The sensitivities and specificities of Hb an LD were also higher than those obtained using self-administered questionnaires for the screening of periodontal disease [21–23] (sensitivity: 0.22, specificity: 0.81; sensitivity: 0.36, specificity: 0.97; sensitivity: 0.55, specificity: 0.98, respectively). Here, GSTM1 is linked to periodontal disorder.