Cotinine levels by e-cigarette use characteristics
| Salivary cotinine (ng/mL) | ||||
| n (%) | M (SD) | Median | Range | |
| Full sample | 173 (100.0) | |||
| Current nicotine use | ||||
| All e-cigarettes contain nicotine | 72 (41.6) | 61.9 (87.3) | 17.4 | 0–369.3 |
| Some contain nicotine | 67 (38.7) | 31.3 (111.7) | 0.0 | 0–864.6 |
| None contain nicotine | 13 (7.5) | 2.3 (7.7) | 0.0 | 0–27.9 |
| Unknown nicotine content | 21 (12.1) | 2.5 (9.6) | 0.0 | 0–44.1 |
| Type of e-cigarette used | ||||
| Customisable/Mod | 56 (32.4) | 59.5 (133.5) | 6.5 | 0–864.6 |
| Juul | 38 (22.0) | 54.3 (90.1) | 6.1 | 0–302.8 |
| Vape pen | 59 (34.1) | 18.2 (38.9) | 0.0 | 0–161.5 |
| Other or unknown | 20 (11.6) | 8.5 (23.2) | 0.0 | 0–98.8 |
| Daily/non-daily e-cigarette use | ||||
| Daily | 25 (14.5) | 114.6 (103.1) | 88.8 | 0–369.3 |
| Non-daily | 148 (85.5) | 25.5 (83.7) | 0.55 | 0–864.6 |
| E-Cigarette only users | 144 (83.2) | |||
| Current nicotine use | ||||
| All e-cigarettes contain nicotine | 51 (35.4) | 47.4 (82.3) | 9.1 | 0–369.3 |
| Some contain nicotine | 60 (41.7) | 24.9 (114.1) | 0.0 | 0–864.6 |
| None contain nicotine | 12 (8.3) | 0.1 (0.5) | 0.0 | 0–1.7 |
| Unknown nicotine content | 21 (14.6) | 2.5 (9.6) | 0.0 | 0–44.1 |
| Type of e-cigarette used | ||||
| Customisable/Mod | 48 (33.3) | 51.5 (137.3) | 3.7 | 0–864.6 |
| Juul | 31 (21.5) | 36.1 (75.1) | 1.5 | 0–283.0 |
| Vape pen | 49 (34.0) | 7.6 (26.7) | 0.0 | 0–161.5 |
| Other or unknown | 16 (11.1) | 0.3 (0.9) | 0.0 | 0–3.3 |
| Daily/non-daily e-cigarette use | ||||
| Daily | 15 (10.4) | 93.0 (100.4) | 57.8 | 0–369.3 |
| Non-daily | 129 (89.6) | 19.9 (85.6) | 0.0 | 0–864.6 |