Investigating the genetic effects of metformin-related targets on IgA nephropathy using Mendelian randomization

The role of metformin and its downstream targets in IgA nephropathy (IgAN) remains unclear. In this study, we used Mendelian randomization to explore potential causal links between genetic proxies of metformin targets, plasma proteins, and the risk of IgAN. Data on plasma protein, metformin target genes, and IgAN data were obtained from the IEU OpenGWAS Project. Single-nucleotide polymorphisms (SNPs) associated with metformin target genes and plasma proteins were selected as instrumental variables. We applied a two-sample and two-step Mendelian randomization approach to examine the causal relationships among these variables. Inverse variance weighted analysis revealed that electron transport flavoprotein dehydrogenase (ETFDH) inhibitors were associated with a reduced risk of IgAN (odds ratio [OR] = 0.948, 95% confidence interval [CI]: 0.923–0.973, p p = 0.012) and negatively correlated with ETFDH inhibitor use (OR = 0.775; 95% CI, 0.709–0.848; p