FNDC5 and type 2 diabetes mellitus: The present meta-analysis discovered that the correlations between an FNDC5 rs3480 (G/A) and susceptibility to T2DM in homozygote (GG vs AA: OR = 1.76, 95% CI = 1.31–2.37, P = 0.0002, I2 = 59%) genetic model was statistically significant.