FGF21 and metabolic dysfunction-associated steatotic liver disease: In the sensitivity analyses for the comparison between patients with NAFLD and controls, after excluding studies with: (i) pediatric/adolescent populations (n = 9; Fig. S3a); (ii) morbidly obese populations undergoing bariatric surgery (n = 4; Fig. S3b); (iii) NOS score < 7 (n = 19; Fig. S3c); (iv) outliers of FGF-21 SMD (n = 3; Fig. S3 d); (v) the use of the definition of MAFLD for the diagnosis of the disease (n = 2; Fig. S3e), FGF-21 levels remained higher in patients with NAFLD compared to controls in all the analyses (Table 2).