Table 4.

Characteristics of 15 studies included in the meta-analysis.

Author	Year	Region	Participants		Types of thyroid dysfunction	Study design
			RA	Control
Shiroky JB	1993	Canada	119	108	Dysfunction Hypothyroidism Hyperthyroidism	Case-control
Andonopoulos AP	1996	Greece	101	70	Dysfunction Hypothyroidism Hyperthyroidism	Case-control
Al-Awadhi AM	1999	Kuwait	48	90	Dysfunction Hypothyroidism SCH Overt hypothyroidism	Case-control
Innocencio RM	2004	Brazil	25	113	Dysfunction Hypothyroidism SCH	Case-control
Antonelli A	2006	Italy	91	180	Dysfunction Hypothyroidism SCH Hyperthyroidism	Case-control
Al-Awadhi AM	2008	Kuwait	177	577	Dysfunction Hypothyroidism SCH Overt hypothyroidism Hyperthyroidism	Case-control
Przygodzka M	2009	Poland	100	55	Dysfunction Hypothyroidism SCH Hyperthyroidism	Case-control
Santos MJ	2010	Portugal	98	102	Hypothyroidism	Case-control
McCoy SS	2012	USA	650	650	Hypothyroidism SCH	Cohort
Kerola AM	2014	Finland	7209	None	Overt hypothyroidism	Case-control
Wang SL	2014	Taiwan	3657	14628	Dysfunction Hypothyroidism Hyperthyroidism	Case-control
Zamora-Legoff JA	2016	USA	497	527	Hypothyroidism	Case-control
Tascilar K	2016	Canada	1357	13570	Hypothyroidism	Case-control
Posselt RT	2017	Brazil	210	141	Hypothyroidism	Case-control
Present Study	2017	China	65	550	Dysfunction Hypothyroidism Hyperthyroidism Overt hypothyroidism SCH	Case-control