Fig. 1

The study design overview for analyzing the causal effects of NSAIDs use on the risk of BPH using Mendelian randomization. Assumption 1: instrumental variables (IVs) exhibit robust associations with the exposures; Assumption 2: IVs are not associated with any potential confounding factors; Assumption 3: genetic instruments exert their sole impact on the outcome through the relevant exposures. SNP: single nucleotide polymorphisms, NSAIDs: non-steroidal anti-inflammatory drugs, LD: linkage disequilibrium, MR: Mendelian randomization, IVW: inverse variance weighted