In conclusion, this MR study using a sample of sub-Saharan Africans provides evidence for a causal effect of circulating GIP and IL-1RA levels on insulin resistance and β-cell function in non-T2D individuals and suggests that circulating levels of several other cytokines and hormones that have previously been reported in relation to T2D are not causal. The gene discussed is GIP; the disease is type 2 diabetes mellitus.