Circulating phylloquinone concentrations and risk of type 2 diabetes : A mendelian randomization study

This study aims to investigate the causal relation between circulating phylloquinone (vitamin K1) concentrations and type 2 diabetes using a Mendelian Randomization (MR) approach. We used data from thee cohorts: the European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct case-cohort study, Diabetes Genetics Replication and Meta-analysis (DIAGRAM) and the UK Biobank, resulting in 69,647 type 2 diabetes cases. We calculated a weighted genetic risk score including four genetic variants previously found to be associated with circulating phylloquinone concentrations. Inverse-variance weighted analysis was used to obtain a risk ratio (RR) for the causal relation between circulating phylloquinone concentrations and risk of type 2 diabetes. Presence of pleiotropy and the robustness of the results were assessed using MR-Egger and weighted-median analyses. Genetically-predicted concentrations of circulating phylloquinone was associated with lower risk of type 2 diabetes with a RR of 0.93 (95% confidence interval: 0.89;0.97) per every ln-nmol/L unit increase in circulating phylloquinone. The MR-Egger and weighted median analyses showed RRs of 0.94 (0.86;1.02) and 0.93 (0.88;0.98), respectively, indicating no pleiotropy. In conclusion, our study supports that higher circulating phylloquinone may be causally related with lower risk of type 2 diabetes, highlighting the importance of sufficient phylloquinone in the human diet.