March 2023

Background: Studies have reported varying relationships between periodontitis and non-alcoholic fatty liver disease (NAFLD). This review aimed to summarise evidence by pooling published data on the association between periodontitis and NAFLD. Methods: PubMed, CENTRAL, Web of Science, and Embase databases were searched for cross-sectional, case-control, or cohort studies published up to 20th June 2022. The PICO statement was: In the general Population does the presence of periodontitis (Intervention) as compared to no periodontitis (Comparison) lead to NAFLD (Outcome). All included studies were to report the association between periodontitis and NAFLD using odds ratios (OR) or risk ratios with 95% confidence intervals (CI). Random effects meta-analysis was conducted to obtain pooled OR with 95% CI. Results: Meta-analysis of seven studies with data of 192,815 participants found no association between periodontitis and NAFLD (OR: 1.04 95% CI: 0.97, 1.12). There was medium heterogeneity in the meta-analysis (I2=58%). The results did not change with the exclusion of any study. A small risk of NAFLD was noted in periodontitis patients on analysis of two cohort studies. Results were non-significant for other study types. Subgroup analysis based on the study population and diagnostic method for NAFLD also failed to find relationships. Conclusion: Current evidence fails to demonstrate a link between periodontitis and NAFLD. Keywords: Periodontitis, systemic diseases, fatty liver, oral