Global burden of periodontal disease and dietary risk correlation: A joint GBD–GDD analysis (1990–2018)

Background Periodontal disease represents a major global health challenge. Existing research on its risk factors has largely relied on single databases and lacks systematic quantitative evaluation of specific dietary components. Therefore, the study aimed to evaluate the associations between six representative dietary factors and disability-adjusted life years (DALYs) for periodontal disease based on data from the Global Burden of Disease (GBD) and Global Dietary Database (GDD). The analysis also sought to elucidate the potential impact of dietary structure on the global burden of periodontal disease from the perspectives of temporal trends, socioeconomic disparities, and geographic inequality. Materials and Methods Data from countries and territories worldwide between 1990 and 2018 were extracted from the GBD and GDD databases. Six dietary factors were analyzed: fruits, non-starchy vegetables, dietary fiber, processed meat, sugar-sweetened beverages, and dietary sodium. Descriptive statistics, Spearman correlation, multivariable regression, estimated annual percentage change (EAPC), Gini inequality index, and ARIMA forecasting were employed to assess spatiotemporal trends in periodontal DALYs and their association with dietary factors. Sensitivity and interaction analyses were conducted to validate robustness. Results Between 1990 and 2018, the global burden of periodontal disease showed pronounced regional heterogeneity, with the highest DALYs in Africa and in countries with low-to-middle Socio-demographic Index (SDI). EAPC analysis revealed a declining trend in high-SDI countries and an increasing trend in several low-SDI regions. Sugar-sweetened beverage intake was positively correlated with DALYs (r = 0.2795, P < 0.001), while fruits and non-starchy vegetables showed weak, non-significant negative correlations. Regression analysis indicated a positive association between risk dietary score and DALYs (β= 0.87, P = 0.018) and a negative association for protective dietary score (β = –1.05, P = 0.002); However, these associations lost significance after adjusting for SDI. SDI remained strongly negatively associated with DALYs (β= –2.26, P < 0.001), underscoring its role as a major determinant of periodontal disease burden. ARIMA/ARIMAX models projected a relatively stable global burden through 2030, with persistent uncertainty in low-SDI countries. Gini coefficient analysis revealed increasing inequality in DALYs (from 0.21 to 0.25), alongside sustained disparities in dietary patterns and socioeconomic development. Sensitivity analyses confirmed the robustness of associations after excluding dietary sodium. Conclusions The global burden of periodontal disease demonstrates marked spatiotemporal inequality. Although dietary structure is significantly associated with DALYs, its effect is moderated by socioeconomic development. Strategies to prevent periodontal disease should consider both nutritional interventions and socioeconomic context to reduce individual risk and narrow global health disparities, ultimately promoting oral health equity.