IGF1 and Familial prostate cancer: Conversely, if rs700752 (a SNP not in LD with, and quite distant from rs11977526) is used as an instrument for IGF levels, a one SD increase in IGF‐I or IGFBP‐3 would reduce the risk of prostate cancer‐specific mortality between ∼25% and 50%, depending on the genotype‐exposure estimates considered.