Mean absolute FEV1 (at the second examination), mean lung function decline and incidence rates of COPD (between the second and third examinations) for increasing airway responsiveness, with 95% CIs, adjusted only for study
| Outcomes | FEV1 at the 2nd examination (L) | ΔFEV1 (mL/year) | ΔFEV1% (%/year) | Incidence of COPDLLN (per 1000/year) | |
| Number of subjects | 4716 | 4716 | 4716 | 4205 | |
| Slope group, by quintiles (% × µmol−1) | <0.44 0.44–0.73 0.74–1.12 1.13–1.84 ≥1.84 | 3.77 (3.70 to 3.84) 3.68 (3.61 to 3.74) 3.49 (3.42 to 3.56) 3.35 (3.29 to 3.42) 3.22 (3.15 to 3.28) | 38.8 (35.1 to 42.5) 38.6 (34.9 to 42.3) 37.0 (33.3 to 40.7) 38.5 (34.8 to 42.3) 36.3 (32.6 to 40.0) | 1.04 (0.94 to 1.14) 1.06 (0.96 to 1.16) 1.07 (0.97 to 1.17) 1.17 (1.08 to 1.27) 1.17 (1.07 to 1.27) | 0.6 (0.1 to 1.1) 1.1 (0.6 to 1.6) 2.3 (1.0 to 3.5) 3.8 (2.4 to 5.1) 5.3 (3.2 to 7.5) |
| Overall P value | <0.001 | 0.20 | <0.001 | <0.001 |
LLN, lower limit of normal.