Moreover, the levels of MMP7, as well as the total protein concentrations, were significantly (p < 0.01) higher in GCF from periodontitis patients.Multiple linear regression analyses were also performed with the total concentrations of MUC4 and MMP7 as well as in relation to protein concentrations as dependent variables, adjusted for age and smoking habits (Table 3 - see PDF). Here, MMP7 is linked to periodontitis.