Clinical and physiological factors associated with pro-surfactant protein B levels#
| Parameter | β coefficient | se | p-value | R2 |
| CT emphysema score ≥4 | 0.132 | 0.040 | 0.001 | 0.006 |
| Smoking pack-years | 0.003 | <0.001 | <0.001 | 0.002 |
| Current smoking | 0.263 | 0.018 | <0.001 | 0.074 |
| Age years | 0.014 | 0.003 | <0.001 | 0.001 |
| Male | 0.033 | 0.017 | 0.049 | 0.003 |
Variables included in the model included baseline forced expiratory volume in 1 s (FEV1), body mass index (BMI), smoking pack-years, current smoking, age, computed tomography (CT) emphysema score and sex. Baseline FEV1 and BMI were removed from the final model. The combined R2 value was 0.096. #: logarithmic scale.