GDF2 and type 2 diabetes mellitus: Xu et al. found in middle-aged and older populations [23] as well as patients with T2DM and NAFLD [10], circulating BMP9 levels positively correlated with HDL and negatively correlated with markers of adiposity such as waist-to-hip ratio (WHR) or BMI, parameters of glucose metabolism (FPG and HbA1c) and TG.