Relationship between dietary diversity and periodontitis: analysis of NHANES 2003–2014

BACKGROUND: Periodontitis is a common chronic oral inflammatory disease with multiple etiologies. The relationship between Dietary Diversity Score (DDS) and periodontitis prevalence remains unclear. OBJECTIVE: To elucidate the DDS-periodontitis prevalence association. METHODS: Logistic regression evaluated the linkage between DDS and periodontitis. Restricted cubic spline (RCS) regression assessed non-linear linkage. Interaction tests identified effect-modifying factors. Weighted quantile sum (WQS) regression identified food categories influencing associations. Mediation analysis investigated the mediating roles of body roundness index (BRI) and red blood cell distribution width (RDW). RESULTS: In the full-adjusted model, higher DDS was linked with lower periodontitis prevalence odds (odds ratio [OR]: 0.95; 95% confidence interval [CI]: 0.93-0.98; p < 0.001), with an evident dose-response relationship. RCS indicated no significant non-linear association between DDS and periodontitis (p-non- linear = 0.144). WQS showed balanced weight distribution of five main foods (all ~20%), indicating a dietary synergy effect. Subgroup analyses revealed significant interactions between DDS and periodontitis within subgroups of age, smoking, BMI, alcohol consumption, and osteoarthritis (p-interaction < 0.05). RDW (2.26%) and BRI (1.69%) partially mediated the linkage between DDS and the periodontitis prevalence. CONCLUSION: Higher DDS is independently associated with reduced prevalence of periodontitis, driven by the synergistic contribution of multiple food categories. Optimizing dietary breadth is important in preventing periodontitis.