Table 1.

Characteristics of included studies in this meta-analysis

Authors	Year	Country/Ethincity	Definition		Sample size		PCOS			Control			HWE
			PCOS	Controls	PCOS	Control	AA	AT	TT	AA	AT	TT
Barber et al.	2008	UK/Caucasian	Rotterdam criteria	Unknown	463	1336	99	231	133	212	644	480	0.870
Yan et al.	2009	China/Asian	Rotterdam criteria	Females proven fertile with normal menstrual cycle and ovarian morphology, and no family history of abnormal menses or hirsutism	215	227	5	55	155	1	43	183	0.361
Li et al.	2013	China/Asian	Rotterdam criteria	Regular menstrual cycle (26–35) and normal ovarian morphology	3599	3082	67	867	2665	29	563	2490	0.650
Kim et al.	2014	Korea/Asian	Rotterdam criteria	Women without special health problem	552	559	7	118	427	8	106	445	0.559
Ramos et al.	2015	Brazil/Caucasian	Rotterdam criteria	Non-hirsute,regular ovulatory cycles, no hormone drug taking at least 3 months before the study	181	96	39	83	59	17	47	32	0.971

HWE Hardy-Weinberg equilibrium