Adachi et al measured lactate dehydrogenase (LDH) and hemoglobin (Hb) concentrations in saliva to diagnose the degree of periodontal tissue damage and the degree of bleeding gums, respectively, in 686 patients, and showed that gastric HP infection is a potential risk factor for the onset and deterioration of periodontal disease.44 This evidence concerns the gene GSTM1 and periodontal disorder.