GDF15 and type 2 diabetes mellitus: Although the functional role of GDF15 is not fully known, elevated GDF15 levels in blood have been reported as a biomarker of several pathological conditions, such as cancer, inflammatory disorders, cardiovascular disease and type 2 diabetes, and as a biomarker of mortality of any kind (Adela and Banerjee, 2015; Hagström et al., 2017; Tsai et al., 2018).