We also performed reverse Mendelian randomization to investigate the causal association between IBD and sex hormones and demonstrated a significant association between IBD and SHBG and total testosterone in men, with an OR of 1.02 (95% CI: 1.00-1.04, P=0.0195) for IBD on SHBG in men and an OR of 1.01 (95% CI: 1.00-1.02, P=0.0200), and was not statistically significant for bioavailable testosterone versus estradiol in men (Figure 2C, Table 7). Here, SHBG is linked to inflammatory bowel disease.