Baseline subject characteristics according to quartile of relative forced expiratory volume in one second (FEV1)
Quartile of relative FEV1 | p-values# | ||||
1 | 2 | 3 | 4 | ||
FEV1 % pred cut-off | ≤89.00 | 89.01–100.89 | 100.90–112.16 | >112.16 | |
Patients n | 405 | 406 | 406 | 406 | |
FEV1 % pred | 75.7±12.8 | 95.3±3.3 | 106.6±3.2 | 121.9±8.9 | <0.001 |
FEV1 L | 2.66±0.56 | 3.38±0.39 | 3.72±0.41 | 4.25±0.55 | <0.001 |
FVC % pred | 85.1±13.0 | 97.0±9.0 | 104.4±7.9 | 114.1±10.7 | <0.001 |
FVC L | 3.82±0.73 | 4.40±0.61 | 4.67±0.57 | 5.10±0.71 | <0.001 |
FEV1/FVC % | 69.8±10.5 | 77.4±7.2 | 80.0±6.5 | 83.7±7.3 | <0.001 |
Age yrs | 50.0±5.4 | 49.2±5.4 | 50.0±5.7 | 50.2±5.5 | 0.27 |
Height cm | 177±7 | 177±6 | 176±6 | 177±6 | 0.65 |
Body mass index kg·m−2 | 24.5±3.1 | 24.5±2.7 | 24.7±2.7 | 24.7±2.5 | 0.06 |
Systolic blood pressure mmHg | 130±19 | 130±18 | 131±17 | 131±17 | 0.11 |
Physical fitness kJ·kg−1 | 1.20±0.45 | 1.40±0.52 | 1.53±0.56 | 1.58±0.57 | <0.001 |
Serum cholesterol mmol·L−1 | 6.7±1.3 | 6.6±1.2 | 6.6±1.2 | 6.5±1.2 | 0.21 |
Smoking status % | <0.001¶ | ||||
Never-smoker | 17 | 23 | 30 | 29 | |
Previous smoker | 24 | 32 | 33 | 39 | |
Current smoker | |||||
1–10 cigarettes·day−1 | 19 | 19 | 12 | 14 | |
>10 cigarettes·day−1 | 40 | 27 | 25 | 18 | |
Current smokers only n | 239 | 184 | 151 | 130 | |
Number of pack-yrs | 22.2±11.0 | 19.8±10.8 | 18.9±9.3 | 16.7±9.1 | <0.001 |
Data are presented as n and mean±sd, unless otherwise stated. FVC: forced vital capacity. #: test for trend; ¶: Chi-squared test. n = 1,623.