GDF15 and diabetes mellitus: The only relevant study conducted to date was a prospective, nested case–control study [15], the results of which were that baseline circulating GDF-15 concentrations were higher in cases than in control participants, and had a nonsignificant positive association with the incidence of diabetes (age and sex-adjusted OR 1.21; 95% CI 0.997, 1.46; p = 0.054).