Dietary factors mediated the causal association between educational attainment and chronic periodontitis: A 2-sample Mendelian randomization study

Dietary factors, influenced by educational attainment (EA) have the potential to affect development and course of chronic periodontitis (CP), whereby, the potential mediating role of dietary factors in the casual associations remain unclear. This study employed Mendelian randomization (MR) to explore the causal effect of EA on CP and to identify and quantify the mediating role of dietary factors, aiming to provide evidence for improving CP management. EA was considered as exposure, dietary factors as mediator, and CP as outcome. Genome-wide association study summary statistics were obtained from 3 large-scale public databases: the Social Science Genetic Association Consortium, the UK Biobank, and the FinnGen project. The main MR method was inverse-variance weighted, supported by complementary methods including MR-Egger regression, weighted median, simple mode, and weighted mode. The reverse causality detection was verified through Steiger filtering. Sensitivity analysis was conducted to assess potential horizontal pleiotropy, heterogeneity, and robustness of the MR analysis. Higher EA was causally associated with a reduced risk of CP (odds ratio = 0.772, 95% confidence interval: 0.663-0.899, P < .001). Among the dietary factors, alcohol and fruit consumption were identified as significant mediators, with mediation effects of -0.17 and -0.11, accounting for 67% and 44% of the total effect, respectively. The robustness of the MR results was confirmed by the sensitivity analysis. This study provides genetically predicted evidence supporting a protective causal effect of EA on CP, and highlights the mediating effect of alcohol and fruit consumption. These findings suggest that modifying specific dietary factors could be an effective strategy in CP management.