Figure 1.

The flowchart of Mendelian Randomization analysis of 1400 metabolites and risk of urinary stones. Among the above metabolites, 309 which were defined as metabolite ratios were excluded in our study. IV = instrumental variables, SNPs = single nucleotide polymorphisms, LD = linkage disequilibrium, IVW = inverse variance weighted, LDSC = linkage disequilibrium score, MR = Mendelian randomization, MR-PRESSO = MR-Pleiotropy RESidual sum and outlier, KEGG = Kyoto Encyclopedia of Genes and Genomes, SMPDB = The Small Molecule Pathway Database.