Baseline data: 11-yr cohort
| Variable | |
| Male | 61.9 |
| Age yr | 50.1±7.4 |
| SI treatment group | 67.2 |
| Baseline cigarettes·day−1 | 30.8±12.7 |
| Pack-yrs | 39.9±18.6 |
| LHS 3 smoking status | |
| Sustained quitters | 17.7 |
| Intermittent quitters | 57.1 |
| Continuous smokers | 25.5 |
| FEV1 | |
| Pre-BD L | 2.64±0.60 |
| Post-BD L | 2.75±0.63 |
| FEV1 | |
| % pred pre-BD | 75.4±8.73 |
| % pred post-BD | 78.5±9.01 |
| Methacholine reactivity | |
| 5 mg·mL−1 % reactors# | 33.6 |
| 25 mg·mL−1 % reactors# | 71.8 |
Data are presented as mean±sd or %. SI: special intervention; LHS: lung health study; FEV1: forced expiratory volume in one second; BD: bronchodilator. #: reactors showed a decline in FEV1 of ≤20% in response to the indicated (or lower) doses.