Figure 2From: Elevation of sputum matrix metalloproteinase-9 persists up to 6 months after smoking cessation: a research study The levels of MMP-7 in the smoking cessation group at the baseline and at 3 and 6 months after stopping smoking. The levels of MMP-7 were significantly higher in the smoking cessation group at the baseline compared to the non-smokers (p = 0.014). MMP-7 declined to the levels of non-smokers at 6 months after the cessation.Back to article page