Table 2– Sputum MMP-9 activity and concentrations, TIMP-1 and TIMP-2 concentrations, and MMP/TIMP ratios in healthy controls and patients with asthma

	Asthma			Healthy control			p-value⁺	p-value^§
	Never-smoker	Smoker	p-value^#	Never-smoker	Smoker	p-value^¶
MMP-9 activity ng·mL⁻¹	27.1 (13.1–41.2)	14.5 (12.5–26.1)	0.035	16.6 (12.5–28.4)	18.9 (13.4–46.4)	0.285	0.178	0.122
MMP-9 ng·mL⁻¹	102.5 (43.5–147.9)	73.4 (49.2–148.6)	0.826	34.0 (24.4–131.0)	69.0 (38.6–184.0)	0.160	0.891	0.084
TIMP-1 ng·mL⁻¹	60.5 (46.7–116.5)	96.7 (55.0–158.0)	0.022	35.3 (14.8–67.4)	101.8 (60.8–149.2)	0.001	0.825	0.011
TIMP-2 ng·mL⁻¹	10.6 (6.3–18.5)	13.1 (9.2–16.8)	0.355	8.0 (4.1–11.2)	13.9 (10.4–18.5)	0.004	0.592	0.034
MMP-9 activity/TIMP-1	0.38 (0.28–0.61)	0.19 (0.12–0.42)	0.002	0.72 (0.30–1.33)	0.33 (0.14–0.46)	0.018	0.402	0.083
MMP-9 activity/TIMP-2	2.6 (2.0–3.1)	1.4 (0.9–2.3)	0.001	3.1 (2.0–5.0)	1.7 (1.1–3.0)	0.024	0.402	0.153
MMP-9/TIMP-1	1.6 (0.7–2.2)	1.0 (0.5–1.8)	0.185	1.3 (0.8–2.4)	0.9 (0.5–2.4)	0.490	0.915	0.957
MMP-9/TIMP-2	9.0 (6.0–11.6)	7.4 (3.8–11.4)	0.345	6.7 (4.3–11.2)	6.4 (4.3–11.2)	0.744	0.791	0.323

Data are presented as median (interquartile range), unless otherwise stated. Bold font indicates p<0.05. MMP: matrix metalloproteinase; TIMP: tissue inhibitors of metalloproteinase. ^#: comparison of never-smokers with asthma and smokers with asthma; ^¶: comparison of healthy never-smokers and healthy smokers; ⁺: comparison of healthy smokers and smokers with asthma; ^§: comparison of healthy never-smokers and never-smokers with asthma.