Zhou et al. evaluated 12 studies and 4,247 participants (2,271 NAFLD patients and 1,976 controls) and found that there was an insignificant difference in circulating RBP4 levels in NAFLD patients versus controls (SMD = 0.08, 95% CI: −0.21 to 0.38), NASH patients versus controls (SMD = −0.49, 95% CI: −1.09 to 0.12), SS patients versus controls (SMD = −0.72, 95% CI: −1.64 to 0.20), and NASH patients versus SS patients (SMD = −0.04, 95% CI: −0.32 to 0.24) (50). This evidence concerns the gene RBP4 and metabolic dysfunction-associated steatohepatitis.