Fig. 1

Overview of MR rationale, design, and procedures. There are three key assumptions for MR study. Assumption 1: the GVs selected as IVs should be strongly associated with the exposures; Assumption 2: the used GVs should not be associated with any potential confounder; Assumption 3: the GVs should influence the outcome risk merely through the exposures, not via any alternative pathway. Abbreviations: ctrl = control; FGP = female genital prolapse; GVs = genetic variants; IV = instrumental variable; IVW = inverse variance weighted; MR = Mendelian randomization; MVMR = multivariable Mendelian randomization; SNP = single-nucleotide polymorphism; TDI = Townsend deprivation index; UVMR = univariable Mendelian randomization; WM = weighted median