Table 1.
Baseline Characteristics of Study Participants by Condition and Overall
| ENDS conditions | |||||
|---|---|---|---|---|---|
| Characteristic | CS (N = 130) |
0 mg/ml (N = 130) |
8 mg/ml (N = 130) |
36 mg/ml (N = 130) |
Overall (N = 520) |
| Age in years | 46.1±12.4 | 45.7±11.4 | 45.6±11.7 | 47.4±11.1 | 46.2±11.6 |
| Male sex, % (N) | 39.2 (51) | 38.5 (50) | 38.5 (50) | 48.5 (63) | 41.2 (214) |
| Race and ethnicity, % (N) | |||||
| Caucasian/White NH | 63.9 (83) | 70.8 (92) | 66.9 (87) | 67.7 (88) | 67.3 (350) |
| African American/Black NH | 30.0 (39) | 25.4 (33) | 28.5 (37) | 27.7 (36) | 27.9 (145) |
| Other | 6.2 (8) | 3.9 (5) | 4.6 (6) | 4.6 (6) | 4.8 (25) |
| Some college or higher, % (N) | 58.5 (76) | 55.4 (72) | 63.9 (83) | 60.8 (79) | 59.6 (310) |
| Income >$39,999, % (N)a | 39.8 (51) | 37.0 (47) | 40.8 (51) | 46.2 (60) | 41.0 (209) |
| Cigarettes smoked per day (7-day average)b | 18.4±7.1 | 18.8±8.3 | 19.4±8.7 | 17.8±6.5 | 18.6±7.7 |
| Exhaled carbon monoxide in parts per million | 23.6±12.5 | 23.4±12.2 | 21.8±9.8 | 21.9±10.5 | 22.7±11.3 |
| Penn State Cigarette Dependence Index score17 | 13.4±3.0 | 13.7±2.7 | 13.2±3.0 | 13.2±3.2 | 13.4±3.0 |
| Menthol cigarette smoking, % (N) | 66.9 (87) | 67.7 (88) | 62.3 (81) | 59.2 (77) | 64.0 (333) |
Note: CS, cigarette substitute; ENDS, electronic nicotine delivery system; NH, non-Hispanic; IQR, interquartile range; CI, confidence interval. Plus-minus values are mean±SD. Demographic characteristics were assessed by self-report at the in-person screening visit (week −1). Cigarettes smoked per day, exhaled carbon monoxide, Penn State Cigarette Dependence Index score, menthol cigarette smoking status, were assessed at the baseline visit (week 0; at randomization). There were no significant differences in baseline characteristics between conditions (p > .05).
aMissing income data by condition: CS (N = 2), 0 mg/ml (N = 3), 8 mg/ml (N = 5), 36 mg/ml (none).
bNumber of cigarettes smoked per day was calculated using self-reported timeline follow-back for the 7 days prior to the randomization visit (collected in-person at week 0).