In order to explore the potential ability to predict emphysema using biomarker levels, we added biomarkers log2 (TIMP-1), log2 (TIMP-2), log2 (MMP-1), log2 (MMP-2), log2 (MMP-7) and log2 (MMP-9) and obtained Model 2 (Table 3). Here, MMP9 is linked to pulmonary emphysema.