Tsai CW, Chang WS, Xu Y, et al. - Researchers examined if and how circulating IGF(insulin-like growth factor)-1 and IGFBP-3 (insulin-like growth factor-binding protein-3) are associated with the risk of developing bladder cancer in this large case control study using a Mendelian randomization approach. Participants included 2011 bladder cancer cases and 2369 healthy controls. A significantly decreased bladder cancer risk was found in relation to higher genetic risk score (GRS) for IGF-1. When individuals were split into high and low IGF-1 groups using the median GRS value in the controls, a 21% decreased bladder cancer risk was noted in the high GRS group vs the low GRS group. There was no link between genetically predicted circulating IGFBP-3 and bladder cancer risk. Overall, it was shown for the first time that there exists a strong inverse association between circulating IGF-1 level and bladder cancer risk.