H. pylori, Periodontal Pathogens, and Risk Factors of Gastric Cancer

Gastric cancer is the second most common malignancy worldwide. Previously, epidemiologic studies have suggested a positive association between self-reported tooth loss and the risk of gastric cancer. However, the mechanism underlying this association remains under question. Objectives: We are conducting a case-control study to evaluate the association between major pathogens of periodontal disease and the risk of gastric cancer precursor lesions. Methods: All of the cases and controls were identified from participants undergoing upper gastrointestinal endoscopy in Bellevue Hospital Center in New York City. Presence and pathogen burden of Porphyromonas gingivalis (Pg), Tannerella forsythensis (Tf), Treponema denticola (Td), and Actinobacillus actinomycetemcomitans (Aa) in the saliva and plaque samples were measured using quantitative real-time PCR. Helicobacter pylori colonization was examined in serum. In the first 30 participants, we evaluated associations between conventional risk factors of gastric cancer and presence of the four major pathogens of periodontal disease. Results: Presence of Tf, Td were significantly associated with older age (p < 0.01); presence of Td was negatively associated with cigarette smoking status (p = 0.04). H. pylori measured in serum was positively associated with pathogen burden of Aa in the plaque samples (p = 0.02~0.07). Conclusion: The findings suggest that age, smoking status, and H. pylori colonization may be important confounders in assessing relationship between pathogens of periodontal disease and the risk of gastric cancer or precursor lesions. Supported by research grants R21DE018438 and U19DE018385 from NIH/NIDCR.