CCL4 and polyp of colon: The two circulatory cytokines causally associated with colonic polyp were: macrophage inflammatory protein-1b (MIP1b, IVW—OR: 0.956, 95%CI: 0.927–0.987, p = 0.005; WM—OR: 0.954, 95%CI: 0.916–0.993, p = 0.021) and interleukin-6 (IL-6, IVW—OR: 0.931, 95%CI: 0.870–0.995, p = 0.035) (Table 1).