |
| 1–2 d | 34 (18.8) | 15 (20.6) | 10 (19.2) | 7 (20.0) | 2 (9.5) | |
| ≥ 3 d | 55 (30.4) | 13 (17.8) | 18 (34.6) | 12 (34.3) | 12 (57.1) | |
| No. of episodes per d, mean (SD) | ||||||
| Baseline (n=179)g | 4.6 (6.3) | 3.5 (5.8) | 3.8 (4.9) | 5.7 (6.7) | 8.6 (8.6) | .005 |
| Follow-up (n=171)g | 2.8 (5.4) | 1.3 (4.0) | 3.2 (5.4) | 3.7 (6.0) | 5.2 (7.8) | .02 |
| No. of puffs per vaping episode, mean (SD) | ||||||
| Baseline | 6.8 (6.1) | 5.5 (5.5) | 5.6 (5.0) | 9.0 (6.6) | 10.3 (7.3) | <.001 |
| Follow-up (n=170)g | 3.1 (5.6) | 1.3 (3.3) | 3.0 (4.9) | 6.1 (7.6) | 4.6 (7.1) | <.001 |
Abbreviations: CESD, Center for Epidemiologic Studies Depression Scale; e-cigarette, electronic cigarette.
Data are expressed as number (percentage) of participants unless otherwise indicated.
None indicates 0 mg/mL; low, 1 to 5 mg/mL; medium, 6 to 17 mg/mL; and high, 18 mg/mL or greater.
Tests of differences in sample characteristics by baseline nicotine concentration vaped were conducted with χ2 tests for categorical variables and 1-way analysis of variance for continuous variables.
Possible range of scores from 0–48, with higher scores indicating greater levels of sensation seeking.
Possible range of scores from 0–60, with higher scores indicating greater severity of depressive symptoms.
Possible range of scores from 11–66, with higher scores indicating greater frequency of engaging in deviant behaviors.
The available sample for this variable is provided due to missing data.