TABLE 3.
Induced sputum levels of inflammatory biomarkers and linear trend over four annual study visits*
| Biomarker | Visit 1 | Visit 2 | Visit 3 | Visit 4 | Linear Trend |
| Total (log) neutrophils | 7.6 (7.4 to 7.9) | 7.6 (7.4 to 7.8) | 7.5 (7.3, 7.8) | 7.4 (7.2 to 7.7) | −0.3 (−0.7 to <0.1) |
| % Neutrophils | 63 (57 to 70) | 60 (53 to 67) | 55 (48 to 62) | 64 (57 to 71) | −0.02 (−0.15 to 0.11) |
| Elastase log, μg/ml | 1.2 (1.0 to 1.4) | 1.4 (1.2 to 1.6) | 1.3 (1.1 to 1.5) | 1.6 (1.4 to 1.8) | 0.5 (0.2 to 0.8) |
| MMP-9 log, ng/ml | 3.5 (3.3 to 3.7) | 3.6 (3.4 to 3.8) | 3.8 (3.6 to 3.9) | 3.5 (3.3 to 3.7) | 0.1 (−0.3 to 0.5) |
| NEAPC log, ng/ml | 2.4 (2.2 to 2.5) | 2.2 (2.0 to 2.3) | 2.2 (2.0 to 2.3) | 2.1 (1.9 to 2.2) | −0.4 (−0.7 to −0.1) |
| SLPI log, ng/ml | 3.9 (3.8 to 4.1) | 3.7 (3.6 to 3.8) | 3.7 (3.6 to 3.8) | 3.7 (3.6 to 3.8) | −0.3 (−0.5 to −0.1) |
| TIMP-1 log, ng/ml | 2.5 (2.4 to 2.6) | 2.6 (2.4 to 2.7) | 2.7 (2.6 to 2.8) | 2.7 (2.6 to 2.9) | 0.5 (0.3 to 0.7) |
| IL-1β log, pg/ml | 3.0 (2.8 to 3.2) | 2.9 (2.6 to 3.1) | 2.9 (2.6 to 3.1) | 3.0 (2.8 to 3.3) | 0.1 (−0.3 to 0.4) |
| IL-6 log, pg/ml | 1.7 (1.4 to 2.0) | 1.5 (1.2 to 1.8) | 1.7 (1.4 to 2.0) | 1.8 (1.4 to 2.1) | 0.2 (−0.3 to 0.7) |
| IL-8 log, pg/ml | 4.7 (4.6 to 4.8) | 4.8 (4.6 to 4.9) | 4.8 (4.6 to 4.9) | 4.7 (4.6 to 4.9) | 0.1 (−0.2 to 0.3) |
| TNF-α log, pg/ml | 0.9 (0.7 to 1.1) | 1.3 (1.1 to 1.5) | 1.4 (1.2 to 1.6) | 1.7 (1.5 to 1.9) | 1.2 (0.7 to 1.6) |
Definition of abbreviations: NEAPC = neutrophil elastase antiprotease complex; SLPI = secretory leukoprotease inhibitor; TIMP-1 = tissue inhibitor of metalloproteinase.
*
Data presented as least square means with 95% confidence intervals. The linear trend (i.e., slope) is based on a standard mixed model, excluding the influence of censoring. Bold values indicate a statistically significant change over time (95% CI does not include zero).