Fig. 2

Analysis of the causal effect of increased circulating IL-18 levels on the risk of SLE. A Scatter plot of genetic association with circulating IL-18 levels (1 SD increase) against the genetic associations with SLE. The slope of the line represents the causal association, with each method having a different line. B Forest plot of the causal effects of circulating IL-18 levels (1 SD increase) on the risk of SLE. The causal effect of circulating IL-18 levels on SLE is estimated using each SNP singly (using the Wald ratio). The MR estimate using all SNPs derived from the IVW methods is shown for comparison. C Funnel plots of individual variant effects for the instrument variables plotted against the inverse of their standard error. D Leave-one-out analysis. Each dot in the forest plot represents the MR estimate (using IVW) excluding that particular SNP. The overall analysis (using IVW) including all SNPs is shown for comparison. IL-18, interleukin-18; SLE, systematic lupus erythematosus; SNP, single-nucleotide polymorphism; MR, Mendelian randomization; IVW, inverse variance weighted