Study ID	Criteria	Description
Albino 2010	Inclusion criteria	Participants with euthyroid benign goitres
	Exclusion criteria	Participants with below normal TSH levels
	Diagnostic criteria	Participants with normal TSH levels, multinodular goitre and excluded malignancy (fine needle aspiration biopsy of the dominant and/or suspect nodules and by cytology studies)
Bonnema 2007	Inclusion criteria	Participants with euthyroid benign goitres
	Exclusion criteria	Participants with a history of cardiac failure or ventricular arrhythmias, previous malignant disease, or physical or psychiatric disabilities suggestive of difficulties in adherence to the protocol
	Diagnostic criteria	The diagnosis was based on clinical examination, 99mTc scintigraphy, and ultrasonography
Cubas 2009	Inclusion criteria	Participants with euthyroid benign goitres
	Exclusion criteria	Participants with previous surgery, TSH‐suppressive therapy with T4, or radioactive iodine treatment, serious medical conditions
	Diagnostic criteria	The diagnostic setup included clinical examination, 131I thyroid scintigraphy, and ultrasonography
Fast 2010	Inclusion criteria	Non‐pregnant, non‐lactating participants older than 18 yr, with a nontoxic nodular goitre (i.e. thyroid volume above 28 mL and two or more nodules larger than 1 cm), the presence of goitre‐related symptoms (i.e. pressure, cosmetic complaints, or both), subclinical hyperthyroidism (i.e. serum TSH < 0.30 mU/L and normal serum T4 and T3 levels), or subclinical hyperthyroidism alone
	Exclusion criteria	Participants with subclinical hyperthyroidism were required to have hyperthyroid symptoms that did not necessitate the use of antithyroid drugs or ‐blockers
	Diagnostic criteria	The diagnostic setup included clinical examination, thyroid function tests, 99mTc scintigraphy, and ultrasonography
Fast 2014	Inclusion criteria	Participants with euthyroid benign goitres
	Exclusion criteria	Participants with previous partial or near total thyroidectomy, a history of 131I therapy, or a history of therapy alone
	Diagnostic criteria	The diagnostic setup included clinical examination, thyroid function tests, and ultrasonography
Nielsen 2006	Inclusion criteria	Participants with euthyroid or subclinical hyperthyroid benign goitres
	Exclusion criteria	Participants who were averse to any treatment, were younger than 18 years, had intrathoracic goitre > 100 mL, had previous 131I therapy, were unable to complete follow‐up, had a 24‐hour thyroid 131I uptake < 20%
	Diagnostic criteria	The diagnostic setup included clinical examination, thyroid function tests, 99mTc scintigraphy, and ultrasonography
T3: triiodothyronine;T4: thyroxine;99mTc: Technetium‐99m; TSH: thyroid stimulating hormone