Fig. 2
Mendelian randomization research process. (A) The total effect between uveitis and colorectal cancer. c represents the overall effect of exposure to colorectal cancer on the outcome of uveitis, while d represents the overall effect of exposure to uveitis on the outcome of colorectal cancer. (B) The overall effect can be divided into two parts .(i) indirect effects (a × b) generated by two-step Mendelian randomization(a represents the effect of uveitis exposure on the outcome of immune cells, b represents the effect of immune cell exposure on the outcome of colorectal cancer). (ii) direct effect (c′=c–a×b). The proportion of the mediated effect is the ratio of the indirect effect to the total effect.
