Correlation among pack year and cytokines and pulmonary function in COPD patients
| Parameters | Statistical values (r) | P-value |
| FEV1%pred | −0.5036 | <0.001 |
| FEV1/FVC ratio | −0.2847 | 0.003 |
| FKN (pg/mL) | 0.4971 | <0.001 |
| NE (ng/mL) | 0.2754 | 0.005 |
| MMP-12 (ng/mL) | 0.4315 | <0.001 |
P<0.05 was considered significant.
COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FKN, chemokine fractalkine;FVC, forced vital capacity; MMP-12, matrix metalloproteinase-12; NE, neutrophil elastase; r, Spearman correlation coefficient.