Participant baseline characteristics and e-cigarette usage
| Whole sample | Unflavoured condition | Flavoured condition | |
| Demographics | |||
| Age, years, mean (SD) | 28.8 (9.9) | 26.1 (7.7) | 31.5 (11.2) |
| Gender, male, n (%) | 46 (55) | 26 (62) | 20 (48) |
| Ethnicity, white, n (%) | 76 (90) | 37 (88) | 39 (93) |
| Employment, working environment as normal, n (%) | 46 (55) | 21 (50) | 25 (60) |
| Cigarette and e-cigarette use (baseline) | |||
| Ever e-cigarette use, yes, n (%) | 34 (40) | 18 (43) | 16 (38) |
| Cigarettes per day, mean (SD) | 11.9 (4.8) | 11.1 (5.1) | 12.6 (4.4) |
| Duration of daily smoking, years, mean (SD) | 9.3 (8.2) | 7.5 (6.6) | 11.1 (9.3) |
| Cigarette dependence, mean (SD) | 3.4 (2.1) | 3.2 (2.2) | 3.5 (2.0) |
| Quit motivation, mean (SD) | 5.5 (1.6) | 5.3 (1.7) | 5.6 (1.5) |
| Cigarette craving, mean (SD) | 31.7 (9.0) | 32.4 (9.0) | 31.1 (9.1) |
| E-cigarette usage (after study week) | |||
| E-liquid strength, 10 mg/mL, n (%) | 77 (92) | 38 (90) | 39 (93) |
| E-liquid quantity used (bottles), mean (SD) | 2.4 (1.5) | 2.0 (1.3) | 2.7 (1.7) |
| Puff count, mean (SD) | 1434 (1219) | 1333 (881) | 1538 (1494) |
| Duration of use, in seconds, mean (SD) | 4705 (8168) | 3289 (1833) | 6049 (11166) |
N=84 for all variables except ‘puff count’ and ‘duration of use’ (measured passively on the device) due to missing or erroneous data (n=81 and n=76, respectively).
Cigarette dependence, quit motivation and cigarette craving were assessed using the Fagerström Test for Cigarette Dependence, Readiness to Quit Ladder and the Questionnaire of Smoking Urges-Brief, respectively.
e-cigarette, electronic cigarette.