IL18 and type 2 diabetes mellitus: However, due to the interference of multiple confounding factors and the “reverse causal effect” in observational studies, it remains unclear whether high levels of IL-18 trigger the onset of T2DM and cause or push the development of the disease as a main confounding factor, an issue that calls for systematic investigations for the development of effective preventive or therapeutic strategies, e.g., by Mendelian randomization (MR) studies (Noyce et al., 2017; Schuetz and Wahl, 2017).