Table 1. Characteristics of studies included in this meta-analysis.

First Authors and year	Country of origin	Study Design	Cases	Controls	Source of genotyping
Dholariya et al. 2013 [15]	India	HB	100	100	Blood
Malisic et al. 2013 [16]	Serbia	HB	47	70	Tissue
Matei et al. 2012 [17]	Romania	HB	21	21	Blood
Ueda et al. 2006 [18]	Japan	HB	68	95	Blood
Morari et al. 2006 [19]	Brazil	HB	69	222	Blood
Santos et al. 2006 [20]	Portugal	HB	99	188	Blood
Agorastos et al. 2004 [21]	Greece	HB	51	30	Cytobrush
Pegoraro et al. 2003 [22]	South Africa	HB	85	340	Blood
Hogdall et al. 2002 [23]	Denmark	HB	211	83	Blood
Li et al. 2002 [24]	China	HB	39	50	Tissue
Buller et al. 1997 [25]	America	HB	190	52	Blood
Peller et al. 1999 [26]	Israel	HB	13	13	Blood