Table 2.
Number of cigarettes smoked per day and measures of smoking behaviour and attitudes (N = 79)
| Packs of ≥25 (n = 39) |
Packs of 20 (n = 40) |
|||||
|---|---|---|---|---|---|---|
| Mean (SD) |
Mean (SD) |
Mean Difference (Packs of ≥25 minus Packs of 20) |
95% CI | p | Cohen’s d | |
| Number of cigarettes smoked per day | ||||||
| Primary analysisa | 16.8 (6.7) | 15.9 (8.5) | −0.9 | −4.3, 2.6 | 0.620 | − 0.11 |
| Secondary analysis* | 16.7 (7.7) | 15.9 (7.7) | −0.8 | −4.3, 2.6 | 0.639 | −0.25 |
| Per protocol analysis | 16.6 (6.7) | 16.1 (4.3) | −0.5 | −4.2, 3.0 | 0.766 | −0.09 |
| Smoking behaviour and attitudes (post-intervention)** | ||||||
| HSIb | 3.1 (1.1) | 2.8 (1.1) | −0.30 | − 0.82, 0.23 | 0.265 | − 0.26 |
| MTSSc | 3.8 (1.4) | 3.4 (1.4) | −0.46 | −1.10, 0.19 | 0.160 | −0.33 |
| AUTOSd | 17.9 (5.2) | 17.6 (5.2) | −0.25 | −2.67, 2.16 | 0.838 | −0.05 |
*adjusted for pack size used at baseline, ** adjusted for same measures taken at baseline
aDue to deviations from normality in the primary and secondary outcomes, all analyses were repeated using a bootstrapping method. These produced similar results
bHSI = Heaviness of Smoking Index (range 0–6)
cMTSS = Motivation to Stop Scale (range 1–7)
dAUTOS = Autonomy Over Smoking Scale (range 0–36)