A protective role of genetically predicted sex hormone-binding globulin on stroke.

INTRODUCTION: The role of sex hormone-binding globulin (SHBG) on stroke has been investigated in several observational studies. To provide the causal estimates of SHBG on stroke and its subtypes, bi-directional and multivariable Mendelian randomization (MR) analyses are performed.

METHODS: The genetic instruments of SHBG were obtained from the UK Biobank. Outcome datasets for stroke and its subtypes were taken from the MEGASTROKE Consortium. The main analysis used in this study is the inverse variance weighting, complemented by other sensitivity approaches to verify the conformity of findings.

RESULTS: We found that the risk of stroke grew by 13% (odd ratio [OR] = 0.87, 95% confidence interval [CI] = 0.79-0.95, P = 0.0041) and the risk of ischemic stroke grew by 15% (OR = 0.85, 95%CI = 0.77-0.95, P = 0.0038) caused by genetically predicted SHBG. The causal association remains robust in the reverse MR and multivariable MR analyses for stroke (reverse MR: all P  > 0.01 for the IVW method; MVMR: OR = 0.72, 95%CI = 0.59-0.87, P  = 0.0011) and ischemic stroke (reverse MR: all P  > 0.01 for IVW; MVMR: OR = 0.70, 95%CI = 0.56-0.86, P  = 0.0007).

CONCLUSION: Our MR study provides novel evidence that SHBG has an inverse association with stroke and ischemic stroke, exerting protective effects on stroke.