Supplementary Material for: Population-Based Structural Evidence: Triadic Effects of Periodontitis, Depression, and Biological Aging on Cognitive Health

Introduction: Cognitive impairment represents critical public health challenges in aging societies. This study investigates periodontitis, depression, and biological aging’s triadic effects on cognition. Methods: Structural equation modeling (SEM) and relative weight analysis (RWA) were applied to analyze data from 2011–2014 National Health and Nutrition Examination Survey (NHANES) (N=1,816). Cognitive function, periodontitis, depression, and biological age (PhenoAge) were assessed with covariates adjustment. Results: SEM revealed periodontitis severity, depressive symptoms, and PhenoAge advancement exhibited significant direct associations with lower cognitive performance after covariate adjustment. Simultaneously, biological aging partially mediated the influence of both depression and periodontitis on cognitive outcomes. RWA showed dominated cognitive variance, while periodontitis, depression and PhenoAge contributed significantly. Conclusions: This confirms triadic interdependencies where biological aging partially mediates periodontitis/depression effects on cognition. Prioritizing periodontal care and mental health may mitigate cognitive decline, especially in low-resource settings.