Table 2. Median levels of serum cytokines as related to CWP progression.

	NP (n=67) †	P (n=18)c	p-values
			Univariate a	Multivariate b
IL-8, pg/ml	14.7 (6.8–38.4)	16.8 (10.5–26.4)	0.056	0.054
TNF-α, pg/ml	2.03 (0.47–18.98)	1.91 (0.73–9.19)	0.817	0.926
TGF-β1, ng/ml	74.4 (30.4–119.8)	90.7 (49.3–122.9)	0.012	0.006
MCP-1, pg/ml	30.6 (10.5–238.7)	37.2 (16.3–64.0)	0.048	0.354

^a Calculated by Mann-Whitney U test, median (range). ^b Calculated using a logistic regression model to adjust for age, BMI, exposure period, smoking status (never/past/current), and pulmonary function (%FVC predicted, %FEV₁ predicted, and %FEV₁/FVC ratio).