ENHO and type 2 diabetes mellitus: Overall, meta-analysis of 15 studies [24, 27, 91–103] (n = 2,813 participants) revealed that the serum levels of adropin were significantly lower in patients with T2DM compared with non-diabetic participants (WMD= -0.60 ng/mL, 95% CI: -0.70 to -0.49, P < 0.001; I2 = 99.48%, P-heterogeneity < 0.001) (Fig. 2).