Table 1. Characteristics of the Studies about the XRCC1 Arg194Trp polymorphism (rs1799782) Included in the Meta-analysis.

Author	Year	Ethnicity	Cancer Site	Genotyping Method	Control Source	Matching Criteria	Adjusted Variables	Case				Control				HWEd	MAFe
								N	AA	AB	BB	N	AA	AB	BB
Dos Reis	2013	Mixed	Oral	PCR-RFLP	PBa	Age, sex, race, smoke	None	150	127	23	0	150	123	24	3	0.174	0.100
Yen	2008	Asian	Oral	PCR-RFLP	PB	None	Age, sex, alcohol, smoke, betel nut chewing	103	48	40	15	98	54	35	9	0.348	0.270
Sturgis	1999	Mixed	Head&neck	PCR-RFLP	HBb	Age, sex, race	Age, sex, ethnicity, smoke, alcohol	203	180	22	1	424	363	61	0	0.110	0.072
Majumder	2005	Asian	Oral	PCR-RFLP	HB	None	None	310	249	58	3	348	285	57	6	0.122	0.099
Harth	2008	Caucasian	Head&neck	RT-PCR	HB	None	Age, sex	258	217	40	1	300	259	39	2	0.690	0.072
Applebaum	2009	Mixed	Head&neck	PCR-RFLP	PB	Age, sex	Age, sex, race, education, smoke, alcohol, HPV16	484	427	55	2	549	485	61	3	0.476	0.061
Majumder	2007	Asian	Oral	PCR-RFLP	HB	None	Age, sex, smoke	309	248	58	3	387	317	62	8	0.022	0.101
Tae	2004	Asian	Head&neck	MAPA	HB	None	Age, smoke, alcohol	120	59	52	9	145	101	39	5	0.611	0.169
Varzim	2003	Caucasian	Larynx	PCR-RFLP	PB	None	None	88	80	8	0	178	160	18	0	0.477	0.051
Csejtei	2009	Caucasian	Head&neck	PCR-RFLP	HB	Age, sex	None	108	96	11	1	102	85	15	2	0.191	0.093
Kowalski	2009	Caucasian	Head&neck	PCR-RFLP	HB	Age	None	92	71	21	0	124	102	22	0	0.278	0.089
Demokan	2005	Caucasian	Head&neck	PCR-RFLP	PB	None	None	95	78	14	3	98	88	8	2	0.004	0.061
Ramachandran	2006	Asian	Oral	PCR-RFLP	PB	Age, sex	Age, sex, smoke, alcohol, betel quid chewing	110	66	37	7	110	90	19	1	0.998	0.095
Olshan	2002	Caucasian	Head&neck	PCR-RFLP	HB	Age, sex	Age, sex	98	82	16	0	161	135	26	0	0.265	0.081
Kietthubthew	2006	Asian	Oral	PCR-RFLP	PB	Age, sex, smoke, alcohol, betel chewing, religion	Other genes, betel quid chewing	106	40	50	16	164	77	67	20	0.365	0.326
Kumar	2012	Asian	Head&neck	PCR-RFLP	PB	Age, sex, habits	None	278	144	111	23	278	121	131	26	0.264	0.329
Gugatschka	2011	Caucasian	Head&neck	TaqMan	PB	None	None	168	148	20	0	463	397	63	3	0.772	0.075
Ho	2007	Mixed	Oral	PCR-RFLP	HB	None	Age, sex, ethnicity, family history, smoke, alcohol, radiation exposure	137	108	29	0	503	433	69	1	0.306	0.071
Rydzanicz	2005	Caucasian	Head&neck	PCR-RFLP	PB	Smoke, occupational exposure	None	182	165	16	1	143	129	14	0	0.538	0.049
Gajecka	2005	Caucasian	Larynx	PCR-RFLP	PB	None	None	290	262	27	1	325	291	33	1	0.950	0.054
Matullo	2006	Caucasian	Head&neck	TaqMan	UKc	None	None	82	78	4	0	1094	951	141	2	0.171	0.066

^aPB: Population based;

^bHB: Hospital based;

^cUK: Unknown or unstated;

^dHWE: Hardy-Weinberg equilibrium in controls;

^eMAF: Minor allele frequency in controls.