In the subgroup of nonobese population but not the obese population, the overall betatrophin level in T2DM patients was much higher than that in the nondiabetic controls (nonobese: random-effect SMD, 0.82; 95% CI 0.42 to 1.21; P < 0.001; obese: random-effect SMD, −0.39; 95% CI, −0.95 to 0.18; P = 0.18). This evidence concerns the gene ANGPTL8 and type 2 diabetes mellitus.