Concerning the heterogeneity of the studies included in meta-analyses. Comment on: “Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis” - Peres, Gabriel; Ianhez, Mayra; Polo, Tatiana C. F. [UNESP]; Abbade, Luciana P. F. [UNESP]; Miot, Hélio A. [UNESP] (Wiley, 2022)