FGF21 and glioblastoma: Additionally, our findings indicated that fibroblast growth factor 21 (FGF21) was associated with a decreased likelihood of developing glioblastoma according to the IVW approach (OR, 0.53; 95% CI: 0.32–0.87; p = 0.01), with the analysis showing no significant heterogeneity (MR Egger Q = 9.59, Q p-value = 0.65) and no horizontal pleiotropy (P Egger Intercept = 0.92, P MR Presso = 0.70) (Figure 2; Supplementary Table S4).