Non-alcoholic Fatty Liver Disease as risk factors for Chronic Kidney Disease: A Bidirectional Mendelian Randomization Study

Background: Chronic kidney disease (CKD) and non-alcoholic fatty liver disease (NAFLD) are two significant global public health concerns. Recent reports suggest that NAFLD may increase the risk of developing CKD. However, the specific causal relationship between these two conditions has not been thoroughly investigated. Methods In this study, we analyzed genome-wide association study (GWAS) summary data of CKD and NAFLD. We identified single nucleotide polymorphisms (SNPs) associated with these diseases as instrumental variables (IVs) at a genome-wide significance level ( P  < 1.0 × 10 − 5 ) at first. Then, for Mendelian randomization (MR) analysis, we primarily used the inverse variance weighted (IVW) method, while employing the MR-Egger, weighted model, simple model, and weighted median methods for quality control. We also conducted sensitivity analysis to ensure the robustness of the results. Results Our MR analysis revealed a significant association between genetically predicted NAFLD and an increased risk of CKD using the IVW method (OR, 0.94; 95% CI, 0.89–1.00; P  = 0.049). However, we found no evidence to support a causal relationship between CKD on NAFLD (IVW: P  = 0.467). Conclusion Based on our findings, there is a causal relationship between NAFLD and CKD. Further investigations are necessary to elucidate the impact of these two diseases, as our results do not support a causal effect of CKD on NAFLD.