ABO Blood Groups and Its Association with Oral Cancer, Oral Potentially Malignant Disorders and Oral Submucous Fibrosis– A Systematic Review and Meta-Analysis

OBJECTIVE: The study aimed to evaluate the association between ABO blood groups and oral cancer, other potentially malignant disorders (OPMD), and oral submucous fibrosis (OSMF). MATERIALS AND METHODS: A search was conducted in Medline, Cochrane databases, Google Scholar, Scopus, Web of Science and Directory of Open Access Journals (DOAJ) for studies evaluating ABO blood groups as risk factors for oral cancer and OPMD among cases and controls. The PRISMA guidelines were followed for the meta-analysis. Participants included patients with oral cancer, and OPMD diagnosed using histopathologic investigations. Sub-group analysis was conducted to evaluate the association between blood groups and OSMF. Quality was evaluated using the Risk of Bias Assessment tool. Fixed effects model was used to assess the odds ratio for the association. RESULTS: There were 1,352, 414, and 299 cases of oral cancer, OPMD, and OSMF and 11,699, 7,382 and 7,307 controls for analysis respectively. Blood group A was significantly associated with both oral cancer (Odds ratio: 1.27 [95% CI, 1.10, 1.47], P= 0.001) and OPMD (Odds ratio: 1.33 [95% CI, 1.01, 1.47], P= 0.04). No association was noted between blood group B and AB with oral cancer, OPMD, and OSMF. Blood group O was significantly associated with lower chances of oral cancer (Odds ratio: 0.81 [95% CI, 0.71, 0.93], P= 0.002). CONCLUSION: Meta-analysis suggests blood group A has a greater risk for developing oral cancer and OPMD. Blood group O was associated with lower chances of oral cancer. No association was noted between ABO blood group system with OSMF.