BACKGROUND The effects of viral hepatitis (VH) on type 2 diabetes (T2D) remain controversial. AIM To analyze the causal correlation between different types of VH and T2D using Mendelian randomization (MR). METHODS Single nucleotide polymorphisms of VH, chronic hepatitis B (CHB), chronic hepatitis C (CHC) and T2D were obtained from the BioBank Japan Project, European Bioinformatics Institute, and FinnGen. Inverse variance weighted, MR-Egger, and weighted median were used to test exposure-outcome associations. The MR-Egger intercept analysis and Cochran's Q test were used to assess horizontal pl...