Incidence and hazard ratio of conversion to tobacco dependence according to metabolic activity
| Metabolic activity | All subjects who had inhaled (n = 228) | Initiated inhalation during follow up (n = 151) | ||
|---|---|---|---|---|
| Incidence (95% CI)† | HR (95% CI) ‡ | Incidence (95% CI) | HR (95% CI) | |
| *Excludes 7 subjects who were ICD-10 tobacco dependent at baseline, and 46 subjects who had never inhaled. | ||||
| †Number of subjects who became tobacco dependent per 1000 person-months. | ||||
| ‡Hazard ratio and 95% confidence intervals from Cox’s proportional hazards models. | ||||
| Total* | 9.8 (7.6 to 12.5) | – | 12.3 (8.7 to 16.9) | – |
| Normal inactivators | 9.1 (6.8 to 11.9) | Ref | 11.0 (7.2 to 16.0) | Ref |
| Slower inactivators | 10.0 (4.0 to 20.6) | 1.1 (0.5 to 2.5) | 10.7 (3.4 to 24.9) | 1.00 (0.4 to 2.5) |
| Slowest inactivators | 25.2 (10.1 to 51.8) | 2.8 (1.3 to 6.3) | 38.5 (14.1 to 84.0) | 3.2 (1.3 to 7.7) |