Correlation Between Periodontitis and Non-Alcoholic Fatty Liver Disease: Systematic Review and Meta-Analysis

Background & Aims Both non-alcoholic fatty liver disease (NAFLD) and periodontitis are prevalent chronic conditions. While prior research indicates a possible connection between these diseases, the conclusions in the existing literature are highly variable and the findings are inconsistent. Consequently, there is an urgent need for a comprehensive evaluation of this relationship. Methods This study conducted a systematic search of the PubMed, Embase, Scopus, and Web of Science databases, encompassing research published up to June 25, 2025, to assess the association between NAFLD and periodontitis. The review incorporated cross-sectional, case-control, and cohort studies. A meta-analysis was performed utilizing a random effects model, with subgroup and sensitivity analyses conducted to investigate potential sources of heterogeneity. Results Following an extensive screening process of the 628 studies initially retrieved, a total of 12 studies were deemed suitable for inclusion in the analysis, comprising 9 cross-sectional studies and 3 cohort studies. A meta-analysis was performed on the adjusted odds ratios (OR) and 95% confidence intervals (CI) derived from the cross-sectional studies. The results showed that there was a significant association between periodontitis and NAFLD (OR: 1.24, 95% CI: 1.12, 1.38). Subgroup analysis based on diagnostic criteria differences indicated that periodontitis diagnosed by clinical attachment loss and NAFLD had a stronger association (OR: 1.38) and lower heterogeneity ( I ² : 25%). The results of the cohort studies suggested a bidirectional relationship between periodontitis and NAFLD, but the heterogeneity was too high, so more high-quality prospective studies are needed to confirm this relationship. Conclusion The current research evidence indicates that there is a significant association between periodontitis based on clinical attachment lever definition and NAFLD.