Prospective cohort studies have shown that untreated patients with periodontitis can also present with decreased serum levels of glucagon-like peptide-1 (GLP-1) compared with healthy periodontal controls.14 Periodontitis patients exhibited a 33% increased risk of hyperglycemia15 and a 1.24-fold increased risk of developing T2D16 after >5 years of follow-up. Here, GCG is linked to periodontitis.