TABLE 1.
Family history of smoking and rate of transitions between smoking stages for each class
| Class 1 High on physiological and pleasurable responses | Class 2 Cough only | Class 3 High on physiological, low on pleasurable responses | Class 4 High on pleasurable, low on physiological responses | |
|---|---|---|---|---|
| n=172 (30.0%) | n=159 (27.8%) | n=141 (24.6%) | n=101 (17.6%) | |
| Age at first cigarette | ||||
| Early: ≤ 12 years | 30.2% | 25.8% | 29.8% | 20.8% |
| Average: 13–16 years | 50.6% | 49.7% | 50.3% | 51.5% |
| Late: ≥ 17 years | 19.2% | 24.5% | 19.9% | 27.7% |
| Regular smoker (n=315)a | 77.9% | 32.7% | 44.0% | 66.3% |
| Timing of first cigarette to onset of regular smoking (n=315)a | (n=134) | (n=52) | (n=62) | (n=67) |
| Rapid: ≤ 1 year | 42.5% | 28.9% | 35.5% | 52.2% |
| Average: 2–3 years | 39.6% | 26.9% | 27.4% | 26.9% |
| Slow: ≥ 4 years | 17.9% | 44.2% | 37.1% | 20.9% |
| Paternal nicotine dependence (ND) risk group status | ||||
| Group 1: high genetic (G), high environmental (E) | 64.5% | 57.9% | 66.7% | 64.4% |
| Group 2: high G, low E | 4.7% | 9.4% | 10.6% | 10.9% |
| Group 3: moderate G, low E | 9.9% | 9.4% | 5.0% | 4.0% |
| Group 4: low G, low E | 20.9% | 23.3% | 17.7% | 20.8% |
| Maternal heavy smoking index | ||||
| Non-smoker | 49.1% | 51.6% | 52.8% | 59.6% |
| Low: 1–2 | 14.6% | 16.4% | 13.6% | 13.1% |
| High ≥ 3 | 36.3% | 32.1% | 33.6% | 27.3% |
a
Statistically significant difference across classes, p <.01