Specifically, the genetically elevated circulating IL-18 levels (1 SD increase) were causally associated with 21.4% higher odds for the risk of SLE (odds ratio [OR] = 1.214; 95% confidence interval [CI] = 1.049–1.404; P = 0.009) and with 14.2% higher odds for the risk of IBD (OR = 1.142; 95% CI = 1.062 − 1.228; P < 0.001). This evidence concerns the gene IL18 and systemic lupus erythematosus.