Table 1.
Baseline Characteristics by Age Group Category
| Characteristic | Age group | |||
|---|---|---|---|---|
| 18–24 | ≥25 | Effect sizea (95% CI) | p | |
| N | 87 | 1163 | ||
| Treatment group, number (%) | .21 | |||
| Gradual reduction | 27 (31.0) | 571 (40.5) | ||
| Immediate reduction | 41 (47.1) | 462 (39.7) | ||
| Control | 19 (21.8) | 230 (19.8) | ||
| Age in years, mean (SD) | 21.9 (1.8) | 46.8 (12.2) | ||
| Gender, number, % male | 58 (66.7) | 643 (55.3) | .04 | |
| Race, number (%) | <.01 | |||
| White | 63 (72.4) | 695 (59.8) | ||
| Black | 8 (9.2) | 365 (31.4) | ||
| Other | 14 (16.1) | 82 (7.1) | ||
| Cigarettes per day | 14.8 ± 6.8 | 17.3 ± 8.6 | 0.3 (0.1, 0.5) | <.01 |
| FTND, mean (SD) | 3.7 ± 1.7 | 4.3 ± 1.7 | 0.3 (0.1, 0.5) | <.01 |
| Psychological Reward at baseline, mean (SD) | 3.6 ± 1.3 | 3.1 ± 1.4 | −0.4 (−0.6, −0.2) | <.01 |
| Smoking Satisfaction at baseline, mean (SD) | 4.8 ± 1.4 | 4.7 ± 1.4 | −0.1 (−0.3, 0.1) | .39 |
| Enjoyment of Respiratory Tract Sensations at baseline, mean (SD) | 4.1 ± 1.7 | 3.4 ± 1.7 | −0.4 (−0.6, −0.2) | <.01 |
| Craving Reduction at baseline, mean (SD) | 4.3 ± 1.9 | 4.5 ± 1.9 | 0.1 (−0.1, 0.4) | .24 |
| Aversion, mean (SD) | 1.3 ± 0.5 | 1.3 ± 0.6 | 0.0 (−0.2, 0.2) | .97 |
| TNEs at baseline, geometric mean (range) | 44.7 (3.7–148.4) | 60.3 (0.2–492.7) | 0.4 (0.2, 0.6)b | <.01 |
| Nicotine metabolite ratio at baseline, mean (SD) | 0.4 ± 0.2 | 0.4 ± 0.2 | 0.1 (−0.1, 0.3) | .42 |
p-Values represent t-tests of differences for continuous variables and chi-square tests for categorical variables. Subjective response scores were in reference to participants’ usual brand cigarettes at baseline. Bold values indicate significant p-value. p-value for TNEs is derived from a t-test comparing log-transformed TNE values. CI = confidence interval; FTND = Fagerström Test for Nicotine Dependence; TNE = total nicotine equivalents.
aEffect size = difference in means (older age group − younger age group) by pooled standard deviation.
bEffect size reported was on log transformed TNEs.