Table 1.

The characteristics of the included studies

				Control subjects			Breast cancer Patients			Control subjects			Breast cancer Patients
Authors	Publication year	Country	Case/control	LL	LM	MM	LL	LM	MM	QQ	QR	RR	QQ	QR	RR	HWE
Stevens et al.	2006	USA	483/483	202	223	58	176	230	77	238	198	47	259	182	42
Antognelli et al.	2009	Italy	547/544	188	125	231	107	115	325	340	152	52	484	50	13
Naidu et al.	2010	Malaysia	387/252	126	109	17	159	178	50	115	115	22	200	158	29
Hussein et al.	2011	Egypt	200/200	81	65	54	70	62	68	46	42	12	51	41	8
Agachan et al.	2006	Turkey	33/52	-	-	-	-	-	-	17	29	6	17	4	12
Gallicchio et al.	2007	USA	58/904	-	-	-	-	-	-	469	353	82	38	15	5
DeRoo et al.	2014	USA	294/646	HR=0.96 (95% CI: 0.78-1.20)						HR=0.97 (95% CI: 0.77-1.22)