FIG. 1.

Flowchart for inclusion of the 35 studies adapted from the PRISMA 2020 statement.²⁷ Six databases were systematically searched during the identification phase. Titles and/or abstracts were screened, and if records were eligible, the full text was assessed during the screening phase, resulting in the total number of studies included. Records refer to the title and/or abstract of a report. A report is a document that provides information about a study. AE, adverse event; Echo, ultrasound echogenicity; fT3, free triiodothyronine; fT4, free thyroxine; IM, immune markers including glutathione peroxidase, malondialdehyde, superoxide dismutase, total antioxidant capacity; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; QoL, quality of life; T3, total triiodothyronine; T4, total thyroxine; TGAb, thyroglobulin antibodies; TPOAb, thyroid peroxidase antibodies; TRAb, thyrotropin receptor antibody; TSH, thyrotropin; Vol, thyroid volume.