Causal association between micronutrients and oral diseases: a bidirectional two-sample Mendelian randomization study

Background Previous studies had shown that multivitamin and mineral deficiencies increase the risk of oral diseases. To this end, we conducted a Mendelian randomization (MR) analysis to assess the causal relationship between micronutrients and oral diseases. Methods We performed bidirectional MR analyses utilizing publicly available summary statistics from independent European-ancestry cohorts. The study investigated potential causal associations between 15 micronutrients levels and the risk of 13 oral diseases. Five distinct MR methods were employed for analysis, with the inverse variance weighted (IVW) method serving as the primary approach for causal inference. Furthermore, sensitivity analyses were conducted to assess potential horizontal pleiotropy and heterogeneity in the results, demonstrating the robustness of the findings. Results MR analyses revealed significant associations between the levels of 7 micronutrients and the risk of 8 oral diseases. Notably, vitamin B9 demonstrated a protective effect against cleft lip and palate (IVW, OR = 0.2584; 95% CI, 0.0919–0.7267; P = 0.0103), vitamin D showed a protective effect against chronic periodontitis (IVW, OR = 0.4595; 95% CI, 0.2455–0.8598; P = 0.0150), and vitamin E exhibited a protective effect against pulp and periapical diseases (IVW, OR = 0.6927; 95% CI, 0.4801–0.9993; P = 0.0496). Reverse MR analyses indicated causal associations between 8 oral diseases and 5 micronutrient levels. These findings were robust across extensive sensitivity analyses. Conclusion Our results strongly supported the important role of micronutrients in oral diseases. These findings provided a valuable reference for better management of oral diseases.