CXCL8 and diabetes mellitus: As shown in Table 3, only the group was significantly associated with the IL-8 levels of GCF (β = 1.17; P = 0.001), while diabetes history and hypertension history were not associated with IL-8 level (β = 0.27, P = 0.486 and β =  − 0.61, P = 0.071).